Chapter 12: AI2524 X.25 Configuration Steps
August 1997 Page 12-33
2524UM
dress. As a result, all outgoing calls from the VAX are sent to cisco
on-tymnet for further processing.
On the router named cisco-on-tymnet , you enter these commands:
x25 route vax-x121-address ip cisco-on-vax
x25 route .* interface serial 0
These commands force all calls with the VAX X.121 address to be sent
to the router with the VAX connected to it. All other calls with X.121
addresses are forwarded out to Tymnet. If Tymnet can route them, a
Call Accepted packet is returned, and everything proceeds normally.
If Tymnet cannot handle the calls, it clears each call and the Clear Re-
quest packet is forwarded back toward the VAX.
Configure XOT (Remote) X.25 Route
A remote X.25 route is one that crosses a TCP connection. Such routes
are called X.25-over-TCP, or XO T, routes. (XOT was previously
called remote routes or tunneled routes.
When an incoming call needs to be forwarded, two fields in the X.25
routing table are consulted to determine a remote X.25 route:
zDestination X.121 address
zX.25 packet's Call User Data (CUD) field (optional)
When the destination address and the CUD of the incoming packet fit
the X.121 and CUD patterns in the routing table, the call is forwarded.
You can also specify an XOT source that causes the XOT TCP con
nection to use the IP address of a specified interface as the source ad-
dress of the TCP connection. If, for instance, a loopback interface is
specified for the XOT connection's source address , TCP can use a pri-
mary interface or any backup interface to reach the other end of th
connection. However, if a physical interface address i s specified as the
source address, the XOT connection is term inated if that interface goes
down.
In global configuration mode, configure an XOT route (thus adding it
to the X.25 routing table):
x25 route [
#position
]
x121-address
[cud
pattern] ip
ip-address
[xot-source

type

number
]