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New Member

Understanding bandwidth requirements

Hey,

So I'm looking to get some more information on bandwidth requirements for primary and secondary subscriber sites for a potential global deployment. Is there a guide somewhere that shows you what bandwidth per phone (for example) is required?

thanks.

4 REPLIES

Re: Understanding bandwidth requirements

When you cluster over wan there is a 40ms RTT requirement between the callmanagers. You can read more here.

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_implementation_design_guide_chapter09186a00806e8c27.html#wp1045846

HTH

Sankar.

New Member

Re: Understanding bandwidth requirements

Yes I was aware of the 40ms RTT - looking more for bandwidth requirements, or an approved method for working this.

Thanks for the link - good information in there.

Re: Understanding bandwidth requirements

Nigel,

Here you go. Check out the SRND for more info, linked below (which I believe Sankar already linked).

?Every 10,000 busy hour call attempts (BHCA) between sites that are clustered over the WAN requires 900 kbps of bandwidth for Intra-Cluster Communication Signaling (ICCS). This is a minimum bandwidth requirement, and bandwidth is allocated in multiples of 900 kbps. The ICCS traffic types are classified as either priority or best-effort. Priority ICCS traffic is marked with IP Precedence 3 (DSCP 24 or PHB CS3). Best-effort ICCS traffic is marked with IP Precedence 0 (DSCP 0 or PHB BE).

?The minimum recommended bandwidth between sites that are clustered over the WAN is 1.544 Mbps. This amount allows for the minimum of 900 kbps for ICCS and 644 kbps for database and other inter-server traffic.

?A maximum round-trip time (RTT) of 40 ms is allowed between any two servers in the Cisco Unified CallManager cluster. This time equates to a 20 ms maximum one-way delay, or a transmission distance of approximately 1860 miles (3000 km) under ideal conditions.

CCM 4.x SRND

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_implementation_design_guide_book09186a00806e8a79.html

Please rate any helpful posts

Thanks

Fred

Bronze

Re: Understanding bandwidth requirements

If you're looking for bandwidth per call, the general chart I use is:

G.711 - 80 kbps for Frame Relay, 100 kbps for VPN

G.729 - 26.4 kbps for Frame Relay, 44.4 kbps for VPN

More details on that formula here:

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

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