Tag Archives: QOS

Enhanced Routing and QOS Models using Software Defined Networking

Quality of service implementations that utilize Integrated Services (IntServ) provides end-to-end service guarantees to IP traffic traversing campus networks. IntServ allows applications to signal their QOS requirements to the network while providing strong guarantees to individual traffic flows from sender to receiver,however IntServ quality of service architectures require all routers to implement a reservation protocol and maintain state information for all flows.

Computation of routes and the maintenance of states requires copious amounts of RAM and Processing power in order to scale to support large route and flow tables. Routers and switches built on merchant Asic are typically equipped with a limited  amounts of ram and processing power when compared to the typical X86 computer. The price of multi-core CPUs and DDR memory modules are at an all time low and this reality should allow the development of  a x86 based SDN controller that will be able to incrementally store router flow and link states.


SNMP or NETFLOW could be used to measure various constraints such as bandwidth,latency and delay. The values measured could be used to perform constrained shortest path route calculations for each node and also to modify route or congestion management characteristics on a per interface basis. 


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Posted by on August 7, 2013 in Uncategorized


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Open Source Unified Communications

Unified Communications or UC is ruled by the Cisco,Microsoft and Avaya. All three companies are developers of great UC software suites but come in at prices that may be out of range  for small and medium sized companies. Now i am huge proponent of cutting costs when possible and as such my advice to small companies is to evaluate Open Source UC tools when looking for a new solution to replace your PBX systems.

The state of affairs in the Open Unified Communications market is as follows. The most popular Open Source UC package would be asterisk but it also a little harder to manage than alternative packages. For a small shop with less than 100 phones my recommendation would be Fonality’s Trixbox. Trixbox has a commercial and community edition which is backed by a large user base. Trixbox’s major drawback is its inability to scale for large installs but this is not an issue for a small company.

The best Open Source UC package for Small and Medium size companies is sipXecs. SIPX is totally sip based and was built to scale up to 1000 users. Unlike asterisks which switches voice streams and was built to sit between endpoints, SIPX functions as a sip proxy and does not require endpoints to pass voice data through the SIPX server, it is this fact that allows SIPX to scale better than asterisks.While not as extensible as asterisks SIPX represents a great option for medium sized companies looking to jump into the UC world and at this moments represents the top of the open source UC pile.


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Posted by on November 17, 2012 in Uncategorized


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