Cisco Cisco Customer Response Solution Downloads Design Guide

End-to-end queuing mechanisms, such as Low Latency Queuing (LLQ). Because voice is 
susceptible to increased latency and jitter on low-speed links, Link Fragmentation and Interleaving 
(LFI) can also be used to reduce delay and jitter by subdividing large datagrams and interleaving 
low-delay traffic with the resulting smaller packets.

Scheduling mechanisms such as Traffic Shaping to optimize bandwidth utilization on output links. 

 and the following section list TCP ports and DSCP markings for use in prioritizing IPCC 

Express and Cisco CallManager mission-critical CTI traffic. The performance criteria used in 
classifying such traffic should include:

No packet drops on the outbound or inbound interface of the WAN edge router

Voice (G.729) loss under 1%

One-way voice delay under 150 msecs

A detailed description of QoS is not within the scope of this design guide. For QoS design 
recommendations, refer to the Quality of Service design guide available online at

As 

 shows, CTI signaling is the only traffic that is automatically DSCP marked. This marking 

can impact the overall response of the IPCC Express application, depending upon what processing is 
done prior to connecting calls to an agent. For example, suppose that the IPCC Express application 
requires a database query to extract and pass the account information as enterprise data to the agent 
desktop. Because the ODBC and RMI data are not marked, they would be tagged as best effort.

CTI messaging between IPCC Express 
JTAPI subsystem and Cisco CallManager 
(both directions)

CTIQBE

TCP 2748

AF31 or EF

CTI (JTAPI) messaging from Cisco 
Agent Desktop to Cisco CallManager

CTIQBE

TCP 2748

None

HTTP

HTTP

TCP 8080

None

Database

JDBC / ODBC

TCP 1433

None

E-mail

SMTP

TCP 25

None

Messaging data between IPCC Express 
and Cisco Agent Desktop

CTI

TCP 42027

None