Fun with Time Consensus position reached at a pre-meeting yesterday evening (So slides are rough:-) Scott, Dan (Brown), Kevin, Stephen, Will, Brenton, Calvin

Drafts A bunch of overlapping drafts draft-farrell-dtnrg-alt-time draft-ellard-dtnrg-reltime-htl draft-fall-dtnrg-schl Some interested folks met yesterday:...and reaced a consensus on how to go forward!

Consensus Outline New drafts: Hop count based on Kevin's draft (just done) Time - Mix of authors of current drafts (TBD) Time based on extension blocks... Consider/favour migrating those to, e.g. a new primary block format in a 5050bis if/when that happens (later) Note: subsequent slides on this are preliminary

Problem How do we enable time-based bundle expiration when not all nodes in the network have accurate (synchronized) clocks?

Solution Sketch (1 of 5) 1.Carry bundle AGE in an extension block, in addition to bundle creation time (as available) in the primary block. –Extension block I-D can be written and advanced to RFC- hood fairly quickly. –Favor migrating this field into the primary header when RFC 5050 is eventually updated/obsoleted.

Solution Sketch (2 of 5) At bundle creation time: Optionally, bundle age extension block is added. The block contains the bundle’s age in (say) msec. If source node has an accurate clock, bundle creation time is set and sequence number can roll over once per second. Otherwise:  Bundle creation time is zero (indicating creation time unknown).  Sequence number is incremented for each bundle and never rolls over.  If node understands bundle age extension block: Node notes current time to enable age update.

Solution Sketch (3 of 5)

Solution Sketch (4 of 5) When bundle is received: If bundle’s creation time is zero:  If bundle age extension block is present: If node understands bundle age extension block:  Node notes current time to enable age update.  If time in transit is provided, node adds that time to age.

Solution Sketch (5 of 5) While bundle is enqueued at node: If bundle’s creation time is zero:  If bundle age extension block is present: If node understands bundle age extension block:  Node deletes bundle if age (as incremented) exceeds TTL. Else (non-zero bundle creation time)  If node has an accurate clock: Node deletes bundle if current time (as incremented) less bundle creation time exceeds TTL.

After that... Issue raised: what about revising the bundle protocol (i.e. a 5050bis) When, who, where, why... And that caused us to think: Where should we try focus DTNRG effort for the next year or so  5050bis, routing, experiments...