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RFC3487: Requirements for Resource Priority Mechanisms for the Session Initiation Protocol (SIP)
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(circuit switched network resources)
(emergency preparedness communications)
(end system resources)
(proxy resources)
Network Working Group H. Schulzrinne Request for Comments: 3487 Columbia University Category: Informational February 2003 Requirements for Resource Priority Mechanisms for the Session Initiation Protocol (SIP) Status of this Memo This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Copyright Notice Copyright (C) The Internet Society (2003). All Rights Reserved. Abstract This document summarizes requirements for prioritizing access to circuit-switched network, end system and proxy resources for emergency preparedness communications using the Session Initiation Protocol (SIP). Table of Contents 1. Introduction ................................................ 2 2. Terminology ................................................. 3 3. Resources ................................................... 4 4. Network Topologies .......................................... 5 5. Network Models .............................................. 6 6. Relationship to Emergency Call Services ..................... 7 7. SIP Call Routing ............................................ 8 8. Policy and Mechanism ........................................ 8 9. Requirements ................................................ 9 10. Security Requirements ....................................... 12 10.1 Authentication and Authorization ....................... 12 10.2 Confidentiality and Integrity .......................... 13 10.3 Anonymity .............................................. 14 10.4 Denial-of-Service Attacks .............................. 14 11. Security Considerations ..................................... 15 12. Acknowledgements ............................................ 15 13. Normative References ........................................ 15 14. Informative References ...................................... 15 15. Author's Address ............................................ 16 16. Full Copyright Statement .................................... 17 Schulzrinne Informational [Page 1] RFC 3487 IEPREP SIP Requirements February 2003 1. Introduction During emergencies, communications resources including telephone circuits, IP bandwidth and gateways between the circuit-switched and IP networks may become congested. Congestion can occur due to heavy usage, loss of resources caused by the natural or man-made disaster and attacks on the network during man-made emergencies. This congestion may make it difficult for persons charged with emergency assistance, recovery or law enforcement to coordinate their efforts. As IP networks become part of converged or hybrid networks along with public and private circuit-switched (telephone) networks, it becomes necessary to ensure that these networks can assist during such emergencies. There are many IP-based services that can assist during emergencies. This memo only covers requirements for real-time communications applications involving the Session Initiation Protocol (SIP) [1], including voice-over-IP, multimedia conferencing and instant messaging/presence. This document takes no position as to which mode of communication is preferred during an emergency, as such discussion appears to be of little practical value. Based on past experience, real-time communications is likely to be an important component of any overall suite of applications, particularly for coordination of emergency- related efforts. As we will describe in detail below, such Session Initiation Protocol (SIP) [1] applications involve at least five different resources that may become scarce and congested during emergencies. In order to improve emergency response, it may become necessary to prioritize access to such resources during periods of emergency-induced resource scarcity. We call this "resource prioritization". This document describes requirements rather than possible existing or new protocol features. Although it is scoped to deal with SIP-based applications, this should not be taken to imply that mechanisms have to be SIP protocol features such as header fields, methods or URI parameters. The document is organized as follows. In Section 2, we explain core technical terms and acronyms that are used throughout the document. Section 3 describes the five types of resources that may be subject to resource prioritization. Section 4 enumerates four network hybrids that determine which of these resources are relevant. Since the design choices may be constrained by the assumptions placed on Schulzrinne Informational [Page 2] RFC 3487 IEPREP SIP Requirements February 2003 the IP network, Section 5 attempts to classify networks into categories according to the restrictions placed on modifications and traffic classes. Since this is a major source of confusion due to similar names, Section 6 attempts to distinguish emergency call services placed by civilians from the topic of this document. Request routing is a core component of SIP, covered in Section 7. Providing resource priority entails complex implementation choices, so that a single priority scheme leads to a set of algorithms that manage queues, resource consumption and resource usage of existing calls. Even within a single administrative domain, the combination of mechanisms is likely to vary. Since it will also depend on the interaction of different policies, it appears inappropriate to have SIP applications specify the precise mechanisms. Section 8 discusses the call-by-value (specification of mechanisms) and call-by-reference (invoke labeled policy) distinction. Based on these discussions, Section 9 summarizes some general requirements that try to achieve generality and feature-transparency across hybrid networks. The most challenging component of resource prioritization is likely to be security (Section 10). Without adequate security mechanisms, resource priority may cause more harm than good, so that the section attempts to enumerate some of the specific threats present when resource prioritization is being employed. 2. Terminology CSN: Circuit-switched network, encompassing both private (closed) networks and the public switched telephone network (PSTN). ETS: Emergency telecommunications service, identifying a communications service to be used during large-scale emergencies that allows authorized individuals to communicate. Such communication may reach end points either within a closed network or any endpoint on the CSN or the Internet. The communication service may use voice, video, text or other multimedia streams. Request: In this document, we define "request" as any SIP request. This includes call setup requests, instant message requests and event notification requests. Schulzrinne Informational [Page 3] RFC 3487 IEPREP SIP Requirements February 2003 3. Resources Prioritized access to at least five resource types may be useful: Gateway resources: The number of channels (trunks) on a CSN gateway is finite. Resource prioritization may prioritize access to these channels, by priority queuing or preemption. CSN resources: Resources in the CSN itself, away from the access gateway, may be congested. This is the domain of traditional resource prioritization mechanisms such as MLPP and GETS, where circuits are granted to ETS communications based on queuing priority or preemption (if allowed by local telecommunication regulatory policy and local administrative procedures). A gateway may also use alternate routing (Section 8) to increase the probability of call completion. Specifying CSN behavior is beyond the scope of this document, but as noted below, a central requirement is to be able to invoke all such behaviors from an IP endpoint. IP network resources: SIP may initiate voice and multimedia sessions. In many cases, audio and video streams are inelastic and have tight delay and loss requirements. Under conditions of IP network overload, emergency services applications may not be able to obtain sufficient bandwidth in any network. When there are insufficient network resources for all users and it is not practical to simply add more resources, quality of service management is necessary to solve this problem. This is orthogonal to SIP, out of the scope for SIP, and as such these requirements will be discussed in another document. Bandwidth used for SIP signaling itself may be subject to prioritization. Receiving end system resources: End systems may include automatic call distribution systems (ACDs) or media servers as well as traditional telephone-like devices. Gateways are also end systems, but have been discussed earlier. Since the receiving end system can only manage a finite number of sessions, a prioritized call may need to preempt an existing call or indicate to the callee that a high-priority call is waiting. (The precise user agent behavior is beyond the scope of this document and considered a matter of policy and implementation.) Schulzrinne Informational [Page 4] RFC 3487 IEPREP SIP Requirements February 2003 Such terminating services may be needed to avoid overloading, say, an emergency coordination center. However, other approaches beyond prioritization, e.g., random request dropping by geographic origin, need to be employed if the number of prioritized calls exceeds the terminating capacity. Such approaches are beyond the scope of this memo. SIP proxy resources: While SIP proxies often have large request handling capacities, their capacity is likely to be smaller than their access network bandwidth. (This is true in particular since different SIP requests consume vastly different amounts of proxy computational resources, depending on whether they invoke external services, sip-cgi [2] and CPL [3] scripts, etc. Thus, avoiding proxy overload by restricting access bandwidth is likely to lead to inefficient utilization of the proxy.) Therefore, some types of proxies may need to silently drop selected SIP requests under overload, reject requests, with overload indication or provide multiple queues with different drop and scheduling priorities for different types of SIP requests. However, this is strictly an implementation issue and does not appear to influence the protocol requirements nor the on-the-wire protocol. Thus, it is out of scope for the protocol requirements discussion pursued here. Responses should naturally receive the same treatment as the corresponding request. Responses already have to be securely mapped to requests, so this requirement does not pose a significant burden. Since proxies often do not maintain call state, it is not generally feasible to assign elevated priority to requests originating from a lower-privileged callee back to the higher-privileged caller. There is no requirement that a single mechanism be used for all five resources. 4. Network Topologies We consider four types of combinations of IP and circuit-switched networks. IP end-to-end: Both request originator and destination are on an IP network, without intervening CSN-IP gateways. Here, any SIP request could be subject to prioritization. IP-to-CSN (IP at the start): The request originator is in the IP network, while the callee is in the CSN. Clearly, this model only applies to SIP-originated phone calls, not generic SIP requests such as those supporting instant messaging services. Schulzrinne Informational [Page 5] RFC 3487 IEPREP SIP Requirements February 2003 CSN-to-IP (IP at the end): A call originates in the CSN and terminates, via an Internet telephony gateway, in the IP network. CSN-IP-CSN (IP bridging): This is a concatenation of the two previous ones. It is worth calling out specifically to note that the two CSN sides may use different signaling protocols. Also, the originating CSN endpoint and the gateway to the IP network may not know the nature of the terminating CSN. Thus, encapsulation of originating CSN information is insufficient. The bridging model (IP-CSN-IP) can be treated as the concatenation of the IP-to-CSN and CSN-to-IP cases. It is worth emphasizing that CSN-to-IP gateways are unlikely to know whether the final destination is in the IP network, the CSN or, via SIP forking, in both. These models differ in the type of controllable resources, identified as gateway, CSN, IP network resources, proxy and receiver. Items marked as (x) are beyond the scope of this document. Topology Gateway CSN IP proxy receiver _________________________________________________ IP-end-to-end (x) (x) x IP-to-CSN x x (x) (x) (x) CSN-to-IP x x (x) (x) x CSN-IP-CSN x x (x) (x) (x) 5. Network Models There are at least four IP network models that influence the requirements for resource priority. Each model inherits the restrictions of the model above it. Pre-configured for ETS: In a pre-configured network, an ETS application can use any protocol carried in IP packets and modify the behavior of existing protocols. As an example, if an ETS agency owns the IP network, it can add traffic shaping, scheduling or support for a resource reservation protocol to routers. Transparent: In a transparent network, an ETS application can rely on the network to forward all valid IP packets, however, the ETS application cannot modify network elements. Commercial ISP offer transparent networks as long as they do not filter certain types of packets. Networks employing firewalls, NATs and "transparent" proxies are not transparent. Sometimes, these types of networks are also called common-carrier networks since they carry IP packets without concern as to their content. Schulzrinne Informational [Page 6] RFC 3487 IEPREP SIP Requirements February 2003 SIP/RTP transparent: Networks that are SIP/RTP transparent allow users to place and receive SIP calls. The network allows ingress and egress for all valid SIP messages, possibly subject to authentication. Similarly, it allows RTP media streams in both directions. However, it may block, in either inbound or outbound direction, other protocols such as RSVP or it may disallow non- zero DSCPs. There are many degrees of SIP/RTP transparency, e.g., depending on whether firewalls require inspection of SDP content, thus precluding end-to-end encryption of certain SIP message bodies, or whether only outbound calls are allowed. Many firewalled corporate networks and semi-public access networks such as in hotels are likely to fall into this category. Restricted SIP networks: In restricted SIP networks, users may be restricted to particular SIP applications and cannot add SIP protocol elements such as header fields or use SIP methods beyond a prescribed set. It appears likely that 3GPP/3GPP2 networks will fall into this category, at least initially. A separate and distinct problem are SIP networks that administratively prohibit or fail to configure access to special access numbers, e.g., the 710 area code used by GETS. Such operational failures are beyond the reach of a protocol specification. It appears desirable that ETS users can employ the broadest possible set of networks during an emergency. Thus, it appears preferable that protocol enhancements work at least in SIP/RTP transparent networks and are added explicitly to restricted SIP networks. The existing GETS system relies on a transparent network, allowing use from most unmodified telephones, while MLPP systems are typically pre-configured. 6. Relationship to Emergency Call Services The resource priority mechanisms are used to have selected individuals place calls with elevated priority during times when the network is suffering from a shortage of resources. Generally, calls for emergency help placed by non-officials (e.g., "911" and "112" calls) do not need resource priority under normal circumstances. If such emergency calls are placed during emergency-induced network resource shortages, the call identifier itself is sufficient to identify the emergency nature of the call. Adding an indication of resource priority may be less appropriate, as this would require that all such calls carry this indicator. Also, it opens another attack Schulzrinne Informational [Page 7] RFC 3487 IEPREP SIP Requirements February 2003 mechanism, where non-emergency calls are marked as emergency calls. (If network elements can recognize the request URI as an emergency call, they would not need the resource priority mechanism.) 7. SIP Call Routing The routing of a SIP request, i.e., the proxies it visits and the UAs it ends up at, may depend on the fact that the SIP request is an ETS request. The set of destinations may be larger or smaller, depending on the SIP request routing policies implemented by proxies. For example, certain gateways may be reserved for ETS use and thus only be reached by labeled SIP requests. 8. Policy and Mechanism Most priority mechanisms can be roughly categorized by whether they: o use a priority queue for resource attempts, o make additional resources available (e.g., via alternate routing (ACR)), or o preempt existing resource users (e.g., calls.) For example, in GETS, alternate routing attempts to use alternate GETS-enabled interexchange carriers (IXC) if it cannot be completed through the first-choice carrier. Priority mechanisms may also exempt certain calls from network management traffic controls. The choice between these mechanisms depends on the operational needs and characteristics of the network, e.g., on the number of active requests in the system and the fraction of prioritized calls. Generally, if the number of prioritized calls is small compared to the system capacity and the system capacity is large, it is likely that another call will naturally terminate in short order when a higher-priority call arrives. Thus, it is conceivable that the priority indication can cause preemption in some network entities, while elsewhere it just influences whether requests are queued instead of discarded and what queueing policy is being applied. Some namespaces may inherently imply a preemption policy, while others may be silent on whether preemption is to be used or not, leaving this to local entity policy. Schulzrinne Informational [Page 8] RFC 3487 IEPREP SIP Requirements February 2003 Similarly, the precise relationships between labels, e.g., what fraction of capacity is set aside for each priority level, is also a matter of local policy. This is similar to how differentiated services labels are handled. 9. Requirements In the PSTN and certain private circuit-switched networks, such as those run by military organizations, calls are marked in various ways to indicate priorities. We call this a "priority scheme". Below are some requirements for providing a similar feature in a SIP environment; security requirements are discussed in Section 10. We will refer to the feature as a "SIP indication" and to requests carrying such an indication as "labelled requests". Note: Not all the following requirements are possible to meet at once. They may represent in some case tradeoffs that must be considered by the designer. REQ-1: Not specific to one scheme or country: The SIP indication should support existing and future priority schemes. For example, there are currently at least four priority schemes in widespread use: Q.735, also implemented by the U.S. defense telephone network ("DSN" or "Autovon") and NATO, has five levels, the United States GETS (Government Emergency Telecommunications Systems) scheme with implied higher priority and the British Government Telephone Preference Scheme (GTPS) system, which provides three priority levels for receipt of dial tone. The SIP indication may support these existing CSN priority schemes through the use of different namespaces. Private-use namespaces may also be useful for certain applications. REQ-2: Independent of particular network architecture: The SIP indication should work in the widest variety of SIP-based systems. It should not be restricted to particular operators or types of networks, such as wireless networks or protocol profiles and dialects in certain types of networks. The originator of a SIP request cannot be expected to know what kind of circuit-switched technology is used by the destination gateway. REQ-3: Invisible to network (IP) layer: The SIP indication must be usable in IP networks that are unaware of the enhancement and in SIP/RTP-transparent networks. Schulzrinne Informational [Page 9] RFC 3487 IEPREP SIP Requirements February 2003 This requirement can be translated to mean that the request has to be a valid SIP request and that out-of-band signaling is not acceptable. REQ-4: Mapping of existing schemes: Existing CSN schemes must be translatable to SIP-based systems. REQ-5: No loss of information: For the CSN-IP-CSN case, there should be no loss of signaling information caused by translation from CSN signaling SIP and back from SIP to CSN signaling if both circuit-switched networks use the same priority scheme. Loss of information may be unavoidable if the destination CSN uses a different priority scheme from the origin. One cannot assume that both CSNs are using the same signaling protocol or protocol version, such as ISUP, so that transporting ISUP objects in MIME [4,5] is unlikely to be sufficient. REQ-6: Extensibility: Any naming scheme specified as part of the SIP indication should allow for future expansion. Expanded naming schemes may be needed as resource priority is applied in additional private networks, or if VoIP-specific priority schemes are defined. REQ-7: Separation of policy and mechanism: The SIP indication should not describe a particular detailed treatment, as it is likely that this depends on the nature of the resource and local policy. Instead, it should invoke a particular named policy. As an example, instead of specifying that a certain SIP request should be granted queueing priority, not cause preemption, but be restricted to three-minute sessions, the request invokes a certain named policy that may well have those properties in a particular implementation. An IP-to-CSN gateway may need to be aware of the specific actions required for the policy, but the protocol indication itself should not. Even in the CSN, the same MLPP indication may result in different behavior for different networks. REQ-8: Method-neutral: The SIP indication chosen should work for any SIP method, not just, say, INVITE. REQ-9: Default behavior: Network terminals configured to use a priority scheme may occasionally end up making calls in a network that does not support such a scheme. In those cases, the protocol must support a sensible default behavior that treats the call no worse than a call that did not invoke the priority scheme. Some networks may choose to disallow calls unless they have a suitable Schulzrinne Informational [Page 10] RFC 3487 IEPREP SIP Requirements February 2003 priority marking and appropriate authentication. This is a matter of local policy. REQ-10: Address-neutral: Any address or URI scheme may be a valid destination and must be usable with the priority scheme. The SIP indication cannot rely on identifying a set of destination addresses or URI schemes for special treatment. This requirement is motivated by existing ETS systems. For example, in GETS and similar systems, the caller can reach any PSTN destination with increased probability of call completion, not just a limited set. (This does not preclude local policy that allows or disallows, say, calls to international numbers for certain users.) Some schemes may have an open set of destinations, such as any valid E.164 number or any valid domestic telephone number, while others may only reach a limited set of destinations. REQ-11: Identity-independent: The user identity, such as the From header field in SIP, is insufficient to identify the priority level of the request. The same identity can issue non-prioritized requests as well as prioritized ones, with the range of priorities determined by the job function of the caller. The choice of the priority is made based on human judgement, following a set of general rules that are likely to be applied by analogy rather than precise mapping of each condition. For example, a particular circumstance may be considered similarly grave compared to one which is listed explicitly. REQ-12: Independent of network location: While some existing CSN schemes restrict the set of priorities based on the line identity, it is recognized that future IP-based schemes should be flexible enough to avoid such reliance. Instead, a combination of authenticated user identity, user choice and policy determines the request treatment. REQ-13: Multiple simultaneous schemes: Some user agents will need to support multiple different priority schemes, as several will remain in use in networks run by different agencies and operators. (Not all user agents will have the means of authorizing callers using different schemes, and thus may be configured at run-time to only recognize certain namespaces.) REQ-14: Discovery: A terminal should be able to discover which, if any, priority namespaces are supported by a network element. Discovery may be explicit, where a user agent requests a list of the supported namespaces or it may be implicit, where it attempts to use a particular namespace and is then told that this namespace is not supported. This does not imply that every element has to Schulzrinne Informational [Page 11] RFC 3487 IEPREP SIP Requirements February 2003 support the priority scheme. However, entities should be able discover whether a network element supports it or not. REQ-15: Testing: It must be possible to test the system outside of emergency conditions, to increase the chances that all elements work during an actual emergency. In particular, critical elements such as indication, authentication, authorization and call routing must be testable. Testing under load is desirable. Thus, it is desirable that the SIP indication is available continuously, not just during emergencies. REQ-16: 3PCC: The system has to work with SIP third-party call control. REQ-17: Proxy-visible: Proxies may want to use the indication to influence request routing (see Section 7) or impose additional authentication requirements. 10. Security Requirements Any resource priority mechanism can be abused to obtain resources and thus deny service to other users. While the indication itself does not have to provide separate authentication, any SIP request carrying such information has more rigorous authentication requirements than regular requests. Below, we describe authentication and authorization aspects, confidentiality and privacy requirements, protection against denial of service attacks and anonymity requirements. Additional discussion can be found in [6]. 10.1 Authentication and Authorization SEC-1: More rigorous: Prioritized access to network and end system resources enumerated in Section 3 imposes particularly stringent requirements on authentication and authorization mechanisms since access to prioritized resources may impact overall system stability and performance, not just result in theft of, say, a single phone call. The authentication and authorization requirements for ETS calls are, in particular, much stronger than for emergency calls (112, 911), where wide access is the design objective, sacrificing caller identification if necessary. SEC-2: Attack protection: Under certain emergency conditions, the network infrastructure, including its authentication and authorization mechanism, may be under attack. Thus, authentication and authorization must be able to survive such attacks and defend the resources against these attacks. Schulzrinne Informational [Page 12] RFC 3487 IEPREP SIP Requirements February 2003 Mechanisms to delegate authentication and to authenticate as early as possible are required. In particular, the number of packets and the amount of other resources such as computation or storage that an unauthorized user can consume needs to be minimized. Unauthorized users must not be able to block CSN resources, as they are likely to be more scarce than packet resources. This implies that authentication and authorization must take place on the IP network side rather than using, say, a CSN circuit to authenticate the caller via a DTMF sequence. Given the urgency during emergency events, normal statistical fraud detection may be less effective, thus placing a premium on reliable authentication. SIP nodes should be able to independently verify the authorization of requests to receive prioritized service and not rely on transitive trust within the network. SEC-3: Independent of mechanism: Any indication of the resource priority must be independent of the authentication mechanism, since end systems will impose different constraints on the applicable authentication mechanisms. For example, some end systems may only allow user input via a 12-digit keypad, while others may have the ability to acquire biometrics or read smartcards. SEC-4: Non-trusted end systems: Since ETS users may use devices that are not their own, systems should support authentication mechanisms that do not require the user to reveal her secret, such as a PIN or password, to the device. SEC-5: Replay: The authentication mechanisms must be resistant to replay attacks. SEC-6: Cut-and-paste: The authentication mechanisms must be resistant to cut-and-paste attacks. SEC-7: Bid-down: The authentication mechanisms must be resistant to bid down attacks. 10.2 Confidentiality and Integrity SEC-8: Confidentiality: All aspects of ETS are likely to be sensitive and should be protected from unlawful intercept and alteration. In particular, requirements for protecting the confidentiality of communications relationships may be higher than for normal commercial service. For SIP, the To, From, Schulzrinne Informational [Page 13] RFC 3487 IEPREP SIP Requirements February 2003 Organization, Subject, Priority and Via header fields are examples of particularly sensitive information. Callers may be willing to sacrifice confidentiality if the only alternative is abandoning the call attempt. Unauthorized users must not be able to discern that a particular request is using a resource priority mechanism, as that may reveal sensitive information about the nature of the request to the attacker. Information not required for request routing should be protected end-to-end from intermediate SIP nodes. The act of authentication, e.g., by contacting a particular server, itself may reveal that a user is requesting prioritized service. SIP allows protection of header fields not used for request routing via S/MIME, while hop-by-hop channel confidentiality can be provided by TLS or IPsec. 10.3 Anonymity SEC-9: Anonymity: Some users may wish to remain anonymous to the request destination. For the reasons noted earlier, users have to authenticate themselves towards the network carrying the request. The authentication may be based on capabilities and noms, not necessarily their civil name. Clearly, they may remain anonymous towards the request destination, using the network-asserted identity and general privacy mechanisms [7,8]. 10.4 Denial-of-Service Attacks SEC-10: Denial-of-service: ETS systems are likely to be subject to deliberate denial-of-service attacks during certain types of emergencies. DOS attacks may be launched on the network itself as well as its authentication and authorization mechanism. SEC-11: Minimize resource use by unauthorized users: Systems should minimize the amount of state, computation and network resources that an unauthorized user can command. SEC-12: Avoid amplification: The system must not amplify attacks by causing the transmission of more than one packet or SIP request to a network address whose reachability has not been verified. Schulzrinne Informational [Page 14] RFC 3487 IEPREP SIP Requirements February 2003 11. Security Considerations Section 10 discusses the security issues related to priority indication for SIP in detail and derives requirements for the SIP indicator. As discussed in Section 6, identification of priority service should avoid multiple concurrent mechanisms, to avoid allowing attackers to exploit inconsistent labeling. 12. Acknowledgements Ran Atkinson, Fred Baker, Scott Bradner, Ian Brown, Ken Carlberg, Janet Gunn, Kimberly King, Rohan Mahy and James Polk provided helpful comments. 13. Normative References [1] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP: Session Initiation Protocol", RFC 3261, June 2002. 14. Informative References [2] Lennox, J., Schulzrinne, H. and J. Rosenberg, "Common Gateway Interface for SIP", RFC 3050, January 2001. [3] Lennox J. and H. Schulzrinne, "CPL: A language for user control of internet telephony services", Work in Progress. [4] Zimmerer, E., Peterson, J., Vemuri, A., Ong, L., Audet, F., Watson, M. and M. Zonoun, "MIME media types for ISUP and QSIG objects", RFC 3204, December 2001. [5] Vemuri, A. and J. Peterson, "Session Initiation Protocol for Telephones (SIP-T): (SIP-T)", BCP 63, RFC 3372, September 2002. [6] Brown, I., "A security framework for emergency communications", Work in Progress. [7] Peterson, J., "A Privacy Mechanism for the Session Initiation Protocol (SIP)", RFC 3323, November 2002. [8] Watson, M., "Short Term Requirements for Network Asserted Identity", RFC 3324, November 2002. Schulzrinne Informational [Page 15] RFC 3487 IEPREP SIP Requirements February 2003 15. Author's Address Henning Schulzrinne Dept. of Computer Science Columbia University 1214 Amsterdam Avenue New York, NY 10027 USA EMail: firstname.lastname@example.com Schulzrinne Informational [Page 16] RFC 3487 IEPREP SIP Requirements February 2003 16. Full Copyright Statement Copyright (C) The Internet Society (2003). All Rights Reserved. This document and translations of it may be copied and furnished to others, and derivative works that comment on or otherwise explain it or assist in its implementation may be prepared, copied, published and distributed, in whole or in part, without restriction of any kind, provided that the above copyright notice and this paragraph are included on all such copies and derivative works. However, this document itself may not be modified in any way, such as by removing the copyright notice or references to the Internet Society or other Internet organizations, except as needed for the purpose of developing Internet standards in which case the procedures for copyrights defined in the Internet Standards process must be followed, or as required to translate it into languages other than English. The limited permissions granted above are perpetual and will not be revoked by the Internet Society or its successors or assigns. This document and the information contained herein is provided on an "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. Acknowledgement Funding for the RFC Editor function is currently provided by the Internet Society. Schulzrinne Informational [Page 17]


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Ideal Notebook
On the other hand, if you're an analog kind of person — you know, the kind of person who likes holding an actual book — then you'll want to grab yourself an Ideal Notebook. Imported from Mexico, Ideal acts as the poor man's Moleskine — mostly because it costs way less — and provides an alternative way to record your thoughts without spending upwards of $20 on a notebook.
$9.00 at CooperHewitt.org
UE Boom
Despite what you think you know about whipping out your acoustic guitar and pumping out the jams, it should be known that not everybody is interested in hearing your take on Radiohead's "Creep." That's why you need to go with a speaker like the UE Boom instead. Tiny, portable, powerful, it allows nearby people to connect via Bluetooth and play songs other than by Radiohead when you're trying to make new friends.
$177.49 at Amazon.com
Samsung Galaxy S7 Edge
Fall is all about starting anew, and if you're thinking of investing in a new phone, the Samsung Galaxy S7 Edge is the first one you should set your eyes on. With it's curved back, thin design, dual pixel 12MP camera and its KNOX-enabled security, this smartphone is galaxies — apologies for the pun — ahead of any other phone on the market today.
Find out more at Samsung.com
Master & Dynamic MW60 Headphones
You might be the kind of person who thinks the music emanating through your dorm or apartment is as grating as nails on a chalkboard; that's why you need a pair of heavy duty headphones to drown out the sound of… well, everything. MW60's Wireless Over Ear Headphones are the supreme amalgamation of "form-meets-function." Connecting via Bluetooth means there are no clumsy wires to detract from the experience, and the chrome-meets-leather look is everything you could ask for.
Find out more at MasterDynamic.com
Dockers Men's Moritz Wingtip Oxfords
It seems like the very last piece of the wardrobe people realize they need is a good pair of shoes. You've long since passed the time where you could wear a pair of Converse with a suit, which is why you need to invest in leather dress shoes to go with the occasions that warrant fanciness. Dockers Men's Moritz Wingtip Oxford is your classic wingtip, offering a rubber sole to give you the comfort you long for while standing or leaning gracefully against a wall.
$58.97 at Dockers.com
Herschel Britannia Messenger Bag
Perfect for going to class, a job interview or taking your laptop to the cafe, this messenger bag is the ideal mix of style and function. Herschel is great at making versatile bags for almost every occasion, and even if you decide to study abroad or take a trip, this makes for the perfect carry-on for any essentials you need to keep you entertained on a long flight.
$94.99 at HerschelSupply.com
Dollar Shave Club Subscription
The days of spending a ton of money on a razor are over. Thank everything that's good and holy that we have subscription services like Dollar Shave Club around to help men everywhere stay fresh and clean. Spend $10 a month for a razor and refills, or splurge for some of the add-ons like easy shave butter, awakening body cleanser, and a plethora of hair styling goo — our word, not theirs. These guys take the thinking out of buying a razor and do everything for you.
Find out more at DollarShaveClub.com
Custom Suit From Indochino
Do yourself a favor and don't ask your dad (or grandpa) advice on where to buy a suit — they're more likely than not going to suggest a place where the suits fit you like a parachute and you'll be drowning in a sea of fabric faster than you can say "holy crap, I should've visited a tailor!" That's where Indochino has everywhere else beat: these guys tailor everything to your body and make sure your suit fits perfectly. You can pick your style, fabric, cut, and even buttons to ensure you get the suit of your dreams.
Find out more at Indochino.com
Buck Mason White Tees
If your collection of T-shirts happen to be stretched-out, oversized, and/or bought during a concert in high school… throw them all out. Well, I guess you should donate them — graphic tees and band tees have been long out of style; nowadays, it's all about the clean white T-shirt. There is no piece of clothing more simple or iconic that a well-fitted clean white shirt. Everybody has their own preferred style, but we're all about this simple crew.
$28.00 at BuckMason.com
Birchbox Men
Like Dollar Shave Club, Birchbox Man offers an array of sample-sized products for dudes to try out while offering the full-sized versions of said products on their site. You can customize your profile to tell the people behind Birchbox what you're like and what you're into and enjoy monthly presents like moisturizer, cologne, and socks. It'll expand your palette and — if nothing else — provide you with a way to easily fill up your dopp kit.
Find out more at Birchbox.com
Mister Pompadour Hair Products
One of the very true stereotypes about college is that you'll be stuck with a bunch of apes who couldn't tell a piece of steak from a slab of cheese. Hygiene is of the utmost importance when you go back to school and Mister Pompadour is your all-encompassing brand when it comes to keeping yourself clean. These guys started with a line of killer styling powders, pastes, clays, and pomades, but have recently taken the deep dive into peppermint shampoo, conditioner, and bodywash. We're not saying you smell bad… it's just something you should keep an eye on.
Find out more at MisterPompadour.com
Acer Chromebook 2
As resourceful as you think you may be, the fact of the matter is that you're going to need a computer for school. Luckily, we live in a time when a personal computer runs under $200 and doesn't weigh as much as a brick. For light lifting, you're going to want to get a laptop as simple and straightforward as an Acer Chromebook, with 2 gigabytes ram, 16 gigabytes memory, and up to 9 hours of battery — for those especially late nights.
$178.97 at Amazon.com
Harry's Travel Kit
Everyone should invest in a nice dopp kit at some point, so why wait until you're back in school to do it? This Travel Kit by Harry's is a great starting point for those used to throwing their toothbrush into their backpack and going about their business. Cotton-nylon water resistant fabric will keep your stuff safe from the perils of a shared bathroom, while a patterned inside adds flair and style to a carry-on item you never usually think about.
$25.00 at Harrys.com
It's a given that you're going to gain weight in college — there's a cafeteria, vending machines, on-campus convenience stores, and no parents nearby to tell you not to eat pizza for dessert. An easy way to maintain your weight — aside from self-control — is using a calorie-counting app like MyFitnessPal to keep track of everything you eat to ensure you don't go overboard. Simply input your meals, log the results, and count how much you consume per day. You can set the app to give you the desired amount of calories for those looking to lose, gain, or maintain their weight.
Find out more at MyFitnessPal.com
Fatboy Lamzac
Because beanbag chairs are so 1995. The Lamzac is a dream for those looking to furnish their apartments or dorms without going the extra mile to, you know, actually purchase furniture. It's quite an ingenious idea — all you do is unfold it, fill, seal, and sit. It comes in six different colors and can be used anywhere: Inside, outside, on the beach, at the park, or as a substitution for a bed in your living room when you've been told to stay out by your roomie.
$54.98 at Huckberry.com
It's hard to put money management skills to use in the real world when there's so much cool stuff for sale. How are students supposed to save money when they're expected to buy books, food, clothes, and precious coffee? That's where Acorns comes in — this app works by rounding every purchase you make up to the nearest dollar and invests all that loose change across 7,000 stocks and bonds to help maximize your return. It's the easiest way for past-you to take care of future-you.
Find out more at Acorns.com
guy gear

subset: commoncrawl


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For their second single, The Sex Pistols followed their call for "Anarchy" with a direct shot at the British monarchy. For publicity-hunting manager Malcolm McLaren, the timing – Queen Elizabeth II's Silver Jubilee in 1977 – couldn't have been more perfect. There was no denying the inflammatory nature of the song's lyrics – with the Queen being referred to as a "moron" in a "fascist regime" – and the closing "no future" refrain became a symbol for the angry working class and the punk movement itself.
The song explodes with energy from its opening chords, which build – along with singer Johnny Rotten's anger – into a brief instrumental break. After Steve Jones' guitar lick, Rotten comes back for a final verse before launching into the aforementioned refrain. Cover Me readers might be interested to know that original Sex Pistol bassist and co-writer Glen Matlock's opening riff was admittedly influenced by 60s' rockers The Move's song "Fire Brigade" (in the chorus) and Eddie Cochran's "C'mon Everybody."
The single sold 200,000 copies in the first week and despite being banned by the BBC went on to top the UK charts. [The BBC were famously believed to have suppressed the song at number 2 on their charts as "punishment," not allowing it to be seen formally at number 1. It reached number 1 on the NME chart.] The iconic song charted again in 2002 and 2007 on its way to becoming one of rocks most legendary hits recognized by Rolling Stone, the Rock and Roll Hall of Fame, and various magazine polls.
There are dozens of generally uninteresting covers of the song that are little more than re-makes. We've sifted through the bollocks and found the ones you should know about. If you've been following this series, you've already heard a few. The unique twists below come from at least five different countries, proving once again that the sun never sets on the British Empire!


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Replacing Gentry
When Marlie agrees to attend a cadaver ball at Vanderbilt Medical School, she did not expect to actually see any cadavers. Or, that a strange apparition would issue her a chilling message.
Despite the cadaver's warning, Marlie is married a year later to Tennessee State Senator, Daniel Cannon, and living in a plantation-style mansion with two step sons. Add to the mix her growing suspicion that something is amiss with the death of Daniel's first wife, Gentry; and newlywed Marlie is definitely in over her pretty Yankee head.
What begins as an innocent inquiry into her new husband's clouded past, ends with Marlie in the midst of a dangerous conspiracy.
A modern twist on the classic Gothic romance novels of Rebecca and Jane Eyre, Replacing Gentry follows Marlie's precarious journey as she learns the truth about the man she married.
Author Julie N. Ford
Julie N. Ford graduated from San Diego State University with a BA in Political Science and a minor in English Literature. In addition, she has a Masters in Social Work from the University of Alabama. Professionally, she has worked in teaching and as a Marriage & Family Counselor. She is the author of two women's fiction novels, The Woman He Married and No Holly for Christmas, published in 2011. In addition, she wrote a romance/chick-lit novel, Count Down to Love, also published in 2011. Count Down to Love was a 2011 Whitney Award finalist. Her next novel, Replacing Gentry, is due for release April 9th, 2013.
Currently, she lives in Nashville, TN with her husband, two daughters and one hedgehog.
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Get Auto Insurance in Cooper City
Let a local Brightway insurance agent help find the right auto insurance coverage in Cooper City.
Let's talk.Let a local Brightway insurance agent help find the right auto insurance coverage in Cooper City.
Let's talk.12185 Sheridan Street
Cooper City, FL 33026
Wherever your car takes you, we can make sure you're going the brighter way. With Cooper City auto insurance, we focus on what truly counts: keeping you confidently in control. Our insurance policies are designed to handle everyday bumps and unexpected challenges that may come your way. Whether you're on a short drive or a long journey, we've got your back.
Start Your QuoteOur focus is simple. To gear you up with a policy that fits like a glove. With a dashboard of options from various insurance companies, we steer you towards premium value without the premium cost, ensuring accessibility to the best insurance rates.
If an accident is your fault, this coverage helps with the other person's expenses. It's your financial shield against legal headaches, including property damage liability.
Dents, crashes, or any car damage? We've got the repairs covered so you can get back on the road.
Your car is more than a ride. It holds your most personal belongings. We cover those too—from laptops to luggage.
If you or your passengers get hurt in a crash, we help cover the medical bills, no matter who's at fault. This includes personal injury protection, a key component of our comprehensive auto insurance policy.
Driving smart means saving smart. Here are some opportunities to reduce your auto insurance policy premiums
Office Hours
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Get a quote on policies customized just for you.


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Believe in your own Magic - Acrylic Circle Plaque
Create a memorable welcome to any room with our Printed Circle Acrylic Plaque. This beautiful sign is handcrafted using premium acrylic and a vibrantly printed design. Display your beautiful plaque in your own home or give it as a gift to make a statement. This would make an ideal gift for your beloved partner, family members, or dear friends on special occasions like anniversaries, birthdays, or any event where you want to express your love and appreciation in an unforgettable way.
Your plaque will be made from high quality acrylic and will feature a professionally printed design. Your sign features a sleek wooden base, but you can elevate your presentation by upgrading to the wooden LED base with a USB plug-in.
Product specifications:
- Premium acrylic
- Size with wooden base: 6.4" (162mm) height x 5.5" (138.5mm) width
- Acrylic Depth: 0.1" (5mm)
- Base size: 1.2" (30mm) height x 5.9" (150mm) width x 1.8" (45mm) depth
- Sharp, detailed printed design
Each order is lovingly packaged and ready to be cherished for a lifetime!


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GTT Communications, Inc. (NYSE: GTT), the leading global cloud networking provider to multinational clients, will present at the Jefferies 2017 Global Technology Conference taking place in Miami, Florida, on May 9, 2017. Mike Sicoli, chief financial officer, will meet with investors that day.
A copy of the company's latest investor presentation is available on the company's website.
About GTT
GTT provides multinationals with a better way to reach the cloud through its suite of cloud networking services, including wide area networking, internet, managed services and voice services. The company's Tier 1 IP network, ranked in the top five worldwide, connects clients to any location in the world and any application in the cloud. GTT delivers an outstanding client experience by living its core values of simplicity, speed and agility. For more information on how GTT is redefining global communications, please visit www.gtt.net.
GTT Investor Relations: Jody Burfening, Carolyn Capaccio LHA +1-212-838-3777 [email protected]
GTT Media Inquiries: Randall Slack GTT +1-908-988-1909 [email protected]


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Stay cool all year long
Now that it is starting to cool down a little, this is the best time with the best available prices to buy a split air conditioner (A/C). Remember, there is no substitute for air conditioning that can cool you down and save plenty of energy with high Seasonal Energy Efficiency Ratio (SEER) A/Cs now available to install.
If you are considering a split system, now is the time to get it started with a free estimate. With more than 7,000 customers on Oahu you can make sure Aire Conditioner Shoppe knows what they are doing. Also make sure to ask what the other A/C companies are giving to you for your warranty.
Aire Conditioner Shoppe gives the best warranty on the split systems available for the private residential homeowner. As a Fujitsu Elite contractor and a Mitsubishi Electric Diamond Contractor, the company now offers a 12-year warranty on parts and compressor, and one-year labor as long as the Aire Conditioner Shoppe installs it.
In most cases, you will find that the Aire Conditioner Shoppe costs a lot less than many companies out there. With more than 36 years of being Hawaii's No. 1 installer, the company allows its customers to really put trust in its slogan: "We do it right the first time!" and "It's easy to do if you know what you are doing."
By opting for an effi cient, split-ductless air conditioning system, you are guaranteed the ideal climate for your home or office every time. The latest split-ductless systems provide zoned comfort, and are engineered in such a way that installation is quick and easy.
These systems are available from the company, which specializes in Fujitsu and Mitsubishi brands.
Some of these systems provide both heating and cooling with the push of a button from a remote control. They also provide individual temperature control, so each room or zone will be the exact temperature that you set.
These systems also have the capability to filter out dust, mold spores and microorganisms. The "Dry Mode" helps to control humidity levels, even when cooling isn't needed. Other standard features include a Sleep Timer, Auto Changeover and a 24-hour Timer Cold Prevention.
The cooling-only, wall-mounted units — designed for single rooms — are slim and stylish. Indoor units have a clean, aesthetic design and are powerful, though small and shorter in length than competing units. The variable speed compressor helps systems adapt to changes in heat brought on by different times of the day. Additionally, these units are so quiet, you won't even know they're on.
In terms of energy savings, owner Neil Wiede-mann pointed out that split-ductless systems are just as, if not more, efficient as central air conditioning.
Wiedemann, who has been in the air conditioning business since 1979, sells and installs split-ductless systems on Oahu. He also sells less expensive window units, which are the choice for apartments, condominiums and houses.
The company has been in business for more than 37 years and also holds an A+ rating from Better Business Bureau. Call for a free estimate on a split-ductless system.
contact // 676-1455 • 262-6163 • 737-1852
web // aireconditionershoppe.com


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Keith Urban to Headline Nashville's New Year's Eve Show Yet Again
For a fourth consecutive year, country star Keith Urban will help Nashville ring in the New Year.
A star-studded lineup for Music City's Jack Daniel's Music City Midnight: New Year's Eve includes Jason Isbell and the 400 Unit alongside his wife, the Highwomen member Amanda Shires. The music will begin with a performance by the Fisk Jubilee Singers, followed by English rock band the The Struts. Urban will headline the event, which is set to take place on Tuesday, Dec. 31, at Bicentennial Capitol Mall State Park in Nashville.
"From the very beginning, our goal was to have a long-term partnership with Keith, and, as we expected, his leadership, talent and involvement has been invaluable to the event's success,"Butch Spyridon, President and CEO of the Nashville Convention & Visitors Corp., tells The Tennessean.
"As you would expect from a consummate professional like Keith, every year the show is completely different and fresh, and we can't wait to see what he brings to ring in 2020," he adds.
The show will continue the tradition of having a music note drop instead of a typical ball drop, accompanied by a standard fireworks display.
Last year's show was a huge success, having been featured during NBC's New Year's Eve national broadcast. The show also brought out many people to enjoy the celebration and music, with 175,000 to 200,000 people in attendance, according to the Nashville Convention & Visitors Corp.
The gates for this year's show will open at 4PM and admission is free for the public.
Keith Urban's Tattoos: See Pics
What's Up With Brett Young's Tattoos?


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As soon as news began to spread about the horrific and utterly senseless murder of an Australian-born baseball player in Oklahoma at the hands of three young black males (or at least, that's how they were first described in the media), I knew what would be coming; specifically, into my e-mail inbox and all around the internet. And even though, oops, turns out one of the three implicated in the killing is actually white, and so the supposed racial angle of the crime has no merit whatsoever, I had no illusions that this would somehow change the reaction from certain quarters. Whenever something like this happens, white supremacist groups make sure to blanket the web with vitriol in which they seek to remind white folks how endangered we are at the hands of black people. Knowing that many whites are anxious about the changing demographics of the nation — which portend that around 2043 we will no longer be the absolute majority of persons in the U.S — playing upon fears of criminal victimization by people of color is seen as a great way to win new recruits to the white nationalist cause. And sure enough, it didn't take long. As soon as I turned on my computer yesterday morning, there it was: an e-mail from an angry and rather blatantly racist white male, spouting all the same nonsense as I've come to expect in moments like this. More savvy than most though, he made sure not to rely on data and arguments from neo-Nazis, but rather from well-known black conservative Walter Williams, who just about a week ago penned a column in which he parroted the line of the white racists, inveighing against the supposed epidemic of black-on-white crime. For Williams, it wasn't the first time he had done this. Several years back, and taking his cues and information straight from the work of white supremacist and separatist Jared Taylor, he had made the same arguments. As Williams noted, and as many a white nationalist has over the years, 83 percent of the time when violent crime is interracial, the perp is black and the victim is white. So although most criminal violence may be intra-racial (that is to say, black-on-black and white-on-white), when the offender and victim differ racially, it is typically the case that someone black is doing the crime and someone white is suffering the consequences. As the sender of yesterday morning's e-mail put it, what do I have to say about that? The answer, of course, is quite a bit, actually. Williams's claim — which he makes upon the basis of Justice Department data from the National Crime Victimization Survey — suggests an incredible imbalance, almost as if blacks were deliberately targeting white people in a veritable orgy of hate! And yet, upon closer inspection the number isn't nearly as meaningful as Williams, or the white supremacists who first began circulating it many years ago, take it to be. Let's look at the data, so as to better understand the logical fallacy in Williams's position. So Just How Dangerous Are Black Folks? The Trouble With Right-Wing Data Analysis First, according to the 2008 data Williams relied on (see Table 42), which is the most recent comprehensive data published by the Justice Department on violent crime victimizations, that year there were approximately 3.6 million violent crimes involving a single-offender. These crimes include assault, both simple and aggravated (mostly simple), robbery, and sexual assault or rape. Of those 3.6 million violent crimes, whites committed 2.1 million of them (58.4%) while blacks committed about 830,000 (22.8%) About 442,000 (or 12%) involved perpetrators whose race was not known to the victim. Thus, for crimes where the race of the perpetrator was known to the victims (about 3.2 million crimes), whites would have committed about 67 percent, and blacks about 26 percent. If we assume the same rough racial distribution for crimes where the perpetrator's race was not known as for crimes where the offender race was known (a reasonable guess), this would mean that whites committed an additional 300,000 crimes, roughly, while blacks would have committed an additional 115,000. In all, this would mean that in 2008, whites committed roughly 2.4 million single offender violent crimes, while blacks would have committed around 950,000. Since there were roughly 31 million African Americans, age 12 and over — and thus eligible for consideration in crime data — in 2008 (this is noted in the same DOJ tables Williams and I are both referencing here), at most, this would mean that for every 1000 blacks in the population there were 30 criminal offenders, and thus, at most, 3 percent of blacks committed a violent crime in 2008 (meaning, importantly, that at least 97 percent did not). And since there were approximately 205 million whites, 12 and over, in the population that year, this would mean that for every 1000 whites in the population there were 12 criminal offenders, and thus, at most, about 1.2 percent of whites committed a violent crime in 2008.* Of course, in truth, and for both groups, the numbers are quite a bit smaller than this. After all, the 30 offenders per 1000 persons (the 3 percent rate of offending for blacks) are not 30 different people. In other words, to say that 3 percent of blacks commit a violent crime each year would assume that each offender committed only one crime, such that the number of offenses equalled the number of offenders, but that isn't the case. There are, as we all know, many offenders who commit multiple offenses each year. As such, the number of offenders would be quite a bit smaller than the number of offenses. Criminologists have estimated, for instance, that 70 percent of criminal offenses are committed by just 7 percent of the total offenders, meaning that there is a small hardcore group of seriously predatory criminals out there doing most of the crime. This would mean that 93 percent of all offenders commit just 30 percent of the crimes. So this would mean that of the 950,000 violent crimes committed by blacks in 2008, 70 percent of them (or 665,000) would have been committed by just 7 percent of all black offenders, while 285,000, roughly, would have been committed by the other 93 percent of offenders. If we assume that the 93 percent who weren't the major repeat offenders only committed one crime each (likely a conservative estimate, but one which errs on the side of the right-wing argument by maximizing the potential numbers of black offenders), this would mean that, at most, the 285,000 offenses actually equate to 93 percent of the offenders. If 285,000 represents 93 percent of all black offenders, then the remaining 7 percent of offenders above that number would come to only an additional 20,000 or so offenders — major hardcore criminals who commit about 665,000 crimes each year. This would mean that at most there might be a little more than 300,000 individual black violent offenders each year. As a percentage of the 12 and over black population in 2008, this would represent only about 1 percent of all blacks who will commit a violent crime in a given year, versus 99 percent who will not. Even if we just restricted the analysis to black males — and even if all these crimes were committed by males, which they were not — it would mean that no more than 2 percent of black males would commit a violent crime in a given year. This alone is an important point to keep in mind, as it suggests that having a generalized fear of black folks, or black men, is the height of statistical irrationality. But…But…What About the Black-on-White Crime Data? How the Right Distorts Interracial Crime Figures As for interracial crime data, this is where right-wing statistical stupidity just becomes downright manipulative. On the one hand, yes, according to the tables, there were indeed far more black-on-white violent crimes (B-W) than white-on-black violent crimes (W-B) in 2008: about 429,000 in the first case and only about 91,000 in the other. Meaning that out of about 520,000 single-offender interracial violent crimes that year, 82.5 percent were black-on-white (B-W) while only 17.5 percent were white-on-black (W-B). My goodness! Perhaps Williams has a point. Well, no, not really. And for someone who is supposedly a reputable scholar, his illogic is particularly glaring. Before explaining why, let us just note at the outset that there is no reason to believe most of these attacks (either the B-W or the W-B) were racially motivated. This data does not refer to hate-related violence, or violence where there has been a discernible racial motivation (as Pat Buchanan recently claimed on Fox), and indeed, the biggest racial disproportion for violent crime, numerically — and year after year — is in the area of robbery, the motivation for which is pecuniary (financial), rather than bigotry. But more than that, even the basic claim that B-W crime is wildly disproportionate and indicative of some kind of race-based targeting by black offenders against white victims is utter nonsense. Here's why. First, relative rates of interracial offending are directly influenced by an important factor, which goes ignored by Williams: namely, the relative rates of criminal offending in general for blacks as opposed to whites. In other words, if the black criminal offending rate in general is 2.5 times higher than the white offending rate, which it was in 2008 (30 per 1000 blacks/12 per 1000 whites), we should logically expect far more black-on-white crimes than white-on-black crimes, simply as a matter of random chance, and having nothing to do with racial targeting. Imagine, for instance, a hypothetical community where there are 6.7 times more whites than blacks (as was true in the U.S. in 2008) and where black offending rates in general are 2.5 times higher than for whites. And let's say that in our hypothetical community, there are 20,000 blacks. Multiplied by 6.7 this would give us 134,000 whites for a total population of 154,000. If, as the real world data suggests, the black violent offending rate is 30 violent crimes per 1000 black persons (or 3 percent), we would expect to see about 600 violent crimes committed by blacks in this community. And if, as the real world data suggests, the white violent offending rate is about 12 violent crimes per 1000 white persons (or 1.2 percent), we would expect about 1608 violent crimes committed by whites in this community. Given relative population sizes (and thus, availability to be victims of one another), we could expect 87 percent of the victims of black violent crime in this restricted white-black sample to be white, since 87 percent of this restricted range, black-white universe, is white; likewise, we'd expect about 13 percent of white crime victims to be black, since 13 percent of this restricted range, black-white universe, is black. This would mean that we could predict about 522 black-on-white violent crimes in a given year, as opposed to only 209 white-on-black violent crimes. In other words, just based on relative population sizes (and thus, victim availability), and general offending rate differences (and thus, perpetrator availability), we should expect 2.5 times more B-W violent crimes than the reverse. In this scenario, about 71 percent of all interracial crimes would be B-W as opposed to W-B. Aha! Walter Williams might say: See, I was right! Random chance would only predict that 71 percent of interracial violence was black-on-white, but in truth, 83 percent of such violence was. And random chance would predict 2.5 times more B-W crime than W-B crime, but in actuality the ratio is 4.7 to 1. So there must be racial targeting! The Importance of Differential Encounter Rates Well, again, no. And again, for reasons that any reasonably competent social scientist should be able to discern; foremost among them, the fact that whites and blacks don't actually encounter each other randomly throughout the population, as if we were evenly distributed throughout the communities where we live. We still tend to live in relative isolation from one another, such that whites do not actually encounter blacks at a rate commensurate with their overall share of the population, and blacks do not encounter whites at a rate commensurate with our share, either. Because of ongoing residential and spatial isolation, the rates of interracial encounter are far less, for both groups, than this. According to the best estimates we have (which are admittedly a bit dated but have not likely changed dramatically, given ongoing patterns of white/black housing isolation from one another), only about three percent of persons encountered by whites are black, on average, while about 57 percent of persons encountered by blacks are white, on average — in both cases far less than population percentages alone would predict. So now we would need to adjust for encounter rates, in order to determine the amount of interracial violent crime that should be expected given random chance and even without any racial targeting. In our hypothetical above, the 600 black offenders would have a 57 percent chance of victimizing a white person, given encounter rates, while our 1608 white offenders would have only a 3 percent chance of victimizing a black person, also because of encounter rates. This would mean that in our hypothetical community we should expect 342 black-on-white violent crimes, compared to only 48 white-on-black violent crimes, for a ratio of 7.1 to 1 — a ratio that is 1.5 times higher than the actual real world ratio of 4.7 to 1. And in this hypothetical community, 88 percent of all interracial crimes would be black-on-white, which is actually higher than the 83 percent of such crimes in the real world. In other words, given general offending rates which are indeed higher for blacks than whites (but which still indicate that the overwhelming majority of blacks are not violent criminal offenders), and given the likelihood of interracial encounters between whites and blacks (and which are especially rare for whites encountering blacks), the rates of black-on-white interracial crime are either pretty much exactly what would be expected without any racial targeting whatsoever, or they are even lower than random chance would predict. Even if we assumed that a reduction in hyper-segregation had increased the likelihood of interracial encounters since the above-referenced interracial encounter rates were estimated, this would not change the fundamental argument here, or the conclusions we should draw concerning the supposed disproportionality of B-W crime. So, for instance, even if we assumed that whites were now 2/3 more likely to encounter blacks than before, due perhaps to the growth of the black middle class, and thus, more blacks moving into previously white spaces (which is likely a very high estimate), this would mean that still, only about 5 percent of those encountered by whites would be black. And, since blacks moving to white areas as they move into the middle class would also result in a dramatic increase in the percentage of whites encountered by those blacks, this would mean that not only the 3 percent W-B encounter rate but also the 57 percent B-W encounter rate would grow. Let's say that it only grew by 10 percent, such that blacks today were only 10 percent more likely than before to encounter whites, which would likely be a conservative estimate. This would mean that rather than 57 percent, now about 63 percent of persons encountered by blacks would be white. Although the encounter rate differences would have shrunk to be sure — from a 19:1 ratio down to a 12.6 to 1 ratio, the resulting statistical logic would remain operative. Under this scenario, in our hypothetical community, we would expect the 600 black offenders to have a 63 percent chance of victimizing a white person, while our white offenders would have a 5 percent chance of victimizing a black person. Thus, we could expect 378 B-W violent crimes, compared to 80 W-B crimes, for a ratio of 4.7 to 1, which is exactly the ratio of B-W to W-B crime in the real world for 2008. And in this hypothetical, 82.5 percent of all interracial crime would be B-W crime, which, once again, exactly mirrors the real-world data referenced by Williams. In other words, and without any racial targeting whatsoever, the interracial crime data about which Williams and various others on the right make such a big deal, would look exactly as it actually looks. Simply put, when it comes to the idea that blacks are targeting whites as some kind of race-based pattern, there is no there, there. Some additional things are also worth noting. First, in 2008, according to the very same table Williams uses for his claim, black and white victims of violent crime were equally likely to have been interracially victimized by members of the other race group. In other words, from the victim perspective, the odds of interracial victimization are the same. From the offender perspective, the odds of black-on-white victimization are greater, but this is entirely a function of population demographics, encounter rates and general offending rates. Once these are controlled for, there is simply no truth to the suggestion that black criminals are targeting whites as victims. And there is one more thing. When we compare interracial offending rates to Census data in 2008 for persons 12 and over (which is also provided in the DOJ report), we discover that at most, 1.4 percent of blacks, 12 and over, criminally victimized a white person that year, and this is assuming that each of the 429,000 B-W violent crimes were committed by unique perpetrators, which is unlikely. If we assume the 70/7 rule as noted above — which left us with about 300,000 individual black offenders rather than 950,000 in 2008 (or only about 1 percent of the 12 and over black population, as opposed to 3 percent before the 70/7 adjustment) — and even if we assumed that three-fourths of black offenders would victimize a white person in a given year (a ridiculously high estimate), this would mean perhaps 225,000 blacks who in a given year would victimize a white person. As such, this would mean that the percentage of the black population victimizing whites in a given year would be no more than 0.7 percent of the black population 12 and over. But even this estimate is high, since 92 percent of all Hispanics are included in the white category (of both crime victims and perps) in DOJ data, and so Hispanics victimized by blacks will appear as "white victims" (see note below). Since Latinos are more likely to live near blacks than non-Hispanic whites are, given economic stratification and levels of urbanicity for Hispanics and blacks as opposed to "real whites," we can safely assume that a significant number of white victims in the data are actually persons of color (Latino and Latina). But even if we assumed that all of the B-W violent crimes were committed against non-Hispanic whites (who numbered about 173 million people age 12 and over that year) this would mean that at most, perhaps 0.25 percent (2.5 tenths of one percent) of all whites were violently victimized by blacks that year. Interracial Homicide Data: or How to Totally Destroy a Right-Wing Meme As for homicide — obviously the most serious of all violent crimes — the supposed interracial imbalance, and the supposed B-W disproportionality is even less impressive. According to FBI data (which is where the racial perp/victim data is tallied for homicide, as opposed to the NCVS tables considered by Williams above), for those crimes where the race of the perp and victim are known, in 2010, there were 447 B-W murders and 218 W-B murders: in neither case a particularly substantial number. Indeed, whites were 6.2 times more likely to be murdered by another white person than by a black person and blacks were about 11 times more likely to be murdered by another black person than by a white person. Although both of these numbers (the 447 and 218) are no doubt lower than the true numbers that year for both directions of interracial homicide (since they only represent murders where the race of the perp is known, and for many homicides that information is not clear), relative ratios would not change much even if that information were available for all homicides. As such we can use these numbers to determine whether the rates of B-W homicide are truly so high, relative to W-B homicide as to suggest some kind of racial targeting of whites by blacks. The key in making this determination is similar to the one employed above for all violent crime: namely, the relative homicide offending rates, generally, for blacks versus whites, since this will directly effect the predicted rates of interracial homicides in each direction. In 2010, of homicides where the race of the offender was known (10,870) blacks committed 53 percent of all homicides (or a total of 5770), while whites committed 48 percent (or 4849). If we extrapolate those percentages to the crimes where the race of the offender was not known, this would mean that of the 4224 homicides with a "race unknown" offender, 2239 would have been committed by blacks, while 2028 would have been committed by whites. In all, this means that in 2010, blacks committed 8009 homicides, while whites committed 6877 homicides. As a percentage of the black population, in 2010, 8009 homicides represent 0.02 percent (2/100ths of 1 percent) of all blacks that year (roughly 39 million) who will kill someone. As a percentage of the white population in 2010 (223.5 million), 6877 homicides would represent 0.003 (3/1000ths of 1 percent) of all whites that year who killed someone. This means that blacks commit homicide, generally, at a rate that is 6.7 times greater than the rate for whites. Now, what does this mean for estimated rates and numbers of B-W homicide as opposed to its W-B counterpart? Let's see. Even if we assumed a random and perfectly mixed white and black population — such that whites and blacks encountered each other at rates relative to their population percentages — the much higher black homicide offending rates alone would predict that there should be 6.7 times more B-W murders than W-B murders. But in fact, as we saw, there were only about twice as many B-W murders as W-B murders. And when we consider the above-mentioned data on relative rates of interracial encounter, the numbers are even more striking. Even if we assume that 5 percent of all persons encountered by whites are black (an increase of 2/3 from prior and clearly documented data), and that only 63 percent of persons encountered by blacks are white (an increase of only 10 percent in the same period), we would expect 12 times more B-W homicides than W-B homicides in a given year. In a community of 3 million people, for instance, in which whites outnumbered blacks 6.7 to 1 (as is the case in the real world) there would be roughly 2,610,000 whites and 390,000 blacks. If 0.02 percent of blacks committed a murder, this would mean that we could expect 78 black homicides that year, and 63 percent of these (or 49 homicides in all) would involve white victims. If 0.003 percent of whites committed a murder that year, this would predict a similar number, roughly 78 murders committed by whites, of which only 4 would involve black victims. In other words, given relative rates of homicide offending along with relative rates of interracial encounter, we could expect 12.25 times more B-W homicides than W-B homicides in any given year. But in fact, in 2010, B-W homicide was only twice as numerically prevalent as the opposite. In other words, B-W homicide is roughly 1/6 as common as random chance would predict. And given the relative population percentages of whites and blacks, blacks are actually more likely to be interracially murdered by a white person than vice-versa. After all, as for homicides where the race of the offender is known, 447 B-W murders as a share of the white community is 2/10,000ths of 1 percent (0.0002) of all whites killed by blacks; meanwhile, 218 W-B homicides as a share of the black community is 5.5/10,000ths of 1 percent (0.00055). So although interracial homicide is incredibly rare in either direction, any given black person is more than 2.5 times as likely as any given white person to be interracially murdered. How anyone could fully examine this data carefully, either for violent crime generally or for homicide in particular, and conclude that there was a black-on-white crime spree underway is beyond the scope of the rational mind to comprehend. But apparently such claims are the stuff of professional scholarship to the likes of Walter Williams, which says a lot about the pathetically low quality of scholarship demanded of right-wing economists, or your garden-variety white nationalist on the internet. That such claims are taken seriously attests to the propaganda value of racist argumentation, and suggests how much work we still have to do to derail this counterfactual narrative before it does even more damage to race relations in America. ________ *It is true, of course, that some of the "white" offenders — and victims, it should be noted — in DOJ data are actually persons of color, namely Hispanics. Although Hispanic victims are treated separate from white victims in FBI Hate Crime data, they are not broken out of the DOJ data discussed here. Because Hispanics are an ethnic group rather than race, they are assigned to the various primary racial groups in almost all government data, and not broken out separately in any given data table, unless noted as such (as with the hate crime data collected by the FBI). In the case of crime data from the DOJ, about 92 percent of Hispanics are classified, racially, as white. You can verify that Hispanics are rolled in with whites and blacks (mostly whites) as victims of violent crime, by adding the numbers of victimizations of those labeled white (in Table 5 of the 2008 data), those labeled black (also Table 5), those labeled "other," which means Asians and Native Americans, principally (also Table 5), those who are listed as being of "mixed race" or more than one race (Table 5) and then those who are Hispanic (in Table 7). The sum of these figures will amount to more (5.42 million) than the total number of violent crime victims listed in table 5, (4.856 million) indicating that Hispanics are, in effect, already being counted in the existing racial totals. As indicated in other government data collections, about 92 percent of Hispanics are classified as white, which is likely to obtain in regard to crime data as well. This means that of the Hispanic victims tallied in Table 7, about 92 percent of them would also be found in the white column of victims in Table 5, thereby artificially inflating the number of "real white" victims. As for offenders, although white supremacists have long argued that Hispanics commit violent crime at a disproportionate rate — somewhere between whites and blacks — the most comprehensive analyses of Hispanic crime suggest this claim is utterly false. Recent analyses done by a prominent far-right conservative and even, in one case, a source long revered by white nationalists, suggest that Hispanic violent crime rates are essentially no different from those of non-Hispanic whites. As such, the 1.2 percent rate, per capita, of criminal offending for whites (including Hispanics), would apply to both Hispanic whites and non-Hispanic whites. This means that with Hispanics representing 34.5 million persons age 12 and over in 2008, and 92 percent of these being classified as white, racially, there would have been 31.7 million Hispanic whites that year. If they offend at a rate comparable to non-Hispanic whites (12 per 1000 persons, or 1.2 percent), this would translate to 380,954 violent crimes by Hispanic whites in 2008, most of which would come from the existing white totals, but many of which would also have been located in the "don't know/not available" category, as with certain white and black crimes (noted above). In all, because Hispanic victimization rates (Table 7) are similar to the overall white victimization rates (seen in Table 5), and because the recent research suggests Hispanic offending rates are also comparable to non-Hispanic white rates (when it comes to violent crime), doing a full methodological extraction of Hispanics from the white totals (both for victims and perps) would result in roughly proportional reductions in the white column for both. The effect on interracial crime figures would be that, a) the numbers of W-B violent crimes would drop (since some of those whites would have been Latino), and b) the number of B-W crimes would also drop (since some of those whites would also have been Latino). If anything, we would expect the effect on white "victims" of interracial crime to be larger than the effect on white perps. Since the black offending rate is disproportionate (roughly 2.5 times the white offending rate), it would stand to reason that there would be more blacks offending against Latinos, proportionately, than the opposite, and for the same reasons as discussed above, in terms of the effects of encounter rates and general offending rates. So while there would be fewer "real" white-on-black crimes too, the reduction in the number of "real" white victims would likely be greater, thereby further reducing the actual interracial crime gap between B-W and W-B crime. In other words, if the data were truly available (and they are not) to estimate the Hispanic/non-Hispanic ethnicity of whites who victimize or are victimized by blacks, and we were to perform the extractions necessary to leave only "real" whites in both categories, the effect would be to make Williams's argument (and that of the white nationalists from whom he initially got this line of attack) even weaker
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Showing Collections: 1 - 3 of 3
Major League Baseball American League (AL) Team Media Guides Collection
Identifier: BAS 540
Scope and Contents
This collection contains media guides published by Major League Baseball teams in the American League. The annual guides published prior to each MLB season generally included a review of the previous season (including statistics), a preview of the upcoming season (including schedules and opponent information), and photographs and bios of players, coaches, and staff. Other content sometimes included broader material about the history of the franchise, information about the city, and other...
Major League Baseball American League (AL) Team Programs and Scorecards Collection
Identifier: BAS 610
Scope and Contents
This collection contains more than 1,200 programs and scorecards published by Major League Baseball teams in the American League. Teams published programs and scorecards for purchase by fans attending the games. The programs and scorecards usually contain at a minimum roster and lineup information and space for attendees to keep score of the game. The programs tend to become larger, longer, and more substantial over the years and sometimes contain additional information about the teams,...
Major League Baseball American League (AL) Team Yearbooks Collection
Identifier: BAS 570
Scope and Contents
This collection consists of Major League Baseball annual team yearbooks published by American League clubs. Aimed at fans, yearbooks typically contained information and articles about players, managers, and coaches, as well as statistics and schedules. Most yearbooks also featured numerous photographs of players and personnel and other team-related images. Some yearbooks contained advertisements. Materials include annual team yearbooks.


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Mission Bay Real Estate
Mission Bay is a neighborhood in progress. Once an industrial wasteland of rail yards and loading docks, Mission Bay is evolving into one of San Francisco's hippest luxury neighborhoods. Located on the edge of the San Francisco Bay between South Beachand the Central Waterfront / Dogpatch neighborhoods, Mission Bay is now home to the UCSF Mission Bay research campus, a variety of biotech industries, and some very fashionable condominium and loft developments. Future plans for the community include a state of the art UCSF hospital, public open spaces, and 500,000 sq. feet of retail space.
As redevelopment of Mission Bay continues, more and more restaurants, shops, and clubs call the neighborhood home. Nearby SOMA and South Beach also boast great dining and a lively nightlife, while groceries and every day goods and services are available in neighboring Potrero Hill. Mission Bay is connected to the rest of the city (and the state) by a good public transit system that includes the MUNI, bus lines, and CalTrain.
Trendy new condo and loft developments define residential real estate in Mission Bay. As part of a master design, a percentage of new homes have been designated as affordable units, although many of the condominiums and lofts in Mission Bay are regarded as high-end luxury developments, including One Berry Street – which was mentioned in the Forbes.com list of "Ten Hot Luxury Lofts" in the U.S.
Homes & Condos for sale in the Mission Bay, San Francisco
Mission Bay Neighborhood Real Estate
Most of the homes for sale in Mission Bay are fashionable condominiums and lofts in stylish new buildings. Sophisticated and modern, many boast the finest in amenities and some feature spectacular views.
Contact us if you want to get in on the real estate action in an emerging San Francisco neighborhood, keep your eye on the real estate market in Mission Bay.


text: This past weekend Kenny Chesney went back to college! The country superstar returned to East Tennessee State University to honor the man who taught him how to play guitar in college, Dr. Jack Tottle. Dr. Tottle founded the Bluegrass, Old-Time and Roots Music Studies Program, which is internationally acclaimed and has graduated GRAMMY, International Bluegrass…… MORE


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Residential Roofing Services
Let's be honest about it, you wouldn't have your garden landscaped by a team that didn't have good reviews, nor would you invest in a carpentry service by a carpenter with a poor reputation. With that in mind, it stands to reason that you shouldn't waste your time with an inferior roofing team. Having catered to the residential roofing needs of homes of all shapes and sizes since first starting our business, it is fair to say that we know a thing or two about delivering a top-quality roofing service that you can rely on. Don't take chances with inferior roofing teams when the number one specialists are here and available for you to use. Call our office today to schedule an appointment with one of our roofing specialists or to learn more about the service that we offer. Trust us, you won't regret it.
Three Reasons Why You Need a Professional Roofer
Whether you are an experienced DIY enthusiast or not, you may think that you are capable of repairing the roof of your home. However, the reality of the situation is that unless you have significant experience in the roofing repair or installation business, this really isn't an option you should think about pursuing. Apart from the skill and expertise that goes into performing all the required tasks of roof repair correctly, the other important point to note is that there is zero room for error when it comes to your roof. While fixing your patio may be a job that you can work on and learn from your mistakes, that luxury simply doesn't exists when it comes to your home's roof. As well as this, three other reasons why you should leave your roofing work to the professionals are as follows:
More Cost-Effective
The simple fact of the matter is that a professional roofing contractor will be able to obtain the necessary materials at a discounted rate. On top of that, they will also have all the tools needed to get the job done in a quick and effective fashion. By contrast, the DIY approach may require a number of the essential tools needing to be bought. Increasing the costs before any work even starts.
Better Quality Materials
The reality is that professionals are experienced at buying the materials needed to complete a roofing repair job effectively. They know what materials work best for different types of roofs and can also know where to find the materials quickly and cost-effectively.
They Know When a Roof is Repairable and When it is Not
One of the biggest issues that many DIY enthusiasts encounter is determining when a roof can be repaired and when it will have to be replaced. Professional roofers are able to identify the differences saving you time and money.
Here to Help
At TDS 5 Home Improvement our clients are our first priority, and no matter how big or small your repair job is, we're up for it.
If you want a tried and trusted residential roofing team then TDS 5 Home Improvement should be the first and only number you call.