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New Member

3560 redundant configuration?

I have customer we are installing 2 3560's, one at building a and one at building b. The buildings are connected with one Optical link and one 5.8GHz link. The 5.8GHz link will plug into one of the 10/100 port and the optical will plug into port 1 Fiber ports. Port 2 fiber will be connected to there exsisting network, this is on both sides.

The Optical will be the primary link at 1000Mbps, I need to configure the switches to failover to the 5.8GHz 100Mbps link in the event the Optical goes down.

I will be recieving IP address's shortly so I can preconfigure the radios and switches prior to installation.

Any recommendations?


Re: 3560 redundant configuration?

Hi Charlie,

Are you running same vlans on both the sides i.e you are extending you vlans from building A to building B. If yes, then STP will block one port automatically at Layer2.

If you are not extending the vlans on both the buildings then you have to do the inter-vlan routing for the vlans in building A at the 3560 locally and same on the building 2 3560.

Once you have the Ip addresses you can set up the floating static/defualt routes on 3560. You need to see how many vlans are there and then you have to add the routes on both the 3560.

conf t

ip routing

ip route x.x.x.x

ip route y.y.y.y 200

You can also run a routing protocol lik rip

conf t

router rip

network x.x.x.x

network y.y.y.y

RIP also support eual-path cost load-balacing. RIP metric is hop-count and in this case the hop-count will be same so RIP will send the traffic using both the links and in case if one fails the traffic will route automaically via the other link.

HTH, Please rate if it does.

-amit singh

New Member

Re: 3560 redundant configuration?

This looks great, in the first example x.x.x.x would be the network # for the first Vlan, correct? And then y.y.y.y 200 would be a higher cost so this would be the backup route or link. Would STP take care of this automatically?

New Member

Re: 3560 redundant configuration?

Thank ou again Amit, I've included the ip's and map to better explain my needs.


Re: 3560 redundant configuration?


The biggest drawback of FSO is that even a bird flies from your link zone, the link will be down for that particular moment and this will confuse the L2 which will result in switch hanging during convergence.This problem of birds and weather I have faced myself.Hence its always recommendiable to implement routing between both of your links and do it through layer 3 routing protocols.

Pls visit this link whose author has faced similar problems

Pls rate helpful posts.