Inter-VLAN routing on 2500 Series router?

Answered Question
Jul 4th, 2007

Does any 2500 Series router with any specific IOS support inter-VLAN routing (Router on a Stick?) I have a 2513 running 12.2(29a) which I am trying to create sub-interfaces for trunking and it will not recognize the "encapsulation isl vlan-id" command. Is it the fact that the router Ethernet port is only 10 Mbps or could it be the IOS? I'm pretty sure I have done this on a 10 Mbps port in a 3640 router with later IOS installed. Is it possible or am I mistaken?

I do have a 2520 router as well in case that makes a difference. Thank you.

I have this problem too.
0 votes
Correct Answer by Paolo Bevilacqua about 9 years 3 months ago

Hi James,

it is not possible to do that, no matter the 2500 specific model or IOS version.

Hope this helps, please rate post if it does!

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Overall Rating: 3.3 (7 ratings)
Correct Answer
Paolo Bevilacqua Wed, 07/04/2007 - 10:18

Hi James,

it is not possible to do that, no matter the 2500 specific model or IOS version.

Hope this helps, please rate post if it does!

jamesd058 Wed, 07/04/2007 - 11:23

Good thing these are borrowed then! Appreciate the information. I'll be working on my CCNP through next year and will need to build a small lab. Would it be worthwhile to have 2611 or 2621 (2 x FaEthernet) even if not an XM model, for things like having a Router on a Stick? I might have a line on a used one. I know 3640's are better, I have one now. Building a lab is not easy nor cheap!!!


mahmoodmkl Wed, 07/04/2007 - 10:23


As the other poster said it is not possible on this platfrom.U may need atleast a 2600.



baydata Thu, 07/05/2007 - 04:20

2500 Series is not suitable for Inter-VLAN Routing. Minimum you required 2600 Series.

inzeos781 Thu, 07/05/2007 - 05:10


You need at a minimum a 2610, which is configured with max memory and flash 64MB/16MB. Once you have that insure that it is running an IP Plus+ IOS later than 12.2T.

The following image would be current and support what you want to do;


However, make sure you have the appropriate license / support etc. You can find this using the feature navigator;

Software: IOS

Major Release: 12.3

Release: 12.3(22)

Platform: 2610-2613


Good luck with your search!

Paolo Bevilacqua Thu, 07/05/2007 - 05:25

I would like to invite the person that is low-rating posts in this thread, that are 100% correct, to desist or explain the reason of such an inappropriate behavior.

Good morning, I'm new in Cisco forum; I need to ask about the ISL on cisco 2621: I would to buy a router 2610 (used) to build my lab to study for CCNA certification. I sow the answer of Inzeos781 in this forum posted Jul 4, 2007 where to configure the ISL is needed minumum 2610 with max memory and image c2600-is5-mz.12.3-22.bin and feature set IP Plus+ IOS later than 12.2T.

This is the version that I would to Buy: IOS (tm) C2600 Software (C2600-I-M), Version 12.3(22), RELEASE SOFTWARE (fc2), System image file is "flash:c2600-i-mz.123-22.bin", (not c2600-is5-mz.12.3-22.bin as Inzeos781 wrote)

1 Ethernet/IEEE 802.3 interface(s)

2 Serial(sync/async) network interface(s)

32K bytes of non-volatile configuration memory.

8192K bytes of processor board System flash (Read/Write)

Question: can I configure the Vlan ISL on this router in an ethernet 10 mbit and not fast ethernet, without maximum memory, only to study? If somebody or Inzeos781 could answer me I will grateful. Thank You in advance.

Camillo (ITALY)

inzeos781 Thu, 07/05/2007 - 05:53

The 2520 in home labs is typically configured to act as a frame relay switch. It is an ideal piece of hardware because it is inexpensive and has four db60 style serial ports.

ryancolson Thu, 09/27/2007 - 10:19

another good router for home use/study is the 1721 as it supports dot1q trunking/inter vlan routing


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