Help with redundant routing problem

[sdawson35]

Hello,

We have 2 sites , each site has 2 msfc's in Catalyst 6500 chassis, there is a single ethernet connection from the 6500 to a 3845 router. We would like to add a second ethernet connection from each chassis to the router to form a crossover so that "router a" would have 2 connections one from "chassis a" and one from "chassis b" same for "router b" then repeat this at the other site. Problem is we are not sure how to do this, can anybody help us or point us in the right direction please ?.

[zhiqiang.yan]

Create vlans

Lan_A

Lan_B

Lan_C

port which connecting from router_A to 6500_A,and router_B to 6500_A in vlan Lan_A

port which connecting from router_A to 6500_B, and router_B to 6500_B in vlan Lan_B

6500_A to 6500_B in vlan Lan_C

all in ospf area 0

traffic from 6500_A to router_A using linking 6500_A to router_A normally.

same to 6500_B to router_B

when the connection is broken.

use Lan_C linking

[sundar.palaniappan]

Hi,

You need a configuration like this one. Choose the VLAN you desire for the connection and configure HSRP. This setup will provide redundancy for your network

3845:

int f0/0

ip add 172.16.1.1 255.255.255.0

ip route 172.16.1.254

6500_A:

int f0/1

description 'connection_to_3845'

switchport access vlan 100

int vlan 100

ip add 172.16.1.2 255.255.255.0

standby 100 ip 172.16.1.254

standby 100 priority 110

6509_B:

int f0/1

description 'connection_to_3845'

switchport access vlan 100

int vlan 100

ip add 172.16.1.3 255.255.255.0

standby 100 ip 172.16.1.254

Feel free to ask any questions you may have.

Good Luck!!

Hope this helps!

Sundar

[gpulos]

just to be sure we know what your saying....

both sites have a 6500 w/2 x MSFCs and a 3845.

you want both sites 3845 to connect to the switch twice for redundancy reasons?

if this is the case, here is what you will need:

1) create a second VLAN on the switches and SVIs on the MSFCs (apply HSRP for your redundancy)

2) configure your 3845 interfaces to be used in the new VLAN created

3) use a routing protocol such as eigrp or ospf to provide the automatic routing/failover when the primary interface fails.