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Webcast-Catalyst9k
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Would there be any difference for the result of ping from Switch connected by Console and Telnet?

Would there be any difference for the result of ping from Switch connected by Console and Telnet?

Here was the case:

Catalyst3750X (logged in by console) ping x 1000 => Destination A (6% loss)
Catalyst3750X (logged in by telnet) ping x 1000 => Destination A (0% loss)

Although source and destination were exactly the same for the both cases, ping loss was observed for the console case only.

6 REPLIES

Re: Would there be any difference for the result of ping from Sw

Hi,

no - this doesn't play a role at all.

You have to know that pinging from a Cisco device is process-switched and has very low priority for the CPU.

Hope that helps

Rolf

Re: Would there be any difference for the result of ping from Sw

In addition to what Rolf said, did consecutive pings also produce the same result? If not, it could be because the switch had to arp for the destination first:

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to x.x.x.x, timeout is 2 seconds:

.!!!!

Success rate is 80 percent (4/5), round-trip min/avg/max = 1/1/1 ms

HTH,
John

*** Please rate all useful posts ***

HTH, John *** Please rate all useful posts ***
New Member

Re: Would there be any difference for the result of ping from Sw

Thank you for your reply. Yes it was continuous ping.

Below is the log:


==== (Login by Console) ====

L3_Switch#
L3_Switch#
L3_Switch#ping 192.168.17.1 repeat 1000

Type escape sequence to abort.
Sending 1000, 100-byte ICMP Echos to 192.168.17.1, timeout is 2 seconds:
.!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!.!!!!!!
!!.!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!.!!!!!!!!!.!!!!!!!!!!!!!!!.!!!!!!!!.
!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!.!!!!!!!!!!!!!!!.!!
!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!.
!!!!!!!.!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!
!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!.!!!!!!!!!!!!!!!.!!!!!!!!.
!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!.!!!!!!!!.!!!!!!!!!.!!!!!!!!!!!
!!!!!!!.!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!
!.!!!!!!!!.!!!!!!!!!!.!!!!!!!!!!!!.!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!.
!!!!!!!.!!!!!!!!!!!!.!!!!!!!!!!!.!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!.!!
!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!.!!!!!!!!!!.!!!!!!!!!!!.!!!!!!!!!!!!!!
!!!!!.!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!
!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!
!!!.!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!
!!!!.!!!!!!!!!!!!!!!
Success rate is 94 percent (940/1000), round-trip min/avg/max = 1/1/4 ms
L3_Switch#
L3_Switch#

==== (Login by Telnet) ====

L3_Switch#
L3_Switch#
L3_Switch#ping 192.168.17.1 repeat 1000

Type escape sequence to abort.
Sending 1000, 100-byte ICMP Echos to 192.168.17.1, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!
Success rate is 100 percent (1000/1000), round-trip min/avg/max = 1/1/4 ms
L3_Switch#
L3_Switch#





As you can see the source and destination were exactly the same, but there were ping loss observed only with console login case.

New Member

Re: Would there be any difference for the result of ping from Sw

Akiyoshi did you changed the console cable and tried with the new one ?? And may i know which type of cable you are using .......?? Are you using the USB converter to Console ???

Actually as all said that shouldn't matter with the console and telnet.......somethings is going wrong with the PC, console cable or converter........

I hope this will help you.....

New Member

Re: Would there be any difference for the result of ping from Sw

Can you do a trace route from both logins? Kind of a wild thought, but it's almost like its taking a different route or getting caught by something.

Rob

Sent from Cisco Technical Support iPhone App

New Member

Re: Would there be any difference for the result of ping from Sw

Can you do this test:
- do a continuous ping from your desktop to R1 and R2
- if there is no drop, do the same test again and see if there is packet loss when you ping from the console, make sure the continuous ping from your desktop is still running

If the issue is not seen again, i expect this is due to mac/arp issue in your network

Sent from Cisco Technical Support iPhone App

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