Subject: [core] #237: Multicast -> reference groupcomm draft

From: "core issue tracker" <[email-masked]>
Date: Tue, 15 May 2012 13:20:40 -0000

#237: Multicast -> reference groupcomm draft

 Peter van der Stok notes (msg03246):

 Probably, this has been stated before, in that case I like to reiterate
 that a reference to the groupcomm draft is called for.

 The subject: a node sends messages about resource state changes to a group
 of clients is indeed at the heart of group communication as pointed out in
 the groupcomm draft.

 This draft also clarifies the different requirements on group
 communication and the protocols that satisfy a subset of these
 requirements.

 In your implementation, each client is forced to ack a unicast when it is
 sent with a CON message, and otherwise the message is not ack’ed and no
 reliability is “guaranteed”.

 Some multicast protocols can guarantee reliability without acking but by
 replicating  a message along different paths.

 IMO, the draft will certainly improve when these possibilities are taken
 into account by explaining how to use an appropriate group communication
 protocol when it is present.

 Another point is the statement that the node should maintain a list of
 clients.

 In principle this is not necessary when a multicast address is used for
 addressing the group. The node only needs to maintain the multicast
 address thus saving RAM space.

 Groups can be maintained in DNS-SD, or the resource directory (Zach
 allowing this).

 How the group communication to the group, using the multicast address, is
 done - with a multicast or with individual unicasts- is the concern of the
 group communication protocol.

 -> add informative reference to groupcomm WIP; write text around that.
 (Note that, in a similar vein, -coap should have an informative reference
 to -observe.)

-- 
-----------------------------+---------------------------------------
 Reporter:  cabo@…           |      Owner:  draft-ietf-core-observe@…
     Type:  editorial        |     Status:  new
 Priority:  minor            |  Milestone:  post-WGLC-1
Component:  observe          |    Version:  observe-05
 Severity:  In WG Last Call  |   Keywords:
-----------------------------+---------------------------------------

Ticket URL: <http://trac.tools.ietf.org/wg/core/trac/ticket/237>
core <http://tools.ietf.org/core/>