Issue with exact 50% icmp ping loss

  • 0
  • 1
  • Problem
  • Updated 3 years ago
  • Solved
Hi Gens,

facing issue with Extreme switches X460 .
As when i am pinging the other node onm vip from the extreme l3 switch

getting the ping response with every alternate ping loss like below
64 bytes from x.x.x.x: icmp_seq=0 ttl=64 time=1.195 ms
64 bytes from x.x.x.x: icmp_seq=2 ttl=64 time=0.963 ms
64 bytes from x.x.x.x: icmp_seq=4 ttl=64 time=1.237 ms
64 bytes from x.x.x.x: icmp_seq=6 ttl=64 time=1.030 ms

and the seq are even for one switch and with other it is odd like below.

64 bytes from x.x.x.x: icmp_seq=1 ttl=64 time=1.105 ms
64 bytes from x.x.x.x: icmp_seq=3 ttl=64 time=0.863 ms
64 bytes from x.x.x.x: icmp_seq=5 ttl=64 time=1.155 ms
64 bytes from x.x.x.x: icmp_seq=7 ttl=64 time=1.475ms


is this the issue with the switch or it is the expected behavior.

help me how to troubleshoot it .


Regards
Raj
 
Photo of Raj Kam

Raj Kam

  • 132 Points 100 badge 2x thumb

Posted 3 years ago

  • 0
  • 1
Photo of Stephen Elliott

Stephen Elliott

  • 1,242 Points 1k badge 2x thumb
this sort of thing is often incorrectly configured LAGs - are you using port sharing?  is it working correctly at both ends?
Photo of Henrique

Henrique, Employee

  • 10,302 Points 10k badge 2x thumb
Hi Raj, would be great to have some network diagram to understand the traffic directions and what's configured between them (LAG, MLAG, VRRP, etc).
Photo of Raj Kam

Raj Kam

  • 132 Points 100 badge 2x thumb
wait let me share that :)
Photo of Raj Kam

Raj Kam

  • 132 Points 100 badge 2x thumb
Hi 

we have two routes towards VIP
#oa  10.196.x.x/32    10.196.a.b   5    UG-D---um--f- route_1_1 21d:9h:52m:40s
#oa  10.196.x.x/32    10.196.a.c   5    UG-D---um---- route_2_1 21d:9h:52m:40s

both have same metric of 5.

and if i ping from the other node then the output is same as alternate ping goes miss .
so from both the side i am facing the same issue.

ospf is working between the node and the two switches


Regards
Raj
Photo of Raj Kam

Raj Kam

  • 132 Points 100 badge 2x thumb
and traceroute to VIP from SWITCH

# traceroute 10.196.x.xtraceroute to 10.196.X.X, 30 hops max
 1                                               *           *           *
 2  10.196.x.x                                3 ms        *           2 ms

--- Packet Response/Error Flags ---
 (*) No response, (!N) ICMP network unreachable, (!H) ICMP host unreachable,
 (!P) ICMP protocol unreachable, (!F) ICMP fragmentation needed,
 (!S) ICMP source route failed, (!u) Transmit error, network unreachable,
 (!f) Transmit error, fragmentation needed, (!t) General transmit error
 # traceroute 10.196.x.x
traceroute to 10.196.X.X, 30 hops max
 1                                               *           *           *
 2                                               *       
 2  10.196.x.x                                             2 ms        *

--- Packet Response/Error Flags ---
 (*) No response, (!N) ICMP network unreachable, (!H) ICMP host unreachable,
 (!P) ICMP protocol unreachable, (!F) ICMP fragmentation needed,
 (!S) ICMP source route failed, (!u) Transmit error, network unreachable,
 (!f) Transmit error, fragmentation needed, (!t) General transmit error
Photo of Henrique

Henrique, Employee

  • 10,302 Points 10k badge 2x thumb
Even with those 2 OSPF routes, the switch is only using the route through route_1_1. You can confirm that based on the flag "f" that means "provided to FIB". 

The second route is active but not being used.

It seems to be related to asymmetric routing.

I would check from point A to B and B to A if that communication is using the same path.
Photo of Raj Kam

Raj Kam

  • 132 Points 100 badge 2x thumb
need to check the routing ?
Photo of Henrique

Henrique, Employee

  • 10,302 Points 10k badge 2x thumb
Correct, I would check the routing on each hop as well as LAG/VRRP configuration.