From: Jim Brown (Jim.Brown@xxxxxxxxxxxxx)
Date: Thu Nov 01 2001 - 21:49:03 GMT-3
Imagine this.... you are peering between sites 'A' and 'B' using loopbacks
across a WAN link. The Ethernet port at site 'A' fails. Site 'B' will
continue to send data across the WAN link. From the perspective of site 'B'
everything is OK because the DLSW connection is maintained between
loopbacks.
The DLSW connection is completely unaware of the fact that the data has
nowhere to go once it arrives at site 'A'. I don't believe DLSW monitors the
availably of interfaces attached to the ring group/bridge group.
Using the same scenario except we peer between the Ethernet ports. If one of
the Ethernet ports fail, the DLSW connection is torn down conserving our
precious WAN bandwidth.
This is my reasoning why it is better to peer between physical interfaces in
certain circumstances. All bets are off with two physical interfaces on the
same router participating in DLSW. You could potentially tear down the
connection when only one of the interfaces fails and leave the other segment
on the same router out in the cold.
I'm only speaking of theory. I might be way off my rocker. I've never used
DLSW in a production environment. So clarification of my ramblings are
welcomed. If a DLSW guru wants to straighten me out I'm all ears.
-----Original Message-----
From: Jason Sinclair [mailto:sinclairj@powertel.com.au]
Sent: Thursday, November 01, 2001 6:27 PM
To: 'fwells12'; Jim Brown; ccielab@groupstudy.com
Subject: RE: DLSW peer question
However,
Based on the logic of single interfaces, if the single interface were to
fail (and they were directly connected!) the a side wouldn't send anyway as
layer 2 would have failed?
Regards,
Jason Sinclair
Network Support Manager
POWERTEL Limited
Level 11, 55 Clarence Street, SYDNEY
Phone: 61-2-8264-3820
Fax: 61-2-9279-2604
Mobile: 0416 105 858
jasons@powertel.net.au
-----Original Message-----
From: fwells12 [mailto:fwells12@hotmail.com]
Sent: Friday, 2 November 2001 10:02
To: Jim Brown; ccielab@groupstudy.com
Subject: Re: DLSW peer question
Good point.
----- Original Message -----
From: "Jim Brown" <Jim.Brown@CaseLogic.com>
To: "'Geir Jensen'" <geir@hfk.vgs.no>; "fwells12"
<fwells12@hotmail.com>;
<ccielab@groupstudy.com>
Sent: Thursday, November 01, 2001 1:45 PM
Subject: RE: DLSW peer question
> In a production environment would it not make more sense
to tie the local
> peer to a single physical interface if there is only one
interface
> participating in DLSW?
>
> If it is tied to the physical interface, when it goes down
then so does
the
> DLSW connection.
>
> If it is tied to a loopback and the physical interface is
down, DLSW
traffic
> will travel to the remote end only to be dropped.
>
> It seems to me tying it to the physical interface would
conserve bandwidth
> during interface failures.
>
>
> -----Original Message-----
> From: Geir Jensen [mailto:geir@hfk.vgs.no]
> Sent: Thursday, November 01, 2001 2:16 PM
> To: fwells12; ccielab@groupstudy.com
> Subject: RE: DLSW peer question
>
>
> I always use the loopback, it's definately more stable
than the
> alternatives. Geir Jensen
>
> -----Original Message-----
> From: fwells12
> Sent: Thu 11/1/2001 9:34 PM
> To: ccielab@groupstudy.com
> Cc:
> Subject: DLSW peer question
>
>
>
> OK, you have a router which has more than one LAN
interface it needs
> DLSW
> traffic forwarded from, let's say e0 and t0. It also has
a loopback
> int with
> ip ad 172.16.10.1/24. The ip's of the e0 and t0
interfaces are
> 172.16.20.1/24
> and 172.16.30.1/24 respectively. What ip address is the
best
> practice to use
> for your dlsw local-peer peer-id statement?
>
> Cheers
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