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New Member

Dropped packets between Catalyst 3550 & Windows 2000

I have a test network set up - with a 3550 switch, with a couple of Vlans configured.

I have an Windows XP laptop & desktop connected - all is ok.

If I connect up any Windows 2000 laptop/desktop then I find I get a connection but I find that I'm dropping packets....at about 10% when pinging devices on on other networks.....or pinging devices on the same vlan.

This is not a port issue or cabling issue ......it seems to be related to the Operating system in some way. I've tried changing the duplex & speed at both ends....same result.

Any input is welcome !

7 REPLIES
Purple

Re: Dropped packets between Catalyst 3550 & Windows 2000

You have verified nic settings? Both ends should match , if your nic is set as auto then the switch port setting must be auto, if you hardcode the nic to 100/full then you must set the switch to 100/full also ,cannot be auto .

New Member

Re: Dropped packets between Catalyst 3550 & Windows 2000

I agree with what grant stated above. I don't see how its an operating system thing; it sounds more like a physical aspect of the cabling itself or the duplex settings mentioned above.

Is this packet loss only happening from the one machine or all of them on the vlan?

New Member

Re: Dropped packets between Catalyst 3550 & Windows 2000

I know this sounds odd.....but I have tried all settings of duplex & link speed between the switch & the W2K machines......if I place an XP machine on this same port then it works fine.

The fact that XP works means the cabling is ok.

I guess I'll update the nic drivers see what that brings....and maybe look at an IOS upgrade on the switch - currently 12.1 (22) EA5

With two XP machines & one W2K machine on the switch - pinging from W2K to XP results in dropped packets......of approx 10% - between the two XP machines is ok. When pinging from either XP to the W2k - "Request timed out"

Re: Dropped packets between Catalyst 3550 & Windows 2000

Hi,

one direction ping problem usually points to a personal firewall involved.

But losing 10% of ping looks really strange.

Have you tested different ping frame sizes?

How many ping frames have you sent while counted that 10%?

Have you tried to capture frames on the W2k PC via Ethereal, e.g., to see if the Pings are really coming?

Best regards,

Milan

New Member

Re: Dropped packets between Catalyst 3550 & Windows 2000

Thanks for the input

Setting the switch to Auto showed me that the W2k devices laptops had negotiated at 10/half

Setting these devices to 10/half solved the packet loss problem on both devices.

Albeit - I'd like them to run at 100mbs - I'll look at driver updates

Previously differing frame sizes in my ping requests were used.

No physical or s/w firewalls are enabled.

Use of etherreal make sense.....I'll test some more !

New Member

Re: Dropped packets between Catalyst 3550 & Windows 2000

ok - I just found some personnel firewall software running on one of the laptops....which I was failing to png ........sorry - I thought I'd been thorough !

So - I'm down to the question - for my W2K laptops with the Cisco switch - why do I need run at 10mbs/half.

I'll go do some reading up on this

Re: Dropped packets between Catalyst 3550 & Windows 2000

I'd guess this might be really a NIC compatibility problem.

Are you using the same NICs on your W2k and WXP machines?

Generally, I'd recommend to download the latest NIC driver from the vendor.

I'd also try to check CCO bugs related to the NIC vendor.

This article might also help you http://www.cisco.com/warp/public/473/46.pdf

Best regards,

Milan

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