Cisco Cisco Unified Contact Center Enterprise 9.0(2) Leaflet

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Cisco Unified Contact Center Enterprise 7.5 SRND
Chapter 12      Bandwidth Provisioning and QoS Considerations
Bandwidth and Latency Requirements
In summary, traffic flows from PG to Central Controller can be classified into the following distinct 
flows:
High-priority traffic — Includes routing and Device Management Protocol (DMP) control traffic. It 
is sent in TCP with the public high-priority IP address.
Heartbeat traffic — UDP messages with the public high-priority IP address and in the port range of 
39500 to 39999. Heartbeats are transmitted at 400-ms intervals bidirectionally between the PG and 
the Central Controller. In Unified ICM Release 7.x, the UDP heartbeat is replaced with TCP 
keep-alive if QoS is enabled on the public network interface through the Unified ICM setup.
Medium-priority traffic — Includes real-time traffic and configuration requests from the PG to the 
Central Controller. The medium-priority traffic is sent in TCP with the public high-priority IP 
address.
Low-priority traffic — Includes historical data traffic, configuration traffic from the Central 
Controller, and call close notifications. The low-priority traffic is sent in TCP with the public 
non-high-priority IP address.
Administrative Workstations (AWs) are typically deployed at ACD sites, and they share the physical 
WAN/LAN circuits that the PGs use. When this is the case, network activity for the AW must be factored 
into the network bandwidth calculations. This document does not address bandwidth sizing for AW 
traffic.
Private Network Traffic Flow
Traffic destined for the critical Message Delivery Service (MDS) client (Router or OPC) is copied to the 
other side over the private link.
The private traffic can be summarized as follows:
High-priority traffic — Includes routing, MDS control traffic, and other traffic from MDS client 
processes such as the PIM CTI Server, Logger, and so forth. It is sent in TCP with the private 
high-priority IP address. 
Heartbeat traffic — UDP messages with the private high-priority IP address and in the port range of 
39500 to 39999. Heartbeats are transmitted at 100-ms intervals bidirectionally between the duplexed 
sides. In Unified ICM Release 7.x, the UDP heartbeat is replaced with TCP keep-alive if QoS is 
enabled on the private network interface through the Unified ICM setup.
Medium-priority and low-priority traffic — For the Central Controller, this traffic includes shared 
data sourced from routing clients as well as (non-route control) call router messages, including call 
router state transfer (independent session). For the OPC (PG), this traffic includes shared non-route 
control peripheral and reporting traffic. This class of traffic is sent in TCP sessions designated as 
medium-priority and low-priority, respectively, with the private non-high priority IP address.
State transfer traffic — State synchronization messages for the Router, OPC, and other synchronized 
processes. It is sent in TCP with a private non-high-priority IP address.
Bandwidth and Latency Requirements
The amount of traffic sent between the Central Controllers (call routers) and Peripheral Gateways is 
largely a function of the call load at that site, although transient boundary conditions (for example, 
startup configuration load) and specific configuration sizes also affect the amount of traffic. A rule of 
thumb that works well for Unified ICM software prior to Release 5.0 in steady-state operation is: 
1,000 bytes (8 kb) of data is typically sent from a PG to the Central Controller for each call that arrives 
at a peripheral. Therefore, if a peripheral is handling 10 calls per second, we would expect to need