Configuring the Cisco SS7/C7
Dial Access Solution System

For additional software configuration information, refer to the following publications:

• Cisco SS7/CCS7 Dial Access Solution System Integration Guidelines

• Cisco AS5300 Universal Access Server Software Configuration Guide

• Cisco AS5800 Universal Access Server Installation and Configuration Guide

• Redundant Link Manager (RLM) 12.0(3)T feature module in CCO

For a complete description of the commands mentioned in this chapter, see the Cisco IOS Dial Services Command Reference publication. To locate documentation of other commands that appear in this chapter, use the command reference master index or search online.

The Cisco SS7/C7 Dial Access Solution System uses the ISDN Q.931 and Q.921 protocols over an RLM module. RLM makes use of UDP to transfer information from the network access server to the CSC and vice versa. The ISDN module works in conjunction with the RLM.

The client or server side must support the RLM protocol, which manages those redundant links between the server and client and handles the link and server failover mechanism.

Extended Q.931
Q.921
UDP
IP

Extended Q.931 provides call control and maintenance functions. The Q.931 implementation is based on the Cisco National ISDN (NI) switch type with custom enhancements. The signalling controller appears as one or more signalling points in an SS7 network, and performs interworking between the various SS7 protocols in use worldwide to the extended NI protocol used between the Cisco SC2200 and network access server.

Q.921 is used to encapsulate the Q.931 messages. It guarantees the in-sequence transmission of Extended Q.931 messages and provides for retransmission. UDP provides for the connectionless transfer of signalling messages across the subnetworks (LAN or WAN), connecting the access servers to the signalling controller.

Continuity test requests are received over an SS7 signalling path and processed within the Signalling Access Server (SAS). The SAS requests that the network access server put the particular bearer in external loopback mode (loopback incoming receive to outgoing transmit) or to insert a transponder in the incoming circuit. The continuity test lasts until a COT message is received.

The COT subsystem supports continuity testing, which is required by the SS7 network to conduct loopback and tone check testing on the path before a circuit is established. COT will detect any failure of DS0 channels. It is required for North American SS7 compliance. You must have installed MICA technologies 2.6.1.0 portware, which supports the COT feature.

Router#show rlm group 1 status 
 
RLM Group 1 Status
 User/Port: RLM_MGR/3000 
 Link State: Up         Last Link Status Reported: Up
 Next tx TID: 1         Last rx TID: 0
 Server Link Group[r1-server]:
  link [10.1.1.1(Loopback1), 10.1.4.1] = socket[active]
  link [10.1.1.2(Loopback2), 10.1.4.2] = socket[standby]
 Server Link Group[r2-server]:
  link [10.1.1.1(Loopback1), 10.1.5.1] = socket[opening]
  link [10.1.1.2(Loopback2), 10.1.5.2] = socket[opening]

Note the following:

• The link state must report being up.

• No errors should be reported.

NoteFor a description of the output display fields, see the show rlm group status command reference page.

Router#show isdn status
 
Global ISDN Switchtype = primary-ni
ISDN Serial1:23 interface
   dsl 0, interface ISDN Switchtype = primary-ni :Primary D channel of nfas group 0
   Layer 1 Status:
       ACTIVE
   Layer 2 Status:
       TEI = 0, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED
Layer 3 Status:
       0 Active Layer 3 Call(s)
   Activated dsl 0 CCBs = 0
ISDN Serial2:23 interface
dsl 1, interface ISDN Switchtype = primary-ni :Group member of nfas group 0
   Layer 1 & 2 Status Not Applicable
   Layer 3 Status:
       0 Active Layer 3 Call(s)
   Activated dsl 1 CCBs = 0
   Total Allocated ISDN CCBs = 0

Note the following information for Serial1:23 (the first half of the messages):

• Layer 1 status should be "ACTIVE."

• Layer 2 status should be "MULTIPLE_FRAME_ESTABLISHED." (It might take several seconds for Layer 2 status to appear.)

• Layer 3 status should be "0 Active Layer 3 Call(s)."

The second half of the messages display information for Serial2:23.