Ping round trip delay expalnation

chee-ben.tan · ‎01-14-2009

Is there any explanation why IOS has this large round trip delay? Any URL explain this will be appreciated.

round-trip min/avg/max = 1/2/4 ms

Example:

Router#ping 10.1.1.1

Type escape sequence to abort.

Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:

!!!!!

Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms

anthonyp · ‎01-14-2009

Hi,

In order to understand your question a little better, is 10.1.1.1 a local IP address or is it external to the router. Additionally, what functions are being performed by the router at the time in case this is caused by the router reaching 100% capability.

chee-ben.tan · ‎01-14-2009

Is external to the router. Just wants some explanation how RTT works in IOS.

Mark Yeates · ‎01-14-2009

Ben,

I would say these are very normal ping response times. From your output The longest time was 4 milliseconds, and the shortest was one millisecond with and average of two.

Usually if there is no ARP entry in the router the router will have to send an ARP query for the destination. That would likely account for the 4ms ping.

Here's a link that goes into greater detail about ping.

http://www.cisco.com/en/US/products/sw/iosswrel/ps1831/products_tech_note09186a00800a6057.shtml#ping_com

HTH,

Mark