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Community Member

Collision Errors on 4006 with in-line power cards but no errors on Cat5K

After moving PC's from Cat5509 with x5225 modules to Cat4006 with X4148 inline power modules collision errors occur to the eventual detriment of the PC. Company standard port config is 10/half duplex. No errors were evident when attached to Cat5k 10/half duplex. When set to FULL duplex, errors decrease and performance of PC is maintained.

Can anyone advise why the PC's are 100% when attached to Cat5K but not 100% when attached to Cat4K and why changing to FULL duplex should have such an impact?

Cisco Employee

Re: Collision Errors on 4006 with in-line power cards but no err

At half-duplex, you will *ALWAYS* have collisions if there is traffic on the link. The following document will explain why and other migration issues. Setting just the switch port to full-duplex will result in decrease performance unless you set the NIC to full-duplex as well.

The 5225R and 4148 use the same front end PHY so compatability should not be an issue.

Did you configure the 4148 ports as host ports, set port host?

Community Member

Re: Collision Errors on 4006 with in-line power cards but no err

Thanks for the URL. We do not enable host ports on any switch. The CatOS is 6.2(3) and we see excessive Rcv-Err, Single-Col, Multi-Coll and Excess-Coll, resulting in a proliferation of runts. This in turn presents an inordinate amount of "In-Lost" packets. My concern is that this bank of PC's never had performance problem when attached to the 5225 cards but do with the 4148 cards using the same NIC, Floor wiring and uplinks back to 6509. We have always used 10 hlf dplx on the 5500 and client PC and this is the first (of many) 4006 installs. I wonder if the improved performance (>Mpps) of the 4006 is causing these problems? Can you advise?

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