RUEI: Dropped Segments and Bad Checksums Caused by Jumbo Frames (Doc ID 1073610.1)

Last updated on MAY 06, 2017

Applies to:

APM - Application Performance Management - Version 10.2.0.5 to 12.1.0.3.0 [Release 10.2 to 12.1]
Information in this document applies to any platform.

Symptoms

High measurements for dropped segments and bad checksums reported by the collector status page:

System -> Status -> Collector -> <collector-host> -> TCP


Packets received on the network interface of the collector contain Jumbo Frames. Jumbo Frames are TCP packets with a payload larger then the standard 1500 bytes.

To verify the frame sizes to see if this is what causes the bad checsums, make a analysis from tcpdump output taken from the collector server with an application like WireShark or tcpdump itself.

To get packets greater then 1500 bytes do:

# tcpdump -i eth0 -s 0 -p greater 1500


To make a file that can be analyzed later, or with an application like WireShark do:

# tcpdump -i eth0 -s 0 -p -w output.pcap greater 1500


Frame size is specified by "Len" on the tcpdump output
i.e.


Frame 11 (2178 bytes on wire, 2178 bytes captured)
Ethernet II, Src: ......................
Internet Protocol, Src: xx.xx.xx.xx, Dst: xx.xx.xx.xx
Transmission Control Protocol, Src Port: 15548 (15548), Dst Port: http (80), Seq: 2424, Ack: 764, Len: 2124

 

 

Changes

 

Cause

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