3750X - High Latency between the 2 Core Switches

[xZamalek]

Hello,

We have 2 3750X switches acts as the core , when i try to ping from one to the other , the ping spikes to 1000ms , also the when the users ping the gateway from their PC they face the same , the configuration seems to be fine , what do i need to look for ? each stack was rebooted already.

[Kasun Bandara]

do you have 2 switch stacks? or are they just single 2 switches without stacking?

[xZamalek]

Hello Kasuan,

2 Switch stack , each stack consist of 2 3750x switches and they are the L3 Gateway for users.

[johnd2310]

Hi,

What is the cpu utilisation on the switch: show processes cpu sorted

Thanks

[xZamalek]

There are some spikes on the the utilization but not all the time , so from the show process cpu history it spikes to 90 and 100% sometimes but on the time of the ping , the CPU utilization is normal , i checked the platform TCAM and the switches takes only half the available resources

[Kasun Bandara]

Ok, so how your gateways distributed between 2 stacks? how users divided between 2 stacks? or only 1 stack act as gateways? also how is the connectivity between stacks deployed?

[xZamalek]

The switches are connected via port channel , users are divided into multiple VLANS , Core 1 acts the primary for some vlans , core 2 is active for remaining vlans.

[Joseph W. Doherty]

Any similar issues pinging through the switches, i.e., not pinging an IP on the switches?

Reason I ask, Cisco devices appear to give low priority to responding to ping.  Often when a Cisco device is "busy" it can be very slow to respond or not respond to all the pings.

[xZamalek]

We pinged the upstream directly connected WAN Routers and the issue still the same , both switches faces the same issue with 1000ms latency either they ping each other on the VLAN interface or ping the directly connected peers either LAN hosts or WAN routers , the TCAM is not utilized at all , thats very strange.

[Joseph W. Doherty]

So, to confirm, pinging between two PCs, on same VLAN (both PCs physically connected to same switch stack, or to different switch stacks), or on different VLANs (both with their VLANs gateways on the same switch stack, and on different switch stacks), all exhibit the occasional 1 sec ping response times?

What do interface and MLS stats show on the 3750s?

[Kasun Bandara]

is this occurred suddenly or issue were there for long time? also did you gone through any bugs for current OS version?