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Bug #5079

closed

Packet retransmission issue because of LpReliability

Added by Chavoosh Ghasemi about 4 years ago. Updated about 4 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Category:
Faces
Target version:
Start date:
Due date:
% Done:

100%

Estimated time:

Description

There are some pieces of evidence that show LpReliability causes multiple retransmissions before either timeout happens at the sender (i.e., 200 ms) or any ack for greater sequence numbers receives by the sender.
This problem has been seen between two testbed hubs where both sides have LpReliability on. Worth mentioning that this problem is not deterministic and happens only for some Interests.

To show this issue, a client ndnpinged Washington hub (wu) through Arizona hub (hobo). Attached is the tcpdump pcap file that is collected on hobo.
Upon receiving Interest /ndn/edu/wustl/ping/1761450254637779364 from the client, hobo sends the Interest to wu. However, before timeout or receiving any Ack it will retransmit the same Interest for 3 times. In return wu sends back 4 Data packets and 12 Nacks.

Here is the output from pcap, particularly for /ndn/edu/wustl/ping/1761450254637779364:

No. Time    Source  Destination Protocol    Length  Info    delta
915 61.626371   10.132.245.39   128.196.203.36  UDP (NDN)   103 Interest /ndn/edu/wustl/ping/1761450254637779364    0.042070
916 61.626475   128.196.203.36  128.252.153.194 UDP (NDN)   119 Interest /ndn/edu/wustl/ping/1761450254637779364    0.000104
918 61.717688   128.196.203.36  128.252.153.194 UDP (NDN)   119 Interest /ndn/edu/wustl/ping/1761450254637779364    0.039450
928 61.808919   128.196.203.36  128.252.153.194 UDP (NDN)   119 Interest /ndn/edu/wustl/ping/1761450254637779364    0.049886
929 61.900236   128.196.203.36  128.252.153.194 UDP (NDN)   119 Interest /ndn/edu/wustl/ping/1761450254637779364    0.091317
930 62.067296   128.252.153.194 128.196.203.36  UDP (NDN)   165 Data /ndn/edu/wustl/ping/1761450254637779364    0.167060
931 62.067405   128.196.203.36  10.132.245.39   UDP (NDN)   137 Data /ndn/edu/wustl/ping/1761450254637779364    0.000109
933 62.100172   128.252.153.194 128.196.203.36  UDP (NDN)   140 Nack /ndn/edu/wustl/ping/1761450254637779364    0.027834
935 62.255842   128.252.153.194 128.196.203.36  UDP (NDN)   140 Nack /ndn/edu/wustl/ping/1761450254637779364    0.150629
937 62.282512   128.252.153.194 128.196.203.36  UDP (NDN)   153 Data /ndn/edu/wustl/ping/1761450254637779364    0.021628
938 62.284511   128.252.153.194 128.196.203.36  UDP (NDN)   140 Nack /ndn/edu/wustl/ping/1761450254637779364    0.001999
940 62.313064   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.025509
942 62.458480   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.140376
943 62.458967   128.252.153.194 128.196.203.36  UDP (NDN)   153 Data /ndn/edu/wustl/ping/1761450254637779364    0.000487
947 62.486449   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.000866
949 62.508351   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.016863
952 62.581047   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.004247
954 62.630670   128.252.153.194 128.196.203.36  UDP (NDN)   153 Data /ndn/edu/wustl/ping/1761450254637779364    0.044582
956 62.651119   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.015408
957 62.652113   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.000994
960 62.678285   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.010253
964 62.711556   128.252.153.194 128.196.203.36  UDP (NDN)   128 Nack /ndn/edu/wustl/ping/1761450254637779364    0.028228

Files

hobo-wu-lp-reliability-2.tcpdump (211 KB) hobo-wu-lp-reliability-2.tcpdump Chavoosh Ghasemi, 02/03/2020 09:59 AM

Related issues 1 (0 open1 closed)

Related to NFD - Feature #5080: Add logging to LpReliabilityClosedEric Newberry

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