All things related to multicast

[Stig Venaas <>]

A new version of ssmping is finally available. The main new features are 
options for specifying size of replies and for querying server version 
and capabilities. Also the Windows clients now display distance (number 
of hops) for IPv6 (but not for IPv4, this seems to be a Windows 
limitation, but I could be wrong). Also as you probably know, IPv6 SSM 
is only available on a few platforms like Linux and Windows Vista.

The new version also contains a new tool called mcfirst that can be used 
 to check whether can receive any given ASM/SSM, IPv4/IPv6 multicast 
session. You just specify group (and source if SSM) and port number, and 
the tool will run until it receives one packet. Optionally you may 
specify how many packets should be received and/or how many seconds it 
should run. If it runs for at least a ms and receives more than one 
packet, it will tell you how many packets and bits per second were 
received. Unless "r"-option is used, it will display one line per packet 
received.

Examples:
$ mcfirst ff0e::2:7ffe 9875
mcfirst joined (*,G) = (*,ff0e::2:7ffe)
Received 235 bytes from 2001:720:410:4:204:75ff:febd:4876 after 409.511 
ms (ttl/hops 245)

$ mcfirst -c 4  224.2.127.254 9875
mcfirst joined (*,G) = (*,224.2.127.254)
Received 255 bytes from 163.117.180.90 after 12.948 ms (ttl/hops 237)
Received 471 bytes from 130.104.10.139 after 52.974 ms (ttl/hops 240)
Received 294 bytes from 141.225.215.20 after 139.631 ms (ttl/hops 236)
Received 641 bytes from 193.190.113.20 after 243.353 ms (ttl/hops 242)
1661 bytes (payload) and 4 packets received in 0 seconds
Average rate: 48.818 kbits of payload per second
Estimated average rate including all headers: 51.735 kbits per second

$ mcfirst -r -t 10  224.2.127.254 9875
mcfirst joined (*,G) = (*,224.2.127.254)
50940 bytes (payload) and 124 packets received in 10 seconds
Average rate: 41.437 kbits of payload per second
Estimated average rate including all headers: 44.276 kbits per second

Sources and Windows binaries are available from the ssmping page at 
http://www.venaas.no/multicast/ssmping/

Happy for any feedback,

Stig