AI2524 Router Card User’s Manual
Page 12-12 August 1997
2524UM
Suppress or Replace the Calling Address
Some attachments require that no calling (s ource) a ddress be presented
in outgoing calls. The requirement is calle d suppressing the calling ad-
dress.
When attached to a PDN, X.25 may need to ensure that outgoing calls
only use the assigned X.121 address for t he calling (source) address.
Routed X.25 normally uses the original source address. Although in-
dividual X.25 route configurations can modify the source address,
Cisco provides a simple command to force the use of the interface ad-
dress in all calls sent; this requirement is called replacing the calling
address.
To suppress or replace the calling address, pe rform the appropriat
task in interface configuration mode:
zSuppress the calling (source) X.121 address in outgoing calls.
x25 suppress-calling-address
zReplace the calling (source) X.121 address in switched calls.
x25 use-source-address
Suppress the Called Address
Some attachments require that no called (destination) address be pre-
sented in outgoing calls; this requirement is called suppressing the
called address.
In interface configuration mode, suppr e ss the called address:
x25 suppress-called-address
Establish a Default Virtual Circuit Protocol
The Call Request packet that sets up a virtual circuit can encode a field
called the Call User Data (CUD) field. Typically, the first few bytes of
the CUD field identify which high-level protocol is carried by the vir-
tual circuit. The router, when acting as a destination host, normally re-
fuses a call if the CUD is absent or if the protocol identification isn't
recognized. The PAD protocol, however, specifies that unidentified
calls be treated as PAD connection requests. Other applications re-
quire that they be treated as IP encapsulation connection requests, per
RFC 877.
In interface configuration mode, configure either PAD or IP encapsu
lation treatment of unidentified calls:
x25 default {ip | pad}