How to bridge two or more network ports on Cisco routers

Bridging network ports is one of the most commonly done things in networking yet a few engineers know how to implement it using Cisco routers. It helps eliminate the need for a switch in some cases. Port bridging is the processing of bundling two or more network ports together and assigning an IP address to them. By so doing, all devices plugged into the bridged ports, become members of the same network with IP addresses from the same subnet.
One would think that implementing a solution like this should be relatively easy. Well, on an platform like the Mikrotik RouterOS, it is, thanks to its graphical user interface. Can the same thing be said of the Cisco IOS? In this article, we will find out.

From the network diagram above, we want to bundle the two interfaces on the router connecting to the layer three switches into one network and assign an IP to the bridge. This is because we want a redundant setup where if one of the switches goes, it does not affect our operations. Each access layer device has two paths to reach the router. Spanning tree is keeping one of the ports in blocking state while the other is forwarding. In the event that the designated port goes down, the alternate port goes into forwarding state.
To do this, we create a bridge and make the two interface members of that bridge and then assign an IP to that bridge. This IP will be biding on any of the interfaces. Here is how it is down.

bridging network ports

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If you find it difficult reading config files, here is the hand-typed version of it:
Router(config)#hostname timigate.com
timigate.com(config)#bridge irb
timigate.com(config)#bridge 1 protocol ieee
timigate.com(config)#bridge 1 route ip
timigate.com(config)#int f0/0
timigate.com(config-if)#bridge-group 1
timigate.com(config-if)#no shut
timigate.com(config-if)#int f0/1
timigate.com(config-if)#bridge-group 1
timigate.com(config-if)#no shut
timigate.com(config-if)#exit
timigate.com(config)#int bvi 1
timigate.com(config-if)#ip add 192.168.1.1 255.255.255.0
timigate.com(config-if)#exit
timigate.com(config)#exit
timigate.com#copy run start.

bridging network ports

That is how quick and easy it is to bridge ports on any Cisco router. Thanks for reading and don’t forget to like our page..

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Timigate

Ashioma Michael, a BSc (Computer Science)., MTCNA, CCNA, and CCNP holder with many years of industry-proven experience in network design, implementation and optimization. He has tutored and guided many professionals towards obtaining their Cisco certifications. Mike works as a senior network engineer with one of the leading internet service providers in West Africa.

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