Cisco Unified Contact Center Enterprise Solution Reference ...

Bandwidth Provisioning
11-18
Cisco Unified Contact Center Enterprise 7.x SRND
Chapter 11 Bandwidth Provisioning and QoS Considerations
Unified IP IVR or Unified CVP PG to Unified IP IVR or Unified CVP
At this time, no tool exists that specifically addresses communication between the Unified IP IVR or
Unified CVP PG and the Unified IP IVR or Unified CVP. However, the tool mentioned in the previous
section produces a fairly accurate measurement of bandwidth needed for this communication.
Bandwidth consumed between the Unified ICM Central Controller and Unified IP IVR or Unified CVP
PG is very similar to the bandwidth consumed between the Unified IP IVR or Unified CVP PG and the
Unified IP IVR or Unified CVP.
The tool is available to Cisco partners and Cisco employees at
http://www.cisco.com/partner/WWChannels/technologies/resources/IPCC_resources.html
If the Unified IP IVR or Unified CVP PGs are split across the WAN, total bandwidth required would be
double what the tool reports: once for Unified ICM Central Controller to Unified IP IVR or Unified CVP
PG and once for Unified IP IVR or Unified CVP PG to Unified IP IVR or Unified CVP.
CTI Server to CTI OS
The worst case for bandwidth utilization across the WAN link between the CTI OS and CTI Server
occurs when the CTI OS is remote from the CTI Server. A bandwidth queue should be used to guarantee
availability for this worst case.
For this model, the following simple formula can be used to compute worst-case bandwidth
requirements:
With no Extended Call Context (ECC) or Call Variables:
BHCA ∗ 20 = bps
With ECC and/or Call Variables
BHCA ∗ (20 + ((Number of Variables ∗ Average Variable Length) / 40) = bps
Example: With 10,000 BHCA and 20 ECC variables with average length of 40 bits:
10,000 ∗ (20 + ((20 ∗ 40) / 40) = 10,000 ∗ 40 = 400,000 bps = 400 kbps
Cisco Unified CallManager Intra-Cluster Communications (ICC)
The Cisco Unified Communications Solution Reference Network Design (SRND) guide states that
900 kbps must be reserved for every 10,000 BHCA. This amount is significantly higher with Unified
CCE due to the number of call redirects and additional CTI/JTAPI communications encompassed in the
intra-cluster communications.
The bandwidth that must be reserved is approximately 2,000 kbps (2 Mbps) per 10,000 BHCA. This
requirement assumes proper design and deployment based on the recommendations in this Unified CCE
design guide. Inefficient design (such as “ingress calls to Site 1 are treated in Site 2”) will cause
additional intra-cluster communications, possibly exceeding the defined requirements.
More specifically, you can use the following formula to calculate the required bandwidth:
Link Size BHCA ∗ 200 = bps
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