<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2//EN">
<HTML>
<HEAD>
<META HTTP-EQUIV="Content-Type" CONTENT="text/html; charset=us-ascii">
<META NAME="Generator" CONTENT="MS Exchange Server version 5.5.2654.19">
<TITLE>RE: [AG-TECH] TTL - Multicast</TITLE>
</HEAD>
<BODY>
<BR>
<BR>
<P><FONT SIZE=2>Actually, our problem is with the vic in windows. We are using windows 2000 machines as capture computers. In linux the -B option works fine.</FONT></P>
<P><FONT SIZE=2>According to the vic-userguide...</FONT>
</P>
<P><FONT SIZE=2>-B</FONT>
<BR> <FONT SIZE=2>Set the maximum value of the bandwidth slider to a user-specified number of kbit/s. This value is limited to 256 kbit/s if the conference address is a multicast address and the TTL in use is greater than 64 (ie, the traffic will leave your multicast region).</FONT></P>
<P><FONT SIZE=2>So in the windows vic the above is true, but in the linux vic this must have changed in the code. It doesn't matter what we set the bandwidth to in windows...if the TTL is 127, it behaves as the guide suggests above.</FONT></P>
<P><FONT SIZE=2>We'd like to be able to have a TTL of 127 and a bandwidth value of much more than 256 kbit/s on our windows capture machines.</FONT></P>
<BR>
<P><FONT SIZE=2>-----Original Message-----</FONT>
<BR><FONT SIZE=2>From: Robert Olson [<A HREF="mailto:olson@mcs.anl.gov">mailto:olson@mcs.anl.gov</A>] </FONT>
<BR><FONT SIZE=2>Sent: Thursday, March 14, 2002 1:45 PM</FONT>
<BR><FONT SIZE=2>To: Nolan, Kevin [NCSUS]; 'ag-tech@mcs.anl.gov'</FONT>
<BR><FONT SIZE=2>Subject: Re: [AG-TECH] TTL - Multicast</FONT>
</P>
<P><FONT SIZE=2>At 12:01 PM 3/14/2002 -0500, Nolan, Kevin [NCSUS] wrote:</FONT>
<BR><FONT SIZE=2>>The problem we're seeing with both VIC and Rat is that as the TTL value </FONT>
<BR><FONT SIZE=2>>gets increased, the amount of data being transmitted is decreased as a way </FONT>
<BR><FONT SIZE=2>>to alleviate network congestion. The problem with this is that our remote </FONT>
<BR><FONT SIZE=2>>sites generally connect via high-bandwidth links, and the associated lower </FONT>
<BR><FONT SIZE=2>>frame rates are unacceptable for real-time communication between </FONT>
<BR><FONT SIZE=2>>sites. Is there any way that we can change these values, or does the </FONT>
<BR><FONT SIZE=2>>source code have to be modified?</FONT>
</P>
<P><FONT SIZE=2>the AG software passes a max-bandwidth option to vic that overrides the </FONT>
<BR><FONT SIZE=2>default:</FONT>
</P>
<P><FONT SIZE=2> vic -t 127 -B 10000 ip/port</FONT>
</P>
<P><FONT SIZE=2>What is rat doing with ttl? is it refusing to let you set the higher-rate </FONT>
<BR><FONT SIZE=2>encodings? I don't think I have any particular settings to make rat work </FONT>
<BR><FONT SIZE=2>properly.</FONT>
</P>
<P><FONT SIZE=2>--bob</FONT>
</P>
</BODY>
</HTML>