OSPF at FRAME-RELAY FULL MESH BROADCAST NETWORK

Compiled by: Mahmud Jami, infojami at yahoo.com

OSPF need a bit different type configuration in Frame Relay networks than Ethernet broadcast network. In this document I am going to configure OSPF in a broadcast/multicast enabled fully mesh Frame-Relay network.

The logical network diagram of my scenario is as follows,

FR Full Mesh logical diagram

In this example,

-We have three (03) routers connected to each other using FR network.

-Each router has two DLCIs to communicate with other two routers DLCIs to form the full mesh network.

-The Frame-Relay network is broadcast multicast enabled

-OSPF is configured as “ip ospf network broadcast” at FR serial interfaces

-One router is configured with higher priority (10) to become DR always.

-One router is configured with second highest priority (2) to become BDR always.

-DR/BDR election can be done also automatically if priority is not set.

-No manual configuration is required for “ospf neighbors”.

-Neighbors will automatically discover.

-Route path will be R1>R2 & R1>3; R2>R1 & R2>R3; R3>R1 &R3>R2.

-A Cisco router is configured to act as Frame-Relay switch.

Routers Frame-Relay participating serial interface IP address are as follows,

-R1 IP is 192.168.10.1 at serial 1/0

-R2 IP is 192.168.10.2 at serial 1/0

-R3 IP is 192.168.10.3. at serial 1/0.

To accomplish all these I used GNS3 and Cisco 3745 IOS 12.4. This can be done using most Cisco IOSs on most Cisco router hardware platform.

Configuration of Router “R1”

Router “R1” has two DLCIs 101 & 301. DLCI mappings are as follows,

-DLCI 101 mapped to R2(192.168.10.2)

-DLCI 301 mapped to R3(192.168.10.3).

Router “R1” running-config is as below,

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname R1

!

boot-start-marker

boot-end-marker

!

!

no aaa new-model

memory-size iomem 5

ip cef

!

!

!

interface FastEthernet0/0

 ip address 192.168.100.1 255.255.255.0

 duplex auto

 speed auto

!

interface FastEthernet0/1

 no ip address

 shutdown

 duplex auto

 speed auto

!

interface Serial1/0

 ip address 192.168.10.1 255.255.255.0

 encapsulation frame-relay

 ip ospf network broadcast

 serial restart-delay 0

 frame-relay map ip 192.168.10.2 101 broadcast

 frame-relay map ip 192.168.10.3 301 broadcast

!

interface Serial1/1

 no ip address

 shutdown

 serial restart-delay 0

!

interface Serial1/2

 no ip address

 shutdown

 serial restart-delay 0

!

interface Serial1/3

 no ip address

 shutdown

 serial restart-delay 0

!

router ospf 100

 router-id 1.1.1.1

 log-adjacency-changes

 network 192.168.10.0 0.0.0.255 area 0

 network 192.168.100.0 0.0.0.255 area 0

!

ip forward-protocol nd

!

ip http server

no ip http secure-server

!

!

control-plane

!

!

line con 0

line aux 0

line vty 0 4

 login

!

!

end

Configuration of Router “R2”

Router “R2” has two DLCIs 102 & 201. DLCI mappings are as follows,

-DLCI 102 mapped to R1(192.168.10.1)

-DLCI 201 mapped to R3(192.168.10.3).

Router “R2” running-config is as below,

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname R2

!

boot-start-marker

boot-end-marker

!

!

no aaa new-model

memory-size iomem 5

ip cef

!

!

no ip domain lookup

!

!

!

interface FastEthernet0/0

 ip address 192.168.200.1 255.255.255.0

 duplex auto

 speed auto

!

interface FastEthernet0/1

 no ip address

 shutdown

 duplex auto

 speed auto

!

interface Serial1/0

 ip address 192.168.10.2 255.255.255.0

 encapsulation frame-relay

 ip ospf network broadcast

 serial restart-delay 0

 frame-relay map ip 192.168.10.1 102 broadcast

 frame-relay map ip 192.168.10.3 201 broadcast

!

interface Serial1/1

 no ip address

 shutdown

 serial restart-delay 0

!

interface Serial1/2

 no ip address

 shutdown

 serial restart-delay 0

!

interface Serial1/3

 no ip address

 shutdown

 serial restart-delay 0

!

router ospf 100

 router-id 2.2.2.2

 log-adjacency-changes

 network 192.168.10.0 0.0.0.255 area 0

 network 192.168.200.0 0.0.0.255 area 0

!

ip forward-protocol nd

!

ip http server

no ip http secure-server

!

!

control-plane

!

!

line con 0

line aux 0

line vty 0 4

 login

!

!

end

Configuration of Router “R3”

Router “R3” has two DLCIs 302 & 202. DLCI mappings are as follows,

-DLCI 302 mapped to R1(192.168.10.1)

-DLCI 202 mapped to R2(192.168.10.2).

Router “R3” running-config is as below,

!

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname R3

!

boot-start-marker

boot-end-marker

!

!

no aaa new-model

memory-size iomem 5

ip cef

!

!

!

no ip domain lookup

!

!

!

interface FastEthernet0/0

 ip address 192.168.20.1 255.255.255.0

 duplex auto

 speed auto

!

interface FastEthernet0/1

 no ip address

 shutdown

 duplex auto

 speed auto

!

interface Serial1/0

 ip address 192.168.10.3 255.255.255.0

 encapsulation frame-relay

 ip ospf network broadcast

 serial restart-delay 0

 frame-relay map ip 192.168.10.1 302 broadcast

 frame-relay map ip 192.168.10.2 202 broadcast

!

interface Serial1/1

 no ip address

 shutdown

 serial restart-delay 0

!

interface Serial1/2

 no ip address

 shutdown

 serial restart-delay 0

!

interface Serial1/3

 no ip address

 shutdown

 serial restart-delay 0

!

router ospf 100

 router-id 3.3.3.3

 log-adjacency-changes

 network 192.168.10.0 0.0.0.255 area 0

 network 192.168.20.0 0.0.0.255 area 0

!

ip forward-protocol nd

!

ip http server

no ip http secure-server

!

!

!

!

control-plane

!

!

line con 0

line aux 0

line vty 0 4

 login

!

!

end

The actual physical network diagram form this scenario is as follows,

The Physical Network Diagram-FR Full Mesh

Configuration of “Cisco router as a Frame-Relay switch”

The running-configuration of “Cisco router as a Frame-Relay switch” is as below,

version 12.4

service timestamps debug datetime msec

service timestamps log datetime msec

no service password-encryption

!

hostname FRSW01

!

boot-start-marker

boot-end-marker

!

!

no aaa new-model

memory-size iomem 5

ip cef

!

!

frame-relay switching

!

!

!

interface FastEthernet0/0

 no ip address

 shutdown

 duplex auto

 speed auto

!

interface FastEthernet0/1

 no ip address

 shutdown

 duplex auto

 speed auto

!

interface Serial1/0

 no ip address

 encapsulation frame-relay

 serial restart-delay 0

 clock rate 64000

 frame-relay intf-type dce

 frame-relay route 101 interface Serial1/1 102

 frame-relay route 301 interface Serial1/2 302

!

interface Serial1/1

 no ip address

 encapsulation frame-relay

 serial restart-delay 0

 clock rate 64000

 frame-relay intf-type dce

 frame-relay route 102 interface Serial1/0 101

 frame-relay route 201 interface Serial1/2 202

!

interface Serial1/2

 no ip address

 encapsulation frame-relay

 serial restart-delay 0

 clock rate 64000

 frame-relay intf-type dce

 frame-relay route 202 interface Serial1/1 201

 frame-relay route 302 interface Serial1/0 301

!

interface Serial1/3

 no ip address

 shutdown

 serial restart-delay 0

!

ip forward-protocol nd

!

ip http server

no ip http secure-server

!

!

!

!

control-plane

!

!

line con 0

line aux 0

line vty 0 4

!

!

end

Beside my full time job, I like to spend my time on professional technical teaching and sharing my experiences with other peoples.

I thing I have good number of students and well wishers. Most of them are doing very good in Bangladesh and abroad. I enjoy solving their technical problems :.). Every day I got a lot of emails, telephone calls related to technical problems and suggestions.

I am Mahmud Jami from Bangladesh.

I think I am a geek guy (check http://en.wikipedia.org/wiki/Geek for defination of the word “geek”) who’s profession is to play seriously with computers.