First things first. Just because an interface is Fast Ethernet does not mean
that the switch or router will support ISL. (In fact, the 4000 series of
switches do not support ISL). ISL is a Cisco-proprietary method of frame
tagging for VLAN's; the industry standard is IEEE 802.1Q. Cisco 802.10 is
used by Cisco for VLAN frame tagging over FDDI.


If you are using only one VLAN and not connecting to anything else that is
not in the VLAN's broadcast domain then you don't need a router. However,
since you are using a firewall it is doubtful this is what you are trying to
do. The router may or may not support ISL, depending on the interfaces and
the IOS software version.

"Donald B Johnson Jr" <[EMAIL PROTECTED]> wrote in message
023e01c03874$8862c4f0$[EMAIL PROTECTED]">news:023e01c03874$8862c4f0$[EMAIL PROTECTED]...
> If you just have one vlan I don't think you need a router
> Duck
> ----- Original Message -----
> From: Andrew Twigger <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Tuesday, October 17, 2000 7:03 AM
> Subject: Vlans over Links
>
>
> > Hi Group
> >
> > I wonder if any body can answer this or point me in the right direction
> for
> > me.
> >
> > I am looking at VLANs and what can be done with them.
> >
> > I know I can use ISL to link two switches together with even a router in
> the
> > middle and have a vlan running from switch to switch. I am also sure
that
> I
> > can use 802.10 to do the same. Also if my understanding is correct you
can
> > only use ISL when all interfaces are fast Ethernet?
> >
> > Question then, can you set up a Vlan between two switches but in between
> the
> > switches is not just a router but a PIX as well, so you  have :-
> >
> > Switch1(VLAN10) - - - -  Router - - -  - PIX - - - - - Router - - - - -
> > Switch (VLAN10)
> >
> > Is this possible? if so do you use ISL or 802.10?
> >
> > Thank in advance.
> >
> > Andrew
> >
> > Andrew S. Twigger MCP, Network+, CCNA
> > Snr Systems Engineer
> > Technical Service's
> > DIALnet PLC
> > e : [EMAIL PROTECTED]
> > t : 0121 624 5050
> > m : 07967 470 964
> >
> >
> > _________________________________
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