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Tag Archives: F5 Load Balancer

Load Balancer Provider in India

Load Balancer Provider in India

Load Balancer Provider in India

Load Balancer Provider in India

IT Monteur Provides Load Balancer, Load balancers, Load balancing, Server Load Balancer, Server Load Balancing Solutions, Array Load balancer, F5 Load Balancer, A10 Load Balancer, Load Balancing, Load Balancer, Delhi, New Delhi, Noida, Gurgaon, India





Internet-based services


Round-robin DNS

An alternate method of load balancing, which does not require a dedicated software or hardware node, is called round robin DNS. In this technique, multiple IP addresses are associated with a single domain name; clients are given IP in round robin fashion. IP is assigned to clients with a short expiration so the client is more likely to use a different IP the next time they access the Internet service being requested.

DNS delegation

Another more effective technique for load-balancing using DNS is to delegate as a sub-domain whose zone is served by each of the same servers that are serving the web site. This technique works particularly well where individual servers are spread geographically on the Internet. For example: A A NS NS

However, the zone file for on each server is different such that each server resolves its own IP Address as the A-record.[2] On server one the zone file for reports:

@ in a

On server two the same zone file contains:

@ in a


Client-side random load balancing

Another approach to load balancing is to deliver a list of server IPs to the client, and then to have client randomly select the IP from the list on each connection. This essentially relies on all clients generating similar loads, and the Law of Large Numbers[4] to achieve a reasonably flat load distribution across servers. It has been claimed that client-side random load balancing tends to provide better load distribution than round-robin DNS; this has been attributed to caching issues with round-robin DNS, that in case of large DNS caching servers, tend to skew the distribution for round-robin DNS, while client-side random selection remains unaffected regardless of DNS caching.

With this approach, the method of delivery of list of IPs to the client can vary, and may be implemented as a DNS list (delivered to all the clients without any round-robin), or via hardcoding it to the list. If a “smart client” is used, detecting that randomly selected server is down and connecting randomly again, it also provides fault tolerance.
Server-side load balancers

For Internet services, a server-side load balancer is usually a software program that is listening on the port where external clients connect to access services. The load balancer forwards requests to one of the “backend” servers, which usually replies to the load balancer. This allows the load balancer to reply to the client without the client ever knowing about the internal separation of functions. It also prevents clients from contacting back-end servers directly, which may have security benefits by hiding the structure of the internal network and preventing attacks on the kernel’s network stack or unrelated services running on other ports.


Scheduling algorithms

Numerous scheduling algorithms, also called load-balancing methods, are used by load balancers to determine which back-end server to send a request to. Simple algorithms include random choice, round robin, or least connections.[6] More sophisticated load balancers may take additional factors into account, such as a server’s reported load, least response times, up/down status (determined by a monitoring poll of some kind), number of active connections, geographic location, capabilities, or how much traffic it has recently been assigned.

An important issue when operating a load-balanced service is how to handle information that must be kept across the multiple requests in a user’s session. If this information is stored locally on one backend server, then subsequent requests going to different backend servers would not be able to find it. This might be cached information that can be recomputed, in which case load-balancing a request to a different backend server just introduces a performance issue.[6]

Ideally the cluster of servers behind the load balancer should not be session-aware, so that if a client connects to any backend server at any time the user experience is unaffected. This is usually achieved with a shared database or an in-memory session database, for example Memcached.






Load balancer features


Asymmetric load

Priority activation

TLS Offload and Acceleration

TLS (or its predecessor SSL) acceleration is a technique of offloading cryptographic protocol calculations onto a specialized hardware. Depending on the workload, processing the encryption and authentication requirements of an TLS request can become a major part of the demand on the Web Server’s CPU; as the demand increases, users will see slower response times, as the TLS overhead is distributed among Web servers. To remove this demand on Web servers, a balancer can terminate TLS connections, passing HTTPS requests as HTTP requests to the Web servers. If the balancer itself is not overloaded, this does not noticeably degrade the performance perceived by end users. The downside of this approach is that all of the TLS processing is concentrated on a single device (the balancer) which can become a new bottleneck. Some load balancer appliances include specialized hardware to process TLS. Instead of upgrading the load balancer, which is quite expensive dedicated hardware, it may be cheaper to forgo TLS offload and add a few Web servers. Also, some server vendors such as Oracle/Sun now incorporate cryptographic acceleration hardware into their CPUs such as the T2000. F5 Networks incorporates a dedicated TLS acceleration hardware card in their local traffic manager (LTM) which is used for encrypting and decrypting TLS traffic. One clear benefit to TLS offloading in the balancer is that it enables it to do balancing or content switching based on data in the HTTPS request.

Distributed Denial of Service (DDoS) attack protection

Load balancers can provide features such as SYN cookies and delayed-binding (the back-end servers don’t see the client until it finishes its TCP handshake) to mitigate SYN flood attacks and generally offload work from the servers to a more efficient platform.

HTTP compression

HTTP compression reduces the amount of data to be transferred for HTTP objects by utilising gzip compression available in all modern web browsers. The larger the response and the further away the client is, the more this feature can improve response times. The trade-off is that this feature puts additional CPU demand on the load balancer and could be done by web servers instead.

TCP offload

Different vendors use different terms for this, but the idea is that normally each HTTP request from each client is a different TCP connection. This feature utilises HTTP/1.1 to consolidate multiple HTTP requests from multiple clients into a single TCP socket to the back-end servers.

TCP buffering


Direct Server Return

An option for asymmetrical load distribution, where request and reply have different network paths.

Health checking

The balancer polls servers for application layer health and removes failed servers from the pool.

HTTP caching

The balancer stores static content so that some requests can be handled without contacting the servers.

Content filtering

Some balancers can arbitrarily modify traffic on the way through.

HTTP security


Priority queuing

Also known as rate shaping, the ability to give different priority to different traffic.

Content-aware switching


Client authentication

Authenticate users against a variety of authentication sources before allowing them access to a website.

Programmatic traffic manipulation



Firewalls can prevent direct connections to backend servers, for network security reasons.

Intrusion prevention system

Intrusion prevention systems offer application layer security in addition to network/transport layer offered by firewall security.

Use in telecommunications



Shortest Path Bridging

The IEEE approved the IEEE 802.1aq standard May 2012, also known and documented in most books as Shortest Path Bridging (SPB). SPB allows all links to be active through multiple equal cost paths, provides faster convergence times to reduce down time, and simplifies the use of load balancing in mesh network topologies (partially connected and/or fully connected) by allowing traffic to load share across all paths of a network.[8][9] SPB is designed to virtually eliminate human error during configuration and preserves the plug-and-play nature that established Ethernet as the de facto protocol at Layer 2.




Use in data center networks

Load balancing is widely used in data center networks to distribute traffic across many existing paths between any two servers.[12] It allows more efficient use of network bandwidth and reduces provisioning costs. In general, load balancing in datacenter networks can be classified as either static or dynamic. Static load balancing distributes traffic by computing a hash of the source and destination addresses and port numbers of traffic flows and using it to determine how flows are assigned to one of the existing paths. Dynamic load balancing assigns traffic flows to paths by monitoring bandwidth utilization of different paths. Dynamic assignment can also be proactive or reactive. In the former case, the assignment is fixed once made, while in the latter the network logic keeps monitoring available paths and shifts flows across them as network utilization changes (with arrival of new flows or completion of existing ones). A comprehensive overview of load balancing in datacenter networks has been made available.

Relationship to fail overs


Top Load Balancer Provider Company in India

Load balancing refers to spreading a service load among multiple server systems. A hardware load balancer or software-based load balancing tool can ensure maximum service availability by offering network traffic distribution services.

For example, if your business has a primary business domain (e.g.,, you want your site available to your current customers and your potential customers 100 percent of the time. Comparing the top server load balancers (SLBs) and effectively utilizing their load-balancing capabilities will help provide this level of availability.

When technical folks discuss load balancing, they generally mean hardware load balancer devices dedicated to the task of balancing network traffic loads. A hardware load balancer is a server computer with a very specialized operating system tuned to manage network traffic using user-created rules.

From Load Balancers to Application Delivery Controllers

While these hardware load balancer devices have since evolved into what are now called application delivery controllers (ADC), load balancing remains at the heart of an ADC. Enterprises and hosting companies rely on load-balancing and ADC devices to distribute traffic to create highly available services.

In addition to providing simple distributed service to multiple servers, load balancers can help prevent denial-of-service attacks, allow legitimate users uninterrupted access to services, protect against single point of failure outages and prevent traffic bottlenecks to systems.

Today we’ll highlight a handful of the leading hardware load balancers as well as several cloud and software-based load balancer options.

Application Delivery Network Load Balancing Services Provider in India

Commercial ADNs

A10 Networks
Avi Networks
Akamai Technologies
Alcatel-Lucent (Enterprise)
Array Networks
Barracuda Networks
Blue Coat Systems
Brocade Communications
Cisco Systems
Crescendo Networks
EdgeCast Networks
Expand Networks
F5 Networks
Foundry Networks
Instart Logic
Ipanema Technologies
Juniper Networks
KEMP Technologies
Limelight Networks
Riverbed Technology
Sun Microsystems
Zeus Technology



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