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YOUNGER PEOPLE LIVING ALONE While the number of younger people (aged 20-29 years) living alone has almost doubled in the past 30 years, the majority still live in family households. Over two thirds (71.2% or 1,765,435 people) of younger people were living in family households in 2001. This compares to 71.8% in 1996, and 88.2% living in family households in 1971. The proportion of younger people living alone in 2001 was 7.1% (176,485 people) and while relatively stable since 1996, this is a rise from 4.7% (86,772 people) in 1971. This is part of a wider trend, with the proportion of people living alone increasing in each of the five year age groups, from 20-25 years to 60-64 years, since 1971. For younger people, this may be because living alone is seen as a practical option between leaving the family home and moving into a couple or group household. OLDER PEOPLE LIVING ALONE Of people aged 75 years and over in occupied private dwellings (942,855 people), more than one third (36.9% or 348,307 people) were living alone, down slightly from 38.3% in 1996, but an increase from 33.2% in 1971. There are large differences in the proportion of men and women in this age group who live alone. In 2001, 21.5% (83,014) of men aged 75 years and over were living alone. In contrast, almost half (47.7% or 265,293) of all women aged 75 years and over were living alone in 2001. This is due to higher female life expectancy, with almost two thirds (61.9% or 410,443 women) of women in this age group being widowed. Although all people aged 75 years and over represent only 5.8% of the Australian population, they represent 21.6% of people living alone. This is an increase from 20.1% in 1996, and 16.3% in 1971. HOUSING OF PEOPLE LIVING ALONE IN 2001 More than one quarter (26.2% or 424,146 people) of people who live alone, live in flats, units or apartments. Around 40% (69,978 people) of younger people (aged 20-29 years) who live alone, live in these types of dwellings. Fifty five percent (893,173 people) of people who live alone, live in separate houses. Of all people who live alone, older people (aged 75 years and over) are more likely to live in this type of dwelling. Older people represent 58.7% (204,289 people) of the people who live alone in separate houses, an indication that many widowed people remain in the family home. A significant proportion (44.4% or 717,172 dwellings) of dwellings occupied by people living alone are fully owned, with a further 14.2% (228,975 dwellings) being purchased. Of the 348,307 dwellings occupied by older people (aged 75 years and over) who live alone, 72.9% (253,777 dwellings) are fully owned. More than one third (36.4% or 588,813 dwellings) of dwellings occupied by people who live alone are rental dwellings. Younger people living alone are more likely to be renting than older people living alone. Of the 176,485 dwellings occupied by younger people (aged 20-29 years) who live alone, 65.7% (115,969 dwellings) are rented. In contrast, only 18.0% (62,644 dwellings) of dwellings occupied by people aged 75 years and over who live alone, are rented. HOW WE'VE CHANGED, 100 YEARS OF FEDERATION CENTENARY OF FEDERATION Federation of the colonies into the Commonwealth of Australia took place on 1 January 1901. In the same year, Australia's States conducted a census. This article uses data from the censuses of 1901 and 2001 to sketch a picture of how we have changed in the last 100 years. The States at Federation were New South Wales, Victoria, Queensland, South Australia, Western Australia and Tasmania. The Northern Territory and the Australian Capital Territory were not established as separate entities until 1911. In this article data for 1901 for the areas covered by the Northern Territory and the Australian Capital Territory are included in South Australia and New South Wales respectively. The Census The Census of 1901 was conducted cooperatively by the States with each publishing their results separately. The 1901 data in this article have been obtained from those reports and from two publications: Official Yearbook of the Commonwealth of Australia No. 1, 1901-1907, published by the Commonwealth Statistician; and A Statistical Account of the Seven Colonies of Australasia 1901-1902, by T.A. Coghlan, Statistician of New South Wales. History In 1901 and during the reign of Queen Victoria, Australia became a Federation. Edmund Barton was appointed as Australia's first Prime Minister in the newly formed Federal Parliament, opened in Melbourne by the Duke of Cornwall and York. The first Governor General, Lord Hopetoun, was instated as the Queen's representative. At the time of Federation, Australian contingents were assisting British forces against the Boer Republics in Africa and were also sent to assist the British in China. Population From an estimated 1,030 people at European settlement in 1788, Australia's population, as counted in the Population Census, grew to 3,773,801 by 1901 and to 18,972,350 by 2001. Indigenous population In 1901, the new Commonwealth acquired the constitutional power to make laws concerning 'census and statistics'. There was some debate concerning the inclusion of tribal Aborigines in the calculation of Australia's population. The debate concluded with section 127 of the Constitution, which stated that in reckoning population, 'Aboriginal natives' would not be included in the calculation, although they may have been counted in the Census. Section 127 was introduced principally so that the numbers of Federal politicians per State, as well as per capita Commonwealth grants, would be based on the total population of European and assimilated part-Aboriginal people. Section 127 was removed from the Constitution following a referendum in 1967. From 1971 Aboriginal people were included in the Census count. In 2001, the Census counted 410,003 people of Indigenous origin, 2.2% of the population. State distribution Australia's most populous State in 1901 was New South Wales (which included the area now called the Australian Capital Territory) with 35.9% of the population. It was also the most populous State in 2001. The combined population of New South Wales and the Australian Capital Territory in 2001 represented 35.2% of the Australian population. While the proportion of the population in New South Wales remained steady over the past century, the distribution in other States has changed. The proportion of the population in Victoria and Tasmania decreased from 31.8% to 24.5% and from 4.6% to 2.4% respectively. The proportion of the population of South Australia and the Northern Territory decreased from 9.6% to 8.8%. Queensland and Western Australia were the States to gain in proportion. Queensland grew from 13.2% in 1901 to 19.3% in 2001, while Western Australia grew from 4.9% to 9.8%. The West Between 1891 and 1901 the population of Western Australia increased nearly three fold due to the discovery of gold. The gold rush predominantly attracted adult males, including married men who left their families behind. Consequently, in the 1901 Census Western Australia had the highest proportion of males to females, the highest average income and the highest median age. Over the century Western Australia's rate of population increase was greater than any other state and by the 1986 Census it had overtaken South Australia to become Australia's fourth most populous State. Sex In 1901 there were more males than females in Australia with males making up 52.4% of the population. In 2001, females make up the greater proportion of Australia's population at 50.7%. An Ageing Nation Australia had a younger population in 1901. Over the century the median age of Australia's population has increased from 22 years to 35 years. The proportion of people aged 0-14 years has decreased from 35.1% in 1901 to 20.7% in 2001 and the proportion of people aged 65 years and over has increased from 4.0% to 12.6%. Birthplace Australia was the birthplace of 77.1% of the population in 1901, with 18.0% born in the United Kingdom. In the 2001 Census, 71.8% of people were born in Australia. The largest overseas born group in 2001 comprised people born in United Kingdom and Ireland at 5.8%, followed by New Zealand at 1.9% and Italy at 1.2%. No other country accounted for one or more percent. Income Income figures were not collected in the 1901 Census but were estimated from various sources at the time. The mean annual income per inhabitant (including children aged under 15 years) for Australia was Ł46. The highest annual mean income (Ł64 per inhabitant) was estimated for Western Australia and the lowest (Ł42 per inhabitant) for Tasmania. Australia changed to decimal currency in 1966, with an exchange of $2 for Ł1. Of the States that existed at Federation, New South Wales had the highest median weekly individual income ($386) in 2001 for people aged 15 years and over. The lowest median weekly individual income was recorded by Tasmania ($314). Religion In 1901, data on Christian religions were released for all States and Australia, but data for other religions were available for some States only. Christians represented 95.9% of the population, with four major religious denominations accounting for 87.1% of the population. These were the Church of England (39.7%), Roman Catholic (22.7%), Wesleyan and other Methodists (13.4%) and Presbyterian (11.3%). In 2001, Christians represented 68.0% of the population, with the two major denominations, Anglican and Catholic, accounting for 46.5% of the population. Buddhism accounted for 1.9% of the population and Islam for 1.5%. In 2001, around a quarter (25.3%) of the population stated they had 'No religion' or chose not to answer the question. Dwellings The Census of 1901 had three classes of dwelling: Inhabited, Uninhabited and Being built. In total there were 786,000 dwellings including 43,000 canvas dwellings or tents. Throughout the century the number of dwellings in Australia has grown ten fold to over 7.8 million in 2001, compared to the population which has grown five fold. Document Selection These documents will be presented in a new window. |


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August is Vision & Learning Month. The goal of Vision & Learning Month is to increase awareness among parents and teachers about the prevalence of undiagnosed or misdiagnosed vision problems. Vision problems can often present as learning challenges, and should be top-of-mind when parents or teachers see a child struggling in the classroom.
One often undiagnosed vision challenge is Computer Vision Syndrome, also called digital eye strain, and it's becoming more and more common.
If there's one thing we've all done in excess this past year, it's staring into screens more often and for longer amounts of time. Staring at your phone, tablet, e-reader or computer screen for work, school or personal Zoom meetings takes a toll on your eyes. That's because the human eye wasn't meant to stare at any object 12 to 24 inches from our eyes for hours at a time.
So much screen-gazing can result in a group of eye and vision-related issues known as Computer Vision Syndrome or digital eye strain.
What is Computer Vision Syndrome?
If you've experienced eye discomfort or vision issues after viewing your screen for lengthy periods—including headaches, eyestrain, dry eye, blurred vision, redness, or neck and shoulder pain—you've likely had a bout of digital eye strain. And, if your symptoms get worse the longer you're staring into a screen, you've almost certainly experience this uncomfortable condition.
What causes Computer Vision Syndrome?
While the time you spend staring into screens is a significant factor, there are a few other conditions that contribute to digital eye strain:
- Poor lighting
- Screen glare from your digital screen
- Ergonomics: not viewing screens from the proper distance
- Poor neck or sitting posture
- Uncorrected vision problems
- A combination of some or all of the above
Time on screens is a major factor in computer vision syndrome, but your individual visual ability can compound that. If you are farsighted, have astigmatism, have difficulty focusing, or if you're over 40 and have or are developing presbyopia—those conditions all contribute to how your eyes respond when staring at digital devices.
Why are screens harder to read than books?
Printed books feature letters and figures in dense, black print with crisp borders against the strong contrast of the page they're printed on. However, a computer screen doesn't offer that same level of contrast or sharp edges—so, your eyes have to work harder to focus and read them effectively. Screens also emit glare and reflections, which makes the challenge for your eyes even more complex.
In short: Screen time makes your eyes work harder, and in a way human evolution hasn't yet addressed.
How is Computer Vision Syndrome treated?
While taking a break from screens is a great start, for some people, that's not enough to solve the visual and physical symptoms of digital eye strain. A visit to your eye doctor for a comprehensive eye examination is the ultimate best way to address the headaches or blurred vision resulting from computer vision syndrome. If you don't address it, your vision problems may continue to worsen. So what can you do? Give your eyes some help with the following recommendations:
- Computer glasses made specifically for use while you're working at your computer or other screen are a smart way to address computer vision syndrome. Even people who don't wear prescription glasses or contact lenses may benefit from a pair of glasses made to address the specific visual demands of your eyes when viewing screens. These glasses may have special lenses and coatings to help you see your best on the computer or other digital screen. Our goal is for you to achieve comfortable, unstrained vision in all settings—whether that's in the classroom, at work, on the computer, driving, reading or playing sports.
- Your computer set-up is another significant factor. The distance from the screen to your eyes should be about 24 inches—that's two feet! And when looking at the screen, your gaze should be positioned slightly downward, meaning that the center of the screen should be about 5 inches lower than your eyes. Minimize bright overhead light and opt for a desk lamp instead, and make sure any windows are to the side to minimize glare. Finally, increase the contrast of your screen to a comfortable level to reduce the strain on your eyes.
- Finally, practice The 20-20-20 Rule: Every 20 minutes, look away from your screen and gaze at something 20 feet away for at least 20 seconds. And don't forget to blink! Taking frequent breaks can help rest your eyes and minimize the effects of digital eye strain from screen use.
If you suspect you or your student may have computer vision syndrome symptoms, make an appointment with your optometrist for an eye exam as soon as possible. We will conduct a comprehensive exam and ask about your symptoms, test your visual acuity and determine the ideal lens power to address your unique situation. Call us today!
With proper vision correction and attention to your screen-viewing behaviors and habits, you can give your eyes the tools they need to see comfortably and clearly again.

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I haven't had any issues with SecureVPN. I've never had a disconnected session and if I cannot get decent enough bandwidth with one of their connections, I move to a different servers and clock the speed of my connection to ensure I can stream effortlessly. I haven't received any cease and desist letters, nor any compromised computer. Although it was a bit time consuming to figure out how to set everything up initially, once it is installed and you get into the rhythm of using it, it's simple.
I initially had an issue with my account (Premium) but the response at their web site helped resolve that quickly (I'm in the U.S.). The number of countries is a lot more than 6. The Kill switch works as designed - if the connection is lost, the network is blocked. Performance is good. With Premium you can have up to 5 active devices (Android, Windows is what I use). I'm very pleased with the Product and the Service (so far).
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Technical fouls are a necessary, but perhaps the most misunderstood part of the game of basketball. While most often called to penalize unsporting behavior, they cover much, much more, and are an important part of an official's arsenal in effectively managing the game, coaches and players.
A video recently posted on YouTube (see below) featured footage of a high school basketball team committing six fouls in which the videographer accuses the officials of miscalling the fouls. Like many, he considered any hard foul resulting in the player falling to the court a flagrant foul. Problem is that such contact is not automatically a flagrant foul; it could be an intentional foul, or it could be just a hard, but ordinary, personal foul.


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Barbara L. Marteney and Kristin M. Safran, of National Testing Laboratories, Ltd., specialize in consulting with bottled water companies regarding testing requirements. They maintain contacts with bottled water regulators, industry associations, and the FDA regarding regulatory changes and bottled water issues. They have authored numerous articles and given presentations regarding state, federal and international bottled water regulations.
Marteney and Safran can be reached by phone at 800-458-3330 or 440-449-2525. Marteney at extension 217 and Safran at extension 215. E-mail [email protected]
undefinedCustomer complaints are an unfortunate but unavoidable part of business. Bottled water complaints typically arise when a customer perceives an off taste, odor or appearance in the water. In most cases, the customer or customer?s family has consumed some of the water before the problem is detected. As a result, their primary reason for calling is to find out
- What did they drink?
How did it get there?
- How will it effect their health?
These are questions that should be equally important to the bottler for reasons of public safety as well as protection of the business. Unfortunately, the source of off taste, odor and/or appearance often can be difficult to identify. There is no single analytical method or piece of equipment in which you can inject a small quantity of water and out comes identification of the culprit. Identifying a product problem often is a complex and frustrating process. The purpose of this article is to cover the first two steps of the problem solving process and offer some tools that bottlers can utilize when troubleshooting these issues.
Overview of the Problem Solving Process
Troubleshooting quality control issues for bottled water follows the same problem solving process as any other industry. The four steps are
- Gather information,
- Analyze and confirm findings (cause and effect diagram),
- Take corrective action plan, and
- Verify corrective action has resulted in desired effect
Step One--Gather Information
Gathering information, the most important step, starts with obtaining information from the customer. While not all encompassing, we recommend beginning with the following questions to the customer.
- What is the customer's complaint (off taste, off odor, off appearance)?
- What is their best comparison to the problem they perceive (tastes like, smells likeor looks like)?
- What is the brand name and product type?
- What is the container size, type of container, type of closure?
- What is the production code?
- When did the customer purchase the container?
- Where did the customer purchase the container?
- When was the bottle opened?
- Was the "off" taste , odor or color immediately apparent upon opening/purchasingor did it develop gradually?
- Is the "off" taste, odor or color still as strong or has it dissipated over time?
- Do they still have the bottle in question? If so, will they give it to you to help in your investigation?
- How/where has the water been stored?
Note: Remember to get the customer?s name, address and telephone number.
Production code information also can help by narrowing the initial focus to the production code(s) affected so applicable quality control, personnel and maintenance records can be obtained. When addressing the "What is it?" question in step two, answers to the above questions can help identify whether the product compliant is potentially microbiological, inorganic or organic in nature.
For example, if an odor was apparent immediately after opening but dissipated over time the problem may be a volatile organic chemical. Although, if the odor dissipated over time and the product was less than 48 hours old when the customer opened the bottle, it is possible that the ozone (an inorganic) had not completely dissipated prior to opening the container. If the odor wasn?t present upon opening but developed over time, storage conditions (volatile organic or microbiological) may be the culprit.
Step 2: Analyze & Confirm
The next step is to analyze all the data obtained from the customer along with in-house records that trace the product from production of raw materials through the bottling process and distribution system to the time the complaint was identified by the consumer.
A cause and affect diagram can assist in the brainstorming process. Potential causes then should be narrowed in focus until a short list of most likely causes is developed. Depending on the cause(s), verification can be done through either analytical testing or attempts to replicate the suspected cause and effect.
A Hypothetical Situation
A customer calls to complain that they have "green stuff" growing inside their five gallon bottle. After the initial gathering of information from the customer, you suspect that the culprit is algae or mold. You request the consumer allow you to pick up the product to send to an independent laboratory for analysis. While the laboratory is analyzing the sample you do a cause effect diagram. (See Figures 1 and 2).
Effect--consumer complaint. Suspected algae or mold in returnable bottle.
Potential causes of product quality problem.
* Equipment?blow molding equipment, bottle washer
- Contamination due to improper parts or insufficient sanitation
- One-micron absolute/HEPA filtration not in place or not functioning efficiently for process water, tanker, holding tank and filler room air
- Deionized water for bottle rinsing
* Personnel
- Failure to inspect bottles going into washer for green or brown stains
- Failure to discard returned bottles with signs of algae/mold
- Failure to detect odors in bottles going into washer
* Raw Materials
- Algae/mold in source water
- Algae/mold in bottle or cap rinse water
- Contaminated returned bottles or water coolers
- Contaminated pre-forms
* Procedures
- Insufficient or unclear procedures regarding material handling, cooler sanitation, bottle inspection, equipment cleaning and sanitation, tanker maintenance/sanitation or product storage and distribution
* Environment
- Air contamination through vents or air intakes of the tanker, storage tanks, water cooler, ozone generators or facility air
Effect--Consumer complaint. Suspected chemical contamination
Potential causes of product quality problem.
* Equipment?carbon beds, softeners, RO units, ozone units, UV lights, blow molding equipment, filler heads
- Mechanical failure due to manufacturing defects or improper/insufficient maintenance
- Contamination due to improper parts or insufficient sanitation
* Personnel
- Insufficient training
- Poor personal hygiene
- Poor management supervision
* Raw Materials
- Defective or contaminated packaging materials: bottles, caps, pre-forms, safety liners
- Defective or contaminated ingredients: source water, minerals
- Defective or inappropriate cleaners
* Procedures
- Insufficient or unclear mechanical procedures: equipment maintenance
- Insufficient or unclear operating procedures: sanitation, material handling, production process, quality control sampling or record keeping
* Environment
- Raw material supplier
- Transportation of raw materials
- Storage areas at the plant
- Process areas
- Filler room
- Ventilation system
- Plant grounds
- Source recharge area
- Transportation and storage of finished product after it leaves the plant
These sample cause and effect diagrams may not be all encompassing. Other sources of contamination unique to your plant and process may exist.
Product quality issues involving off taste, odor or appearance are either microbiological (bacteria, yeast, molds, algae), organic (volatile organic chemicals, plasticizers) or inorganic (metals, ozone). Putting together a customized problem-solving process that fits your business before there is a problem will help you be prepared to efficiently address issues as soon as they arise or even avoid them in the first place.
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Boasting incredible highs amidst a lot of well-played music, MSG's 2012 installment was certainly a good time. Phish bounced back from a poor showing last year at the Garden, and considering the four months off between performances, they sounded practiced and polished. The band was sharp as they closed out a year widely considered to be their strongest since their return, however, their daring side only came out in spots. The risk taking that prevailed over the past two years was curbed significantly, amounting to less than one serious jam per set and leaving the run feeling fairly clean. When Phish did jump into the unknown they met with incredible success, begging the question of why they didn't make the leap more often. Phish played most songs with strength and precision, though setlists were, generally, composed of standard rotation songs with very few surprises. And while the band fed off the big city energy—a hallmark of MSG shows—when looked at in the context of 2012, the holiday shows didn't necessarily hold up to the year's best offerings. To highlight the run, the band dropped three jams—"Tweezer," "Down With Disease" and "Carini"—that belong on the top shelf of this era, but when it came to putting together whole shows, the guys fell a bit short.
It's not surprising that this era's most musically complete holiday runs—2009 and 2010—followed fall tours. Without being in the groove, or at least in close proximity to a run of shows, it's tough for Phish to step on stage for four days and crush. It's also not surprising that the band played less-than-spectacular run in The Garden, a once-legendary venue that has hosted mostly middle-of the road shows throughout this era featuring stellar moments here and there. Over these four nights, the highs were, undoubtedly, quite high, but the band played a lot of filler throughout the run where it felt like they were on cruise control. Included in these parts were four first sets that didn't bring much to the table aside from "Stash" and "Wolfman's" on night one, and a solid, though far from amazing, "Bathtub Gin" on night two. With a week of space separating us from the year-end run, let's look back at the four-night flow.
The band came out of the gates with a bang on the 28th, setting hopes and improvisational expectations fairly high for the next three nights. A very solid opening show featured a six song second set, a gorgeous 20-minute "Tweezer" that immediately jumped out as the strongest of the year, the most creative take on "Wolfman's Brother" in quite some time, and a strong supporting cast of "Stash," "Maze" and "David Bowie." A "Little Drummer Boy" theme ran throughout the show illustrating the band's playful side and giving the show a dose of holiday cheer. After the dust settled on the four night run, an argument could be made for the 28th being the most balanced and complete shown of the run.
The second night at The Garden fell incredibly flat on these ears, effectively crushing any momentum built on the 28th. With nary an attempt at any true improv, each song translated as a painfully standard rendition. "Golden Age," although jammed a bit, didn't hold up to the many standout versions of the year, and when Trey bailed out of a potential "Waves" jam in the second slot of the second set for "Prince Caspian," one got the feeling that it would be one of those uninspired, song-based shows. And that is precisely what transpired. The 29th holds virtually zero replay value, and even the highest point of the night—"Bathtub Gin"—relied on linear, guitar-led shredding. While this type of show may work for some, in my opinion, it translated as one of the band's least impressive efforts of the year. The clunker on the 29th left the fate of the Holiday Run hinging on the 30th. And Phish came through in droves.
The second set of the 30th was —easily—the set of this Holiday Run, featuring 40 minutes of sinful improvisation balanced by stellar versions of "Slave" and "Harry Hood" to cap things off. The meat of the set—"Disease > 20 Years Later > Carini"—was the one time in New York that the band constructed a phenomenal run of jamming. Over the course of 2012, multi-song sequences like this one comprised many of the year's overwhelming highlights, and this chunk of dark music echoed the times when the band really built a passage that amounted to more than the sum of its parts. Both "Disease" and "Carini" hold up as their respective versions of the year, while "Carini's" ominous psych-rock textures—about as rare in recent Phish as a great "YEM"—could be championed as a jam of the era. Most of the creative improv of 2012 has focused on uplifting themes, thus this segment of the 30th stood out that much more. Although Trey made one of the most head scratching, vibe crushing and out of place calls of all time with "Number Line" out of this mind-bending story, one couldn't really complain after such extensive theatrics. And to resolve the supernatural meat of the set, the band served up glorious versions of "Slave" and "Hood," both of which featured incredibly dynamic work by Trey and hold up as blue-chip versions of the era. When all was said and done, the band had dropped one of the top sets of the year that didn't take place in Colorado.
Throughout history, New Year's shows have often been musical afterthoughts of their respective runs, and since the return, only 2010 showcased a New Year's show that was the best of its run. This year, after the 30th, one hardly expected the band to match or top their masterful performance—and lo and behold, they didn't. The first and third sets of the 31st were both well played and incredibly straightforward, highlighted by high-energy rock and roll. Though par for the course, those sets are usually sandwiched around some substantial music in the second set, but this year's main event featured only one memorable song pairing in "Ghost > Piper." The fourth consecutive New Year's Eve "Ghost" reached sublime planes of harmonic interplay and "Piper" contained torrid, full-band jamming at a break-neck pace, but for three sets of music, a twenty-minute takeaway is fairly slim pickings. This show was very fun, no doubt, and had the run included a bit more meat, it would have fit congruently. New Year's Eve was very fun experience and certainly didn't fall flat like the 29th, but as the memories fade, it will hold little replay value.
Aside from the few centerpiece jams of MSG—which were undeniably awesome— 2012's Holiday Run was relatively tame. The highs were quite high, but when considered as full two-setters and a complete run, the shows fell short of 2012's best offerings. If one gets off on tight, high energy Phish, there was plenty of that to go around, but if one is questing for adventurous jamming, the run had just enough to make it palatable. For whatever reason, there seemed to be a prevailing sentiment in the community before these shows that the band was going to host a blowout in the Big Apple, returning MSG to its legendary status in the pantheon of Phish venues. And while the run certainly didn't disappoint anyone and contained enough timeless moments to be considered a success, it won't go down in history as eternally memorable.


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Kaweco introduces cruelty-free, vegan inks in sustainable packaging, looks at the other side of the pandemic.
Kaweco: Our passion goes just as profound for the smallest details as it does for the massive difference between our writing instruments and cheap, mass-made products. Our designs stem from another era when tradition and craftsmanship were still synonymous and some clocks seemed to go a little slower. We took


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Whether you choose to travel with Viking by river or by sea, we bring you closer to your destinations on state-of-the-art ships. In addition to our refined onboard ambience and understated elegance, we are known for our graceful staterooms, including the first-ever true (two-room) suites. From more space and comfort to additional features and amenities, discover the benefits of reserving a Viking Suite.
Basel to Bergen
15 Days | 11 Tours | 6 Countries
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10 Days | 8 Tours | 3 Countries
Amsterdam to Amsterdam
10 Days | 8 Tours | 2 Countries


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Aspects to Consider When Looking for an Excellent Auto glass replacement company
Excellent auto glass replacement company s have features that have made them to earn that name. This are organization whose quality of services is good, punctuality is okay, customer care staff is perfect and they generally have the passion to ensure that they deliver the best to their clients. This article will discuss more on this aspects and some mays to discover if a auto glass replacement company has the feature or not.
One of the stated aspect above is punctuality. Punctuality ca be explained in different directions. First of all, it can be the tine taken for the service providers to attend you. It can also be explained as the tome taken for your project to come to completion. Any good service provider must be punctual and this means that you should get to know how to discover this. One way you can do this is by checking out on comments given by previous clients. Clients will always look at how long their staff will take before they come to serve them. Ensure you go through some of their comments and discover by your own if the auto glass replacement company is punctual or not.
The next thing you need to check out is the customer care of the different service provider. It is a good thing to be served perfectly from start to the end. From the moment you are doing discovery calls or any kind of enquiries to when you will be receiving the exact kind of service. The customer care need to be kind and ready to offer yiu the best of service. Just take your time and do a discovery call or rather visit them for a physical consultation. You should not be ready to settle for a auto glass replacement company whose customer care service staff will be extra rude to any kind if enquiries you make during consultation or even when offering service to you. If you sense ay of that behaviour, choose to avoid such auto glass replacement company and go look for another one.
In addition to that, ensure that you have checked out on the quality of their services. You deserve the best and this means you should never assume that a auto glass replacement company offers quality services and you just go for them. Get your time to scrutinize through and conauto glass replacement company whether it is true or not. If you get to see the kind of feedback provided by already served clients, you can find a concrete solution of the quality of services offered by these forms. Checking out on the performance history as well will enable you learn their quality too. Any auto glass replacement company that has been offering excellent services will always have their record of performance graph growing high and higher.
Lastly, be keen to choose a trustworthy auto glass replacement company . You need one which you can trust with your nee. A trustworthy auto glass replacement company will be transparent with most of their aspects such as price rates, feedback and reviews. It will have all important credentials from license to certifications.


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- Ships within 1-2 days with UPS or DHL
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Read our shipping & return policy here
Earrings with our signature piece Dove, hanging in a hoop. A timeless piece that carries with it a profound message of hope and peace, making it not just a piece of jewelry but a symbol to cherish. It is not only a personal keepsake but also a thoughtful gift. Sold separately.Measurements: 42 x 16 mm. Dove 26 x 16 mm.
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All jewelry is delivered in a beautiful box wrapped in an exclusive envelope case.
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All our jewelry is charity jewelry. We donate a large part of our income to the charity projects we work closely with. When you receive or buy a piece of jewelry from our collections, you become part of giving to someone in need. Read more here.
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Enhanced No-Load Bias Ratio via its Wave Design Center Pack
One of the known shortcomings of a typical torque biasing differential is its loss of drive (behaving much like an open diff) under zero or near-zero torque conditions (for example, when there is 'no-load' applied through the drivetrain, either at vehicle stationary and/or transition from engine driving vehicle to engine braking and back).
The Wavetrac differential uses a patent pending design to improve grip in low traction conditions. Precisely engineered, converging / diverging wave profiles are placed on one side gear and its mating preload hub. As the two side gears rotate relative to each other, each wave surface climbs the other, causing them to move apart. This imparts an increased normal force through the side gears, increasing the bias ratio as a function of load. This increase occurs automatically only when conditions find it necessary, and it 'reverts' back to its nominal bias ratio quickly and seamlessly, maintaining optimal drivability and performance at all times. It's like having two differentials in one: you get the benefit of a higher bias ratio when needed without detriment to the car's handling.
Interchangeable Friction Plates Provide Controlled Bias
Here's something else you won't find in any other design:
The Wavetrac diff's behavior can be altered in the field to suit your needs. It comes standard with carbon-fiber bias plates for the best all around performance. Interchangeable plates using materials with different friction coefficients to fine-tune the bias ratio are sold separately.
These friction plates provide a mechanism to tune the response of the differential as a function of applied torque load. The applied torque load manifests itself as an axial load from the differential pinions into the housing. This axial force is then considered a normal force into the friction plate, and as a function of the effective coefficient of friction, will provide a resistive torque to the rotational motion of the differential pinions. The resistive torque will add to the resistance of relative rotation of all components within the differential. The resistive force, however, is non-uniform since it is a function of the axial load from the differential pinions. The unbalance of the resistive torque will manifest as non-uniform energy absorption within the differential causing a bias ratio.
Superior Design, Materials, and Construction
Designed from a clean sheet, the new Wavetrac Differential brings current gear technology to the market. Internally, its gear tooth forms are optimized for strength and improved oil film retention over competitive designs. Our gear package is smaller, reducing overall mass, yet is more durable. Attention was also paid to the side gear/axle interface, putting as much material thickness as possible in this critical area – most important when power levels get high.
Each Wavetrac Differential is crafted from the highest quality materials available. The internal gears are made from high strength 9310 alloy steel. The diff bodies are machined from case hardened steel billet. To complete the package, every Wavetrac differential is built exclusively using high quality, high strength fasteners from ARP, the world leader in fastener technology.


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The Texas Tribune: In Pilot Program, Student IDs Track the Students
By Maurice Chammah, The Marshall Project, and Nick Swartsell, The Texas Tribune
Oct. 8, 2012
Students scan their radio frequency identification tags as they pass through the lunch line at Jones Middle School in San Antonio, September 14, 2012. Image Credit: Jennifer Whitney
"In Pilot Program, Student IDs Track the Students" was first published by The Texas Tribune, a nonprofit, nonpartisan media organization that informs Texans — and engages with them — about public policy, politics, government and statewide issues.
SAN ANTONIO — For Tira Starr, an eighth grader at Anson Jones Middle School, the plastic nametag hanging around her neck that she has decorated with a smiley face and a purple bat sticker offers a way to reflect her personal flair. For administrators, it is something else entirely: a device that lets them use radio frequency technology — with scanners tucked behind walls and ceilings — to track her whereabouts.
Anson Jones is the first school in San Antonio's Northside Independent School District to roll out the new nametags, which are part of a pilot program intended to ensure that the district receives all of the state dollars to which it is entitled.
In Texas, school finance is a numbers game: schools receive money based on the number of students counted in their homeroom classes each morning. At Anson Jones, as at other schools, many students were in school but not in homeroom, so they were not counted and the district lost money, said Pascual Gonzalez, a spokesman for the district.
"We were leaving money on the table," he said, adding that the district expects a $2 million return on an initial investment of $261,000 in the technology at two pilot schools.
But the radio frequency identification nametags have prompted concerns from civil liberties groups and electronic privacy watchdogs, which fear a Big Brother atmosphere in Texas public schools.
Matthew Simpson, a policy strategist for the American Civil Liberties Union of Texas, said the technology was easy to acquire, meaning people outside a school might be able to monitor a student if they obtained the student's unique tracking number.
Simpson said the technology was originally designed for shipping goods and for cattle. "It was never intended for people," he said.
But students and educators at Anson Jones say they are excited about the practical advantages — getting to eat lunch faster by scanning their bar codes in the lunch line, or being able to locate a child quickly in an emergency.
Northside is not the first district to use the tracking devices. Two Houston-area districts began the program several years ago. The Spring district, for example, started using the technology in 2004 as a way to track elementary students getting on and off buses. It expanded the program to high school students three years ago and has so far recovered $400,000, said Karen Garrison, a spokeswoman for the district.
"Our system still focuses on safety but has the added benefit of recovering average daily attendance funding," Garrison said.
Wendy Reyes, the principal of Anson Jones, said only one parent had complained about the program at her school. On the first day of classes at Jay High School, home to the other pilot program school in Northside, several parents staged a small protest across the street from the school's entrance, though most did not have students in the district.
Many students, teachers and parents at the middle school feel the technology's benefits outweigh privacy concerns, Reyes said.
Madelene Garra was among those praising the program. "It gives the kids a little bit more responsibility, knowing that we as a faculty are keeping up with them," she said. "Once they get out there in the real world, they're going to have to be on the job on time, and they're going to have to be accountable."
Texas Tribune donors or members may be quoted or mentioned in our stories, or may be the subject of them. For a complete list of contributors, click here.
This article originally appeared in The Texas Tribune at https://www.texastribune.org/2012/10/08/san-antonio-schools-pilot-rfid-program/.
The Texas Tribune is a member-supported, nonpartisan newsroom informing and engaging Texans on state politics and policy. Learn more at texastribune.org.


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Retired General's Sobering Message: Americans Must Confront Obama's Tyranny
"Our government is so broken now, that each day we go down over the cliff even more and more. The lack of strong leadership not only in the Executive branch, but a lack of really strong leadership in Congress, both in the Democrats and the Republicans. I am not even sure that our traditional process is going to straighten our government in sufficient time to save us. That leaves us to what options we have. If you look under the constitution we have impeachment. Now we know with the partisan politics that isn't going to happen. So we have Obama for another three years."
"So what do we do as people? Do we let it go on and go through the regular election process and hope it will get better? 'Hope is not a strategy by the way'".
"We need millions to stand up in our State Capitols and in Washington D.C. and we need to have that done within the next twelve months".
"And I would say if we can make citizen arrests, and I challenge our government and people that if we have people that are conducting treason against the United States and the best interest of our country, violating the constitution, violating our laws, just as they are doing with these excessive executive orders coming out of the White House, where you have a President and his team that doesn't care about the constitution, they will do anything they can to win.
They will do anything, they will go for the throat and that is what we have to do because we are in battle to save the United States"
- Retired General Paul E. Vallely


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Demonization is the first step toward making something illegal. Over the past couple of months, Bitcoin and other cryptocurrencies have experienced a tremendous surge in popularity. Personally, I was completely floored the other day when my nephew wanted to ask me questions about investing in Bitcoin. It seems like the whole world is getting caught up in the cryptocurrency revolution, and needless to say, the powers that be cannot be thrilled about this. Independently-controlled cryptocurrencies represent an existential threat to the global debt-based central banking system that we have today, and so the elite have a very strong incentive to bring about the demise of Bitcoin and other emerging cryptocurrencies.
So it is no surprise that one of the key mouthpieces for the elite, the Washington Post, has begun to demonize Bitcoin. And if you are going to demonize something, one of the fastest ways to do that is to link it with racists. The following is an excerpt from an article that the Post just published entitled "Bitcoin's Boom Is A Boon For Extremist Groups"…
Even before Charlottesville, Richard Spencer, a prominent member of the alt-right, a group that espouses racist, anti-Semitic and sexist views and seeks a whites-only state, had gone as far as declaring bitcoin "the currency of the alt right." But far-right political leaders and experts on extremist movements alike say the adoption of bitcoin gained new urgency after Charlottesville as extremists looked for ways to operate beyond the reach of government control and the shifting policies of U.S. tech companies.
For those of us that are accustomed to thinking critically, we see right through what the Washington Post is trying to do. The Bitcoin phenomenon has absolutely nothing to do with Richard Spencer and his ilk, but every time the liberal elite want to demonize someone or something they trot out their favorite boogeyman once again.
Just like every other currency, Bitcoin can be used for good purposes or for bad purposes. But the Washington Post article would have us believe that Bitcoin is at the core of some great "racist conspiracy" that is about to take America by storm…
Extremist figures who invested in bitcoin as a bulwark against efforts to block their political activity now find themselves holding what amount to winning lottery tickets. The proceeds could be used to communicate political messages, organize events and keep websites online even as most mainstream hosting services shun them, experts say.
The truth, of course, is that these sorts of racists are a very, very small fraction of one percent of the U.S. population. They are so small in numbers that they are not even worth mentioning, but the Washington Post and other liberal outlets love to give them attention because they make the perfect enemies for the narratives that they are trying to promote.
Later on in the article, there was an effort to link Bitcoin to drug traffickers, money launderers and those who use the Internet for other dark purposes…
Extremists are hardly alone in benefiting from surging bitcoin values. Early buyers include cryptography enthusiasts, libertarians and professional investors – as well as drug traffickers, money launderers and others who regularly conduct transactions on the "dark Web," a part of the Internet only accessible using specialized software that helps shield online activity.
The "logical conclusion" that many on the left are going to come to after reading such an article is that Bitcoin must be banned.
In the months and years ahead, I would expect to see a major push to crack down on cryptocurrencies. And once independent cryptocurrencies have been dealt with, the elite will promote their own versions as the long-term solution.
According to the Post article, the Southern Poverty Law Center is currently tracking 200 Bitcoin wallets that they believe are owned by extremists. Apparently, every single transaction that involves these accounts is being monitored…
Public blockchain records make such monitoring possible. Researchers can study the times, dates and amounts of any transaction, along with what accounts are involved. That does not include the actual names of account holders, but such records can illuminate identities. The SPLC, for example, looks on the donation pages of extremist websites for bitcoin accounts that are seeking contributions.
If the elite are ultimately able to convince the general public that Bitcoin and other cryptocurrencies are for racists, criminals, tax evaders and drug dealers, that will make it much easier to crack down on them.
But of course blockchain technology is here to stay. Once the elite are able to move the public away from "unregulated cryptocurrencies", they will simply introduce "Fedcoin", "Utility Settlement Coin" or whichever other digital currency that they want to promote at the time.
For the moment, however, the cryptocurrency revolution is still raging. Even as I write this article, the price of Bitcoin is flying all over the place. At the moment it is sitting at $14,730, but that will change in a few moments.
I would anticipate even more volatility as we head into 2018, and other experts seem to be of the same opinion. For example, just consider what Nick Colas is saying…
Nick Colas, co-founder of DataTrek Research, has been following the bitcoin phenomenon for at least four years. Looking ahead to 2018, he sees more volatility for an asset that has soared nearly 1,600 percent over the past year.
In fact, he figures bitcoin could slosh in a range between $6,500 and $22,000; it was around $15,750 in Wednesday morning trade.
"Bottom line: bitcoin can rally to $22,000 and still be reasonably priced, or plummet to $6,500 and also be correctly valued," Colas said in his daily note. "We expect to see bitcoin trade for both prices in 2018."
But as I have said before, the key to this phenomenon is not how high the price of Bitcoin can climb.
Rather, the key is if Bitcoin or other cryptocurrencies can truly become methods of exchange that are widely used outside of the control of national governments and global central banks.
If we can create a truly autonomous financial system that is independent of the current debt-based system, that would be a wonderful thing for humanity.
Unfortunately, the elite are going to fight very hard to keep that from happening, because control over currencies is one of the main factors that allows them to have so much control over the entire planet.
Michael Snyder is a Republican candidate for Congress in Idaho's First Congressional District, and you can learn how you can get involved in the campaign on his official website. His new book entitled "Living A Life That Really Matters" is available in paperback and for the Kindle on Amazon.com.


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Art and music are my passions but it's all art to me.
Internationally acclaimed artist Debra Hurd studied art at both Southern University in Chattanooga, Tennessee and the Ringling School of Art and Design in Sarasota, Florida. For 15 years she was a graphic designer in Florida and Austin, Texas.
She is also an accomplished pianist, having studied music since early childhood. Debra's wild boogie-woogie and honky-tonk style still finds her in the recording studios and at live performances in Austin. She loves jazz, classical, and salsa styles, too.
As a painter, Debra is famous for her insightful paintings of animals, her vivid city scenes and her passionate and perceptive depictions of jazz, rock, and blues musicians. Being a musician, she has both a great respect and a feel for the emotions of musicians of the past and present. She works in oils, using a knife to get bold and instant color. She finds the knife to be a great tool of expression. She reaches the observer through the use of dramatic color and texture.
Debra explains: A very ordinary scene can be perceived differently when painted with a bit of exaggerated color and awareness of light. The ordinary then becomes the extraordinary. Color is critical. When I'm asked which color is my favorite, I tend to think in terms of which two or three colors I like in combination.


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getting their fresh ass used and abused by horny older men. Other inmates, guards, cops, interrogating officers, everybody
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All models were at least 18 y.o. at the time of the photography.
This site is 'Title 18 U.S.C. Sec.
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Photo courtesy OSHA |
The trouble I'm having is that there seems to be more consensus in Congress about tax reform than there is from the experts on sewing ergonomics. I've consulted five different sources (The U.S. Labor Department's Occupational Safety and Health Administration guidelines, Sewing.org, Carolyn Woods' Organizing Solutions for Every Quilter: An Illustrated Guide to the Space of Your Dreams, Leslie L. Hallock's Creating Your Perfect Quilting Space: Sewing Room Makeovers for Any Space and Any Budget, Lynette Ranney Black's Dream Sewing Spaces: Design and Organization for Spaces Large and Small, 2nd Ed.), and I'm getting wildly different advice from all of them about the correct height of sewing, pressing, and cutting surfaces. Today, we're going to discuss the height of the sewing surface.
Proper Sewing Surface Height, per OSHA |
I want to clarify that, in ergonomic discussions, the sewing surface is the STITCH PLATE OF YOUR SEWING MACHINE. If your machine is recessed into a cabinet like mine will be, then the surface of the cabinet is the sewing surface. However, if your machine is sitting on top of a table, then your actual sewing surface is going to be several inches higher than table top.
All of the experts I consulted recommend that your sewing cabinet or table allows you to sit with your body centered on the needle of your sewing machine so you aren't constantly twisting your spine and leaning sideways in order to sew -- this sounds obvious to someone who sews, but the carpenter/handyman/husband building your sewing cabinet might think your body should be aligned with the center of the sewing machine if you don't tell them otherwise. To determine the height of your sewing table or cabinet, start with a good, adjustable, supportive chair that enables you to sit with your knees and hips bent at approximately 90 degree angles, with your feet flat on the floor. Once your chair is adjusted properly, sit down and bend your arms at right angles, palms down with your forearms parallel to the floor, and have someone measure from your elbow to the floor (some sources just said to measure from your elbow to the floor, others specified measuring from the bottom of your elbow or from the midpoint of the joint -- and this wass the beginning of the confusion). Got that measurement? Okay. Depending on whose advice you're taking, that elbow-to-floor measurement is either your correct sewing surface height, OR you should add anywhere from 5 1/2 to 7" to get your ideal sewing surface height. This means that my own ideal sewing cabinet should be anywhere from 29" to 34" tall. Well, it was 30 1/2" tall before we took it apart, and the commercial sewing cabinet manufacturers offer their cabinets in standard heights ranging from 29" to 30 1/4". I did notice that I was hunching my back and shoulders when I was free-motion quilting with my old setup, but that could have had more to do with inadequate task lighting than with the sewing surface height. It's hard to know whether raising my sewing surface would be helpful or whether it would create a whole new world of pain and suffering!
Koala's Quilt Pro Plus IV, 29 1/4" Sewing Surface Height |
Tomorrow we'll look at the correct height of the other two main work stations in a sewing room: the cutting table and the pressing station. Onwards and upwards!
PSST!! I'd Love to Quilt for YOU!
By the way, if you or any of your quilty friends has a quilt top or two that needs quilting, I'd be delighted to quilt for you! My turnaround for edge-to-edge quilting is currently running about 2 weeks, and you can click here to find out how to book your quilt with me.


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Request for Comments: 8079
Category: Standards Track
S. Garcia Murillo
V. Pascual
February 2017
Guidelines for End-to-End Support of the RTP Control Protocol (RTCP) in
Back-to-Back User Agents (B2BUAs)
SIP Back-to-Back User Agents (B2BUAs) are often designed to also be on the media path, rather than just to intercept signalling. This means that B2BUAs often implement an RTP or RTP Control Protocol (RTCP) stack as well, thus leading to separate multimedia sessions that the B2BUA correlates and bridges together. If not disciplined, this behaviour can severely impact the communication experience, especially when statistics and feedback information contained in RTCP messages get lost because of mismatches in the reported data.
This document defines the proper behaviour B2BUAs should follow when acting on both the signalling plane and media plane in order to preserve the end-to-end functionality of RTCP.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force (IETF). It represents the consensus of the IETF community. It has received public review and has been approved for publication by the Internet Engineering Steering Group (IESG). Further information on Internet Standards is available in Section 2 of RFC 7841.
Information about the current status of this document, any errata, and how to provide feedback on it may be obtained at http://www.rfc-editor.org/info/rfc8079.
Copyright Notice
Copyright © 2017 IETF Trust and the persons identified as the document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal Provisions Relating to IETF Documents (http://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as described in the Simplified BSD License.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. Signalling/Media Plane B2BUAs . . . . . . . . . . . . . . . . 4 3.1. Media Relay . . . . . . . . . . . . . . . . . . . . . . . 5 3.2. Media-Aware Relay . . . . . . . . . . . . . . . . . . . . 6 3.3. Media Terminator . . . . . . . . . . . . . . . . . . . . 11 4. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12 5. Security Considerations . . . . . . . . . . . . . . . . . . . 12 6. References . . . . . . . . . . . . . . . . . . . . . . . . . 13 6.1. Normative References . . . . . . . . . . . . . . . . . . 13 6.2. Informative References . . . . . . . . . . . . . . . . . 14 Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . 15 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction
Session Initiation Protocol (SIP) [RFC3261] Back-to-Back User Agents (B2BUAs) are SIP entities that can act as a logical combination of both a User Agent Server (UAS) and a User Agent Client (UAC). As such, their behaviour is not always completely adherent to standards and can lead to unexpected situations. [RFC7092] presents a taxonomy of the most commonly deployed B2BUA implementations and describes how they differ in terms of the functionality and features they provide.
Such components often do not only act on the signalling plane (intercepting and possibly modifying SIP messages), but also on the media plane. This means that, in order to receive and manage all RTP and RTCP [RFC3550] packets in a session, these components also manipulate the session descriptions [RFC4566] in the related offer/ answer exchanges [RFC3264]. The reasons for such behaviour can be different. The B2BUA may want, for instance, to provide transcoding functionality for participants with incompatible codecs, or it may need the traffic to be directly handled for different reasons. This can lead to several different topologies for RTP-based communication, as documented in [RFC7667].
Whatever the reason, such behaviour does not come without a cost. In fact, whenever a media-aware component is placed on the path between two or more participants that want to communicate by means of RTP/ RTCP, the end-to-end nature of such protocols is broken. While this may not be a problem for RTP packets, which can be quite easily relayed, it definitely can cause serious issue for RTCP messages, which carry important information and feedback on the communication quality the participants are experiencing. Consider, for instance, the simple scenario only involving two participants and a single RTP session depicted in Figure 1:
+--------+ +---------+ +---------+ | |=== SSRC1 ===>| |=== SSRC3 ===>| | | Alice | | B2BUA | | Bob | | |<=== SSRC2 ===| |<=== SSRC4 ===| | +--------+ +---------+ +---------+
Figure 1: B2BUA Modifying RTP Headers
In this common scenario, a participant (Alice) is communicating with another participant (Bob) as a result of a signalling session managed by a B2BUA: this B2BUA is also on the media path between the two and is acting as a Media Relay. This means that two separate RTP sessions are involved (one per side), each carrying two RTP streams (one per media direction). As part of this process, the B2BUA is also rewriting some of the RTP header information on the way. In this example, just the Synchronization Source (SSRC) of the incoming RTP streams is changed, but more information may be modified as well (e.g., sequence numbers, timestamps, etc.). In particular, whenever Alice sends an RTP packet, she sets her SSRC (SSRC1) in the RTP header of her RTP source stream. The B2BUA rewrites the SSRC (SSRC3) before relaying the packet to Bob. At the same time, RTP packets sent by Bob (SSRC4) get their SSRC rewritten as well (SSRC2) before being relayed to Alice.
Assuming now that Alice needs to inform Bob that she has lost several packets in the last few seconds, she will place the related received RTP stream SSRC she is aware of (SSRC2) together with her own (SSRC1) in RTCP Reports and/or NACKs. Since the B2BUA is making use of different SSRCs for the RTP streams in the RTP session it established with each participant, blindly relaying Alice's incoming RTCP messages to Bob would cause issues. These RTCP messages would reference SSRCs Bob doesn't know about, which would result in precious feedback being dropped. In fact, Bob is only aware of SSRC4 (the one his source RTP stream uses) and SSRC3 (the one he's receiving from the B2BUA in the received RTP stream) and knows nothing about SSRC1 and SSRC2 in the messages he received instead. Considering the feedback being dropped because of this may contain precious information (e.g., related to packet loss, congestion, and other network issues or considerations), the inability to take them into account may lead to severe issues. For instance, Bob may flood Alice with more media packets she can handle and/or not retransmit the packets she missed and asked for. This may easily lead to a very bad communication experience, if not eventually to an unwanted termination of the communication itself.
This is just a trivial example that, together with additional scenarios, will be addressed in the following sections. Nevertheless, it is a valid example of how such a simple mishandling of precious information may lead to serious consequences. This is especially true if we picture more complex scenarios involving several participants at the same time, multiple RTP sessions (e.g., a video stream along audio) rather than a single one, redundancy RTP streams, SSRC multiplexing, and so on. Considering how common B2BUA deployments are, it is very important for them to properly address RTCP messages in order to be sure that their activities on the media plane do not break or interfere with anything relevant to the session.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].
In addition, this document uses, where relevant, the RTP-related terminology defined in [RFC7656].
3. Signalling/Media Plane B2BUAs
As described in the Introduction (Section 1), it's very common for B2BUA deployments to act on the media plane rather than just on the signalling plane alone. In particular, [RFC7092] describes three different categories of such B2BUAs: (1) a simple Media Relay that is effectively unaware of anything that is transported; (2) a Media- aware Relay that inspects and/or modifies RTP and RTCP messages as they flow by; and (3) a full-fledged media termination entity that terminates and generates RTP and RTCP messages as needed.
[RFC3550] and [RFC7667] already mandate some specific behaviours in the presence of certain topologies. However, due to their mixed nature, B2BUAs sometimes can't or won't implement all relevant specifications. This means that it's not rare to encounter issues that may be avoided with more disciplined behaviour in that regard, that is, if the B2BUAs followed at least a set of guidelines to ensure no known problems occur. For this reason, the following subsections describe the proper behaviour that B2BUAs, whatever above category they fall in, should follow in order not to impact any end- to-end RTCP effectiveness.
3.1. Media Relay
A Media Relay, as identified in [RFC7092], simply forwards all RTP and RTCP messages it receives without either inspecting or modifying them. Using the terminology in "RTP Topologies" [RFC7667], this can be seen as an RTP Transport Translator. As such, B2BUAs acting as Media Relays are not aware of what traffic they're handling. This means that both packet payloads and packet headers are opaque to them. Many Session Border Controllers (SBCs) implement this kind of behaviour, e.g., when acting as a bridge between an inner and outer network.
Considering that all headers and identifiers in both RTP and RTCP are left untouched, issues like the SSRC mismatch described in the previous section would not occur. However, similar problems could still happen for different reasons, for instance, if the session description prepared by the B2BUA, whether it has been modified or not, ends up providing incorrect information. This may happen, for example, if the Session Description Protocol (SDP) on either side contains 'ssrc' [RFC5576] attributes that don't match the actual SSRC being advertised on the media plane or if the B2BUA advertised support for NACK because it implements it while the original INVITE didn't. Such issues might occur, for instance, when the B2BUA acting as a Media Relay is generating a new session description when bridging an incoming call rather than using the original session description. This may cause participants to find a mismatch between the SSRCs advertised in the SDP and the ones actually observed in RTP and RTCP messages or to have them either ignore or generate RTCP feedback packets that were not explicitly advertised as supported.
In order to prevent such an issue, a Media Relay B2BUA SHOULD forward all the SSRC- and RTCP-related SDP attributes when handling a multimedia session setup between participants: this includes attributes like 'ssrc' [RFC3261], 'rtcp-fb' [RFC4585], 'rtcp-xr- attrib' [RFC3611], and others. However, certain SDP attributes may lead to call failures when forwarded by a Media Relay, as they have an implied assumption that the attribute describes the immediate peer. A clear example of this is the 'rtcp' [RFC3605] attribute, which describes the expected RTCP peer port. Other attributes might include the immediate peer's IP address, preferred transport, etc. In general, the guideline is to require rewriting of attributes that are implicitly describing the immediate peer. B2BUAs SHOULD forward all other SDP attributes in order to avoid breaking additional functionality that endpoints may be relying on. If implementors have doubts about whether this guidance applies to a specific attribute, they should test to determine if call failures occur.
The cited 'rtcp' example is also relevant whenever RTP/RTCP multiplexing [RFC5761] support is being negotiated. If the B2BUA acting as a Media Relay is unaware of the specifics of the traffic it is handling, and as such may not have RTP/RTCP parsing capabilities, it SHOULD reject RTP/RTCP multiplexing by removing the 'rtcp-mux' SDP attribute. If instead the Media Relay is able to parse RTP/RTCP, and can verify that demultiplexing can be performed without any RTP Payload Type rewrites (i.e., no overlap between any RTP Payload Types and the RTCP Payload Type space has been detected), then the B2BUA SHOULD negotiate RTP/RTCP multiplexing support if advertised.
It is worth mentioning that, by leaving RTCP messages untouched, a Media Relay may also leak information that, according to policies, may need to be hidden or masqueraded, e.g., domain names in CNAME items. Besides, these CNAME items may actually contain IP addresses: this means that, should a NAT be involved in the communication, this may actually result in CNAME collisions, which could indeed break the end-to-end RTCP behaviour. While [RFC7022] can prevent this from happening, there may be implementations that don't make use of it. As such, a B2BUA MAY rewrite CNAME items if any potential collision is detected, even in the Media Relay case. If a B2BUA does indeed decide to rewrite CNAME items, then it MUST generate new CNAMEs following [RFC7022]. The same SHOULD be done if RTP extensions involving CNAMEs are involved (e.g., "urn:ietf:params:rtp- hdrext:sdes:cname" [RFC7941]). If that is not possible, e.g., because the Media Relay does not have RTP header editing capabilities or does not support these extensions, then the B2BUA MUST reject the negotiation of such extensions when negotiating the session.
3.2. Media-Aware Relay
A Media-aware Relay, unlike the Media Relay addressed in the previous section, is aware of the media traffic it is handling. This means it inspects RTP and RTCP messages flowing by and may even modify their headers. Using the terminology in [RFC3550], this can be seen as an RTP Translator. A B2BUA implementing this role typically does not inspect the RTP payloads, which would be opaque to them: this means that the actual media would not be manipulated (e.g., transcoded).
This makes them quite different from the Media Relays previously discussed, especially in terms of the potential issues that may occur at the RTCP level. In fact, being able to modify the RTP and RTCP headers, such B2BUAs may end up modifying RTP-related information like SSRC / Contributing Source (CSRC), sequence numbers, timestamps, and others in an RTP stream before forwarding the modified packets to the other interested participants. This means that, if not properly disciplined, such behaviour may easily lead to issues like the one described in the introductory section. For this reason, it is very important for a B2BUA modifying RTP-related information across two related RTP streams to also modify, in a coherent way, the same information in RTCP messages.
It is worthwhile to point out that such a B2BUA may not necessarily forward all the packets it receives. Selective Forwarding Units (SFUs) [RFC7667], for instance, may be implemented to aggregate or drop incoming RTCP messages while at the same time originating new ones on their own. It is important to clarify that a B2BUA SHOULD NOT randomly drop or forward RTCP feedback of the same type (e.g., a specific XR block type or specific Feedback messages) within the context of the same session as that may lead to confusing, if not broken, feedback to the recipients of the message due to gaps in the communication. As to the messages that are forwarded and/or aggregated, it's important to make sure the information is coherent.
Besides the behaviour already mandated for RTCP translators in Section 7.2 of [RFC3550], a media-aware B2BUA MUST handle incoming RTCP messages to forward following these guidelines:
Sender Report (SR) [RFC3550]:
If the B2BUA has changed the SSRC of the sender RTP stream a Sender Report refers to, it MUST update the SSRC in the SR packet header as well. If the B2BUA has changed the SSRCs of other RTP streams too, and any of these streams are addressed in any of the SR Report Blocks, it MUST update the related values in the SR Report Blocks as well. If the B2BUA has also changed the base RTP sequence number when forwarding RTP packets, then this change MUST be reflected in the 'extended highest sequence number received' field in the Report Blocks. In case the B2BUA is acting as a Selective Forwarding Unit (SFU) [RFC7667], it needs to track in the outgoing SR, the relevant number of packets sent, and the total amount of bytes sent to the receiver.
Receiver Report (RR) [RFC3550]:
The guidelines for SR apply to RR as well.
Source Description (SDES) [RFC3550]:
If the B2BUA has changed the SSRC of any RTP stream addressed in any of the chunks of an incoming SDES message, it MUST update the related SSRCs in all the chunks. The same considerations made with respect to CNAME collisions at the end of Section 3.1 apply here as well.
If the B2BUA has changed the SSRC of any RTP stream addressed in the SSRC/CSRC identifiers included in a BYE packet, it MUST update them in the message.
If the B2BUA has changed the SSRC of any RTP stream addressed in the header of an APP packet, it MUST update the identifier in the message. Should the B2BUA be aware of any specific APP message format that contains additional information related to SSRCs, it SHOULD update them accordingly as well.
Extended Reports (XRs) [RFC3611]:
If the B2BUA has changed the SSRC of the RTP stream associated with the originator of an XR packet, it MUST update the SSRC in the XR message header. The same guidelines given for SR/RR, with respect to SSRC identifiers in Report Blocks, apply to all the Report Block types in the XR message as well. If the B2BUA has also changed the base RTP sequence number when forwarding RTP packets, then this change MUST be reflected in the 'begin_seq' and 'end_seq' fields that are available in most of the Report Block types that are part of the XR specification.
Receiver Summary Information (RSI) [RFC5760]:
If the B2BUA has changed any SSRC of RTP streams addressed in an RSI packet, it MUST update the SSRC identifiers in the message. This includes the distribution source SSRC, which MUST be rewritten with the one the B2BUA uses to send RTP packets to each sender participant, the summarized SSRC, and when a Collision Sub- Report Block is available, the SSRCs in the related list.
Port Mapping (TOKEN) [RFC6284]:
If the B2BUA has changed any SSRC of RTP streams addressed in a TOKEN packet, it MUST update the SSRC identifiers in the message. This includes the Packet Sender SSRC, which MUST be rewritten with the one the B2BUA uses to send RTP packets to each sender participant, and the Requesting Client SSRC when the message is a response, which MUST be rewritten using the related sender participant(s) SSRC.
Feedback Messages [RFC4585]:
All Feedback messages have a common packet format, which includes the SSRC identifier of the Packet Sender and the SSRC identifier of the media source the feedback is related to. Just as described for the previous messages, these SSRC identifiers MUST be updated in the message if the B2BUA has changed the SSRC of the RTP streams addressed there. It MUST NOT, however, change a media source SSRC that was originally set to zero, unless zero is actually the SSRC that was chosen by one of the involved endpoints, in which case the above-mentioned rules as to SSRC rewriting apply. Considering that many Feedback messages also include additional data as part of their specific Feedback Control Information (FCI), a media-aware B2BUA MUST take care of them accordingly, if it can parse and regenerate them, according to the following guidelines:
A media-aware B2BUA MUST properly rewrite the Packet ID (PID) of all addressed lost packets in the NACK FCI if it changed the RTP sequence numbers.
A media-aware B2BUA MUST properly rewrite the additional SSRC identifier in the specific FCI if it changed the related RTP SSRC of the media sender.
Receiver Estimated Max Bitrate (REMB) [RTCP-REMB]:
[RTCP-REMB] describes an RTCP payload-specific Feedback message that reports the receiver's available bandwidth to the sender. As of the time of this writing, REMB has been widely deployed but has not been standardized. The REMB mechanism will not function correctly across a media-aware B2BUA that changes the SSRC of the media sender unless it also changes the SSRC values in the REMB packet.
Explicit Congestion Notification (ECN) [RFC6679]:
The same guidelines given for SR/RR management apply, considering the presence of sequence numbers in the ECN Feedback Report format. For the management of RTCP XR ECN Summary Report messages, the same guidelines given for generic XR messages apply.
Apart from the generic guidelines related to Feedback messages, no additional modifications are needed for Picture Loss Indication (PLI), Slice Lost Indication (SLI), and Reference Picture Selection Indication (RPSI) Feedback messages.
Of course, the same considerations about the need for SDP and RTP/ RTCP information to be coherent applies to media-aware B2BUAs. This means that, if a B2BUA changes any SSRC, it MUST update the related 'ssrc' attributes, if present, before sending it to the recipient. Besides, it MUST rewrite the 'rtcp' attribute if provided. At the same time, while a media-aware B2BUA is typically able to inspect/ modify RTCP messages, it may not support all RTCP messages. This means that a B2BUA may choose to drop RTCP messages it can't parse. In that case, a media-aware B2BUA MUST advertise its RTCP level of support in the SDP in a coherent way in order to prevent, for instance, a UAC from sending NACK messages that would never reach the intended recipients. It's important to point out that, in case a compound RTCP packet was received and any RTCP message in it needs to be dropped, then the B2BUA SHOULD NOT drop the whole compound RTCP packet, but only the selected messages.
The same considerations on CNAMEs made in regard to Media Relays apply to Media-aware Relays as well. Specifically, if RTP extensions involving CNAMEs are involved (e.g., "urn:ietf:params:rtp- hdrext:sdes:cname" [RFC7941]) and negotiated because the B2BUA supports them, then the B2BUA MUST update the CNAME value in there as well, if it was changed. It is worth pointing out that, if the new CNAME is larger than the old one, this would result in a larger RTP packet than originally received. If the length of the updated packet exceeds the MTU of any of the networks the packet will traverse, this can result in the packet being dropped and lost by the recipient.
A different set of considerations is worthwhile for RTP/RTCP multiplexing [RFC5761] and Reduced-Size RTCP [RFC5506]. While the former allows for a better management of network resources by multiplexing RTP packets and RTCP messages over the same transport, the latter allows for a compression of RTCP messages, thus leading to less network traffic. For RTP/RTCP multiplexing, a B2BUA acting as a Media Relay may use it on either RTP session independently. This means that, for instance, a Media Relay B2BUA may use RTP/RTCP multiplexing on one side of the communication and not use it on the other side, if the endpoint does not support it. This allows for a better management of network resources on the side that does support it. In case any of the parties in the communications supports it and the B2BUA does too, the related 'rtcp-mux' SDP attribute MUST be forwarded on the other side(s). If the B2BUA detects that any of the parties in the communication do not support the feature, it may decide to either disable it entirely or still advertise it for the RTP sessions with parties that do support it. In case the B2BUA decides to involve RTP/RTCP multiplexing, it MUST ensure that there are no conflicting RTP Payload Type numbers on either side. When there are, it MUST rewrite RTP Payload Type numbers to prevent conflicts in the session where the RTP/RTCP multiplexing is applied. Should RTP Payload Types be rewritten, the related information in the SDP MUST be updated accordingly.
For Reduced-Size RTCP, the considerations are a bit different. In fact, while a Media Relay B2BUA may choose to use it on the side that supports it and not on the side that doesn't, there are several reasons for discouraging such behaviour. While Reduced-Size allows for less network traffic related to RTCP messaging in general, this gain may lead a Reduced-Size RTCP implementation to also issue a higher rate of RTCP Feedback messages. This would result in increased RTCP traffic on the side that does not support Reduced-Size and could, as a consequence, actually be counterproductive if the available bandwidth is different on the two sides. Negotiating a session with both sides would allow the B2BUA to discover which one supports Reduced-Size and which doesn't and decide whether or not to allow the sides to independently use Reduced-Size. Should the B2BUA decide to disable the feature on all sides, which is suggested in case Reduced-Size is not supported by all parties involved, it MUST NOT advertise support for the Reduced-Size RTCP functionality on either side, by removing the 'rtcp-rsize' attribute from the SDP.
3.3. Media Terminator
A Media Terminator B2BUA, unlike simple Media Relays and media-aware ones, is able to terminate media itself. As such, it can inspect and/or modify RTP payloads as well. This means that such components, for instance, can act as media transcoders and/or originate specific RTP media. Using the terminology in "RTP Topologies" [RFC7667], this can be seen as an RTP Media Translator. Such a topology can also be seen as a back-to-back RTP session through a middlebox, as described in Section 3.2.2 of [RFC7667]. Such a capability makes them quite different from the previously introduced B2BUA typologies. Since such a B2BUA would terminate RTP itself, it can take care of the related statistics and feedback functionality directly, with no need to simply relay any message between the participants in the multimedia session.
For this reason, no specific guideline is needed to ensure a proper end-to-end RTCP behaviour in such scenarios, because most of the time, there would be no end-to-end RTCP interaction among the involved participants in the first place. Nevertheless, should any RTCP message actually need to be forwarded to another participant in the multimedia session, the same guidelines provided for the media- aware B2BUA case apply.
For RTP/RTCP multiplexing support, the same considerations already given for the Media Relay management also apply to Media Terminators.
Some different considerations might be given as to the Reduced-Size RTCP functionality instead. In fact, in the Media Terminator case, it is safe to use the feature independently on each side, as the B2BUA would terminate RTCP. In that case, the B2BUA SHOULD advertise and negotiate support for Reduced-Size if available and MUST NOT otherwise.
4. IANA Considerations
This document does not require any IANA actions.
5. Security Considerations
The discussion in the previous sections on the management of RTCP messages by a B2BUA worked under the assumption that the B2BUA has actual access to the RTP/RTCP information itself. This is indeed true if we assume that plain RTP and RTCP are being handled, but they may not be once any security is enforced on RTP packets and RTCP messages by means of Secure RTP (SRTP) [RFC3711].
While typically not an issue in the Media Relay case, where RTP and RTCP packets are forwarded without any modification regardless of whether or not security is involved, this could definitely have an impact on Media-aware Relays and Media Terminator B2BUAs. As simple example, if we envisage an SRTP / Secure RTCP (SRTCP) session across a B2BUA where the B2BUA itself has no access to the keys used to secure the session, there would be no way to manipulate SRTP headers without violating the hashing on the packet. At the same time, there would be no way to rewrite the RTCP information accordingly either.
For this reason, it is important to point out that the operations described in the previous sections are only possible if the B2BUA has a way to effectively manipulate the packets and messages flowing by. This means that, when media security is involved, only the Media Relay scenario can be properly addressed. Attempting to cover Media- aware Relay and Media Termination scenarios when involving secure sessions will inevitably lead to the B2BUA acting as a man in the middle; consequently, its behaviour is unspecified and discouraged. More considerations on this are provided in [RFC7879].
It is also worth pointing out that there are scenarios where an improper management of RTCP messaging across a B2BUA may lead, willingly or not, to situations not unlike an attack. As a simple example, improper management of an REMB Feedback message containing, e.g., information on the limited bandwidth availability for a user, may lead to missing or misleading information to its peer. This may cause the peer to increase the encoder bitrate, maybe up to a point where a user with poor connectivity will inevitably be choked by an amount of data it cannot process. This scenario may thus result in what looks like a Denial-of-Service (DoS) attack towards the user.
6. References
6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, <http://www.rfc-editor.org/info/rfc2119>. [RFC3261] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M., and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, DOI 10.17487/RFC3261, June 2002, <http://www.rfc-editor.org/info/rfc3261>. [RFC3264] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with Session Description Protocol (SDP)", RFC 3264, DOI 10.17487/RFC3264, June 2002, <http://www.rfc-editor.org/info/rfc3264>. [RFC3550] Schulzrinne, H., Casner, S., Frederick, R., and V. Jacobson, "RTP: A Transport Protocol for Real-Time Applications", STD 64, RFC 3550, DOI 10.17487/RFC3550, July 2003, <http://www.rfc-editor.org/info/rfc3550>. [RFC3611] Friedman, T., Ed., Caceres, R., Ed., and A. Clark, Ed., "RTP Control Protocol Extended Reports (RTCP XR)", RFC 3611, DOI 10.17487/RFC3611, November 2003, <http://www.rfc-editor.org/info/rfc3611>. [RFC4566] Handley, M., Jacobson, V., and C. Perkins, "SDP: Session Description Protocol", RFC 4566, DOI 10.17487/RFC4566, July 2006, <http://www.rfc-editor.org/info/rfc4566>. [RFC4585] Ott, J., Wenger, S., Sato, N., Burmeister, C., and J. Rey, "Extended RTP Profile for Real-time Transport Control Protocol (RTCP)-Based Feedback (RTP/AVPF)", RFC 4585, DOI 10.17487/RFC4585, July 2006, <http://www.rfc-editor.org/info/rfc4585>. [RFC5104] Wenger, S., Chandra, U., Westerlund, M., and B. Burman, "Codec Control Messages in the RTP Audio-Visual Profile with Feedback (AVPF)", RFC 5104, DOI 10.17487/RFC5104, February 2008, <http://www.rfc-editor.org/info/rfc5104>. [RFC5506] Johansson, I. and M. Westerlund, "Support for Reduced-Size Real-Time Transport Control Protocol (RTCP): Opportunities and Consequences", RFC 5506, DOI 10.17487/RFC5506, April 2009, <http://www.rfc-editor.org/info/rfc5506>. [RFC5760] Ott, J., Chesterfield, J., and E. Schooler, "RTP Control Protocol (RTCP) Extensions for Single-Source Multicast Sessions with Unicast Feedback", RFC 5760, DOI 10.17487/RFC5760, February 2010, <http://www.rfc-editor.org/info/rfc5760>. [RFC5761] Perkins, C. and M. Westerlund, "Multiplexing RTP Data and Control Packets on a Single Port", RFC 5761, DOI 10.17487/RFC5761, April 2010, <http://www.rfc-editor.org/info/rfc5761>. [RFC6284] Begen, A., Wing, D., and T. Van Caenegem, "Port Mapping between Unicast and Multicast RTP Sessions", RFC 6284, DOI 10.17487/RFC6284, June 2011, <http://www.rfc-editor.org/info/rfc6284>. [RFC6679] Westerlund, M., Johansson, I., Perkins, C., O'Hanlon, P., and K. Carlberg, "Explicit Congestion Notification (ECN) for RTP over UDP", RFC 6679, DOI 10.17487/RFC6679, August 2012, <http://www.rfc-editor.org/info/rfc6679>. [RFC7022] Begen, A., Perkins, C., Wing, D., and E. Rescorla, "Guidelines for Choosing RTP Control Protocol (RTCP) Canonical Names (CNAMEs)", RFC 7022, DOI 10.17487/RFC7022, September 2013, <http://www.rfc-editor.org/info/rfc7022>. [RFC7656] Lennox, J., Gross, K., Nandakumar, S., Salgueiro, G., and B. Burman, Ed., "A Taxonomy of Semantics and Mechanisms for Real-Time Transport Protocol (RTP) Sources", RFC 7656, DOI 10.17487/RFC7656, November 2015, <http://www.rfc-editor.org/info/rfc7656>. [RFC7941] Westerlund, M., Burman, B., Even, R., and M. Zanaty, "RTP Header Extension for the RTP Control Protocol (RTCP) Source Description Items", RFC 7941, DOI 10.17487/RFC7941, August 2016, <http://www.rfc-editor.org/info/rfc7941>.
6.2. Informative References
[RFC3605] Huitema, C., "Real Time Control Protocol (RTCP) attribute in Session Description Protocol (SDP)", RFC 3605, DOI 10.17487/RFC3605, October 2003, <http://www.rfc-editor.org/info/rfc3605>. [RFC3711] Baugher, M., McGrew, D., Naslund, M., Carrara, E., and K. Norrman, "The Secure Real-time Transport Protocol (SRTP)", RFC 3711, DOI 10.17487/RFC3711, March 2004, <http://www.rfc-editor.org/info/rfc3711>. [RFC5576] Lennox, J., Ott, J., and T. Schierl, "Source-Specific Media Attributes in the Session Description Protocol (SDP)", RFC 5576, DOI 10.17487/RFC5576, June 2009, <http://www.rfc-editor.org/info/rfc5576>. [RFC7092] Kaplan, H. and V. Pascual, "A Taxonomy of Session Initiation Protocol (SIP) Back-to-Back User Agents", RFC 7092, DOI 10.17487/RFC7092, December 2013, <http://www.rfc-editor.org/info/rfc7092>. [RFC7667] Westerlund, M. and S. Wenger, "RTP Topologies", RFC 7667, DOI 10.17487/RFC7667, November 2015, <http://www.rfc-editor.org/info/rfc7667>. [RFC7879] Ravindranath, R., Reddy, T., Salgueiro, G., Pascual, V., and P. Ravindran, "DTLS-SRTP Handling in SIP Back-to-Back User Agents", RFC 7879, DOI 10.17487/RFC7879, May 2016, <http://www.rfc-editor.org/info/rfc7879>.
Alvestrand, H., Ed., "RTCP message for Receiver Estimated Maximum Bitrate", Work in Progress, draft-alvestrand- rmcat-remb-03, October 2013.
The authors would like to thank Flavio Battimo and Pierluigi Palma for their invaluable feedback in the early stages of this document. The authors would also like to thank Colin Perkins, Bernard Aboba, Albrecht Schwarz, Hadriel Kaplan, Keith Drage, Jonathan Lennox, Stephen Farrell, Magnus Westerlund, Simon Perreault, and Ben Campbell for their constructive comments, suggestions, and reviews that were critical to the formulation and refinement of this document.
Authors' Addresses
Lorenzo Miniero
Sergio Garcia Murillo
MedoozeEmail: email@example.com
Victor Pascual
OracleEmail: email@example.com