Frame relay is a packet-switching telecommunication service designed for cost-efficient data transmission for intermittent traffic between local area networks (LANs) and between endpoints in wide area networks (WANs).
The service, once widely available and implemented, is in the process of being discontinued by major Internet service providers. Frame Relay can be configured with multiple configurations and in different topology’s shown in the figure below.
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A – Partial Mesh:
This topology is less expensive to implement and has less redundancy than the full mesh topology. Some nodes are organized in a full mesh scheme but others are only connected to one or two in the network. Partial mesh topology is commonly found in peripheral networks connected to a full meshed backbone.
B – Full Mesh:
Every node has a circuit connecting it to every other node in a network.This is very expensive to implement but has the greatest amount of redundancy. In the event that one of those nodes fails, network traffic can be directed to any of the other nodes. Full mesh are usually reserved for backbone networks.
C – Hub and Spoke:
In this network topology, one physical site act as Hub, while other physical sites act as spokes. Spoke sites are connected to each other via Hub sites. In Hub-and-spoke topology, the network communication between two spokes always travel through the hub.
Configuration
In this example, we are going to setup a network topology based on Hub-and-Spoke, with Frame Relay (point to point).
This is the topoly we are going to setup:
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The (Packet Tracer) Frame Relay switch is configured as following:
| Interface | DLCI / Name |
| Serial0 | DLCI 102 BE |
| Serial1 | DLCI 103 GER |
| Serial2 | DLCI 201 NL – BE |
| DLCI 301 NL – GER | |
| Frame Relay | |
| Serial0 BE – | Serial2 NL – BE |
| Serial1 GER – | Serial2 NL – GER |
The first router we configure is router BE:
Router-BE> enable Router-BE# configure terminal Router-BE(config)# interface serial 1/0 Router-BE(config-if)# encapsulation frame-relay Router-BE(config-if)# exit Router-BE(config)# interface serial 1/0.102 point-to-point Router-BE(config-subif)# frame-relay interface-dlci 102 Router-BE(config-subif)# ip address 1.1.1.1 255.255.255.252 Router-BE(config-subif)# end Router-BE# show frame-relay map Serial1/0.102 (up): point-to-point dlci, dlci 102, broadcast, status defined, active
Second we configure router GER:
Router-GER> enable Router-GER# configure terminal Router-GER(config)# interface serial 1/0 Router-GER(config-if)# no shutdown Router-GER(config-if)# encapsulation frame-relay Router-GER(config-if)# exit Router-GER(config)# interface serial 1/0.103 point-to-point Router-GER(config-subif)# frame-relay interface-dlci 103 Router-GER(config-subif)# ip address 2.2.2.1 255.255.255.252 Router-GER(config)# end Router-GER# write Router-GER# show frame-relay map Serial1/0.103 (up): point-to-point dlci, dlci 103, broadcast, status defined, active
Then we configure the router on NL:
Router-NL> enable Router-NL# configure terminal Router-NL(config)# interface serial 1/0 Router-NL(config-if)# no shutdown Router-NL(config-if)# encapsulation frame-relay Router-NL(config)# interface serial 1/0.201 point-to-point Router-NL(config-subif)# ip address 1.1.1.2 255.255.255.252 Router-NL(config-subif)# frame-relay interface-dlci 201 Router-NL(config-subif)# exit Router-NL(config)# interface serial 1/0.301 point-to-point Router-NL(config-subif)# frame-relay interface-dlci 301 Router-NL(config-subif)# ip address 2.2.2.2 255.255.255.252 Router-NL(config-subif)# end Router-NL# write Router-NL# show frame-relay map Serial1/0.201 (up): point-to-point dlci, dlci 201, broadcast, status defined, active Serial1/0.301 (up): point-to-point dlci, dlci 301, broadcast, status defined, active
Then we need to configure routing between these routers. You can choose OSPF or EIGRP or another routing protocol, but for this tutorial we used static routing:
Configure Router-BE to reach the network 2.2.2.0 :
Router-BE> enable Router-BE# configure terminal Router-BE(config)# ip route 2.2.2.0 255.255.255.252 1.1.1.2 Router-BE(config)# end Router-BE# write
Configure Router-GER to reach the network 1.1.1.0 :
Router-BE> enable Router-BE# configure terminal Router-BE(config)# ip route 1.1.1.0 255.255.255.252 2.2.2.2 Router-BE(config)# end Router-BE# write
Now both site’s (GER & BE) should be able to ping each other, thru NL!
You can download the Packet Tracer file here !
