[Xorp-users] running IP multicast using xorp with click

[Bruce M. Simpson]

Yaping Zhu wrote:
> ...
> and, the only interface between xorp and Click (or whatever data plane 
> environment) is the multicast forward table, is it correct?
>
> so that the data plane (of Click) has to support: multicast forwarding. when 
> receiving packets destinated to multicast group address, it looks up the 
> forwarding table, and copy the packets through multiple interfaces for the 
> group. is it also correct?
>   

It seems like the following work would need to be done:

 * implement Click elements which can run to implement multicast forwarding.
   Someone's already done this for IPv6, IPv4 may require work:
    http://read.cs.ucla.edu/click/packages/multicast6

 * implement the parts of the XORP MFEA necessary to communicate with Click.
   Currently these don't exist.

 * The autoconf scripts in config/ would need to be updated to learn 
about the existence of Click elements supporting a new multicast 
forwarding API.

 * The Click version of the FEA process would need to be modified to 
pick up the new MFEA back-end supporting Click.

XORP's MFEA uses the IP MROUTING family of interfaces which exist in the 
BSDs and which are also supported by Linux to talk to the multicast 
forwarding cache.

Pavlin may have more to say on this as most likely the MFEA would need 
refactoring to accomodate multiple APIs. Windows, for example, uses a 
completely different API which involves a number of userland DLLs.

This is not an insignificant amount of work, as it requires refactoring 
the MFEA, however, it's not a huge project either.

cheers
BMS