Tags network-engineering

SIP and Fragments: Together Forever?

IP Fragmentation of SIP Messages is an enduring source of trouble. Fragmentation of SIP traffic is a problem on the rise. It appears when everything has been working fine, and seemingly without cause,  some SIP messages are lost in the network. The result is a frustrating scenario where some SIP messages are delivered fine, but others are not. To explain SIP fragmentation, let's start at the be...


Polycom and Adtran AOS Geo-Redundancy Support

Background The Polycom SoundPoint IP SIP Phones and Adtran IADs are used for Hosted IP PBX Access Devices, managed by the BroadWorks platform. In a non-geographically-redundancy network, the devices use SIP to register to a single SIP SBC IP address. To support geographic redundancy of SBCs, the devices must support registration to multiple IP addresses. It must select the proper IP address in...


Net Neutrality: Nobody Wants an ISP To Mangle Their Data

"Network Neutrality" advocates teach us that banning certain Active Queue Management (AQM) algorithms will result in greater freedom on the Internet. For example: Barack Obama wants to ban "Paid Prioritization," which Cisco calls "Low Latency Queueing". Even folks interested in computers, but who don't build or run networks, seem to have some downright strange opinions. For example, when Net...