Latency While Pinging Gateway of Vlan's Which is in our Core Switch

[Thavamani_Shanm]

Hello, We have a BD8810 core switch and few models of Extreme EXOS Edge switches (like X430, X440, X460). All of our servers are connected to our core switch. Clients are connected in our Edge Switches. Our core switch having multiple VLAN's. Each vlan have own Tag ID. So, required VLAN's are created in our Edge Switches with relevant Tag ID in core switch. Now, the issue is, From past two days we are facing a issue while pinging the Gateway IP addresses of each VLAN's which are configured in our core. The issue is, reply time in ms is more than 150ms. It was less than 1ms previously. We don't know where the actual issue is? In configuration or is any loop or any slot problem in core. Please help us to resolve this issue.

[Roy_Noh]

Most of cases I've seen was about looping but there was an interesting case which might be helpful for you.
One of my customer has a syslog server attached on a dist switch and the server was dead for some reason.
There were still lots of syslog packets coming from other servers and it hits the switch CPU.
It is because that ARP and FDB was not resolved on the switch so the packets were handled as slow path traffic.
The issue was gone after they replaced the syslog server.
We checked it by tcpdump in debug mode.

[Vellachery__Sum]

Thavamani,

The "top" indicates bcmRX process is spiking. The bcmRX process handles traffic that is being received by the switches CPU.


In most situations this indicates a possible loop in the network. Please follow the steps which i have suggested earlier.

[Thavamani_Shanm]

Sir,

Thanks for your reply. Please check the below image showing output of top command.

[Vellachery__Sum]

Thavamani,

What is the EXOS version running on the BD8K switch?

The below-mnetioned articles should be also helpful for you:-

https://gtacknowledge.extremenetworks.com/articles/Q_A/Which-commands-can-be-used-to-detect-a-loop

https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-configure-ELRP-to-disable-ports

[Vellachery__Sum]

Thavamani,

To narrow down the issue, check for the following information:-
- Top ==> to see if there is any particular process is spiking up
- clear l2stats
- Execute "show l2stats"
- Run the above output for 3-4 times and figure out which vlans have large number of packets going to the cpu.

- Once you figure out the vlans which has large number of packets going to the CPU. Run ELRP on those vlans.
- Type enable elrp-client
Enables the Extreme Loop Recovery Protocol (ELRP) client (standalone ELRP) globally.
- Type configure elrp-client one-shot ports all print-and-log
Starts one-time, non-periodic ELRP packet transmission on the specified ports of the VLAN.

If any layer 2 loop is detected it would be printed in the logs, check for the physical connections.