Troubleshooting Guide

Cisco ICM 4.1 and Earlier Versions
Intelligent Call Processing (ICP), a service of AT&T, allows customer premises equipment to participate in
call routing at the network level. The ICM CallRouter uses ICP to receive call routing requests, and to return
call routing responses to the AT&T SS7 signaling network.
Within ICM, the ICP interface is implemented as a dedicated computer and process, called the Network
Interface Controller (NIC). Figure 1 represents the relationship between the NIC and the AT&T ICP network.
Figure 1  Relationship Between the NIC and the AT&T ICP Network: ICM Version 4.1 and Earlier
When ICM is connected to the AT&T ICP network, ICM is considered as a Customer Routing Point (CRP).
ICM communicates with the AT&T network through SS7 links to a pair of mated Signal Transfer Points
(STPs). The STPs carry message traffic between nodes and the Network Control Point (NCP). The NCP is an
AT&T network node that processes 800−number call routing requests received from telephone switches in the
AT&T network.
The AT&T NIC connects the ICM CallRouter to a pair of STPs in the network through two 56−Kbps circuits
called A−links. AT&T provides these links as part of the ICP service. The A−Links come as a pair, which
means that link redundancy is a standard feature. Each A−Link terminates in an SS7 card in the ICP NIC
platform.
Cisco ICM 4.2 and Later Versions
SS7 gateways are ICM nodes that provide SS7 network connectivity for various NICs in an ICM deployment.
All gateways provide the SS7 Message Transfer Part 2 (MTP2), Message Transfer Part 3 (MTP3), and SCCP
SS7 network layers. Some gateways also implement the Transaction Capabilities Application Part (TCAP) of
SS7 and TCAP User layers as well.
SS7 gateways can use ISA SS7, or PCI Quad SS7 network interface cards. Note that ISA SS7 interface cards
are not supported in versions later than ICM 6.0.
Figure 2 shows a full "mated pair" configuration where two routers with two NICs are connected to two
gateways that each are connected to two STP (Signaling Transfer Points). This fully redundant configuration
allows for any single point of failure in ICM without affecting the ability of ICM to route calls.
Figure 2  Relationship Between the NIC and the AT&T ICP Network: ICM Version 4.2 and Later