[Xorp-users] IGMP report group ...?

[Pavlin Radoslavov]

Hervé Léonard <lherve at interfaceconcept.com> wrote:

> 
> Hi,
> 
> In fact, i do some other tests...
> 
> The flag 'ALLMULTI' for the network card driver (in ifconfig) was not the
> root cause of the group membership in xorp router.
> 
> It was in fact the IGMP version number for the interface in Xorp
> configuration.
> 
> With the IGMP version 2 (by default) the IGMP membership doesn't work. But
> with version 3, it does.
> 
> I thought that only one router on the LAN can send IGMP Query, it is the
> Querier IGMP. And this Querier IGMP should deal with 3 versions of IGMP for
> all different kinds of hosts on the LAN...
> 
> Is that the case with Xorp?

Few things:

* Yes, only the elected Querier should send IGMP Query messages.
* If the Querier is configured for IGMPv3, it should deal with all
  IGMP control messages from other routers and hosts: IGMPv1,
  IGMPv2, IGMPv3.
  The XORP IGMPv3 router-side implementation supports that.
* If the Querier is configured for IGMPv2, the IGMPv3 hosts MUST
  operate in IGMPv2 compatibility mode. If they don't, then you need
  to find the root cause for that: is it on the host side (e.g., the
  host IGMP implementation) or are there some other factors (e.g., 
  firewall entries on either the host or the router side as I
  mentioned in my earlier email on the subject).
* Setting the XORP IGMP version to 3 is a perfectly acceptable
  solution. In the future IGMPv3 and MLDv2 will become the default
  configuration for XORP.

Pavlin