Re: [nsp] Trunking questons

From: Basil Dolmatov (dol@info.east.ru)
Date: Fri Feb 04 2000 - 05:11:17 EST


On Fri, 4 Feb 2000, Rich Sena wrote:

> > > Problem is that when I number the subinterface on the 7513 I lose
> > > connectivity. Basically what I am doing is moving the addresses to the
> > > subinterfaces, encapsulating isl, and setting a bridge group on the 7513
> > ===================================^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > If you set bridge-group, then you switch off routing IP on this
> > interface, so you will have no connectivity over this interface to
> > router. You have to use IRB in order to include router into bridging
> > domain
>
> Yeah I foubnd that out the hard way...
>
> > > then stting trunking on the 6509 desirable
> > Check that 6509 is configured for ISL. This box can have 802.1q as
> > default trunking method...
>
> Yep it is ISL
>
>
> OK I have more questions here - I got 2 answers to one of the parts of my
> question...
>
> 1 stated that I needed to set each subnet into a seperate sub-interface on
> the interface that is connected to the switch and 1 said that I could
> combine the subnets on the same interface - more than likely both are
> right just different ways of doing the same thing. What I want to know is
> what are the advantages of each. In my situation I want to segment the
> broadcast domains with the VLANs - and I was hoping to reclaim the half
> dozen or so wasted addresses from my subnets in the process - but it has
> occured to me that I may not be able to set the single sub-interface into
> multiple VLANs - is that a true statement? Can the sub-interface on the
Yes. This is true... Subinterface on router trunk interface corresponds
to VLAN 1<->1.

> 7513 exist in multiple VLANs or do I need to keep the subnets (one for
> each VLAN) and set up a differnt sub-interface for each on the 7513...
>
Please, do not mix "subnets" and "VLANs"... They are different in nature,
and you can have several _subnets_ (concerning IP-addressing scheme) bounded
to one VLAN, but this practice is deprecated and should be avoided, if
possible. Best design is to have separate IP address space (i.e.
separate subnet) for each VLAN.

 
---------------------------------------------------------
Basil (Vasily) Dolmatov CCIE #5347, CCNP-Security, CCDA
East Connection ISP, Moscow, Russia. (http://www.east.ru)



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