In a recent post on the AudioCodes corporate blog, I discussed the need for businesses to remain on-line at all times. The ability to continue service should the connection to the service provider or on premise equipment go down – High Availability - is a critical one for all businesses, large and small alike. The blog discussed the various elements of High Availability, including survivability, resiliency and redundancy and the importance AudioCodes attaches to providing these capabilities in its Session Border Controllers (SBC), especially redundancy, across the range of sessions, from tens to thousands. Click here to read more.
SBC HA in the Lync Environment for SIP Trunk Connectivity
SBC HA redundancy, can function in both Active/Standby and Active/Active modes. Under normal operations in the Active/Standby mode, a continuous synchronization takes place between the active and standby SBC. Signaling, media and configuration are checkpointed between the two SBCs, ensuring that there is no loss of service of active sessions should the active SBC fail. In that continuous synch, registration for analog devices in the Lync environment is also supported. The standby SBC continuously checks for a Heartbeat failure of the active SBC, and should the active SBC fail, full control is transferred to the standby SBC. As both SBCs use the same virtual IP address, the standby SBC executes an IP Takeover, and the transfer is seamless to the outside, as traffic will now flow to the standby SBC using the same IP address.
In the Active/Active mode, during normal operations the two SBCs share the traffic load to maximize efficiency. However, in case one of the SBCs fails, the other takes over, according to the process described above.
Beyond providing redundancy between two SBCs, the High Availability functionality can also support load balancing of multiple mediation servers operating in a Lync environment, ensuring that Lync capabilities (Drop and Insert, Active Directory, Call Forking, etc.) continue to function should one or more of the mediation servers fail.
Supporting Few to Thousands of Sessions
AudioCodes SBC HA redundancy support of a few sessions to thousands of sessions, is also true in the Lync environment. Redundancy for many vendors, however, seems to be reserved for only the larger carrier and enterprise networks. To handle requirements for High Availability redundancy for small to medium businesses some SBC vendors offer their customers over-sized carrier-class SBCs. This mismatch forces customers to deploy SBCs which don’t fit neatly into the enterprise environment, as they are more expensive, have unnecessary features on the one hand and may be missing other features necessary for this environment on the other.
We call this “Going duck hunting with a Howitzer” – overly complex and in the end, not very effective).
At AudioCodes, we have witnessed a sharp increase in demand for High Availability Redundancy in small to medium businesses. Perhaps these businesses have reached the conclusion that even in these smaller business environments they simply can’t take the risk that something will take down their network. AudioCodes has moved to satisfy this demand from the smaller businesses by installing High Availability redundancy in the Company’s Mediant 500 and 800 SBCs in addition to the higher-session SBCs.
(BTW: no ducks were harmed in the writing of this article)