Ping stress (>=990 bytes)

Joel Sherrill joel.sherrill at
Mon Aug 18 19:52:37 UTC 2008

Gene Smith wrote:
> Keith Robertson wrote:
>> Gene Smith wrote:
>>> Another question on dropped packets. I am able to ping (even flood ping)
>>> up to a length of 980 bytes with no loss. When I go over this my tcp/ip
>>> stack seem to go bad. Regular pings (56 bytes) sometimes don't respond,
>>> or responds with a huge amount of data (1022 bytes). Is there a maximum
>>> ping length in rtems?  I see no bad stats in netdemo. My (newly made)
>>> driver has buffers for 1536 bytes.
>>> Wondering if others can ping the rtems stack with >=990 bytes?
>> On rtems 4.8.1 (and earlier as well), I can successfully ping rtems
>> devices with packets of 65507 bytes (the icmp max).  It takes longer,
>> but it works fine.
>> This is on the powerpc/virtex bsp.
>> Keith
> Thanks for verifying this. Had a problem in the driver where the send
> length wasn't being initialized right. Also, needed to allocate more
> receive/xmit buffers in the driver to receive/send 65507 byte frames. So
> now I can ping with -s 65507. Looks pretty good!
YEAH! Any patches you need to submit or a BSP. :-D
> -gene
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Joel Sherrill, Ph.D.             Director of Research & Development
joel.sherrill at        On-Line Applications Research
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