All things related to multicast

[Marshall Eubanks <>]

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