On Wed, 23 Jun 2004, Zeppy B. Vilan wrote: > hello people, > > i would like to ask your help regarding my multicast problem. i can > recieve and transmit using multicast in access grid lobby. but every 1 > to 2 minutes i got freeze and after 1 to 2 minute it will back again?
I attended one of the Internet2 Multicast Workshops (highly recommended, if rather technical...) and one of the instructors mentioned that timing is very important when reporting/diagnosing problems. I.e. the 2 minute cycles correlate with timeouts of IGMP or PIM state on a router. Offhand I'd not disagree with John and Mike's replies that it may be a PIM problem - but I'm still not an expert. I've had weird checksum problems here with some Nortel equipment - PIM packets with bad checksum rejected by a Juniper upstream, but only if the first packet had an odd packet length. I read also of some older Cisco versions that got checksums wrong. (I don't think that's your problem, it's just an FYI for the archive...) I have some links to tools, RFCs etc at http://andrew.triumf.ca/AG/multicast/ The original Internet2 presentation is available at http://multicast.internet2.edu/workshops/vancouver/ and includes some good troubleshooting guides My problems were with joining, and the beacon wasn't much help (once joined, the client stayed joined), so I wrote some simple test tools in C and Perl to send/receive packets on arbitrary groups then look with tcpdump and log on to the routers to check state. I later found similar things online (e.g. mping.exe for DOS) I'd suggest initially testing across a single network segment or across your campus to make quite sure it works 100% there, before getting involved with WAN issues. I imagine you already did that... -- Andrew Daviel, TRIUMF, Canada Tel. +1 (604) 222-7376 [email protected]
