RE: [ssm] IPv6 Multicast Throughput problems in 802.11

"Tiago Sousa" <> Tue, 15 November 2005 15:35 UTC

Received: from ([] by with esmtp (Exim 4.32) id 1Ec2q8-0008Nm-IH; Tue, 15 Nov 2005 10:35:20 -0500
Received: from ([] by with esmtp (Exim 4.32) id 1Ec2q6-0008NZ-9w for; Tue, 15 Nov 2005 10:35:18 -0500
Received: from (ietf-mx []) by (8.9.1a/8.9.1a) with ESMTP id KAA00855 for <>; Tue, 15 Nov 2005 10:34:45 -0500 (EST)
Received: from ([] by with esmtp (Exim 4.43) id 1Ec37J-00080D-5r for; Tue, 15 Nov 2005 10:53:08 -0500
Received: from laptop ( []) (authenticated bits=0) by (8.13.4/8.13.4) with ESMTP id jAFFaIVn015123 (version=TLSv1/SSLv3 cipher=RC4-MD5 bits=128 verify=NO); Tue, 15 Nov 2005 15:36:18 GMT
Message-Id: <>
From: Tiago Sousa <>
To: 'Toerless Eckert' <>
Subject: RE: [ssm] IPv6 Multicast Throughput problems in 802.11
Date: Tue, 15 Nov 2005 15:34:31 -0000
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
X-Mailer: Microsoft Office Outlook, Build 11.0.6353
X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2527
Thread-Index: AcXp+AtCqHwwwE+cQgaMQZVosoeSAgAAJseA
In-Reply-To: <>
X-FCTUC-DEI-SIC-MailScanner-Information: Please contact for more information
X-FCTUC-DEI-SIC-MailScanner: Found to be clean
X-FCTUC-DEI-SIC-MailScanner-SpamCheck: not spam (whitelisted), SpamAssassin (score=-4.399, required 3, autolearn=not spam, ALL_TRUSTED -1.80, BAYES_00 -2.60)
X-Spam-Score: 0.0 (/)
X-Scan-Signature: 41c17b4b16d1eedaa8395c26e9a251c4
Content-Transfer-Encoding: 7bit
X-Mailman-Version: 2.1.5
Precedence: list
List-Id: Source-Specific Multicast <>
List-Unsubscribe: <>, <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>

Thanks for your reply.

What packet size do you use ?

I've used already several packet sizes with minimal consequences on wireless
multicast throughput. At least when compared with the strong decrease that I
am seeing in my results. The best results, as expect, happens with UDP
packet size of 1500 bytes.

There's also a configuratin on access-points for how much bandwidth
multicast (aka: broadcast) can use. That's often tuned down to a very low 
default value.

My access point is a Belkin 54g (F5D7130) and, at least, through the web
page I can't see anything related with multicast or broadcast.

I've used successfully multiple megabits across 802.11b, not sure
what your problem is...

At this point neither do i...



On Tue, Nov 15, 2005 at 02:26:04AM -0000, Tiago Sousa wrote:
> Hello to all
> I am testing the PIM-SSM daemon (both freebsd and linux) and mrd6 (another
> IPv6 multicast routing daemon) in a wireless link. 
> The problem I encountered with both pim6sd daemon and mrd6 is that I'm
> sending multicast traffic at 4 Mbps and the throughput in the mobile node
> (which is very near from de access point) rounds 40 kbps.
> I am using the mad-flute tool to send the multicast SSM traffic and the
> tcpdump plus trpr to analyze the data. I have also used IxChariot and the
> results are the same.
> Anyone knows why the throughput decreases so much in the wireless link?
> (The multicast TTL is well defined, I have experimented with several
> pci/pcmcia cards and drivers and several access points configurations
> (different channels and rates (801.11b and 802.11g)). The results are
> always the same).
> I would appreciate any help/hint that helps me to explain these results.
> Thanks.
> Tiago Sousa

ssm mailing list

ssm mailing list