Re: Why use layer 3 capable Ethernet cards in a router?


"Farouq" <farouq_taj@xxxxxxxxxxx> wrote in message
news:1174558710.596948.15030@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
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?

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


Thanks.

Farouq



.

Relevant Pages

  • Re: gateway IP address
    ... An Ethernet (Layer 2) network is a 'local' environment, ... a gateway IP address can ... send the Ethernet frame to the router, so that it can pass it to the device ...
    (comp.dcom.sys.cisco)
  • Re: XP Home safe file sharing (newbie)
    ... >> Zone Alarm is an excellent internal layer of protection, ... >> You really, really, need an outer layer, ie a NAT router, protecting your ... >Router is NAT or NOT! ... The C45 IS a NAT router. ...
    (microsoft.public.windowsxp.network_web)
  • Re: XP vulnerabilities?
    ... >> Get a DSL router with NAT and then use ONE firewall application. ... The personal firewall will block outbound. ... whole issue of "stealth" became less important on January 25, ... Each layer is necessary because no layer produces ...
    (alt.computer.security)
  • Re: ARP requests on my net?
    ... My router is the one which needs to know ... AFAIK, TCP/IP uses IP, not ARP. ... ARP should be in Level 2, the P2P LAN layer. ... layer 4, two levels above MACs. ...
    (Fedora)
  • Re: Question bruteforcing
    ... because your router does not have the same OS, ... The router will give you one extra layer in your ... some may exploit an unknown vulnerability ... But to come full circle this is where a router would offer protection ...
    (Fedora)