if the problem is non-propogation of multicast, gossiper is a solution. for some reason a lot of people seem to confuse “something like” with “definitely use,” and of course i didn’t mean it that way.

i don’t know what other problems you’re trying to solve.

–b

Long time!

A couple of comments / thoughts.

One needs to be careful w.r.t. multicast. At layer II – IGMP based multicast is usually fine in the enterprise. However – as soon as you move to layer III – as you suggest – you are into a whole new level of pain. Protocol Independent Multicast (PIM) is not usually supported across the backbone etc etc.

Also whatever the group protocol – the participating endpoints must be discovered; note that Gossiper allows for multicast discovery – see synchronized void join(InetAddress from).
So local multicast discovery – used in conjunction with a ‘smart overlay’ is a good approach.

With respect to the Gossip protocol itself – it has the same advantages and disadvantages as its social namesake. No doubt useful for propagating information across an unstructured population – its current popularity is a function of Amazon’s use of it (also Astrolabe) – rather than perhaps intrinsic suitability. There are more efficient lower latency messaging approaches that may be used with ‘smart’ populations of self-organizing cloud resource.

We will be making a press release early in the New Year which touch upon this area.

Best Wishes / Merry Xmas

Richard

The whole experience has been somewhat reminiscent of getting clustering to work on WLS 6 ;-)

I guess one of the nice things about using a VPN overlay is that once you do get multicast working on it (see day 4) then you’re no longer beholden to the vagaries of whatever you network team (or cloud) choose to support.

I’ve passed your Gosspier suggestion onto the Paremus team.

Relying in multicast for clustering almost always fails because so many LANs don’t support it, and it doesn’t work over WANs.

they should replace it with something like Gosspier from Cassandra

https://svn.apache.org/repos/asf/incubator/cassandra/trunk/src/java/org/apache/cassandra/gms/Gossiper.java