08-30-2013 02:00 AM - edited 03-04-2019 08:54 PM
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.
08-30-2013 05:02 AM
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
08-30-2013 12:17 PM
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
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09-05-2013 06:47 PM
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.
09-05-2013 09:15 PM
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.....
09-05-2013 08:59 PM
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
09-05-2013 09:48 PM
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
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