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TOPIC: PING Results ( Host to Switch Ping)

PING Results ( Host to Switch Ping) 8 years 2 weeks ago #28226

  • Malik
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Hello

Any one can advice me why the PING time for the Host to Swithc is more...
I can ping Host A to Host B , normal time , But when i try to Ping my Swithch form host A, it gives me quite noticeable time ... I am using HP 2524 Switch.
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Re: PING Results ( Host to Switch Ping) 8 years 2 weeks ago #28228

  • S0lo
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Does it take time for every ping attempt or just the first one?. Could you post your ping output for us to have a glimpse.
Studying CCNP...

Ammar Muqaddas
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Re: PING Results ( Host to Switch Ping) 8 years 1 week ago #28248

  • Malik
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Hello

Here is Out Put:
Min / Avg / Max : 4.795 / 11.213 /155.944 ms

Truly i am not sure if it was forst time result or each time. But question is from Host A to Host B time is normal.. why it takes too much time for SWITCH.

Regards,
Malik
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Re: PING Results ( Host to Switch Ping) 8 years 1 week ago #28250

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Min / Avg / Max : 4.795 / 11.213 /155.944 ms

That output looks more like the switches output not the host!!. Or did I misunderstand you.

Any way, the only thing I could think of is that when the switch tries to reply it had to first send a broadcast ARP to discover Host A's MAC. While doing so it responds to the ping (ICMP echo) with an ICMP port unreachable message (Not echo reply). In other words the first ping gets dropped so it times out. When the second ping comes to the switch it responds immediately to it with an ICMP echo reply since the switch now has the MAC of host A. The same thing happens for the rest of the pings.

It seams that such behavior does not happen when pinging host B because hosts (at least Windows) do no drop the first ping packet, they wait for ARP until it gets the MAC of host A then the ping reply is sent correctly.

Does this make any sense?
Studying CCNP...

Ammar Muqaddas
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