Subject: [dtn-users] 1 Hour Data Flow Test Results - DTN2.8.0 Changeset 3550 plus BundleList and Experimental TBRouter patches - revisited

From: "Zoller, David A. (MSFC-EO60)[HOSC SERVICES CONTRACT]" <[email-masked]>
Date: Mon, 23 Jul 2012 11:15:38 -0500

Greetings all,
During follow on experimenting, I noticed that that the sooner Node1 establishes its connection to Node2 after Node2 has connected to Node1 then the worse the impact. I went back to the Experimental TableBasedRouter version and ran a test that did not fare so well. Despite my early jubilation, it looks like there is more digging to be done into the dynamics when two links are active for the same set of pending bundles.

That reminds me that during an early debug session I once ended up with 95 opportunistic links for the same destination (link-0 thru link-94). I wonder if those types of TCP links should be maintained after disconnection since those ports will not accept a connection and new connection are usually from a new OS assigned port number.

Best regards,
DZ

DTN2 - One Hour Data Flow with the Receiver (Node2) Brought Online After 30 Minutes

Test 1 - the latest code available on Sourceforge + patches

*         DTN2 changeset 3550 plus patches up to and including the Experimental TBRouter patch plus some statistics collection code.

*         OASYS changeset 2298 with all patches applied.

*         Data flow is 160 non-custody bundles per second for 60 minutes

*         576,000 UDP packets were transmitted (1316 byte payload)

*         471,667 packets were processed into bundles  (1316 byte payload)

*         104,333 packets were lost due to UDP socket buffer overflow

o   40MB socket buffer holds ~30k packets or ~187 seconds of data

Timeline Highlights
Seconds after Node1 started

14

Data flow started at 160 packets/sec

14-1826

Successfully received 289,987 bundles at 160 bundles/sec

1827

Node2 makes contact (link-0 created) - reroute_all_bundles entered - ingest halts

1835

reroute_all_bundles finished (elapsed 8.8 secs)

1835

Node1 establishes connection to Node2 - reroute_all_bundles entered

1848

reroute_all_bundles finished (elapsed 12.6 secs)

1848 - 2615

Ingest crawls at 2 bundles per 10secs, Transmit avg starts at 500 Bundles/sec and tapers down to 320 (all received bundles transmitted)

2615 - 2775

Ingest spikes to avg 320 bundles/sec while transmit to Node 2 averages 313 bundles/sec

2775

Ingest and transmit settles into avergage 160 bundles/sec

3614

Data flow terminates

Processing complete shortly after the 1 hour data flow

David Zoller
COLSA Corporation
Marshall Space Flight Center