Subject: LFB Class text extracted from the ForCES FE Model Draft

From: "Deleganes, Ellen M" <[email-masked]>
Date: Tue, 14 Dec 2004 08:43:22 -0800

Here is the LFB Class text extracted from the original ForCES FE Model
Draft to start to build the LFB Class definitions.

Regards,

Ellen

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From: Jamal Hadi Salim <[email-masked]>
Date: Tue, 14 Dec 2004 22:04:03 -0500

Out of curiosity:
What is the charter limit in regards to LFBs?
For some reason in my mind i thought we stop at qos/diffserv (+IPV4/6
forwarding and whatever peripheral LFBs such as port/interface).
Is this not the case anymore? Wheres the line - I cant seem to find
such details in the charter.

cheers,
jamal

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From: Jamal Hadi Salim <[email-masked]>
Date: Wed, 15 Dec 2004 08:39:22 -0500

> Draft to start to build the LFB Class definitions.

I am making certain observations (I suppose i never paid good attention
to this text before); So lets start with section 1.3. "IP interface LFB"
(more comments later).

1.3 has a statement that this is the repository for interface MIB
counters.
This is news to me. What i have seen as standard practise is that
those counters can exist on a port which has no L3 protocol address at
all - pick an ethernet port in a bridge for example, or a PPPOE interface
in which both PPP(which would have the attached IPV4 address) and the
parent ethernet device have those counters.
Is there some RFC (SNMP or otherwise) that defines this?

Also is this LFB seen as the mother of LPM? i.e is it the general IPv4/6
forwarding LFB? It seems to do some IP validation - which to me appears
to be a cosmetic effort to just make it do some packet processing
just because;->  Which brings forward the question: do we need to
have LFBs always process packets if they are associated with the data
path?

The way i would model a port with an IP address attached is to describe
it as a port LFB with an attached Protocol address LFB (what you refer
to as the IP interface LFB). The Protocol Address LFB is merely a
management peripheral LFB and by itself does not process packets; rather
it is used by other LFBs in the LFB topology as a reference on how to
process a packet (example the IPV4 Forwarding LPM would both at the
ingress and egress).

cheers,
jamal

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From: Jamal Hadi Salim <[email-masked]>
Date: Mon, 20 Dec 2004 23:06:23 -0500

So answering my own email (after a side discussion with Joel):

> Is there some RFC (SNMP or otherwise) that defines this?

This still needs fixing. The counters apply to Sub-IP Interfaces as well
not just to IP interfaces.

> just because;->  

Ok, this i can now live with. Should be noted that common practise is to
have IP addresses attached on top of intercaes/ports and that IP
processing happens on ports which have such addresses further downstream
in the LFB topology. The description in the model is better actually.

cheers,
jamal