Beta Draft Confidential
About SVCs
About Network ID Addressing
ATM Services Configuration Guide for CBX 3500, CBX 500, GX 550, and B-STDX 9000 1/19/0516-17
About Network ID Addressing
A network ID can be used to identify an inter-exchange carrier (IXC). You can
configure network ID addressing on ATM and Frame Relay UNI logical ports.
Depending on the administering authority, a network ID may be a 3-, 4-, or 8-digit
carrier identification code (CIC) or a 4-digit data network identification code (DNIC,
X.121). A network ID enables you to associate a network-to-network connection with
a particular IXC (using a route determination ID) and enables end-users to
pre-subscribe to a particular IXC (using a source default network ID) and override this
selection on a call-by-call basis (using a signaled transit network selection [TNS]).
Signaled TNSs are screened by matching them against a list of pre-subscribed source
validation network IDs. It is also possible to “ignore” the signaled TNS to allow
routing based on the called party address instead of the TNS value; the signaled TNS
is essentially stripped at the ingress port.
An SVC is routed based on one of the following addresses provided at the ingress port
(selected in listed order):
• Signaled TNS
• Signaled Called Party
• Provisional Default TNS
You can configure both route determination network IDs and route determination port
prefixes/addresses on a logical port at a network-to-network connection. A
combination of source validation network IDs and route determination network IDs
can coexist on the same port. You can provision network IDs on ATM UNI 3.x, 4.0,
Interim Inter-switch Signaling Protocol (IISP), or FRF.4 ports.
You can configure a maximum of 1024 configurable addresses for a logical port
(where configurable addresses equal the sum of all port addresses, prefixes, user parts,
and network IDs). The maximum number of network IDs for a logical port equals
1024 minus the sum of port addresses, prefixes, and user parts.
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