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New Member

VLAN Routing on 1720/1721

I cant get vlan routing to work on any 1720/1721 router, I've tried several different routers with different IOS versions and none works.

The problem is to set the command: encapsulation dot1q, but it doenst exist!

Not even on a crypto/firewall based IOS.

Do someone have any ideas that can help?

//Rulif

12 REPLIES
New Member

Re: VLAN Routing on 1720/1721

Did you implement (configure) a routing protocol like OSPF, EIGRP, IGRP or RIP?

New Member

Re: VLAN Routing on 1720/1721

No not at all, havent even come that far. I just made a subinterface and tried to enable dot1q encapsulation. Same goes for my teacher he hasnt been able to get this to work either on any 1721 we have :(

//Rulif

Hall of Fame Super Silver

Re: VLAN Routing on 1720/1721

Rulif

I tried to create VLAN subinterfaces on a 1720 and agree that it looks like the platform does not support it. I tried it on a 1721 and it worked for me. At least I could create the subinterface and enter the encapsulation command on it. I am not doing actual VLANs on these router so I can not say that it passed traffic or did real trunking. But it sure looks like it works correctly.

I am running the advanced secrity feature set on these routers.

Did you create the subinterface and attempt to do the encapsulation on the subinterface?

HTH

Rick

New Member

Re: VLAN Routing on 1720/1721

Yes thats correct but the router doesnt accept the encapsulation dot1q command. According to Ciscos data sheet for the 1700 series VLAN Routing should work on all 1700s regardless of IOS features, but it seems it is not the case.

//Rulif

Re: VLAN Routing on 1720/1721

Hi Friend,

Encapsulation command will only work if you have a minimum of IP PLUS feature.

So can you try upgrading your router with IOS having IP PLUS feature and update if it works.

Ankur

New Member

Re: VLAN Routing on 1720/1721

Hello there

Currently using c1700-k9o3sy7-mz.122-8.T5.bin on my 1720 with no luck. And we have simular IOSes on the 1721s at my school and we are not able to make it work on them either :(

//Rulif

Re: VLAN Routing on 1720/1721

Hi Friend,

If you have tested all IOS then you are hitting the bug CSCsa70023.

http://www.cisco.com/cgi-bin/bugtool/onebug.pl?bugid=CSCsa70023

HTH, if yes please rate the post.

Ankur

New Member

Re: VLAN Routing on 1720/1721

Hi there!

I would like to, but i dont have rights to post there :( Tried several different IOSes on 1721 now without success. The error I always get is:

Router(config)#int fa0.1

Router(config-subif)#encapsulation dot1q

^

% Invalid input detected at '^' marker.

Router(config-subif)#

//Rulif

Re: VLAN Routing on 1720/1721

Hi

Can u try to enable encapsulation on the physical interface before enabling it on logical i mean sub-interfaces.sometimes it works.

And can u post the output of show version.

Thanks

Mahmood

Re: VLAN Routing on 1720/1721

Hi Rulif,

Your 1721 is surely hitting this bug which I mentioned in my last post.

Below is the description for the bug

CSCsa70023 Bug Details

Headline Unable to configure dot1q encapsulation on Cisco 1721

Product IOS

Feature OTHERS

Severity 3 Severity

Status Junked Status help

First Found-in Version 12.2T, 12.3T, 12.3, 12.3(4)T10 All affected versions First Fixed-in Version Version help

Release Notes

Symptom: A Cisco 1721 Series Router may return an unrecognized command error when configuring dot1q encapsulation (output below).

router_vlan(config-subif)#encapsulation dot1q 1 na

^

% Invalid input detected at '^' marker.

router_vlan(config-subif)#

Condition: This was observed on a Cisco 1721 running any IOS.

Workaround: None.

HTH, if yes please rate the post.

Ankur

New Member

Re: VLAN Routing on 1720/1721

Hello

Thanks that makes sense. But it seems it applys to the 12.4 ISO aswell tried several of those too. Hope cisco can/will fix this.

Rulif

Re: VLAN Routing on 1720/1721

Hi Rulif,

Yes this bug is not resolved in any IOS so only solution for time being is to get the router replaced.

HTH, if yes please rate the post

Ankur

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