Intervlan routing on 877

Unanswered Question
Aug 4th, 2007

Dear All,

Is it possible to configure InterVlan on 877 series? I tried configuring subinterfaces on Fa 1-3 and failed. Can someone please suggest.

IOS Version:

C870 Software (C870-ADVSECURITYK9-M), Version 12.4(4)T2.

I have this problem too.
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Paolo Bevilacqua Sat, 08/04/2007 - 11:22

Not possible with the software you have currently.

You need an advance IP service images for VLAN support on the 87x. To get it, you need access to CCO download using a service contract that you can buy from any reputable reseller, plus the image upgrade license.

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shjengschool Sun, 08/05/2007 - 07:00

Hi p.bevilacqua,

I have upgraded the IOS to C870 Software (C870-ADVIPSERVICESK9-M), Version 12.4(15)T1 and it is still not allowing me to do configure subinterfaces for fa1,2 or 3.

Am I doing something wrong. Please advice.



Paolo Bevilacqua Sun, 08/05/2007 - 08:26

What you are trying to do is tagging and I think is not supported, except possibly on port FA4 of an 877.

You can put each FA port in a different VLAN via "switchport access vlan " and then configure "int VLANxx" for IP address, etc.

Hope this helps, please rate post if it does!

shjengschool Sun, 08/05/2007 - 21:30


Sorry for not explaning what am I going to achieve.

I have Cat 2950 Series switch on which I have configured 5 Vlans. For intervlan communication am trying to use 877 as a router on a stick model.

One of the port (trunk) from 2950 can be connected to 877 Fa port for intervlan routing.

Please advice if am doing mistakes.



mohammedmahmoud Mon, 08/06/2007 - 00:21

Hi Sunoj,

As Paolo has stated earlier in this thread, if you are using Advanced IP Services Cisco IOS Software Image, then yes you can do a router-on-a-stick, as this is the only feature set that supports 802.1q trunking on the 870 series, while your Advanced Security Software Image doesn't.


Mohammed Mahmoud.

Paolo Bevilacqua Mon, 08/06/2007 - 01:38

Hi Mohammed,

I haven't tried myself but I think what Sunoj is telling us is that he can't configure subinterfaces meaning he can't do "router on a stick".

I suppose the FA port on the 877 can be used as access ports only then.

As I said above (my mistake I wrote 877 instead of 871), perhaps port FA4 of such model could support tagged encapsulation.

shjengschool Mon, 08/06/2007 - 08:42

I have installed Advanced IP Services as per p.bevilacqua suggestion. But still no luck. Any advices?



Paolo Bevilacqua Mon, 08/06/2007 - 08:52

Hi Sunoj,

what I'm telling you is that you won't be able to configure "switchport mode trunk", instead you will be able to configure each port in a different VLAN, and up to 4 VLAN "virtual" interfaces, and you will be able to do inter-vlan routing this way, of course with limited performances.

Paolo Bevilacqua Mon, 08/06/2007 - 09:58

To further clarify, the "limited performances" is not because you are connecting each vlan to a different port, but because the 87x platform does everything in software and the CPU is not enough to router fastethernet at wire speed.


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