01-01-2009 02:39 PM - edited 03-06-2019 03:13 AM
Hi,
I have some 2600 routers that do not allow for encapsulation to be set when a sub-interface is created. I guess this is due to IOS but was wondering how you configure a sub-interface without the encap command available. I imagine it is a possibility since it allows for the creation of the sub-if but can't figure out how. Is it done by using the bridge group commands?
Thanks,
Richard
01-01-2009 02:54 PM
Hello Richard,
if the encapsulation command is not supported I think you cannot use Vlan subinterfaces.
In this kind Of IOS images bridge-group commands are supported on physical interfaces.
Once it happened to me to load an IOS image in a Cisco 7200 or 7500 with the same behaviour I tried to use them with no success.
The Cisco engineer that was following us told us to change it.
missing to define a way to multiplex demultiplex frames over the trunk should cause forwarding problems.
However, you can try with the bridge-group command if supported and using BVIs (IRB) but I usually saw bridge-group supported on main interfaces only
Hope to help
Giuseppe
01-01-2009 03:05 PM
Thanks Guiseppe,
How should the distant end sub-interface that supports dot1q be set up if using the bridge-group command on the physical interface at the local device?
Richard
01-01-2009 11:21 PM
Hello Richard,
sorry if I've been unclear:
if enc command is missing AND bridge-group can be given only on main interface
THEN
you cannot use VLan subifs
Look for an IOS upgrade.
Hope to help
Giuseppe
01-01-2009 11:37 PM
Hi,
This is a common issue with low end IOS versions on 26xx routers, typical solution is to upgrade IOS and maybe memory on router, depending on the chosen IOS. Take a look at this previous post:
More posts on this issue can be found searching for "encapsulation dot1q unrecognized".
Regards.
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide