Cisco ip sla http probe

[freegeeks]

I'm investigating some webserver performance issues, because I have no access to the end hosts, I'm using the ip sla feature on the Cisco routers that are under my control. I have some HTTP probes running and I'm seeing an HTTP RTT of 500 ms, TCP RTT is around 30 ms.
For me this proves that this is not a network problem but a problem on application layer. Am I wrong? I don't have a lot of experience with optimizing webservers (I'm a network guy) and google doesn't give me a lot of info what is considered to be a reasonable HTTP RTT, but a HTTP response of 500 ms seems awfull to me especially because TCP 3 way handshake connection is fast (30 ms).

 

[alkemyst]

probes can point the finger of where to dig deeper.

What are the details on the webserver? Hardware, software/OS, and traffic being served? What kind bandwidth they have and what is it attached too?

Many companies are trying to get by with L3 Switches and their traffic shaping and support of big WAN links is pretty limited in scale. Real routers do much of the stuff in hardware and have deeper pipes to handle it.

 

[freegeeks]

probes can point the finger of where to dig deeper.

What are the details on the webserver? Hardware, software/OS, and traffic being served? What kind bandwidth they have and what is it attached too?

Many companies are trying to get by with L3 Switches and their traffic shaping and support of big WAN links is pretty limited in scale. Real routers do much of the stuff in hardware and have deeper pipes to handle it.

i don't have details on the webserver. I'm sure that on my side I have no congestion. This is a layer 3 vpn mpls service. The only thing under my management are the 2 routers on each site and the mpls backbone. Just trying to find more info about http performance

 

[alkemyst]

Without details there really is no way to know if it's going to be normal.

You can set up IP SLA to monitor a couple well-known sites and see the results from them.

HTTP RTT normally is closer to TCP RTT IRC, maybe like double it...not almost 10x though.