Is This Doable

Unanswered Question
Sep 24th, 2007

hi all.

i have the following scenario and i want to see if it doable or not..

i have an 2600 router with two fastethernet interfaces.

the Scenario:

1- i want to connect Fast0/0 to the isp.

2- i want to connect Fast0/1 to a network with two vlans, so i want to implement two subinterfaces on it fast0/1.1 and fast0/1.50 with dot1q protocol, and each subinterface is the gatway for 1 of the vlans.

will this scenario work and both of the vlans can gain access to the internet ??

I have this problem too.
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Kevin Dorrell Mon, 09/24/2007 - 23:10

Yes, this will work provided you have the IP-plus feature set. I'm not sure whether the IP base feature set supports dot1q. Try the encapsulation command - if it accepts it, then you can do it.

I suppose you are using NAT towards the ISP rather than global Internet addresses. In that case, you will need to set ip nat outside on your F0/0, and ip nat inside on each of your F0/1 subinterfaces, and then the NAT translation commands in the normal way.

Kevin Dorrell


thaershunnar Mon, 09/24/2007 - 23:46

Thank Kevin..

Unfortunately the router i have does not support ip plus.. so immediatly i searched cisco to upgrade the ios and i found a lot of versions that can do the work.

the problem now is that i need to upgrade the hrdware too, i am not really sure.

for exampl one of the images i found is

c2600-is-mz.123-3c.bin (64/32)

and all the images have the number (64/32)

but the show version command on my router shows the following

cisco 2611XM (MPC860P) processor (revision 0x100) with 27648K/5120K bytes of mem


so i think i have a memory problem.. am i right ????

Kevin Dorrell Tue, 09/25/2007 - 00:01

It would seem that you need to upgrade the memory.

But before you do so, just check that your existing software does not support dot1q. What version is it?

interface F0/1.50

encapsulation ?

Kevin Dorrell


thaershunnar Tue, 09/25/2007 - 00:27

I have a new thought..

as i told you befor the sho version command shows:

cisco 2611XM (MPC860P) processor (revision 0x100) with 27648K/5120K bytes of memory.

but in other lines in shows:

32K bytes of non-volatile configuration memory.

16384K bytes of processor board System flash (Read/Write)

so i think that my router is (32/16). what do you think ???

Kevin Dorrell Tue, 09/25/2007 - 00:41

No, I'm afraid the 32 refers to Megs of DRAM, not to the NVRAM. You seem to have enough flash though.

Kevin Dorrell


thaershunnar Tue, 09/25/2007 - 01:07

Returning to the main subject, i want to say i am not using NAT, and the Servers connected to the gatway have public IPs, i just need to seperate the servers into 2 vlans. So there is no NAT.


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