[c-nsp] Re: Vlans above 1005 on WIC-4ESW

[Per Carlson]

On Wed, Apr 13, 2005 at 01:17:38PM +0300, Bulgaria Online - Assen Totin wrote:
> 
> I'm not very familiar with the 1700, but... are you trying to create a
> separate Vlan interface ("switch" mode), or a sub-interface of an
> Ethernet/FastEthernet interface ("routers" mode)?

The WIC-4ESW module does only support SVI's (interface Vlan). 

> Does your device/IOS support VTP? If you are looking for a separate
> Vlan intervace, you might need this command:
> 
> vtp mode transparent

Sure, am using transparent mode, but it's configured under the 
'vlan database' command.

> Getting a bit off-topic, the number of dot1q VLANs supported should
> not be considered a "hardware" limitation but rather a limitation of
> the deployment mechanism, chosen by Cisco. (After all, this is merely
> a tag into the Ethernet frame...). When it comes to switches, they
> store VLANs below 1005 in a special "database" while VLANs above 1005
> are not stored there. 

In new switches (2950, 3550, 3750 etc), the 'vlan database' is no longer
used (at least in transparent mode). Instead you configure the Vlan's
from the regular CLI.

As the WIC-4ESW demands Vlan configuration through the database, I
suspect that the hardware is inherited from older switch models, like
the 3500XL, which (if I don't remember wrongly) only supportcws Vlan's up
to 1005.

> Cisco routers with IP+ IOS, on the other hand,
> create dot1q subinterfaces on any Ethernet interface (even a 10 Mbps
> one) without problems.

The 'fixed' FastEthernet port on the 1712 behaves like a normal router
port, and is configured using subinterfaces. 

-- 

Regards, Per Carlson

Whenever people agree with me I always feel I must be wrong.
  -- Oscar Wilde