Solved: 3750X stack, intervaln routing, icmp reply

avilt · ‎01-25-2012

I have my current L3 switch 4006 in production. From a client PC, if I ping to various vlan interfaces, consistently I am getting the icmp reply in less than 1ms.

I am preparing to replace this switch so I have bought two 3750X series switchs working in a stack. L2 switch is connected to this stack with cat6 copper cable with ether channel as uplinks. Now in the new environment sometimes I am getting the icmp reply in <1ms but once in a while it reaches 20ms or even 100ms.

Is it a normal behaviour? How can I investigate this further?

nkarpysh · ‎01-25-2012

Hello,

If you are pinging SVI configured on 3750 itself - then ping latency is not a symptom of a problem. Becuase this ICMP is being replied by the CPU and different platforms may have it architectured differently. Also the CPU load can bring some additional delay. To check the link delay itself it woul be more practical to ping remote ip and consider difference between 4006 and 3750. As of now ping would be handled in HW by both platforms.

Nik

HTH,
Niko

View solution in original post

nkarpysh · ‎01-25-2012

Hello,

If you are pinging SVI configured on 3750 itself - then ping latency is not a symptom of a problem. Becuase this ICMP is being replied by the CPU and different platforms may have it architectured differently. Also the CPU load can bring some additional delay. To check the link delay itself it woul be more practical to ping remote ip and consider difference between 4006 and 3750. As of now ping would be handled in HW by both platforms.

Nik

HTH,
Niko