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The following configurations and information are required for the CAD software to work properly.

The Cisco Agent Desktop application uses the TCP Ping command to verify that it can communicate 
with the active VoIP servers. This is done even if no agents are configured to use a VoIP Monitor service 
for the silent monitoring feature. If Ping is disabled on the machine running a CAD VoIP Monitor Server, 
the silent monitoring feature will not work properly.

There are certain CAD modules that rely upon reverse DNS lookups. If this feature is turned off on the 
machines running CAD services, there will be a loss of some functionality and errors will be generated 
and logged. 

Network Address Translation (NAT) is only supported between the Cisco Agent Desktop and the CRS 
servers. Port Address Translation (PAT) is not supported. 

Quality of Service (QoS) becomes an issue when more voice and application-related traffic is added to 
an already growing amount of data traffic on your network. Accordingly, Unified CCX and 
time-sensitive traffic such as voice need higher QoS guarantees than less time-sensitive traffic such as 
file transfers or emails (particularly if you are using a converged network).

QoS should be used to assign different qualities to data streams to preserve Unified CCX mission-critical 
and voice traffic. The following are some examples of available QoS mechanisms:

Packet classification and usage policies applied at the edge of the network, such as Policy Based 
Routing (PBR) and Committed Access Rate (CAR).

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 Unified 

CCX and Cisco Unified 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 Enterprise Quality of Service Solution Reference Network Design guide 
available online at: