quick question

[Derek Atkins]

Keep in mind that your timers may be of different resolution.  For
example, your "other machine" may have 1ms granularity, whereas your
linux box as 0.1ms granularity.  I would be surprised if you saw 0ms
in one direction and 3-4ms in the other.  But you're seeing '0' and
'0.6' which are basically equivalent if the former has a 1ms
granularity.

In other words, anything <1ms appears as 0ms, and obviously 0.6 < 1

-derek

Nick Oleksinski <noleks at lsil.com> writes:

> Has anyone ever seen a situation where outgoing pings from a machine are
> slow on a LAN but ping reflections (ie another machine on the LAN
> pinging the Linux box) are very fast?  I'm getting this on a Linux box
> using a 3Com 3C905C-TX ethernet card and kernel 2.4.1.  The times look
> something like this:
> 
> FROM ANOTHER MACHINE TO THE PC (wmpc75):
> noleks tcsh[2]$ ping -s wmpc75
> PING wmpc75: 56 data bytes
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=0. time=0. ms
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=1. time=0. ms
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=2. time=0. ms
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=3. time=0. ms
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=4. time=0. ms
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=5. time=0. ms
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=6. time=0. ms
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=7. time=0. ms
> 64 bytes from wmpc75 (147.145.153.37): icmp_seq=8. time=0. ms
> ^C
> ----wmpc75 PING Statistics----
> 9 packets transmitted, 9 packets received, 0% packet loss
> round-trip (ms)  min/avg/max = 0/0/0
> noleks tcsh[3]$ 
> 
> 
> TO ANOTHER MACHINE FROM THE PC (wmpc75):
> noleks tcsh[2]$ ping wm27
> PING wm27 (147.145.152.27): 56 octets data
> 64 octets from 147.145.152.27: icmp_seq=0 ttl=254 time=1.8 ms
> 64 octets from 147.145.152.27: icmp_seq=1 ttl=254 time=0.6 ms
> 64 octets from 147.145.152.27: icmp_seq=2 ttl=254 time=0.6 ms
> 64 octets from 147.145.152.27: icmp_seq=3 ttl=254 time=0.6 ms
> 64 octets from 147.145.152.27: icmp_seq=4 ttl=254 time=0.6 ms
> 64 octets from 147.145.152.27: icmp_seq=5 ttl=254 time=0.6 ms
> 64 octets from 147.145.152.27: icmp_seq=6 ttl=254 time=0.7 ms
> 
> --- wm27 ping statistics ---
> 7 packets transmitted, 7 packets received, 0% packet loss
> round-trip min/avg/max = 0.6/0.7/1.8 ms
> noleks tcsh[3]$ 
> 
> Thanks
> -Nick
> -
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-- 
       Derek Atkins, SB '93 MIT EE, SM '95 MIT Media Laboratory
       Member, MIT Student Information Processing Board  (SIPB)
       URL: http://web.mit.edu/warlord/    PP-ASEL-IA     N1NWH
       warlord at MIT.EDU                        PGP key available
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