All things related to multicast

["Richard Mavrogeanes" <>]

Joel,
 
Yes, MLDv2 snooping...but this may be too limiting a statement because 
vendors can/should implement what works for them to enable end-to-end IPV6 
multicast. Some vendors do some proprietary things to enhance multicast 
behavior I seem to recall, but the result is consistant with snooping...that 
is, you can join a group the switch already has without a trip to the router, 
flooding is avoided, and group leaves are pretty quick thus avoiding local 
oversubscription.
 
We have multicast-enabled hundreds of colleage and K-12 networks in the last 
few years, as well as district-level networks that interconnect many schools. 
 To your point, there remains FUD on the part of the local IT manager with 
regard to multicast rollout...but we've been able to overcome these 
objections and I would say multicast is at last becoming conventional wisdom. 
 I think this is true because it works when properly deployed and gives the 
deploying institution capabilities otherwise virtually impossible.
 
My concern is that those forward-thinking institutions planning a migration 
to IPV6 will encounter the same trouble the industry as a whole has only 
recently begun to overcome with IGMPv2 and IGMPv3.  I think I'm hearing it's 
not possible to deploy IPV6 multicast in any sort of reasonable end-to-end 
way...yet.  Please keep in mind that my perspective for this thread is 
largely inside the enterprise, not so much the WAN.
 
/rich
 
 

        -----Original Message----- 
        From: Joel Jaeggli 
[mailto:]
 
        Sent: Sat 5/20/2006 3:08 PM 
        To: Richard Mavrogeanes 
        Cc: Alan Crosswell; 

 
        Subject: Re: IPV6 Multicast
        
        

        Richard Mavrogeanes wrote:
        > Alan,
        > 
        > Well, the next release supports IPV6, and perhaps multicast too.
        > 
        > The trouble/question is local Ethernet switch support ("snooping" 
behavior), and I'm hoping someone has some war stories to share.  It was bad 
enough getting the switch vendors fully onboard with IGMP, and I wonder where 
they are with IPV6 multicast.  Obviously, IPV6 is not so useful if it can't 
reach the end user (desktop).
        
        By "snooping behavior" I assume you mean mldv2 snooping?
        
        It always seems like people are looking for a reason to not deploy 
this
        (foo multicast technology).    "If we just had igmpv2/v3/mld/v2 
capable
        switches there'd be no impediment to use rolling it out."
        
        The fact of the matter is l2 switching hardware will almost always
        evolve more slowly than host stacks or routers. Looking inside 
ethernet
        frames is an expensive exercise for most l2 switches.
        
        What do you do with an elephant with three balls?
        
        Walk it, and pitch to the giraffe...
        
        > /rich
        > 
        >
        >       -----Original Message-----
        >       From: Alan Crosswell 
[mailto:]
        >       Sent: Sat 5/20/2006 12:54 PM
        >       To: Richard Mavrogeanes
        >       Cc: 

        >       Subject: Re: IPV6 Multicast
        >      
        >      
        >
        >       Abiline and most of the gigapops support it.  There are some 
issues with
        >        some international networks not yet support embedded RP.  
Campuses are
        >       pretty far behind.  NYU is one of the few that has done v6 
multicast
        >       with NYSERNet.  In the first ever v6 multicast hands on 
workshop in
        >       Albuquerque a few months ago, we viewed content that was 
being multicast
        >       from Syracuse.
        >      
        >       Put it in a product and I'll have an excuse to replace my 
Vbrick 1200's:-)
        >      
        >       /a
        >      
        >       Richard Mavrogeanes wrote:
        >       > I'd like to explore this group's experience with IPV6 
multicast, in particular, what do we believe is the current state of the 
Internet2 backbone network and what do we think is the state of enterprise 
routers and switches to allow it?
        >       >
        >       > Looking forward to an interesting thread...
        >       >
        >       > /rich
        >       >
        >      
        >
        
        
        --
        -------------------------------------------------
        Joel Jaeggli 
()
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