All things related to multicast

["Richard Mavrogeanes" <>]

Thanks Marshall!
 

        -----Original Message----- 
        From: Marshall Eubanks 
[mailto:]
 
        Sent: Sun 8/13/2006 8:16 PM 
        To: Richard Mavrogeanes 
        Cc: 
;
 

 
        Subject: Re: testing
        
        

        First, I said you should use even ports for RTP.
        
        Second, I (and others) use rtpdump etc. for a quick and dirty look at 
        all UDP multicast sources, RTP
        or not, as at least it will tell you something. AFAICT this software 
        expects even ports for the source.
        That's a pretty minor issue, but not a zero issue, especially as in 
        interdomain multicast you frequently find
        yourself relying on the kindness of strangers to debug things.
        
        Regards
        Marshall
        
        On Aug 13, 2006, at 7:51 PM, Richard Mavrogeanes wrote:
        
        > Marshall,
        >
        > I don't wish to be picky, I just want to make sure I understand.  
        > Isn't the issue exactly zero, and not just "less" without RTP?  I'm 
        > trying to construct any case where it would matter.
        >
        > Granted, RTP brings other advantages and we support RTP too (for 
        > unicasts).
        >
        > /rich
        >
        >
        >       -----Original Message-----
        >       From: Marshall Eubanks 
[mailto:]
        >       Sent: Sun 8/13/2006 7:47 PM
        >       To: Richard Mavrogeanes
        >       Cc: 
;
 

        >       Subject: Re: testing
        >      
        >      
        >
        >       RTP expects the even/odd RTP / RTCP pairing. True, you can 
override
        >       it, but
        >       the standard RTP monitoring tools then won't work well. Of 
course,
        >       this is less of an issue
        >       if you don't use RTP.
        >      
        >       Regards
        >       Marshall
        >      
        >      
        >       On Aug 13, 2006, at 7:00 PM, Richard Mavrogeanes wrote:
        >      
        >       > The MPEG-2 is not RTP, it is MPEG-2TS.
        >       > But since the port is associated only with the group, I 
don't see
        >       > why it would matter what port number you select.
        >       >
        >       > /rich
        >       >
        >       >
        >       >       -----Original Message-----
        >       >       From: Marshall Eubanks 
[mailto:]
        >       >       Sent: Thu 8/10/2006 1:16 PM
        >       >       To: 

        >       >       Cc: 

        >       >       Subject: Re: testing
        >       >
        >       >
        >       >
        >       >       Dear Frank;
        >       >
        >       >       Not seeing it from here :
        >       >
        >       >       bash-2.05b$ rtpdump -F ascii 233.88.214.137/4444
        >       >       <silence>
        >       >
        >       >       BTW, you should use even ports for RTP.
        >       >
        >       >       The whole question of multicast ports is a vexing 
one. Of 
        > course, you
        >       >       need to look at
        >       >
        >       >       http://www.iana.org/assignments/port-numbers
        >       >
        >       >       Most multicasters just pick some at random (and, 
remember, 
        > most
        >       >       multicast is RTP,
        >       >       so if you pick port X, X should be even, and you will 
use X
        > +1 for
        >       >       RTCP AND if
        >       >       you are sending audio + video, then you will be using 
X+2 
        > and X+3 as
        >       >       well.
        >       >
        >       >       The trouble with just picking a random one is IANA 
will 
        > eventually
        >       >       assign it (unless
        >       >       it is up high in the private address space).
        >       >
        >       >       AmericaFree.TV currently uses ports from 7500 to 
8090, but 
        > I am
        >       >       intending to switch this to ports in the
        >       >       private port space :
        >       >
        >       >             The Dynamic and/or Private Ports are those from 
        > 49152 through
        >       >       65535
        >       >
        >       >       I have proposed a number of times that the multicast 
        > community pick a
        >       >       port range (or ranges) for
        >       >       streaming, either through IANA or just in the private 
        > address space,
        >       >       but this has never seemed to find favor in Mboned.
        >       >
        >       >       My current thinking is that multicast needs at least 
1000 
        > ports (I
        >       >       could see sourcing 1000 SSM channels
        >       >       from one server), and so why not pick, say, 60,000 to 
        > 61,000 ? At any
        >       >       rate, that is my current thinking for
        >       >       AmericaFree.TV (which currently has 46 channels and 
thus 
        > needs almost
        >       >       200 ports now).
        >       >
        >       >       (I will post this separately to the I2 WG mailing 
list.)
        >       >
        >       >       Regards
        >       >       Marshall
        >       >
        >       >       On Aug 10, 2006, at 12:53 PM, 

 wrote:
        >       >
        >       >       > We are just getting started with multicasting, 
wondering 
        > if anyone
        >       >       > can see our multicast VBrick streams
        >       >       >
        >       >       > MPEG2 at 233.88.214.138, port 4443
        >       >       > MPEG4 at 233.88.214.137, port 4444 for video and 
4644 
        > for audio
        >       >       >
        >       >       > We are connecting to I2 through the Connecticut 
        > Education Network
        >       >       > (CEN). Last spring we could see our SAPs and 
streams on 
        > CEN, but
        >       >       > they were not making it to I2 for some reason.
        >       >       >
        >       >       > Also, we set up a special subnet just for I2 
activities. 
        > Just
        >       >       > wondering if most institutions keep the firewall 
        > completely open to
        >       >       > all ports for this, or whether there is a set of 
        > "mutlicast-
        >       >       > activity" friendly ports suggested be kept open, to 
        > specific IPs on
        >       >       > the subnet.
        >       >       >
        >       >       > Thanks,
        >       >       >
        >       >       > Frank Fulchiero
        >       >       > Digital Media Specialist
        >       >       > Connecticut College
        >       >       >
        >       >
        >       >
        >       >
        >      
        >      
        >