RE: [nsp] ISL/dot1Q trunks on 26xx

From: Frank Bruce (fbruce@cisco.com)
Date: Thu Feb 08 2001 - 10:17:02 EST


http://www.cisco.com/warp/public/105/39.html#odr_point refers to the 12.0
release another good source of IOS internals type information is
http://www.ciscopress.com/book.cfm?series=2&book=57 "Inside Cisco IOS
Software Architecture (CCIE Professional Development)".

Cisco IOSR Software uses Interface Descriptor Blocks (IDB) to store
interface specific information such as protocols configured, timers, etc.,
so that IOS device drivers can interact efficiently with the different types
of interfaces. An IDB is used for each of the following types of interfaces:

. Physical
. Dialer
. Virtual
. Hidden
. Subinterfaces
. Tunnel
. Loopback

Each physical interface consists of a hardware IDB and at least one software
IDB, although more than one software IDB may be supported and mapped to the
same physical interface. The hardware IDB contains physical state
information of the interface. The software IDB contains application specific
information for the router.

Hardware IDBs are allocated from the fast memory pool if it exists on the
platform. If not, they are allocated from process memory.

New software IDBs can be allocated after system initialization to create
subinterfaces and virtual interfaces such as loopback interfaces, and
tunneling interfaces. Software IDBs are allocated from process memory.

Regards

Frank Bruce
Consulting SE, NSP West
Cisco Systems Ltd
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-----Original Message-----
From: Brian [mailto:signal@shreve.net]
Sent: 08 February 2001 14:58
To: Kevin Gannon
Cc: Scott Morris; 'Andrew Smith'; 'Charles Sprickman';
cisco-nsp@puck.nether.net; jared@puck.nether.net
Subject: RE: [nsp] ISL/dot1Q trunks on 26xx

If anyone has this table of IDB limits and knows a link to it, please
post!

On Mon, 11 Dec 2000, Kevin Gannon wrote:

> The TAC have a table of the limits which vary on IOS version also.
> Also there was at one time a "geek" version of some of the IOS to increase
> the limit again.
>
> Regards,
> Kevin
>

-----------------------------------------------
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              email me for a quote

Brian Feeny e:signal@shreve.net
CCNP+Voice/ATM/Security p:318.222.2638x109
CCDP f:318.221.6612
Network Administrator
ShreveNet Inc. (ASN 11881)



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