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Task #3627

closed

Use /localhop component in Sync prefix to reduce duplicate NACKs

Added by Vince Lehman over 8 years ago. Updated almost 8 years ago.

Status:
Closed
Priority:
Normal
Target version:
Start date:
05/25/2016
Due date:
% Done:

100%

Estimated time:

Description

Currently, Sync Interests are multicasted at each router which can result in Interests traversing a loop; these loops cause NFD to send a Duplicate NACK in response.

If instead the Sync prefix was prefixed with the /localhop component, the Interests would only be multicasted and delivered to immediate neighbors.

Actions #1

Updated by Junxiao Shi about 8 years ago

Using /localhop cannot reduce Nack-Duplicates in the case of ChronoSync Interests.

ScopeControl restricts /localhop Interest forwarding as follows:

  • If PIT entry has at least one InRecord from a local face, it can be forwarded to local faces and non-local faces.
  • If PIT entry has all InRecords from non-local faces, it can only be forwarded to local faces.

As soon as the local NLSR has expressed a sync Interest, NFD can forward a sync Interest received from one remote router to another remote router, and cause the same amount of Nack-Duplicates.

Actions #2

Updated by Lan Wang about 8 years ago

What's the rationale for this rule "If PIT entry has at least one InRecord from a local face, it can be forwarded to local faces and non-local faces."?

Actions #3

Updated by Junxiao Shi about 8 years ago

Answer to note-2:

The alternate is: "If PIT entry does not have any InRecord from a non-local face, it can be forwarded to non-local faces".

This breaks the scenario when two nodes try to send the same Interest to each other.

Actions #4

Updated by Lan Wang about 8 years ago

In what case will two nodes try to send the same Interest to each other using /localhop and why would you like to forward the interest to other nodes in this case?

Actions #5

Updated by Ashlesh Gawande almost 8 years ago

  • Assignee set to Ashlesh Gawande
Actions #6

Updated by Ashlesh Gawande almost 8 years ago

Rules have changed: https://redmine.named-data.net/issues/3836

I have tested this on a 34 node topology, no Duplicate NACKs are generated by sync interests (this reduced Duplicate NACKs from ~47000 to ~15000, those generated are by LSA interests).

Actions #7

Updated by Ashlesh Gawande almost 8 years ago

  • Status changed from New to Closed
  • % Done changed from 0 to 100
Actions #8

Updated by Nicholas Gordon almost 8 years ago

  • Target version set to v0.3.1
Actions #9

Updated by Ashlesh Gawande almost 8 years ago

  • Status changed from Closed to Feedback

advertise and withdraw does not work when security is turned on after this patch.

Validation of received interest fails:
Name prefix update error (code: 403)

Not sure if it is because of this patch.

My bad, the interest needs to be signed when security is enabled. It is working as expected.

Actions #10

Updated by Ashlesh Gawande almost 8 years ago

  • Status changed from Feedback to Closed
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