Slow response - icmp communication

selvialagar

I've tried to implement icmp protocol in my application(vc++.net 2003).I am using windows xp..My program works fine..but it takes lot of time to reply the message..what is the reason for it?Round trip time on an average is 800ms...but it takes lot of time to display like "Reply from....".

My second problem is replying address is different from the address i gave. is this normal? or any other problem in network..i'm working in LAN....Please give me the some solutions....

Stang02GT

ICMP messages are constructed at the IP layer, usually from a normal IP datagram that has generated an ICMP response. IP encapsulates the appropriate ICMP message with a new IP header (to get the ICMP message back to the original sending host) and transmits the resulting datagram in the usual manner.

For example, every machine (such as intermediate routers) that forwards an IP datagram has to decrement the time to live (TTL) field of the IP header by one; if the TTL reaches 0, an ICMP Time to live exceeded in transit message is sent to the source of the datagram.

Each ICMP message is encapsulated directly within a single IP datagram, and thus, like UDP, ICMP is unreliable.

selvialagar

Thanks for your reply....i want to know what are the possible reasons for late response of IP datagrams.....when i ping using run command, the reply comes very quickly..but in my program the response is very late..can i use netBIOS for resolving IP addresses..

Arulmurugan

Quote:

Originally Posted by selvialagar

Thanks for your reply....i want to know what are the possible reasons for late response of IP datagrams.....when i ping using run command, the reply comes very quickly..but in my program the response is very late..can i use netBIOS for resolving IP addresses..

Hi,

I feel name to IP address resolving does not matter here, some thing else going wrong. If really name to IP address resolving does matter means, only the first ICMP reply can be delayed, not for all.

I don't know i am not able to see your porgam, if you help me i can lookinto you source code.

Regards,
Arul

Arulmurugan

Hi,
Average RTT 800 ms is not acceptable in LAN env, again that depends on network device. Better you run ethereal on your machine and sniff the packet and see the time difference, when your running your own Ping program.

Reply address should be same as, what you have given, if not so then the can be a address conversion problem. Check you source code. I think here also ethereal may help you.

Regards,
Arul

selvialagar

Thanks for your reply. I solved the problem. You are correct.Address conversion problem is happened in my program..thank you very much for your valuable comment.

Arulmurugan

Quote:

Originally Posted by selvialagar

Thanks for your reply. I solved the problem. You are correct.Address conversion problem is happened in my program..thank you very much for your valuable comment.

Oh.., thats great, what happend the slow response? Have you fine tuned anything?.

-Arul

selvialagar

The address conversion problem is occured in my program.i didn't correctly resolve the destination address.that is the reason for the late response.Is there any book on networking related to protocols especially programming in vc++.net?

Arulmurugan

Quote:

Originally Posted by selvialagar

The address conversion problem is occured in my program.i didn't correctly resolve the destination address.that is the reason for the late response.Is there any book on networking related to protocols especially programming in vc++.net?

Hi Selvialagar,
In my experience i nerver worked on VC++, .net and Windows platform, so i do not have any idea on this.

All the best!.
Regards,
Arul