LAN Switching with 3x 2811 routers with NM-16ESW mod

Answered Question
Mar 18th, 2010

I have a bet with 2 network guys on my job that states you cannot create a switched network with

only the NM-16ESW modules. Without the traffic going across the route processor.

I do not have access to a large volume of routers anymore, but I'm pro in saying connectivity can be achieved so as long as there is a L3 connection some where. So, essentially the lab would look like the following:

Router 0 - 3825 w/ESW

Fa2/0 - Trunked to Router 1

Int VLAN 3 - IP Address

Router 1 - 2811 w/16ESW

Fa0/0 - Trunked to Router 2

Fa0/1 - Trunked to Router 3

Router 2 - 2811 w/16ESW

Fa0/0 - Trunked to Router 1

Router 3 - 2811 w/16ESW

Fa0/0 - Trunked to Router 1

Kinda vague but this is a basic challenge lab. The question isn't whether you need a L3 device, the question is can the 16ESW Module provide switching without going across the 2811 routed interfaces and route processor. The other mind ignoring factor is the waste of a 2811 router if this was put in place, but that should not be the thought factor.

Any help would be helpful.

Akilla21

I have this problem too.
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Correct Answer by Leo Laohoo about 6 years 8 months ago

If memory serves me correctly, the NME-16ESW is a cut-down version of a 3750 switch.  Your need to determine if you can load IP Services feature set and use the command "ip routing".

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Correct Answer
Leo Laohoo Thu, 03/18/2010 - 14:12

If memory serves me correctly, the NME-16ESW is a cut-down version of a 3750 switch.  Your need to determine if you can load IP Services feature set and use the command "ip routing".

aqeel.karim Thu, 03/18/2010 - 23:51

Of course the router can handle the IPServices IOS and yes, ip routing can be enabled. But enabling IP routing goes against my theory, that switching across the 16ESW can be accomplished without going across the route processor.

Leo Laohoo Fri, 03/19/2010 - 17:38

I meant loading the IP Services feature set into the 16-port switch module.

aqeel.karim Sat, 11/20/2010 - 05:58

Leo,

I was finally able to lab this up with Packet Tracer. And my findings are correct, you can pass L2 traffic on 2811 routers using the 16-Port LAN module. I still needed a L3 interface for the vlan's but that wasn't the question.  Take a look at the labs.

glen.grant Sat, 11/20/2010 - 07:36

   Not really sure what the question is here . If the question is can you just use the 16 port switchports to route between routers and run a routing protocol the answer is yes you can .  We do this all the time even with the little 4 port hwics  , you don't have to use the internal router interfaces to go between routers if you have a switchcard installed  you can use the switchcard ports to route  , the only difference being  at least on the 4 port hwics we have used is that you cannot make the ports a routed port and you have to use layer 3 SVI's  and assign the switchport into that vlan , not sure about the 16 port model . Sorry unless you have packet tracer you can't read your file...

aqeel.karim Sun, 11/21/2010 - 07:32

Glen,

That was the exact question. And the attachment contains txt files and images, no Packet tracert lab files. And to answer your questions, yes the 16-ESW can turn L2 interfaces to routed interfaces. I've done that with it too.

Aqeel

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