Hmmm,
I disagree cause I am using only dot1q STP and I have a STP instance for each
VLAN... It is an enhancement that I have heard is trying to make it into the
dot1q standard... If you connect "NON Cisco" devices you can only have a single
instance of STP but if you are using all Cisco equipment, multiple instances
work just fine...
Everett
Oleg Kostine wrote:
> One little detail:
> If you use 802.1q on Cisco you have only one STP domain for all vlans over
> the trunk.
> 29xx,35xx or 6x00 manuals is a good source for more info.
>
> -----Original Message-----
> From: Dmitri Kalintsev [mailto:dek@hades.uz]
> Sent: 20 September 2000 12:57
> To: cisco-nsp@puck.nether.net
> Subject: Re: [nsp] ISL and 802.1q trunk
>
> On Wed, Sep 20, 2000 at 06:07:48PM +0800, Cho Man Fai wrote:
> >
> > Dear all,
> >
> > Can ISL and 802.1q trunk exist in the same network? Any workaround to do
>
> Sure they can. One little detail - if you run VLANs with numbers higher than
> 1000 when you use 802.1q, you'll have to manually map them into lower
> numbers
> when you need them to cross ISL trunk.
>
> > so without changing the whole network to 802.1q? What's the pros and cons
> > of the two trunking protocol?
>
> 802.1q is an industry standard, though not all cisco catalysts support it.
> 802.1q will support up to 4096 VLANs, where ISL will support only 1024 (or
> 1000? correct me if I'm wrong). ISL does not really care about "native VLAN"
> for trunk port, 802.1q does - it must match on both sides of the trunk or
> you'll get lost packets.
>
> In general, the answer probably is "use 802.1q where you can, and ISL where
> you must".
>
> SY,
> --
> CCNP,CCDP (R&S) Dmitri E. Kalintsev
> CDPlayer@irc Chief of Network Operations @ Sonorous Networks
> dek @ hades.uz phone: +27 11-327-1524 fax: 327-7648
> http://hades.uz UIN:7150410 cell +27 82-336-1033
--
<><><><><><><><><><><><><><><><><><><><><><><><><><><>
"Failure is not an option"
Gene Cranz, Apollo 13 mission
<><><><><><><><><><><><><><><><><><><><><><><><><><><>
Everett Dowd edowd@clark.net
CCIE #2409 http://www.clark.net/pub/edowd
Just bein' virtual =8^) Welcome to the 'net
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