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Why use layer 3 capable Ethernet cards in a router?

We have an MPLS network and have installed 3825 routers at each of the locations.

Video conferencing, voice and data traffic is presented to seperate Ethernet interfaces on the routers Ethernet interfaces. I have two modules installed:

NM-2FE2W-V2

The video, voice and data traffic is seperated into different VLANs.

Now I have been asked to replace the above Ethernet cards because they are not layer 3 capable.

Having searched the Cisco website I've found the following layer 3 module:

HWIC-2FE

The above is layer 3 capable and you can install upto two of these in a 3825 router.

My question is why would we need the layer 3 cards? The VLAN tagging is layer 2 anyway. Routing between VLANs, should this be required, can be done by the router.

Can someone please clarify?

Thanks.

Farouq

Reply to
Farouq
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Not many switch ports are layer-3 ... obviously. If your need is layer-2, there is no immediate need for layer-3 ports. The "big" difference are the capability to enter "no switchport" which then turns it into a router port i.e. layer-3 So the need for router ports are the question here, and keep in mind that QoS is different in layer-3.

HTH Martin

Reply to
Martin Bilgrav

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