The Internetwork Design Guide has increased its guidelines over the years :
-)
>From the IDG - January 1994...
"In general,Frame Relay designs should feature a maximum of 10 to 50 DLCIs
per interface in a given internetwork. The specific number depends on
several factors that should be considered together:"
>From the IDG - July 2001...
"How many DLCIs can be configured per serial port? It varies depending on
the traffic level. You can use all of them (about 1,000), but in common
use, 200-300 is a typical maximum. If you broadcast on the DLCIs, 30-50 is
more realistic due to CPU overhead in generating broadcasts. Specific
guidelines are difficult because overhead varies by configuration. However,
on low-end boxes (4,500 and below), the architecture is bound by the
available I/O memory. The specific number depends on several factors that
should be considered together: "
Both editions then go on to state exactly the same factors (protocols,
level of broadcast traffic, line speed etc), in the same words. Including
a rather dubious statement that is either wrong, or I'm just
mis-interpreting it. "If static routing is implemented, you can use a
larger number of DLCIs per line, because a larger number of DLCIs reduces
the level of broadcasting". Sounds like a dodgy reason to me.
It's actually not a bad read.
http://www.cisco.com/univercd/cc/td/doc/cisintwk/idg4/nd2009.htm#xtocid1346013
JMcL
---------------------- Forwarded by Jenny Mcleod/NSO/CSDA on 09/07/2001
04:25 pm ---------------------------
"Chuck Larrieu" @groupstudy.com on 09/07/2001 08:47:25
am
Please respond to "Chuck Larrieu"
Sent by: [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
cc:
Subject: RE: Capacity guidelines [7:11174]
let's see ( putting on my thinking cap )
the DLCI field of the frame relay header is 10 bits, meaning a maximum of
1023 DLCI numbers.
did not find anything on the frame relay forum site www.frforum.com, but
according to Darren Spohn's Data Network Design ( out of print but a third
edition is being written ):
DLCI 0 = in channel signaling ( lmi-type ansi )
DLCI 1-15 are reserved
DLCI 1008-1022 are reserved ( I always thought it was 1005-1022. wonder
where I got that from )
DLCI 1023 = in channel layer management ( lmi-type cisco )
that leaves 16-1007 as possible DLCI's for production - or 992 total.
interesting.
Chuck
-----Original Message-----
From: Mike Mandulak [mailto:[EMAIL PROTECTED]]
Sent: Sunday, July 08, 2001 12:38 PM
To: Chuck Larrieu
Subject: Re: Capacity guidelines [7:11174]
As I recall the theoretical limit on the number of DLCIs is 999. This from
a
Mark Miller book. The book is at work so I can't check it right now. Not
sure of vendor specific limits either.
----- Original Message -----
From: "Chuck Larrieu"
To:
Sent: Sunday, July 08, 2001 3:00 PM
Subject: RE: Capacity guidelines [7:11174]
> I'm curious about this statement. Can you clarify?
>
> I know I've read on CCO about limits to numbers of subinterfaces (
actually
> to total numbers of interfaces in general ), due to constraints of the
> router architecture.
>
> I don't believe I have come across any reference to limits on the number
of
> DLCI's supported, although it wouldn't surprise me to learn that there
are
> limits for whatever reason - hardware, memory, or architectural
> considerations. Or Telco side limitations.
>
> Chuck
>
> -----Original Message-----
> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]]
> Sent: Sunday, July 08, 2001 11:25 AM
> To: [EMAIL PROTECTED]
> Subject: RE: Capacity guidelines [7:11174]
>
>
> Frame relay serial circuits commonly support 200-330 dlci's as a maximum.
Message Posted at:
http://www.groupstudy.com/form/read.php?f=7&i=11410&t=11174
--------------------------------------------------
FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html
Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
