From: Mark Newcomb (MNewcomb@wsgi.com)
Date: Wed Mar 26 2003 - 13:18:52 GMT-3
The issue is that the 2501 does not have a 100mb interface, which is
required for ISL. I get this from the following URL:
http://www.cisco.com/en/US/tech/tk389/tk390/technologies_tech_note09186a0080
0949fc.shtml#prereq
VLAN-trunking allows 100Mb Fast Ethernet, or 1000Mb Gigabit Ethernet
interfaces to place a tag on the packet that identifies the VLAN to which
the packet belongs. When the other end of the Inter-Switch Link (ISL) Trunk
receives this tagged packet, it will place it in the correct VLAN. The ISL
tag is a 30 byte header that is added around the Fast Ethernet frame.
Because of this, ISL is a point-to-point technology and will only work
between two Cisco devices (switches or routers) that support ISL on their
100Mb Fast Ethernet or 1000Mb Gigabit Ethernet interfaces. For more details
on the ISL packet and header, see the ISL Functional Specification. The
figure below provides a visual description of ISL trunks.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Mike Williams
Sent: Tuesday, March 25, 2003 7:30 PM
To: 'Danny Andaluz'; 'Larry Letterman'; 'Jennifer Bellucci';
ccielab@groupstudy.com
Subject: RE: ISL on C2500?
I know I recall hearing/reading this somewhere, but I can't find docs to
back it up.....
Mike W.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Danny Andaluz
Sent: Tuesday, March 25, 2003 6:06 PM
To: Larry Letterman; Jennifer Bellucci; ccielab@groupstudy.com
Subject: Re: ISL on C2500?
I remember seeing on some message board somewhere that you could trunk
on a 2500 Ethernet interface as long as you used 802.1q. Has anyone
heard this before?
----- Original Message -----
From: "Larry Letterman" <lletterm@cisco.com>
To: "Jennifer Bellucci" <jennifer_bellucci@hotmail.com>;
<ccielab@groupstudy.com>
Sent: Tuesday, March 25, 2003 2:29 PM
Subject: Re: ISL on C2500?
> Its not addable, its an issue that the chipset for the 2500 series
> does not support. Recall the 2500 platform is quite old and was around
before
> Vlans became a popular item...
>
> Larry Letterman
> Network Engineer
> Cisco Systems
>
>
> ----- Original Message -----
> From: Jennifer Bellucci
> To: ccielab@groupstudy.com
> Sent: Tuesday, March 25, 2003 8:26 AM
> Subject: Re: ISL on C2500?
>
>
> Thanks to everyone who replied. Shame on Cisco. You'd think that
> they
would
> add the feature just for the sake of it, for training people or
something.
> I
> heard that there is actually a IOS version specifically used for
testing, I
> am not talking about the traffic gen version.
>
> Bye
>
> ----- Original Message -----
> From: "Jennifer Bellucci" <jennifer_bellucci@hotmail.com>
> To: <ccielab@groupstudy.com>
> Sent: Monday, March 24, 2003 11:54 PM
> Subject: ISL on C2500?
>
>
> > Hi People
> >
> > I was doing a lab and then had a minor diversion into trunking and
the
> like.
> > As most of my lab was made up of 2500's I was wondering if there
> is a
IOS
> > image that enable you to use ISL encap on a...say something like a
2501.
> I
> > tried in hope on 12.2 and nothing.
> >
> > I remember seeing a thread on this some time back but my brain is
already
> > threatening to sue for negligence. Any help would be appreciated.
And...I
> know
> > you can do it on FA and like ports, I am talking specifically on
10MB
> ether's
> > on the model mentioned.
> >
> > After trying 12.1.18 and 12.2, I think I need to get a life or do
> something
> > really stupid and become a wife or something.
> >
> > Enough of my boring ramblings.
> >
> > Er...please help.
> >
> > Jbell...0x2142
> > Jennifer_bellucci@hotmail.com
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