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RE: More 6509 problems...

  • From: Danny Snyder
  • Date: Thu Feb 01 21:45:07 2001

Now that I think about it, I was given somewhat of an explanation of what
was happening.....I didn't remember until now though.

Basically the MSFCs act as the route processors for the 6509s.  A simple
description of what these do is inter-VLAN routing.  If you look at show
trunk off of the Supervisor engine on a 6509, you see that there is an ISL
trunk from the supervisor to the MSFC.  In an ethernet-only environment,
this is no big deal and is fairly straight-forward.  In the case of the
FlexWAN modules, the switch creates a "hidden" VLAN- that is a VLAN numbered
outside the allowed range for VLAN ids.  If for some reason this VLAN cannot
be created and associated with the serial (or other interface off of the
FlexWAN), the circuit shows as being up/down when it should be up/up because
the communication between the FlexWAN module and MSFC isn't happening
correctly.

With IOS 12.1.3aE4 (also earlier versions, but I'm not sure how much
earlier) on the MSFC, cef is enabled and cannot be turned off.  Again, this
does not present a problem for an ethernet network.  With the FlexWAN,
distributed cef must be enabled for the hidden VLAN to be created correctly.
There are debugging commands to see what is going on with the hidden VLANs,
but you cannot get information about these through non-debugging commands.
Once the hidden VLAN is created correctly, the interface can go up/up since
communication between the FlexWAN and MSFC is then allowed to happen.

I didn't ask for details as to what specifically happens with distributed
cef turned vs. having it turned off, and I was really suprised that not
having *one* global configuration command was causing all of my problems....

That's everything I can recall about this....hope that helps.

--Danny




-----Original Message-----
From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of
Rodney Dunn
Sent: Thursday, February 01, 2001 5:22 PM
To: Danny Snyder
Cc: Kenny Sallee; agudgeon@firstnet.co.uk; nanog@merit.edu
Subject: Re: More 6509 problems...



Danny,

The interface status should be independent of
the swithcing path.  I've never seen the line
state be affected by the switching mechanism
(although I have seen the opposite).

Can you email me the case# you had so I can take
a look?

rodney


On Tue, Jan 30, 2001 at 02:22:21PM -0600, Danny Snyder wrote:
>
> Ya got me on that one....Cisco didn't really say why and I didn't think to
> ask them either....
>
> --Danny
>
>
>
>
> -----Original Message-----
> From: Kenny Sallee [mailto:k_sallee@yahoo.com]
> Sent: Tuesday, January 30, 2001 11:28 AM
> To: agudgeon@firstnet.co.uk; 'Danny Snyder'
> Cc: nanog@merit.edu
> Subject: Re: More 6509 problems...
>
>
> How would CEF cause an interface to be up/down?  Just curious....Kenny
>
> ----- Original Message -----
> From: "Alison Gudgeon" <agudgeon@firstnet.co.uk>
> To: "'Danny Snyder'" <dsnyder@nowdocs.com>; <nanog@merit.edu>
> Sent: Tuesday, January 30, 2001 8:36 AM
> Subject: RE: More 6509 problems...
>
>
> >
> > Hi
> >
> > Hybrid IOS
> >
> > I've got IP CEF DISTRIBUTED set globally.  Did you have it enabled or
> > disabled on the T3 interface?
> >
> > Ali
> >
> > -----Original Message-----
> > From: Danny Snyder [mailto:dsnyder@nowdocs.com]
> > Sent: 30 January 2001 16:21
> > To: agudgeon@firstnet.co.uk; nanog@merit.edu
> > Subject: RE: More 6509 problems...
> >
> >
> > Alison,
> >
> > I've had VERY similar problems with a 6509 (Sup 1a + MSFC2) with a
FlexWAN
> > and a PA-2T3+.  After spending the better part of two weeks on the phone
> > with Cisco, we finally determined that ip cef distributed needed to be
> > turned on in global configuration.
> >
> > Also, are you running native IOS or Catalyst OS on the Supervisor and
IOS
> on
> > the MSFC ?
> >
> > Danny Snyder
> > Network Administrator
> > NowDocs, Inc.
> >
> >
> >
> >
> > -----Original Message-----
> > From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu]On Behalf Of
> > Alison Gudgeon
> > Sent: Tuesday, January 30, 2001 10:18 AM
> > To: nanog@merit.edu
> > Subject: More 6509 problems...
> >
> >
> >
> > Hi,
> >
> > Is anyone doing the following:
> >
> > 6509 (supervisor 1a + msfc) - with a flexWAN adapter to take a Packet
Over
> > Sonet OC-3 card.
> >
> > I'm having great problems getting up/up on the interface, the current
> > situation is up/down, a hardware loop at the telco kit brings the line
> up/up
> > but otherwise just up/down.  Config is default I've just put IP's on.
> >
> > I'm running very new code - 12.1(4)E1
> >
> > many thanks in advance for any help.
> >
> >
> > Kind Regards
> >
> >
> > Alison
> >
> >
>






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