Border gateway and switch redundancy

[Carl King]

Hi,

I'd like to establish a more robust border router/switch redundancy plan and would like to know if this seems like it would be reliable.

I'm looking at using a couple of 3945 routers and 3750 switches in the configuration shown below.

The article found at http://www.cisco.com/en/US/products/hw/switches/ps628/products_configuration_example09186a00800ef797.shtml

outlines  the config between a single switch and router but I am looking at doing this with dual routers and switches.

My question is, has anyone done this before and did it prove to be reliable?

Thanks Carl

[Marwan ALshawi]

yes this is a good design

by using port channel with vlans trunked in it from the router to the stack using diffrent physical switchport and switch for each link will provide you with good level of physical and logical rednandacy

however using two links for the Internet is something that you need to control using routing, PBR or both with IPSLA for best path selection or loadbalancing

hope this help

if helpful Rate

[Calin C.]

Hello,

I have such design in my environment and it work just fine until now. The truth is that we don't care about load balancing of the Internet traffic right now as we have 2 x 100Mbits Internet and none of the lines are yet overloaded. We let BGP (best path) to decide the best outgoing line.

When one of the line will get over utilized, then I think we'll do some of the solutions proposed by marwanshawi.

Cheers,

Calin

[Carl King]

Thanks Gents, That's helps a lot.

Additionally, would it be possible to do something similar with non Stackwise switches as well?

We have our /22 divided into /24's each on a respective vlan and trunked into the border routers. Each has a subinterface with an IP in the respective vlan and an HSRP IP for each as well. If I were to add the cross links where RouterA is trunked to SwitchB and vice versa would the router's subinterfaces on this link require IP's as well or would it perform L2 traffic switching to SwitchB if SwitchA should fail?

What I'm wondering is, would the router switch between subinterfaces if one of the subinterfaces was IP'd and the other wasn't?

Here's an example config where the same uplinking strategy is used but without stackwise switches and without port channeling on the router.

RouterA

Int g0/3  <-- Trunked to SwitchA

int g0/3.1

     encapsulation dot1Q 300

     ip address 1.1.1.2

     standby 1 ip 1.1.1.1

int g0/2 <-- trunked to SwitchB

int g0/2.1

     no ip address

     encapsulation dot1Q 300

RouterB

Int g0/3  <-- Trunked to SwitchA

int g0/3.1

     encapsulation dot1Q 300

     ip address 1.1.1.3

     standby 1 ip 1.1.1.1

int g0/2 <-- trunked to SwitchB

int g0/2.1

     no ip address

     encapsulation dot1Q 300

Carl