[Nfd-dev] Ethernet multicast over multiple wireless hops

[Thiago Teixeira]

Sorry, please disconsider this!



From: Thiago Teixeira
Sent: Wednesday, January 11, 2017 7:54 PM
To: 'Junxiao Shi' <shijunxiao at email.arizona.edu>
Cc: <nfd-dev at lists.cs.ucla.edu> <nfd-dev at lists.cs.ucla.edu>; Teng Liang <philoliang2011 at gmail.com>
Subject: RE: [Nfd-dev] Ethernet multicast over multiple wireless hops

Hi Junxiao,

Thanks for your comments.
I noticed that faces that use UDP or TCP tunnels seem to relay information over multiple hops, using the same strategy. Ethernet does not.
Could you clarify why this happens please?

I looked into the NFD Developer Guide and this older post:
http://www.lists.cs.ucla.edu/pipermail/ndn-interest/2015-June/000720.html

Thank you,
Thiago


From: Junxiao Shi [mailto:shijunxiao at email.arizona.edu]
Sent: Wednesday, December 21, 2016 8:46 PM
To: Thiago Teixeira <tteixeira at engin.umass.edu<mailto:tteixeira at engin.umass.edu>>
Cc: <nfd-dev at lists.cs.ucla.edu<mailto:nfd-dev at lists.cs.ucla.edu>> <nfd-dev at lists.cs.ucla.edu<mailto:nfd-dev at lists.cs.ucla.edu>>; Teng Liang <philoliang2011 at gmail.com<mailto:philoliang2011 at gmail.com>>
Subject: Re: [Nfd-dev] Ethernet multicast over multiple wireless hops

Hi Thiago
NFD forwarding as of v0.5.0 is not designed for wireless networks.

Whether an Interest will be forwarded out of the same face as it came in is up to the strategy, as nothing in forwarding pipelines prevents such forwarding.
For BestRouteStrategy2, delete these lines https://github.com/named-data/NFD/blob/037f4ab4b62f42447c78d25ede0755f98409c9cb/daemon/fw/best-route-strategy2.cpp#L71-L73 enables such forwarding.

Incoming Data pipeline will not forward a Data out of the same face as it came in. This can be changed by deleting these lines https://github.com/named-data/NFD/blob/037f4ab4b62f42447c78d25ede0755f98409c9cb/daemon/fw/forwarder.cpp#L365-L367

I do not know the implication on loop detection and PIT aggregation after those changes are made. I'm CCing Teng Liang who recently implemented a broadcast-based forwarding strategy for sensor networks where each node has only one wireless NIC, as he may have a better idea on the implication.

Yours, Junxiao

On Wed, Dec 21, 2016 at 3:14 PM, Thiago Teixeira <tteixeira at engin.umass.edu<mailto:tteixeira at engin.umass.edu>> wrote:
I have a topology of five wireless nodes all running NFD v.0.5. on Ubuntu 16.04. I am using Ethernet as the transport method with one multicast group, as follows face_system.ether. mcast_group 01:00:5E:00:17:AA.

When I test connectivity using NDN-Ping it works between one hop neighbors, but not over multiple hops. I assume that is because the architecture prevents it from sending Int/Data packets over the same face it received, in order to prevent loops. Am I right?

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