Subject: RE: ICMPv6 rate limiting factor

From: "Richard Draves" <[email-masked]>
Date: Mon, 29 Oct 2001 19:05:58 -0800

The Microsoft implementation limits to two errors per second, just for
this reason.

Rich

> -----Original Message-----
> From: Lori Napoli [mailto:[email-masked]] 
> Sent: Monday, October 29, 2001 6:59 PM
> To: [email-masked]
> Subject: ICMPv6 rate limiting factor
> 
> 
> RFC 2463 states that it is a MUST to limit the rate of ICMPv6 
> error messages that are sent.  Traceroute is a utility that 
> relies on ICMP error messages.  One of the parameters for 
> traceroute is the number of probes
> that are sent for each hopcount.   RFC 2463 gives an example 
> of 1 second as
> a conservative default if timer based rate limiting was 
> implemented.   If
> this is used,  traceroute won't receive a reply for each 
> probe if multiple probes are sent for each hopcount since 
> some will be supressed due to the rate limiting factor.  What 
> are other implementations doing in regard to ICMPv6 rate limits?
> 
> Thanks
> Lori
> 
> 
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---

From: Pekka Savola <[email-masked]>
Date: Tue, 30 Oct 2001 08:24:10 +0200 (EET)

> The Microsoft implementation limits to two errors per second, just for

That is only good enough if you assume the tracerouter is over 500ms away, 
because traceroute by default sends out three probes..

I've commented on the new ICMP draft that this issue should be taken into
consideration, and apparently it will, as the draft didn't progress at
IETF51.

B.t.w. Linux uses a token bucket mechanism here and is not affected.

B.t.w.2. Cisco implementation is(/was) also broken, another issue I
mentioned here and on [email-masked], they promised they'd be working on
it.

-- 
Pekka Savola                 "Tell me of difficulties surmounted,
Netcore Oy                   not those you stumble over and fall"
Systems. Networks. Security.  -- Robert Jordan: A Crown of Swords

---

From: Ole Troan <[email-masked]>
Date: Tue, 30 Oct 2001 12:35:29 +0000

> mentioned here and on [email-masked], they promised they'd be working on

the latest releases use an adjustable token bucket algorithm.

/ot