Solved: About delay limits for IP Phones running SCCP.

rodmont74 · ‎10-29-2007

Hi, my company is planning deploying 3 CUCM clusters in South America for 10 countries. Cluster in Argentina will support andian countries and Colombia has average 200ms round-trip time back and forth Argentina. There is no QoS tools yet provided in network, they all should be applied before deployment but I don't think we can reduce propagation time since Colombia is linked Miami before data is resent to Argentina.

I would like to know if SCCP would suffer from that time (about 100ms end-to-end delay current measured). I couldn't research all Cisco docs about that but my peers don't think it's a big deal since US reports they run a cluster for India which longer times. Of course SRST would be reset to those longer times if it's needed. Something else will research later...

Thanks a lot.

paolo bevilacqua · ‎10-29-2007

Hi,

SCCP works fine even with much higher delays than you mentioned.

You should rather look into CCM 6.0 and the latest model phones (7942, etc), as these implement iLBC that can dramatically reduce you bandwidth and enhance voice quality when used over the Internet.

Remember, of the traditional ITU codecs, none was designed for packet networks and possivle packet loss.

Hope this helps, please rate post if it does!

View solution in original post

paolo bevilacqua · ‎10-29-2007

Hi,

SCCP works fine even with much higher delays than you mentioned.

You should rather look into CCM 6.0 and the latest model phones (7942, etc), as these implement iLBC that can dramatically reduce you bandwidth and enhance voice quality when used over the Internet.

Remember, of the traditional ITU codecs, none was designed for packet networks and possivle packet loss.

Hope this helps, please rate post if it does!

rodmont74 · ‎10-30-2007

Thank you very much for the information. Also I will research into iLBC (which I am no aware of yet) and 7942G phones. For South America Cisco and its resellers recommend yet 4.2 or 4.3 as there is not enough trainned people on 6.x. That's OK unless we need a new feature very much. Most of our shops will go on IP Communicator as 70 to 80% people are mobile consultants.

Regards.