05-20-2010 02:12 PM - edited 03-15-2019 10:51 PM
CallManager 7.1(3)
1 Pub, 1 Sub @ Corporate, 200 phones
1 Sub @ Remote Site A across WAN full T1, 50 phones
1 Sub @ Remote Site B across WAN full T1, 50 phones
How much bandwidth is used between Pubs and Subs for the Informix database synchronization (ICCS)?
Thought I saw a formula in SRND but can’t find it. I seem to recall 900K and 80ms RTT as a minimum bandwidth from somewhere.
Surely number of phones and calls per hour factor into it, or is there even a formula?
05-20-2010 02:35 PM
The info is under the deployment models chapter from SRND
A minimum of 1.544 Mbps (T1) bandwidth is required for Intra-Cluster Communication Signaling (ICCS) for 10,000 busy hour call attempts (BHCA) between sites that are clustered over the WAN. This is a minimum bandwidth requirement for call control traffic, and it applies to deployments where directory numbers are not shared between sites that are clustered over the WAN. The following equation may be used as a guideline to calculate the bandwidth for more than 10,000 BHCA between non-shared directory numbers at a specific delay:
Total Bandwidth (Mbps) = (Total BHCA/10,000) * (1 + 0.006 * Delay), where Delay = RTT delay in msec
This call control traffic is classified as priority traffic. Priority ICCS traffic is marked with IP Precedence 3 (DSCP 24 or PHB CS3).
In addition to the bandwidth required for Intra-Cluster Communication Signaling (ICCS) traffic, a minimum of 1.544 Mbps (T1) bandwidth is required for database and other inter-server traffic for every subscriber server remote to the publisher.
http://www.cisco.com/en/US/docs/voice_ip_comm/cucm/srnd/7x/models.html#wp1043996
And just for clarification
Pre 6.1 releases it was 900 kbps and 40 ms RTT.
6.1 and above 1 T1 and 80 ms RTT
HTH
java
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