Re: A concern about draft-acg-mboned-multicast-models recommendations

Hi,

Thanks Dale.

Yes, the general principle we agreed was on inter-domain deprecation. I suspect Jim has read the draft, but not caught up on the mail list, which if he's new here is only to be expected :)

For intra-domain, what consenting adults do in their own networks is up to them, if it's constrained, but I do sense a wish to document recommendations for adoption of SSM intra-domain too, to explore what missing pieces there might be (e.g. around service discovery), and to understand for which applications ASM is still beneficial/preferred (which may include local applications with highly dynamic bidirectional participants).

But I think it's important not to get lost in detail when making the high-level recommendation on inter-domain ASM, hence the split of the document, and my question in the previous email.

Tim 

> On 27 Feb 2018, at 23:18, Dale W. Carder <[email protected]> wrote:
> 
> Hi Jim!
> 
> I think we're converging towards deprecating ASM for *inter-domain* 
> use, and what we say about intra-domain models is a bit in flux.  
> 
> I think the latest is at the bottom of Tim's most recent message:
> https://www.ietf.org/mail-archive/web/mboned/current/msg02543.html
> 
> glad to have you here!
> 
> Dale
> 
> 
> Thus spake James A. (Jim) Stevens ([email protected]) on Tue, Feb 27, 2018 at 04:29:00PM -0600:
>> Hi, I’ve only recently joined MBONED, so this email may be rehashing old
>> discussions. (If so, please just point me to the prior discussions.)
>> 
>> With respect to multicast service models, I support customers who field
>> hundreds to thousands of nodes where each node is a member of multiple
>> (typically five to ten) multicast groups where most of the groups have
>> dozens to hundreds of members that partially overlap in membership between
>> the groups.  All of the members of the multicast groups are both multicast
>> sources and receivers.  The nodes are spread out over multiple IP links
>> (typically wireless).  The multicast groups are within a single IP routing
>> domain that can contain dozens to hundred of IP links and subnets.  The IP
>> links are typically other than standard WiFi or cellular IP links and have
>> limited throughput capacity – ranging from tens of kilobits/sec to a few
>> megabits/sec – so a key concern is to keep overhead down.
>> 
>> For this multicast scenario with many dynamic bidirectional sources and
>> receivers, we use ASM rather than SSM model to reduce management overhead
>> and simplify source discovery by not having to track which nodes have
>> joined which groups in order to do an SSM join to all the members of the
>> group.
>> 
>> The draft-acg-mboned-multicast-models-02 recommends “the use of SSM for all
>> multicast scenarios.” For this multicast scenario, I don’t see how SSM
>> efficiently satisfies this many multiple sources and receivers – especially
>> since the multicast members are dynamically joining and leaving.
>> 
>> Thus, I argue that SSM is not always the best multicast model and there
>> shouldn’t be a blanket recommendation to use SSM for all possible multicast
>> applications. In addition, I recommend section 7.6 address the fact that
>> SSM is not as efficient as ASM for the case of many dynamic bidirectional
>> sources and receivers.
>> 
>> Or, am I overlooking something on how to use SSM to address scenarios with
>> many dynamic bidirectional sources and receivers?
>> 
>> Thanks,
>> 
>> Jim Stevens
> 
>> _______________________________________________
>> MBONED mailing list
>> [email protected]
>> https://www.ietf.org/mailman/listinfo/mboned
> 
> _______________________________________________
> MBONED mailing list
> [email protected]
> https://www.ietf.org/mailman/listinfo/mboned

_______________________________________________
MBONED mailing list
[email protected]
https://www.ietf.org/mailman/listinfo/mboned