Switch – Bandwidth Port Mismatch causing Packet loss

switch

I have private network service between a data center and my office location. After moving a server from the office to the data center, we noticed significant packet loss. This greatly affects the speed of our file sharing (SMB is particularly affected).

The Data Center engineers suggested that our switches we set to 100mbps but we only have a 30mbps pipe in the private network so up to 70% of the packets could be lost at the switch.

We tried setting the ports to 10 mbps but they could not connect. Could QoS bandwidth throtling be used in this case? We are using Dell PowerConnect 6224 at the office and PowerConnect 5424 at our Data Center.

Any ideas on how to resolve this?

Best Answer

Your data engineers meant to set your server's interface to 100baseTX, the question to ask them now is which duplex should the interface be set to: Full or Half-Duplex. You'll see these kinds of packet loss issues with host's network interface Duplex Mismatches.

There are issues with duplex auto-negotiation, (Which lets the interface decide which speed matches best with the connecting NIC). You can read here about it before making that decision as to what setting to use: http://kb.pert.geant.net/PERTKB/DuplexAndAutoNeg

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On a router it would be something like:

interface FastEthernet2/0
 ip address 192.168.9.1 255.255.255.0
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!

access-list 151 deny   ip 192.168.0.0 0.0.255.255 any
...etc
access-list 151 permit ip any any

So maybe a L3 switch would be similar?

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All but 1 of the problems you've described and all but 1 of the tests you've conducted appear to have the switch/router link in common (if I read and understood your post correctly). I know you've tried a different cable and switch port but have you looked at the configuration of the switch port and router port for that link? Check the speed and duplex setting on both ends and make sure they match.

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