SRST fallback to CallManager bandwidth requirements to rehome

[damion.littlewood]

Hi, does anybody have an idea of how much WAN bandwidth would be generated by 100 IP Phones when they rehome to a central Call Manager after being on SRST?

I have a requirement to install sites with between 100 and 700 phones and it would be good to know if my network will get flooded.

Thanks.

[ebreniz]

The number of IP phones and line appearances supported in Survivable Remote Site Telephony (SRST) mode at each remote site depends on the branch router platform, the amount of memory installed, and the Cisco IOS release. (For the latest SRST platform and code specifications, refer to the SRST documentation at Cisco.com.) Generally speaking, however, the choice of whether to adopt a centralized call processing or distributed call processing approach for a given site depends on a number of factors such as

IP WAN bandwidth or delay limitations

Criticality of the voice network

Feature set needs

Scalability

Ease of management

Cost

If a distributed call processing model is deemed more suitable for the customer's business needs, the choices include installing a local Cisco CallManager server or running Cisco CallManager Express on the branch router.

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_implementation_design_guide_chapter09186a0080447510.html