[c-nsp] 7600 vs 12404

Per Carlson ml at carlson.homeunix.net
Mon Nov 8 07:01:42 EST 2004

On 2004-11-08 12:38, Mikael Abrahamsson wrote:
> On Mon, 8 Nov 2004 sthaug at nethelp.no wrote:
>>It's probably hair-splitting - but a 6500 can be operated with a pure L3
>>configuration (IP addresses directly on all ports, no externally visible
>>VLANs, no MAC address learning). In such a configuration, I would claim
>>it's completely irrelevant to me whether part of the box operates as an
>>Ethernet switch internally, as long as it does the job. I'd call it a
> But can you put IP-adresses on subinterfaces (tagged) on those ports, as 
> you would be able to do on a 7200/7300/12000, ie reuse the same tag on 
> several ports as completely different? I thought this could only be done 
> on the OSMs?

With the introduction of Sup720, you can configure subinterfaces also on 
  ports on WS-X-cards, according to this document at CCO:

But there is an important note:
"Because VLAN IDs are global to the switch, you can use a VLAN 
internally, on a subinterface, or with a Layer 3 VLAN interface.
Note: You cannot configure a VLAN used on one interface or subinterface 
on another interface or subinterface."

So, if you would like to use two different subinterfaces, both with 
'encapsulation dot1q 100', it can't be done as would expect of a *true* 

I'm still wondering how this 'internal Vlan' will treat a incoming BPDU...


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