On 10 Oct 2000 17:04:53 -0400, Joseph Ezerski <[EMAIL PROTECTED]> wrote:
:I am not sure, but logic seems to dictate that both interfaces belong to the
:same layer 2 network. The way I am picturing it is like this:
:
:In any regular layer 2 switched network, you can have many devices of the
:same type. You could have many clients or servers, or printers or even
:routers. So why wouldn't the same hold true for your scenario? Now, when
:you bring it up to layer 3, you definitly have two distinct subnets working.
:The differnece would lie in how your end users are configured, ie- Which
:interface IP do you assign as their default gateway...
:
:Sorry for the oversimplification. It's my first day on the list and I am
:trying to get involved.
What troubles me is that I tend to think of the fast ethernet interfaces
as separate physical circuits, and as such having a subinterface on two
of them with the same encapsulation ID should imply that they are indeed
different circuits. In a router, the syntax is much like that used with
frame-relay interfaces, "encapsulation ISL [identifier]", rather than as
seen on a switch, "VLAN [identifier].
If I have two frame-relay interfaces that go to different circuits but
both of them have a DLCI 16, they aren't bridged at layer 2. If I have
two ethernet interfaces and both have IPX encapsulation SNAP, they are
not bridged. From a configuration standpoint, it would make logical
sense that the ISL "encapsulation color ID' would follow that of other
sub-interfaces. Yet from a switch standpoint, the VLAN ID should imply
that they're connected.
Still confused, and don't have the gear to test in the lab.
:-----Original Message-----
:From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
:Sent: Tuesday, October 10, 2000 12:47 PM
:To: [EMAIL PROTECTED]
:Subject: ISL VLANS on a router - bridged?
:
:
:On a switch, if a unique VLAN ID appears on more than one trunked
:interface, that VLAN is part of the same layer 2 network and broadcast
:domain across all interfaces where it appears, based on the VLAN number.
:
:Is this also true on a router? That is, if I have the following
:configuration, what happens? Do VLAN 2 on switches connected to
:both interfaces see each other?
:
:interface FastEthernet0/0.2
: description VLAN 2 to switch A
: encapsulation isl 2
: ip address 192.168.1.254 255.255.255.0
: no ip redirects
: no ip directed-broadcast
:
:interface FastEthernet0/1.2
: description VLAN 2 to switch B
: encapsulation isl 2
: ip address 192.168.2.254 255.255.255.0
: no ip redirects
: no ip directed-broadcast
:
:Two separate subinterfaces of two separate physical interfaces connected
:to two different LANs, but with the same ISL encapsulation "color". Are
:they bridged? Would the IP address ranges both appear on both LANs?
:
:Can't find this in CCO anywhere.
--
Jay Hennigan - Network Administration - [EMAIL PROTECTED]
NetLojix Communications, Inc. NASDAQ: NETX - http://www.netlojix.com/
WestNet: Connecting you to the planet. 805 884-6323
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