Simultaneous calls via SIP on a UC560?

Audy Bautista · ‎04-28-2010

On the UC560, is there a limitation to the number of simultaneous calls I can have with my SIP provider? Thanks.

Steven DiStefano · ‎04-28-2010

Usually bandwidth constrained. Knowing the symetrical SLA the SIP trunk SP guarantees to the demarcation router at the UC500 site will usually dictate how many you want to allow, minus some reservation for data perhaps, using CAC (configured with CCA).

Audy Bautista · ‎04-28-2010

The SIP provider is coming in as a T1 which will be the client's backup circuit for Internet as well. So knowing that it's a T1, how can I calculate?

Audy Bautista

audy@rfa.com

Cell: 646-210-0935

Direct: 212-659-4833

Steven DiStefano · ‎04-28-2010

G711 Preferred? Figure approx 87kbps bi directional per call (64kbps + Ethernet overhead + L3 IP overhead)

G729 negotiation? COmpression lends more bandwidth for calls as it only needs about 32kbps per call...

http://www.cisco.com/en/US/tech/tk652/tk698/technologies_tech_note09186a0080094ae2.shtml

Leaving some bandwidth for data only is a good idea, so you can set CAC in CCA to a max number of calls to 'reserve some for data'. Not to be confused with QOS which will always give priority to voice signaling and media over data. What you want to protect is the ability for some data to get through too :-)

Steve