Avaya 555-245-600 manual Resource sizing

Resource sizing

Table 45: IP WAN bandwidth requirements in each direction, for Example 8: WAN bandwidth

Requirement	Between	Between	Between
	sites 1 and 2	sites 1 and 3	sites 2 and 3
Simultaneous media streams for “P001”	39	20	10
LAN bandwidth (kbps)	484	248	124

In Table 45, the number of simultaneous media streams for “P001” represents the 99.9th percentile for the number of simultaneous streams, as determined by applying the standard infinite-server queueing model.

To this point, all the discussion regarding bandwidth relates only to bearer traffic (media streams). Network packet traffic that is related to signaling is very different from the bearer traffic because it tends to occur in bursts. For example, while the bearer traffic that is associated with a particular call tends to involve a constant, steady stream of packets throughout the duration of that call, the signaling traffic for that same call tends to occur in bursts during call setup and teardown.

The bandwidth that is required for signaling is generally negligible in comparison to the bandwidth that is required for bearer traffic. However, since Avaya products use Separation of Bearer and Signaling (SBS), the bearer traffic and signaling traffic use distinct paths. Therefore, signaling bandwidth must be given its due consideration, despite the fact that it is negligible in comparison to bearer bandwidth.

Signaling traffic is more prone to bursts than bearer traffic because the former consists of messages that are associated with call set-ups and tear-downs, as opposed to traffic that is uniformly distributed throughout entire call durations. However, the “burst” effect is somewhat assuaged for larger call volumes. Although the precise bandwidth requirement for a given configuration depends on the nature of the endpoints involved, a reasonable approach is to allocate an overhead of 50 bits per second (bps) for each IP endpoint in the network, as well as the following (as applicable) for every 1000 calls:

●11 kbps for messaging between the S8700-series Server and an IPSI circuit pack on a G650 Media Gateway

●8 kbps for the H.248 link between a C-LAN circuit pack and a G700 or G350 Media Gateway

Note:

The 11 kbps and 8 kbps associated with 1000 calls should not be amortized to produce estimates for systems with very light traffic. For example, 11 bits per second and 8 bits per second will not support an individual call.

Issue 6 January 2008 223