Configuring X.25 237
Example 8-4 shows RouterA's configuration for deployment in a PVC role. Note that RouterB
and RouterC would need to be similarly configured.
The configuration of the x25 pvc command can be expanded to include up to nine protocols in
a single pvc statement or configured for one protocol per circuit.
Additional Configuration Options
In some cases, you must tweak the default settings of an X.25 installation based on service
provider mandates or customer requests. There are a number of items that can be configured to
change the way in which X.25 operates:
·
Range of VCs--Incoming, outgoing, and two-way circuits are possible options.
·
Packet size--Inbound and outbound packet size can be specified on the interface.
·
Window size--Inbound and outbound window size can be specified on the interface.
·
Window modulus--This is the limit of the sequence number counter.
Configuring the Range of Virtual Circuits
As mentioned, X.25 can be implemented using both PVCs and SVCs. Table 8-3 describes the
VC ranges and options.
Example 8-4
RouterA PVC Configuration
RouterA(config)#interface ethernet 0
RouterA(config-if)#ip address 10.1.10.1 255.255.255.0
RouterA(config-if)#interface serial 0
RouterA(config-if)#encapuslation x25
RouterA(config-if)#ip address 10.1.11.1 255.255.255.0
RouterA(config-if)#x25 address 42495092091
RouterA(config-if)#x25 pvc 2 ip 10.1.11.2 51472092091 broadcast
RouterA(config-if)#x25 pvc 5 ip 10.1.11.3 51171092091 broadcast
Table 8-3
VC Ranges
VC Type
Range
Default
Command
PVC
14095
None, but must be >0
x25 pvc circuit
SVC (incoming only)
14095
14095
0
0
x25 lic circuit
x25 hic circuit
SVC (outgoing only)
14095
14095
0
0
x25 loc circuit
x25 hoc circuit
SVC (two-way)
14095
14095
1
1024
x25 ltc circuit
x25 htc circuit