ISDN Switch Types

There are many standards for switches because most standards were released during or after the deployment of most ISDN switches. Therefore, a variety of ISDN switch manufacturers pose different requirements for configuring CPE. In Table 9-7, the Cisco supported switches from the latest IOS release are listed.

Table 9-7. ISDN Switch Types

Switch Type	Description
basic-1tr6	1TR6 switch type for Germany
basic-5ess	Lucent 5ESS switch type for the U.S.
basic-dms100	Northern Telecom DMS-100 switch type for the U.S.
basic-net3	NET3 switch type for UK, Europe, Asia, and Australia
basic-ni1	National ISDN switch type for the U.S.
basic-qsig	QSIG switch type
basic-ts013	TS013 switch type for Australia (obsolete)
ntt	NTT switch type for Japan
vn3	VN3 and VN4 switch types for France

In the U.S. and Canada, two settings have high importance when you are trying to set up the switch-BRI interoperations: SPID, and Local Directory Numbers (LDNs). The SPID represents a subscriber number and subscriber address. Although the number is defined as a regular phone number with format xxx-xxx-xxxx, the address's purpose is to assign a unique number to the endpoint (such as a terminal). The service provider assigns the SPIDs and they must be configured on the router in exactly the same way as the LEC provides them. Depending on the switch type connected to the CPE, SPIDs might not be necessary.

In the U.S., National ISDN-1 and DMS-100 ISDN switches require SPIDs to be configured, but the AT&T 5ess switch does not.

If they are required, the SPID number is usually a ten-digit telephone number plus two or four extra digits, for example, SPID = 40847647400100 and 40847647410200 represent the following:

• 408 Area code

• 476 CO (exchange) code

• 4740 and 4741 Station IDs for each B channel

• 01 and 02 Terminal identifiers

Another part of the setting is the LDN. The LDN is configured to receive incoming calls. For example, LDN1 = 4764740 and LDN2 = 4764741, represent the following:

• 476 Exchange code

• 4740 and 4741 Station ID

With AT&T switch-type 5ESS, only one LDN is necessary to identify the service. For more information about switch settings, see Chapter 10, "ISDN Design Solutions."