Subject: packet redirect as a core LFB

From: Jamal Hadi Salim <[email-masked]>
Date: Fri, 17 Jun 2005 09:40:28 -0400

Folks,

Should we be thinking of moving the redirect part out of the protocol
draft as well and making it a core LFB?

It could definetely be refered as a core LFB and therefore creating
speacial message types for it seems a little overzelous. It may also
help speedup the closure of the protocol draft.

cheers,
jamal

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From: Weiming Wang <[email-masked]>
Date: Fri, 17 Jun 2005 23:46:53 +0800

Jamal,

I'm afraid we should at least have some foreseeing on how a core LFB will deal with the redirection without using a special message before we decide to throw away the special message scheme. Shall we use something like a redirect event notification sent by the core LFB or any other means then? 

cheers,
weiming
----- Original Message ----- 
From: "Jamal Hadi Salim" <[email-masked]>

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From: Jamal Hadi Salim <[email-masked]>
Date: Fri, 17 Jun 2005 11:58:27 -0400

On Fri, 2005-17-06 at 23:46 +0800, Weiming Wang wrote:
> Jamal,
> 
> I'm afraid we should at least have some foreseeing 
> on how a core LFB will deal with the redirection 
> without using a special message before we decide 
> to throw away the special message scheme. 
> Shall we use something like a redirect event 
> notification sent by the core LFB or any other means then? 
> 

By core LFB i meant it being an important LFB that must be implemented.
This is in addition to the FE protocol LFB and FE Object LFB.

We actually started to implement the redirect - after the discussion on
the list where it is clear that we need this to be %100 compliant. This
is in addition to the hardware scheme we currently use(that i described
in some email).
We are finding that, it infact has LFB properties. 
Example:
- configure from CE->FE on what to filter, whether to totally redirect
or just send a copy/mirror, and what port to redirect it on.
- From FE->CE it is an event when a packet arrives - which is also part
of the LFB definition.
- Also injecting packets from the CE->FE is looked at as configure in
what we are doing right now. 

- Capability (part of LFB definition) sounds useful too to describe what
a specific redirect LFB can do etc.

cheers,
jamal

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From: "Joel M. Halpern" <[email-masked]>
Date: Fri, 17 Jun 2005 15:25:49 -0400

We need to define an interoperable mechanism for forwarding packets between 
the FE and the CE (both directions).   This is a protocol, not just an 
LFB.  It seems to make more sense in the PL and TML, rather than in some 
LFB document somewhere.

Yours,
Joel

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From: Jamal Hadi Salim <[email-masked]>
Date: Fri, 17 Jun 2005 15:47:28 -0400

On Fri, 2005-17-06 at 15:25 -0400, Joel M. Halpern wrote:
> the FE and the CE (both directions).   

agreed.

> This is a protocol, not just an LFB.  

A redirector looks to me more like an LFB than it is a protocol.
Certainly it is configured via PL protocol and even though is modelled
as an LFB doesnt have to be running in the forwarding path.
[It has attributes such as where to send to etc, throws events such as
sending those packets to the CE and depending on capability it may not
have some features etc].
One could in fact argue it is two LFBs, a classifier that selects a
packet and another that slaps a header on it before shipping it.
 
> It seems to make more sense in the PL and TML, 
> rather than in some LFB document somewhere.

Which would be fine with me. Shouldnt matter where it goes

cheers,
jamal

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From: "Wang,Weiming" <[email-masked]>
Date: Mon, 20 Jun 2005 11:43:19 +0800

Jamal and Joel,

It seems that we agree well that a redirector in FE is an LFB. Now the only question is if we should use a specific redirect PL message or not. I understand Joel's 'protocol' thought as using such PL message, while Jamal's 'event' thought as not using such PL message, am I right?

It let me agreed the 'event' scheme was a good solution for several days, before I noticed a big problem with it. The problem is, how then we recognize the redirect data from general control data at the TML level if we use a 'event' to send redirect data from FE to CE? As you know, to recognize it is important for TML to avoid DoS attack from the redirect data. 

Thanks,
Weiming