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RE: Quick Vlan question [7:49533] posted 07/24/2002
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There are some router models that have 10Mb interfaces that support trunking
(Dot1Q).  What differentiates them is the IOS feature set.  You need IP+ on
some of the older models whereas most of the newer models have 100Mb
interfaces and support trunking with just the IP feature set.

If your router is a Cisco device and it turns out it will support trunking,
then once you setup the trunking parameters, you would then create
sub-interfaces for each VLAN.


-----Original Message-----
From: Priscilla Oppenheimer [mailto:nobody@xxxxxxxxxxxxxx] 
Sent: Wednesday, July 24, 2002 6:33 PM
To: cisco@xxxxxxxxxxxxxx
Subject: RE: Quick Vlan question [7:49533]

=?iso-8859-1?q?maine=20dude?= wrote:
> Hi,
> If I have two Vlans and want to route between them using an external 
> router, but the router has only 10mb ports, how can it be done? I 
> can't use ISL or 802.1q because it isn't supported on 10mb/s ports,
> correct? Does every Vlan need a separate physical connection?
> or do i use sub interfaces?

You say 10mb ports, i.e. plural. If the router has two ports, use them both,
one for one VLAN and one for the other. It's as simple as that.

I have this same problem in my home lab due to ancient equipment. I simply
put e0 on the router in subnet and e1 on the router in subnet

I connect one of my switches to the router using two ports on the switch,
one going to e0 and one going to e1 on the router. These don't even have to
be trunk ports, just any old ports.

On the switch I have some devices in VLAN 1 ( and some in VLAN 2
( The devices use the appropriate router address for their
default gateway.

I have the swtich connected to another switch in a redundant fashion to get
some practice with trunking, etc., but the router just acts like an ordinary
router from the pre-VLAN days when life was simple. ;-)

Priscilla Oppenheimer

> please advise.
> thank you
> -DJ
> ---------------------------------
> Get a bigger mailbox -- choose a size that fits your needs.

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