From: Scott Morris (swm@emanon.com)
Date: Wed Sep 17 2003 - 12:49:06 GMT-3
Where's "32" coming from? Your pvc's in the example you state are 1/25,
2/35, 3/45 correct? They would be assigned to subinterface .1, .2 and
.3 respectively if you let the router automagically do things. (based
on the vpi part)
As for you asking about the ILMI discovery, I can niether confirm nor
deny this as it would be under NDA. But it seems to me that it would be
an awfully good thing to know if I were the person creating the evil
exams. (smirk)
A little paranoia is healthy. Too much, and the WILL find you!
As for keeping the brain full... I think it has to do with an unhealthy
social life... (grin) Naaahhh.. Just a vast collection of useless
knowledge! Occasionally I just put some of it to good use!
Best of luck!
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ccie2be
Sent: Wednesday, September 17, 2003 10:51 AM
To: Group Study; swm@emanon.com
Subject: Re: ATM addressing - PVC discovery
Hey Scott,
Just as I figured (I was 99.999% sure that you would know about this.
How you and people like Fred, Brian McGahan and Brian Dennis are able to
amass and keep such a detailed knowledge of so many things - that still
remains a mystery to me).
Please see comments in-line
----- Original Message -----
From: "Scott Morris" <swm@emanon.com>
To: "'ccie2be'" <ccie2be@nyc.rr.com>; "'Group Study'"
<ccielab@groupstudy.com>
Sent: Wednesday, September 17, 2003 9:47 AM
Subject: RE: ATM addressing - PVC discovery
> Actually, you have to use the 'subinterface' parameter on that line in
> order for subinterfaces to be created.
>
> However, you need to remember that subinterface numbers are merely a
> logical representation of what the PVC is. Whether you have atm
> 1/0.32 or atm1/0.1 representing whatever PVC you choose, it doesn't
> matter to anyone but you!
This seems to contradict what Pildush writes on page 568 in Solie's
book, Practical Studies and what's in the cisco documentation ie. the
vpi # must = the subinterface #. For example, suppose that there are 3
PVC's configured on the switch which have the following vpi/vci values:
vpi vci
pvc1 1 25
pvc2 2 35
pvc3 3 45
You seem to be saying that it's OK to create a single atm multipoint
subinterface, for example, interface atm 0.32 multipoint, for all 3
pvc's even though they each have different vpi values. By using the atm
ilmi-pvc-dicovery subinterface command, all 3 pvc's will be put on the
int atm 0.32 multipoint subinterface. Am I understanding you correctly?
>
> They're assigned "pseudo-logically" (sure, that's a word. Really.)
> because people tend to do things like that for their own
> documentation. It's kinda like that DLCI 101 in Frame Relay. Whether
> you assign it to Serial 0/0.13 or Serial 0/0.101 makes no difference
> to anyone but you!
>
> But you're correct, if you are not told what PVCs you have, then it
> may make perfect sense to discover them. Just be careful on the
> wording of your lab scenario whether you're allowed to do that or not.
> ;)
For the practical aspect of the exam, if that's true, then there's no
need for Cisco to tell the test taker what the vpi/vci values are for
the pvc's configured on the ATM switch. Right? They could just say
something like, "Configure connectivity with pvc's between rtr 1,2 and
3." And, as long as the test taker knew to set up the pvc for ILMI and
how to do pvc discovery, all would be well.
>
> <Just because you're paranoid doesn't mean there isn't someone behind
> you>
Having failed the lab twice before, I feel having paranoia about the
exam is actually quite a good thing :-)
>
> Scott
>
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
> Of ccie2be
> Sent: Wednesday, September 17, 2003 6:50 AM
> To: Group Study; swm@emanon.com
> Subject: Fw: ATM addressing - PVC discovery
>
>
> ----- Original Message -----
> From: ccie2be
> To: Group Study
> Sent: Tuesday, September 16, 2003 10:46 PM
> Subject: ATM addressing - PVC discovery
>
>
> Hi all,
>
> This is a question regarding using the atm ilmi-pvc-discovery command.
>
> According to Cisco's documentation, "The discovered PVCs are assigned
> to the subinterface number that matches the VPI number of the
> discovered PVC. For example, if subinterface 2/0.1 is specified using
> the interface atm command in Step 6, then all discovered PVCs with a
> VPI value of 1 will be assigned to this subinterface."
>
> It seems that if you don't what pvc's there are, then it makes sense
> to discover them. But, if you don't know what pvc's there are, then
> you won't know what the vpi is and if you don't know that, then how
> can you know what subinterface to create for them to be assigned to?
> Sounds like a catch 22, doesn't it?
>
> Thanks, dt
>
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This archive was generated by hypermail 2.1.4 : Wed Oct 01 2003 - 07:24:29 GMT-3