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How much bandwidth is used between Pubs and Subs for the database synchronization (ICCS)?

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?

Cisco Employee

Re: How much bandwidth is used between Pubs and Subs for the dat

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.

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



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