[Roll] [roll] #11: Decision on prefix packing in DIO messages

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#11: Decision on prefix packing in DIO messages
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 Reporter:  jpv at …               |       Owner:  jpv at …        
     Type:  enhancement         |      Status:  new          
 Priority:  major               |   Milestone:               
Component:  rpl                 |     Version:               
 Severity:  Active WG Document  |    Keywords:               
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 Currently RPL requires one DAO per message.

 JP's proposal below:

 Hi Jonathan,

 What I was referring to was to pack prefix in DAO, a very light change in
 the spec (just make use of TLV) and factor the common fields. This allows
 to reduce the number of packets very significantly as we get closer to the
 root.

 There two benefits here:
 1) You send one DAO between C and D instead of 3
 2) You can also pack the Reverse Route Stack whenever possible for all
 prefix sharing the same routes.

 Let's suppose that:
 1) X advertises two prefixes X1 and X2
 2) Y advertises two prefixes Y1, Y2 and Y3
 3) Z advertised one prefix: Z1

 Instead of sending 6 DAO, C would send one DAO to D would look like this:
 X1,X2[XBC], Y1,Y2,Y3[YBC], Z1[ZBC]

 Note that you could when possible also aggregates prefixes at the same
 time if they share a common path.

 BAck to you timing question Richard, it depends of the sequence of events
 but there is no need to wait.
 C could start with one DAO and then start to pack at it receives more, the
 same reasoning applies to other
 nodes.

 Others, thoughts ?

 Thanks.

 JP.

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Ticket URL: <https://svn.tools.ietf.org/wg/roll/trac/ticket/11>
roll <http://tools.ietf.org/wg/roll/>