3Com Router User Manual

							Typical X.25 Configuration Example227
[Router-Serial0]x25 map ip 168.173.24.1 x121-address 30561001
[Router-Serial0]x25 map ip 168.173.24.2 x121-address 30561002
Configure Virtual Circuit 
RangeI. Networking Requirement
The link layer protocol of routers interface Serial0 is X.25l, with the virtual circuit 
range: permanent virtual circuit section [1, 8], incoming-only channel section [9, 
16], two-way channel section [17, 1024], and the outgoing-only channel section is 
disabled.
II. Configuration Procedure
[Router]interface serial 0
[Router-Serial0]link-protocol x25
[Router-Serial0]x25 vc-range in-channel 9 16 bi-channel 17 1024
Transmit IP Datagram 
via X.25 PVCI. Networking Requirement
In the following diagram, the permanent virtual circuit section allowed by the 
packet network is [1,8], the PVC numbers assigned to Router A and Router B are 3 
and 4 respectively. The IP network addresses of Ethernet A and B are 202.38.165.0 
and 196.25.231.0 respectively. It is required to exchange routing information 
between Ethernet A and B with RIP routing protocol, so that PC A and PC B can 
exchange information without adding static route.
II. Networking Diagram
Figure 70   X.25 PVC bearing IP data packet
III. Configuration Procedure
1Configure Router A:
[Router]interface ethernet 0
[Router-Ethernet0]ip address 202.38.165.1 255.255.255.0
[Router-Ethernet0]interface serial 0
[Router-Serial0]ip address 192.149.13.1 255.255.255.0
[Router-Serial0]link-protocol x25
[Router-Serial0]x25 x121-address 1004358901
[Router-Serial0]x25 vc-range bi-channel 9 1024
[Router-Serial0]x25 pvc 3 ip 192.149.13.2 x121-address 1004358902 
broadcast packet-size 512 512 window-size 5 5
[Router-Serial0]quit
[Router]rip
2Configure Router B:
[Router]interface ethernet 0
X.25
windowsize: 5 5
packetsize: 512 512
RouterA
RouterB
IP: 192.149.13.1
X.121: 1004358901IP: 192.149.13.2
X.121: 1004358902 PVC 3 PVC 4
EtherNet AEtherNet B
PC BPC A
Serial 0 Serial 0 
						

							228CHAPTER 16: CONFIGURING LAPB AND X.25
[Router-Ethernet0]ip address 196.25.231.1 255.255.255.0
[Router-Ethernet0]interface serial 0[Router-Serial0]ip address 
192.149.13.2 255.255.255.0
[Router-Serial0]link-protocol x25
[Router-Serial0]x25 x121-address 1004358902
[Router-Serial0]x25 vc-range bi-channel 8 1024
[Router-Serial0]x25 pvc 4 ip 192.149.13.1 x121-address 1004358901 
broadcast packet-size 512 512 window-size 5 5
[Router-Serial0]quit
[Router]rip
In above configuration, the permanent virtual circuit numbers of routers A and B 
are different: 3 and 4 respectively. Virtual circuit refers to the end-to-end logical 
link between the calling DTE and the called DTE, while logical channel refers to the 
logical link between two directly connected devices (either between DTE and DCE, 
or between the ports of two packet switching exchanges). A virtual circuit consists 
of several logical channels, and each logical channel has a separate number. The 
virtual circuit between routers A and B is shown in (suppose this virtual circuit 
passes four packet switching exchanges in the network).
Figure 71   A virtual circuit consisting of several logical channels
Therefore, the PVC 3 and PVC 4 mentioned above actually refer to the numbers of 
the logical channels between the router and the switch directly connected to it. 
However, on one side of this virtual circuit, the logical channel number can be 
used to identify this virtual circuit without causing misunderstanding. This is why 
no strict distinction is made between virtual circuit and logical channel.
Ty p i c a l  X . 2 5  
Sub-Interface 
Configuration ExampleI. Networking Requirement
Multiple sub-interfaces are configured on a physical interface to connect with 
multiple peers of different network sections. In the following diagram, Router A is 
configured with two sub-interfaces, respectively interconnected with Router B and 
Router C.
RouterBPBX
PBX
PBX
LC 3
LC 4
LC 243
LC 24
LC 3
PBXRouterA
RouterBPBX
PBX
PBX
LC 3
LC 4
LC 243
LC 24
LC 3
PBXRouterA 
						

							Typical X.25 Configuration Example229
II. Networking Diagram
Figure 72   Diagram of X.25 sub-interface configuration
III. Configuration Procedure
1Configure Router A:
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte
[Router-Serial0]x25 x121-address 100
[Router-Serial0]interface serial 0.1
aCreate sub-interface serial 0.1
[Router-Serial0.1]ip address 10.1.1.2 255.255.0.0
[Router-Serial0.1]x25 map ip 10.1.1.1 x121-address 200
bCreate sub-interface serial 0.2
[Router-Serial0.1]interface serial 0.2
[Router-Serial0.2]ip address 20.1.1.2 255.255.0.0
[Router-Serial0.2]x25 map ip 20.1.1.1 x121-address 300
2Configure Router B:
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte
[Router-Serial0]x25 x121-address 200
[Router-Serial0]x25 map ip 10.1.1.2 x121-address 100
3Configure Router C:
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte
[Router-Serial0]x25 x121-address 300
[Router-Serial0]x25 map ip 20.1.1.2 x121-address 100
4Configure Router D:
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dce
[Router-Serial0]interface serial 1
[Router-Serial1]link-protocol x25 dce
[Router-Serial1]interface serial 2
[Router-Serial2]link-protocol x25 dce
[Router-Serial2]quit
[Router]x25 switching 
[Router]x25 switch svc 100 interface serial 0
[Router]x25 switch svc 200 interface serial 1
[Router]x25 switch svc 300 interface serial 2
S0S0
S0S0 S2
RouterBRouterC RouterD
RouterA
S1 
						

							230CHAPTER 16: CONFIGURING LAPB AND X.25
SVC Application of XOTI. Networking Requirement
Router B and C connect through Ethernet interface, and build TCP connection 
between them. X.25 packets forward through TCP, and configure SVC to 
implement the SVC function.
II. Networking Diagram
Figure 73   SVC application networking diagram of XOT
III. Configuration Procedure
1Configure Router A
aBasic X.25 Configuration
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte ietf
[Router-Serial0]x25 x121-address 1
[Router-Serial0]x25 map ip 1.1.1.2 x121-address 2
[Router-Serial0]ip address 1.1.1.1 255.0.0.0
2Configure Router D 
aBasic X.25 Configuration
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte ietf
[Router-Serial0]x25 x121-address 2
[Router-Serial0]x25 map ip 1.1.1.1 x121-address 1
[Router-Serial0]ip address 1.1.1.2 255.0.0.0
3Configure Router B 
aStart X.25 switching
[Router]x25 switching
bConfigure X.25 local switching
[Router]x25 switch svc 1 interface serial 11/0/2
cConfigure XOT switching
[Router]x25 switch svc 2 xot 10.1.1.2
dConfigure ethernet 0.
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.1.1.1 255.0.0.0
eConfigure Serial 11/0/2
[Router-Ethernet0]interface serial 0
[Router-Serial0]link-protocol x25 dce ietf
PC1
S0
S0S0
S0 E0E0
PC2
E0 E0Router B
Router ARouter C
Router D 
						

							Typical X.25 Configuration Example231
4Configure Router C 
aStart X.25 switching
[Router]x25 switching
bConfigure X.25 local switching
[Router]x25 switch svc 2 interface serial 0
cConfigure XOT switching
[Router]x25 switch svc 1 xot 10.1.1.1
dConfigure Ethernet 0
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.1.1.2 255.0.0.0
eConfigure Serial 0
[Router-Ethernet0]interface serial 0
[Router-Serial0]link-protocol x25 dce ietf
PVC Application of XOTI. Networking Requirement
Router B and C connect through Ethernet interface, and build TCP connection 
between them. X.25 packets forward through TCP, and configure PVC to 
implement the PVC function.
II. Networking Diagram
Figure 74   PVC application networking diagram of XOT
III. Configuration Procedure
1Configure Router A 
aBasic X.25 Configuration
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte ietf
[Router-Serial0]x25 x121-address 1
[Router-Serial0]x25 vc-range in-channel 10 20 bi-channel 30 1024
[Router-Serial0]x25 pvc 1 ip 1.1.1.2 x121-address 2
[Router-Serial0]ip address 1.1.1.1 255.0.0.0
2Configure Router D 
aBasic X.25 configuration
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte ietf
PC1
S0
S0S0
S0 E0E0
PC2
E0
E0 Router B
Router ARouter DRouter C 
						

							232CHAPTER 16: CONFIGURING LAPB AND X.25
[Router-Serial0]x25 x121-address 2
[Router-Serial0]x25 x25 vc-range in-channel 10 20 bi-channel 30 1024
[Router-Serial0]x25 pvc 1 ip 1.1.1.1 x121-address 1
[Router-Serial0]ip address 1.1.1.2 255.0.0.0
3Configure Router B 
aStart X.25 switching
[Router]x25 switching
bConfigure Ethernet 0
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.1.1.1 255.0.0.0
cConfigure Serial 0
[Router-Ethernet0]interface serial 0
[Router-Serial0]link-protocol x25 dce ietf
[Router-Serial0]x25 x25 vc-range in-channel 10 20 bi-channel 30 1024
[Router-Serial0]x25 xot pvc 1 10.1.1.2 interface serial 0 pvc 1
4Configure Router C 
aStart X.25 switching
[Router]x25 switching
bConfigure Ethernet 0
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.1.1.2 255.0.0.0
cConfigure Serial 0.
[Router-Ethernet0]interface serial 0
[Router-Serial0]link-protocol x25 dce ietf
[Router-Serial0]x25 vc-range in-channel 10 20 bi-channel 30 1024
[Router-Serial0]x25 xot pvc 1 10.1.1.1 interface serial 0 pvc 1
Application of X.25 Load 
BalancingI. Networking Requirements
Configure hunt group on Server RouterA which serves as an X.25 switch and 
simultaneously enable the function of substitution of destination address and 
source address, so that the caller can treat router RouterB, RouterC and RouterE 
equally as one destination, and the calls of X.25 terminal can be sent to routers 
RouterB, RouterC and RouterE to achieve load balancing. Therefore the load 
balancing of routers on X.25 network can be implemented. As an X.25 switching 
exchange, router RouterD performs the XOT function and connects RouterA and 
RouterE. Router RouterB, RouterC and RouterE are DTEs in a hunt group. They 
provide X.25 terminals with identical services. 
						

							Typical X.25 Configuration Example233
II. Networking Diagram
Figure 75   Networking diagram of typical configuration of X.25 hunt group
III. Configuration Procedure
1Configure RouterA
aConfigure the link layer protocol of interface Serial1 to X.25 and specify it to 
operate in DCE mode.
[Router]interface serial 1
[Router-Serial1]link-protocol x25 dce
bConfigure the link layer protocol of other synchronous serial interfaces to X.25 
and specify it to operate in DCE mode. Their configuration is identical to the 
configuration of interface Serial 1.
cConfigure IP addresses on interface Ethernet 0.
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.1.1.1 255.255.255.0
dEnable X.25 switching in system view.
[Router]x25 switching
eCreate X.25 hunt group named hg1 with property of rotary in system view.
[Router]x25 hunt-group hg1 round-robin
fAdd Serial 1, Serial 2 and XOT Tunnel to hunt group.
[Router-X25-huntgroup-hg1]interface serial 1
[Router-X25-huntgroup-hg1]interface serial 2
[Router-X25-huntgroup-hg1]channel xot 10.1.1.2
gConfigure X.25 switching route whose forwarding address is hunt group hg1 
and enable the substitution of destination address and source address.
[Router]x25 switch svc 2222 sub-dest 8888 sub-source 3333 hunt-group 
hg1
hConfigure X.25 switching route to forward to X.25 terminal.
[Router]x25 switch svc 1111 interface serial 3
[Router]x25 switch svc 1119 interface serial 11
2Configure RouterB
aConfigure the interface Serial0s link layer protocol to X.25 and specify it to 
operate in DTE mode.
QuidwayAQuidwayB
QuidwayC
QuidwayE QuidwayD
S1S0
S2
S0
E0
E0S0 S0 10.1.1.1
10.1.1.2
X.25 Terminalhuntgroup
2222 1111
8888
8888
8888
X.25 Terminal
X.25 Terminal1112
1119
S3
S4
S11
RouterA
RouterB
RouterC
RouterDRouterE 
						

							234CHAPTER 16: CONFIGURING LAPB AND X.25
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte
[Router-Serial0]x25 x121-address 8888
The configurations of RouterC and RouterE are identical with the configuration of 
RouterB
3Configure RouterD
aConfigure link layer protocol of interface Serial 0 to X.25 and specify it to 
operate in DCE mode. 
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dce
bConfigure IP addresses on interface Ethernet 0. 
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.1.1.2 255.255.255.0
cEnable X.25 switching in system view.
[Router]x25 switching 
dConfigure X.25 switching route whose forwarding address is XOT Tunnel. 
[Router]x25 switch svc 1111 xot 10.1.1.1
eConfigure X.25 switching route that is forwarded to router RouterE
[Router]x25 switch svc 8888 interface serial 0
X.25 Load Balancing 
Carrying IP Data 
Transmission I. Networking Requirements
X.25 packet switching networks interconnect IP networks in different areas and 
X.25 networks carry IP data. At the same time, ISPs provide the function of X.25 
network load balancing and implement the configuration of load balancing with 
subscribers, to achieve the line load balancing when a server is accessed by 
different clients.
II. Networking Diagram
Figure 76   X.25 hunt group carrying IP data transmission
III. Configuration Procedure
In this example, ISP performs the configuration of load balancing on packet 
switching exchange, therefore only the common X.25 configuration needs to be 
implemented on routers.
PC B
10.2.1.2
QuidwayA
S0
1.1.1.3 S0
1.1.1.1
2.1.1.3
S1
S0
1.1.1.2
QuidwayC
Server A
10.3.1.2
Server B
10.3.1.3
PC A
10.1.1.2X.25
packet
switching
network E0
10.1.1.1
E0
10.2.1.1E0
10.3.1.1 3333
1111
2222
QuidwayB 
						

							Typical X.25 Configuration Example235
Note that you must configure a virtual IP address and two static routes on 
interface Serial 1 to deceive the router because two lines connected to the same 
peer exist in router RouterC. Thus load balancing can be achieved because router 
RouterC will deem that there are two routes connected to network segment 
10.1.1.0.
1Configure RouterA
aConfigure interface Ethernet 0.
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.1.1.1 255.255.255.0
bConfigure interface Serial 0.
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte
[Router-Serial0]x25 x121-address 1111
[Router-Serial0]ip address 1.1.1.1 255.255.255.0
[Router-Serial0]x25 map ip 1.1.1.3 x121-address 3333
[Router-Serial0]x25 vc-per-map 2
cConfigure static route to RouterC.
[Router]ip route-static 10.3.1.0 24 1.1.1.3
2Configure RouterB
aConfigure interface Ethernet 0.
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.2.1.1 255.255.255.0
bConfigure interface Serial 0.
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte
[Router-Serial0]x25 x121-address 2222
[Router-Serial0]ip address 1.1.1.2 255.255.255.0
[Router-Serial0]x25 map ip 1.1.1.3 x121-address 3333
[Router-Serial0]x25 vc-per-map 2
cConfigure static route to RouterC.
[Router]ip route-static 10.3.1.0 24 1.1.1.3
Configure router RouterC
dConfigure interface Ethernet 0.
[Router]interface ethernet 0
[Router-Ethernet0]ip address 10.3.1.1 255.255.255.0
eConfigure interface Serial 0. 
[Router]interface serial 0
[Router-Serial0]link-protocol x25 dte
[Router-Serial0]x25 x121-address 3333
[Router-Serial0]ip address 1.1.1.3 255.255.255.0
[Router-Serial0]x25 map ip 1.1.1.1 x121-address 1111
[Router-Serial0]x25 map ip 2.1.1.1 x121-address 1111
[Router-Serial0]x25 map ip 1.1.1.2 x121-address 2222
[Router-Serial0]x25 map ip 2.1.1.2 x121-address 2222
fConfigure interface Serial 1.
[Router]interface serial 1
[Router-Serial1]link-protocol x25 dte 
						

							236CHAPTER 16: CONFIGURING LAPB AND X.25
[Router-Serial1]x25 x121-address 3333
[Router-Serial1]ip address 2.1.1.3 255.255.255.0
[Router-Serial1]x25 map ip 1.1.1.1 x121-address 1111
[Router-Serial1]x25 map ip 2.1.1.1 x121-address 1111
[Router-Serial1]x25 map ip 1.1.1.2 x121-address 2222
[Router-Serial1]x25 map ip 2.1.1.2 x121-address 2222
gConfigure the static route to RouterA and RouterB.
[Router]ip route-static 10.1.1.0 24 1.1.1.1
[Router]ip route-static 10.1.1.0 24 2.1.1.1
[Router]ip route-static 10.2.1.0 24 1.1.1.2
[Router]ip route-static 10.2.1.0 24 2.1.1.2
Interconnect LANs via 
Annex G DLCIsI. Networking Requirements
Two Routers are directly connected via serial interfaces. Router A works as Frame 
Relay DCE whereas Router B as Frame Relay DTE.
II. Networking Diagram
Figure 77   Interconnect LANs via an Annex G DLCI
III. Configuration Procedure
1Configure RouterA:
aCreate an X.25 template.
[Router]x25 template profile1
bConfigure the local X.25 address.
[Router-x25-profile1]x25 x121-address 10094
cMap the destination X.25 address to the destination IP address.
[Router-x25-profile1]x25 map ip 202.38.163.252 x121-address 20094
[Router-x25-profile1]quit
dConfigure an IP address for the local interface.
[Router]interface serial 1
[Router-Serial1]ip address 202.38.163.251 255.255.255.0
eConfigure the link layer protocol of the interface to Frame Relay.
[Router-Serial1]link-protocol fr
[Router-Serial1]fr interface-type dce
fConfigure a Frame Relay DLCI.
[Router-Serial1]fr dlci 100
gConfigure the DLCI to be Annex G DLCI.
[Router-fr-dlci-100]annexg dce
hAssociate the X.25 template with the DLCI.
IP:202.38.163.251 IP:202.38.163.252
DLCI=100
Router A
Router B