Seeking clarification of "unregistered packet"
2009-05-19 18:50:06 GMT
I have a couple questions about the following material from RFC 4541, 2.1.2: > 3) An unregistered packet is defined as an IPv4 multicast packet with > a destination address which does not match any of the groups > announced in earlier IGMP Membership Reports. > > If a switch receives an unregistered packet, it must forward that > packet on all ports to which an IGMP router is attached. A switch > may default to forwarding unregistered packets on all ports. > Switches that do not forward unregistered packets to all ports > must include a configuration option to force the flooding of > unregistered packets on specified ports. Is the ability to "force the flooding of unregistered packets on specified ports" only important on switches which are only processing v1 and v2 packets (or v3 packets ignoring "include source" and "exclude source")? If it is relevant for a switch which processes fully general v3 Joins, the definition of "unregistered packet" seems a little ambiguous. Consider traffic from source S1 to group G which no Joins seen. This traffic (S1,G) is unregistered packets. If we then see a Join for (S2,G), we have now seen the group G mentioned in a Join. How am I supposed to treat the (S1,G) traffic? Is it still unregistered packets? Or am I supposed to stop forwarding that traffic to "specified ports"? My problem may be that I simply do not understand what kinds of devices I might have on "specified ports" that I may need to flood unregistered(Continue reading)