Subject: [Forces-protocol] Issue 4&5: Congestion control, DoS protection, and Reliability

From: [email-masked]
Date: Fri, 19 Mar 2004 00:06:03 +0800

Hi all,

To speed up, pls allow me to activate these issues. Actually we have had quite 
a lot discussions related to these topics. I just try to first list some items. 
Pls add some more.

* For DoS Protection and Congestion control

1. The idea to distinguish packets by Data packets and Control packets should 
be used to protect against DoS and control congestion, where Data packets are 
actually redirected packets by FE to CE.

2. To further protect DoS and control congestion, something like a FE DoS 
Protection & Congestion Control Policy should be included in ForCES protocol. 
The policy may include that like priorities and rate limiting parameters for 
both C and D packet streams, and may be mapped to ForCES protocol layer 
scheduler or OS layer scheduler (need more discussion on which is better). For 
D packet stream, because it is a dataflow in FE model before being encapsulated 
as a ForCES message, it is possible an LFB be adpoted to do such rate limiting. 
For C packet stream, it is surely done out of the FE model scope. 

3. A DoS (or Congestion) alert mechanism is necessary for ForCES protocol. 

4. Even without DoS, congestion can also happen, for sometimes there may be too 
many C packets that need to be transmitted. 

5. Do we need to consider congestion at the CE side? (Avri raised this question 
to me). 

* For reliability

1. A built-in mechanism for reliability like ACK, Checksum, and Dual-phase 
commit must be included in the protocol specification. 

2. Differentiation of reliability for different protocol messages may be 
achieved at the transport layer and/or at the protocol (core) layer. 

I just stop here currently. Pls move forward quickly.

Regards,
Weiming

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From: Alex Audu <[email-masked]>
Date: Thu, 18 Mar 2004 12:47:25 -0600

Hello Weiming,

I don't think it is possible for us to come up with a mechanism to
determine if an FE is being
DOS'd. The final determination of that may depend on situation at hand,
since attack
signatures are typically different for different DOS attacks. I think
the final decision as to
if a DOS is really occuring is best left to policy on the NE. This is
outside ForCES scope.
But we can have FE report resource usage status to CE. I think FACT
already has
such report.

Regards,
Alex.

[email-masked] wrote:

>[snip]

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From: "Wang,Weiming" <[email-masked]>
Date: Fri, 19 Mar 2004 15:44:27 +0800

Hello Alex,

I think what you said is exactly what I meant. That is, something like 'DoS
Alert Policy' as called in GRMP should be used to determine when a DoS is
considered and an alert event is sent from FE to CE. Actually I don't think to
manage this policy is outside the scope of ForCES, it can surely be set up as a
kind of FE attribute to FE by CE. And moreover, I'm afraid a pure resource usage
status report is not enough for DoS alert purpose.

On the other hand, I have to say what set in current GRMP for 'DoS alert policy'
seems a little naive. We need improvement on this, that is, to find a better and
more efficient description for the policy.

Thank you.

Weiming

----- Original Message -----
From: "Alex Audu" <[email-masked]>
To: <[email-masked]>
Cc: <[email-masked]>
Sent: Friday, March 19, 2004 2:47 AM
Subject: Re: [Forces-protocol] Issue 4&5: Congestion control, DoS protection,
and Reliability

---

From: Alex Audu <[email-masked]>
Date: Fri, 19 Mar 2004 14:01:42 -0600

Hello Weiming,

That is good, but what I am saying is, you can't make a general 
characterization that
every high resource usage is a DOS scenario. It may just be that the FE 
is just being
overloaded with good traffic.

Cheers,
Alex.