Avaya 555-245-600 manual IP bandwidth and Call Admission Control

Traffic engineering

Communication Manager and SES server processor occupancy

SIP incurs Communication Manager server processing time (as discussed in a previous section), just like any other type of Communication Manager call. Special care should go into accounting for the SIP features present in an average call. Calls involving notifications because of bridging or subscriptions can be significantly more CPU intensive than simple calls.

Since SES is an integral part of all SIP calls, its CPU resource requires proper accounting just like Communication Manager servers. Additionally, SES is more than just a SIP proxy, routing a SIP message, it is an all-in-one solution housing multiple additional servers and functions defined in the SIP standard: presence, event, personal profile, etc. Therefore, the SES is much more involved than the Communication Manager server in the processing of SIP messages, especially those outside of traditional call setup and teardown. A comprehensive traffic model for SES must account for both call and non-call related traffic load.

IP bandwidth and Call Admission Control

IP bandwidth analysis for media streams begins with determining the number of bidirectional media streams that are associated with each type of call supported by the system. Throughout this discussion, calls between two IP stations are assumed to use shuffling. That being the case, Figure 66: Connectivity modes between two IP endpoints on page 202 indicates that an intrasite call between two IP endpoints requires a single bidirectional media stream through the LAN at that site. Figure 65: Examples of media streams between Avaya endpoints on page 200 indicates that each intrasite call between an IP endpoint and a circuit-switched endpoint (including PSTN trunks) also requires a single bidirectional media stream through the LAN at that site. In addition, Figure 65: Examples of media streams between Avaya endpoints on page 200 indicates that each interport network intrasite call between two circuit-switched endpoints (including PSTN trunks) also requires a single bidirectional media stream through the LAN at that site (assuming that IP-PNC is used, as opposed to a circuit-switched center stage). In fact, the only intrasite call that does not require a single bidirectional media stream through the LAN at that site is an intraport network call between two circuit-switched endpoints which requires no IP resources because the call is completed solely across the circuit-switched TDM bus of the PN. Each intersite call requires exactly one bidirectional media stream through each participating site’s LAN, as well as a single bidirectional media stream through the WAN that connects the two sites.

The preceding discussion is summarized in Figure 70: Required number of bidirectional IP

media streams for intra-site calls on page 217 and Figure 71: Required number of bidirectional IP media streams for inter-site calls on page 217.

Figure 70 and Figure 71 provide information about the required number of bidirectional media streams per call. This information can be combined with call usage information to provide IP bandwidth usage estimates, as shown in Example 6: IP bandwidth considerations.

216 Avaya Application Solutions IP Telephony Deployment Guide