c2600 Encapsulation problem

[sbsinfo67]

Hi

i have some problems with a 2600 cisco router (2620)

routeur série 2600 ---> 2620 avec IOS C2600 software (C2600-I-M) version 12.0 (7)T release software (fc2)

The problem is:

Exemple

routeur#conf t
routeur(config)#int fa0/0.2
routeur(config-subif)#ip address 192.168.1.1 255.255.255.0

routeur(config-subif)#encapsulation dot1Q 20
                                        ^
% invalid input detected at '^' marker

Why??? is their a IOS problem???

The problem is the same when i configure encapsulation  first and then the ip address

i want to buy a other cisco router
CISCO 2600 SERIES ROUTER - 2610 16/32MB 4X ISDN
IOS C2600 Software (C2600-I-M), Version 12.2 Bridging software. X.25 software, Version 3.0.0. Basic Rate ISDN software, Version 1.1
do you think that the encpsulation works on this router

Thanks
Best regards
JG

[John Blakley]

I attached a text file that shows you what version of IOS you should be on to support 802.1q on your platform. The only requirement hardware-wise that I'm aware of is that the router needs to have a fastethernet port in order to support 802.1q encapsulation. If the other router that you're looking at has only an ethernet port, then you probably won't be able to support vlans on it.

HTH,

John

[Peter Paluch]

John,

Purely technically, the 802.1Q tagging scheme is nothing different from using 802.2LLC or 802.2SNAP encapsulations on the same interface in that the 802.1Q tag is inserted into the payload part of the frame, and does not need to be processed by the NIC itself. It can be entirely processed in software.

There are small corner cases here, like the fact that the max frame size will grow from 1518 bytes up to 1522 bytes, and that the VLAN tag processing can indeed be done more efficiently in hardware than in the operating system itself. Therefore, Cisco has - for quite a long time - mandated that the 802.1Q encapsulation is supported only on FastEthernet ports, most probably because of some hardware support to offload software operations. However, since a certain IOS version - I do not remeber which it is - even 2610 routers sporting 10Mbps Ethernets do support 802.1Q on them - we use them extensively in our labs.

So this purely depends on the vendor and its willingness to support new technologies over old interfaces. But from a technical standpoint, tagging is nothing special at all.

Best regards,

Peter

[John Blakley]

Interesting. Nothing I have in my lab that has 10baseT interfaces support 802.1q. I looked up what you said and found that it's very limited:

http://www.cisco.com/en/US/products/hw/routers/ps259/prod_bulletin09186a00800921e4.html

It's been supported since 12.1(5)T, but like you said, was limited to FE in prior versions.

Thanks for the clarification!

John

[cadet alain]

Hi,

What's weird is that it let you configure ip addressing before configuring encapsulation.

Regards.

Alain.

[amikat]

Hi,

Your router has IP Feature Set (licence) only. To support 802.1Q Vlan you must have at least IP Plus Feature Set (indicated by c2600-IS-M software version). The same applies for the router you would like to buy (ie. that one does NOT support IEEE 802.1Q Vlan either).

Best regards,

Antonin