Questions

network latency issue

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network latency issue

JPru22
There are 2 servers on my network with which users are consistently experiencing latency issues while accessing these servers. Keep in mind that some users are in the same building as these servers and 2-3 hops away, while others are in a different country. I have been using Sniffer and Ethereal to look at packets from select users to these servers, and I may just not know how to analyze the data, but I do see things such as TCP out-of-orders as well and retransmissions/fast retrasmissions, and I am not sure if these are problems and how do I narrow down whrere the casue is coming from. The only commonality that all users share is the backbone switches (Cisco 6500) and the servers. The switchports show no signs (no CRC, collisions, drops...nothing) Does anyone have any ideas on what the cause could be or how I can go about finding the culprit to the latency problems?
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    lowlands

    Check your duplex settings (bot for server and the clients that connect to them. Another thing to look at, if these happen to be HP servers, is the HP teaming if you use that. You might have to break and recreate the team.

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    JPru22

    The servers are Dell. Both servers and switchports are set to auto and showing full/1000. The logs do not show any duplex mismatch errors on either port (there are no errors on user ports as well). Is there a benefit to hard setting the duplex/speeds rather than leaving them at auto?

    In addition, I have already checked for NIC compatibility and the server group does not see anything in the server logs to indicate a problem.

    If there is a degradation of the CAT6 wouldn't I see something on the switchports? CRC, input/output errors?

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    georgeou

    Are all three servers in the same building? I would recommend you do a speed check between the three servers copying a large file both ways and timing it. Then tell me what you're getting in terms of speed.

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    lowlands

    Check your duplex settings (bot for server and the clients that connect to them. Another thing to look at, if these happen to be HP servers, is the HP teaming if you use that. You might have to break and recreate the team.

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    0 Votes
    JPru22

    The servers are Dell. Both servers and switchports are set to auto and showing full/1000. The logs do not show any duplex mismatch errors on either port (there are no errors on user ports as well). Is there a benefit to hard setting the duplex/speeds rather than leaving them at auto?

    In addition, I have already checked for NIC compatibility and the server group does not see anything in the server logs to indicate a problem.

    If there is a degradation of the CAT6 wouldn't I see something on the switchports? CRC, input/output errors?

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    0 Votes
    georgeou

    Are all three servers in the same building? I would recommend you do a speed check between the three servers copying a large file both ways and timing it. Then tell me what you're getting in terms of speed.