Ping Issues across WAN link : help needed

Kaushik Ray · ‎11-11-2014

Hello I am trying to ping across a WAN circuit and see the following issues:

The interface configuration is as follows:

interface GigabitEthernet0/0.100
encapsulation dot1Q 100
ip address 172.28.88.254 255.255.255.254
end

The issues seems to be related to the MTU size allowed on the circuit; any advise on this will be much appreciated.

RTR#ping 172.28.88.255 repeat 1000 size 100
Success rate is 99 percent (999/1000), round-trip min/avg/max = 1/1/4 ms

RTR#ping 172.28.88.255 repeat 1000 size 200
Success rate is 99 percent (996/1000), round-trip min/avg/max = 1/1/4 ms

RTR#ping 172.28.88.255 repeat 1000 size 500
Success rate is 99 percent (994/1000), round-trip min/avg/max = 1/1/4 ms

RTR#ping 172.28.88.255 repeat 1000 size 800
Success rate is 98 percent (989/1000), round-trip min/avg/max = 1/1/4 ms

RTR#ping 172.28.88.255 repeat 1000 size 1200
Success rate is 97 percent (978/1000), round-trip min/avg/max = 1/2/16 ms

RTR#ping 172.28.88.255 repeat 1000 size 1400
Success rate is 96 percent (968/1000), round-trip min/avg/max = 1/2/36 ms

RTR#ping 172.28.88.255 repeat 1000 size 1450
Success rate is 92 percent (924/1000), round-trip min/avg/max = 1/2/4 ms

Or there could be other issues present?

Thanks

Joseph W. Doherty · ‎11-11-2014

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Posting

Bigger packets are more likely to congest or have a bit error during transmission (or ping responder might be made busier), and so also more likely to be dropped. So, it's not unreasonable that you see the drop percentage increase a bit.

However, without knowing more about your circuit or your ping responder, cannot say whether your results are "normal". Many WAN circuits can pass your ping tests without any drops.

For example, as your interface is a Ethernet port, with a VLAN tag, are there any other subinterfaces? Does your "WAN" have any kind of bandwidth limit less than port speed?

Kaushik Ray · ‎11-11-2014

thanks for your reply Joseph.

there are other subinterfaces as follows:

interface GigabitEthernet0/0.101
description | WAN - DATA VRF
encapsulation dot1Q 101
ip vrf forwarding DATA1
ip address 172.28.88.252 255.255.255.254
end

and the ping response

ping vrf DATA1 172.28.88.253 size 1450 repeat 1000
Type escape sequence to abort.
Sending 1000, 1450-byte ICMP Echos to 172.28.88.253, timeout is 2 seconds:
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!.!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!.!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!.!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!
!.!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!.!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!
Success rate is 98 percent (987/1000), round-trip min/avg/max = 1/2/4 ms

The main interface is as below and there is no bandwidth limiting on the router

interface GigabitEthernet0/0
mtu 1450
no ip address
duplex full
speed 100
end

Joseph W. Doherty · ‎11-11-2014

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

MTU 1450?

So the WAN link is 100 Mbps, p2p? (I.e. it's not an Ethernet handoff to something that might have some CIR restriction? Nor is it multipoint?)

Kaushik Ray · ‎11-11-2014

The current MTU is set to 1450. do you think this could be causing the issue?

The WAN link is 10Mbps P-P; the Interface on the router connects directly to the WAN link service provider. Will have to check with them

Joseph W. Doherty · ‎11-11-2014

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages whatsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

I don't know if it causing your issues, but if possible, a standard size Ethernet MTU would be better.