Cisco 1700 - Manual (Page 81)

D-5
Cisco 1700 Router Hardware Installation Guide
78-5405-03
Appendix D Ordering and Configuring an ISDN Line
Note SPIDs have significance only at the local-access ISDN interface. Every router that
uses ISDN must be assigned SPIDs (if used by the service provider) by the service
provider for that router.
When the router connects to the service provider’s central office ISDN switch, it
sends the SPIDs to the switch. If the router is not configured with the correct
SPIDs, it cannot place or receive calls. Use the isdn spid command to define the
SPID and the LDN on the router for both ISDN BRI B channels, as follows:
Router(config-if)# isdn spid1 spid-number [ldn]
Router(config-if)# isdn spid2 spid-number [ldn]
Note Although the LDN is usually optional, it might be required so that the router
answers calls made to the second directory number.
ISDN Configuration Options
For information on how to configure Cisco 1700 router to dial into a central-site
router over ISDN, refer to the Cisco 1700 Router Software Configuration Guide that
came with your router.
For more advanced information on configuring ISDN for Cisco 1700 routers,
refer to the chapter “Configuring ISDN” in the Dial Solutions Configuration Guide
publication, which is on Cisco.com. This document includes information on the
following topics:
Snapshot Routing
You can also configure snapshot routing for the router ISDN interface. During
snapshot routing, the router is configured to bring up the ISDN line, dynamically
learn about remote routes, and then take down ISDN line. The router saves the
learned routes for a specified period of time, even though routing updates are not
exchanged while the ISDN line is down. See the chapter “Configuring DDR” in
the Wide-Area Networking Configuration Guide publication for detailed
information about snapshot routing.