advice on router purchase

Unanswered Question
Mar 6th, 2008

hi all

can someone please point me in the direction of a cisco router which has 4 ethernet ports (1 for each different network/subnet). Is this possible as the ones I seem to have come across only have one ethernet port and i cant seem to find expansion cards to suit. Please advise. the reason i need 4 is because we have 4 seperate net conenctions and i want to keep each one separate.


I have this problem too.
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andrew.burns Thu, 03/06/2008 - 08:22


Something like an 1841 with an HWIC-4ESW will give you 6 Fast Ethernet ports. However, the requirements are not very precise - if you consider the following questions the answer may change:

1) What kind of Ethernet? 10/100/1000 ?

2) What features do you need? (netflow, security, qos, nat, etc.)

3) Do they need to be physically separate ports, or would a trunk to a switch be possible?

4) What's the budget?

There are many things to consider, not just the requirements now but in the following years too.



solpandor Fri, 03/07/2008 - 02:01

Andrew thanks for your reply, answer to your q's


2)we would like nat and (if poss)qos

3)i would like them to be separate as to create 3 diff networks but are you saying that if it is trunked to a switch then i could create x no of separate vlans on diff subnets?

4)budget not sure but we not that tight on the purse strings


andrew.burns Fri, 03/07/2008 - 02:28


1) If you need gigabit then the 1841 won't do

2) I was thinking about a L3-switch but if you need NAT then that pretty much rules those out. QoS support is universal now so that shouldn't be a limiting factor.

3) Yes, it's not always recommended from a security standpoint but it's certainly possible, although if you were routing between them then the bandwidth would also be shared.

So, if budget isn't too much of a constraint then a 3825 will give you two 10/100/1000 ports plus slots for additional ethernet modules as required. For example, the HWIC-4ESW gives you 4 10/100, (there are 9 and 16-port versions also) and the HWIC-1GE-SFP gives you another gigabit port.

The data sheet is here:

Hope that gives you more ideas on possibilities.

HTH - plz rate useful posts (not just mine!)


solpandor Fri, 03/07/2008 - 03:23


the HWIC-4ESW - will this enable me to break the network up into 4 network? as its labelled a ethernet switch module, im thinking that it will just act as a switch? please clarify. also, whats the difference between HWIC-4ESW and this HWIC-2FE?



andrew.burns Fri, 03/07/2008 - 03:56


Yes, the way it works is that you would create 4 VLAN's and put a switchport into each VLAN. Then create 4 VLAN interfaces, which would give you your 4 separate networks.

This doc shows how to do it:

In answer to the second question, the HWIC-2FE adds 2 additional fast ethernet ports which work just like the in-built ones, i.e. no need for the VLAN config - just put the ip directly on the interface.



Joseph W. Doherty Fri, 03/07/2008 - 05:13


If you're planning to use this router purely for LAN routing, you would probably be better served by a small mulitlayer switch. The small software routers, although them have 100 Mbps and even gig Ethernet interfaces, don't often have the performance to substain Ethernet rates.

If you're also going to use this router for WAN routing, consider sizing it to support the WAN bandwidth. If most of the LAN traffic will be to/from the WAN link, you'll be fine. If there's still a lot of intra-LAN traffic, you might want both a small multilayer switch and the WAN router.

Joseph W. Doherty Fri, 03/07/2008 - 05:40

Touché! (Right you are, he did note that in his second post.)


Although still from a strictly performance standpoint, I consider most of software routers inadequate for obtaining maximum LAN routing performance. (Often even file copying from one host to another at 100 Mbps.) Assuming the NAT isn't required between LAN subnets, and again assuming there's LAN to LAN traffic, fronting a WAN router with a LAN router works well. In this instance, perhaps a 3560-8PC with whatever is needed for the WAN connection.


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