Network Collisions 3

[rewas]

I am experiencing significant collisions on a 100BaseT network when just one Wintel computer on the lan is recieving packets from a NT Server (4.0). As more computers are switched on more collisions occur. The nic on the server is set to auto the same as the workststion. I have connected the server to the 100baseT hub, workstation on the same hub, when only these two machine are on and communicating - still the same problem. I have set the server nic to 100 half duplex likewise the workstation every other device on the network turned of (bar the active equipment) - still the same problem. The server card is not chattering nor is the card on the workstation. I have swapped hubs (twice), still no resolution. Any help would be appreciate

 

[wybnormal]

My thought is the generic card in NT has a bad driver. Other ideas are a cheap hub, bad cable somewhere on the chain or a possible misconfiguration( unlikely).

If you run a continious PING from one end to the other, what happens? Check it from both sides. You should have lose ANY packets with a setup like this unless you cross a WAN which I doubt since you are pushing video streams. With the linux side, -t will let you pick a paket size.. bump it up since I'm guessing with the video stream, NT is trying to send the largest packet possible.. at least I'm assuming NT is the capture device.

Let us know what happens

Mike S

PS- A sniffer would make quick work of what is really happening if you have one or can borrow it

 

[wybnormal]

I found out that my Anixter link was broken. They redesigned their site and here is the new link to the following white paper I suggested to people to read in order to learn about shielded/unshielded cable and why all the pins are important.

Mike S


UTP vs. STP: A Comparison of Cables, Systems, and Performance Carrying
High-Data-Rate Signals

http://www.anixter.com/techlib/vendor/cabling/d0503p02.htm

 

[Guest_imported]

Hi all,

This has made very good reading. I would like to obtain a copy of some software that is capable of capturing the Ethernet Collisions and providing a count or some sort of percentile value.

I need this information like yesterday...

UncleSam

 

[wybnormal]

Search on Etherpeek, I dont remember the web site off the top of my head. There are several that run off Linux... most require a certain type of card due to needing a "promiscuous" mode in order to catch the errors. Some cards ignore errors which is not what you want

Mike S

 

[UncleSam1]

Thanks Mike,

I beleive I require NIC Packet Drivers in order to capture the collisions. Unfortunately Windows 98SE uses NDIS Drivers which drops the collided packets before it serves up the good ones to the various Sniffer packages.

I have tried two windows based ones viz PacketBoy from NDG Software and IRIS from eEye Digital Security.

Are you aware of any means of circumventing this?

Regards

UncleSam

 

[XoverIP]

lemme ask you diz....

what type of device(s) is/are interconnecting your network segment(s)?

have you utilizied the managment features available?...did you know you could have a SNMP device sitting [seemingly] transparently on a segment that can observe for a given period then report these stastics?

 

[UncleSam1]

I have three PCs...ont Desktop and two Laptops.

I have win98SE on each, PCMCIA/NDIS Drivers on laptops.

Have tried SNMPc from Castlerock Software to no avail. I create traffic and collisions by copying large volumes of data back and forth between the three machines. I am able to see the collision light (the little red LED) on the Hub lightup yet....

 

[wybnormal]

I found the magic link

Here is the discription:

Ethereal is a free network protocol analyzer for Unix and Windows. It allows you to examine data from a live network or from a capture file on disk. You can interactively browse the capture data, viewing summary and detail information for each packet. Ethereal has several powerful features, including a rich display filter language and the ability to view the reconstructed stream of a TCP session.

http://www.ethereal.com/

Mike S

 

[Guest_imported]

I liked your defition of the hub and switch. I have a question about multiple swithes connected together. If one computer takes to another compter that is attached to a different switch, does the switch broadcast or does it know the route it needs to take?

 

[UncleSam1]

Thanks Mike / skoobe,

Managed to find what I required.

Cheers

 

[Guest_imported]

Have you terminated the final PC in your network with a crossover patch?

 

[karm]

What happens if you have a mix of 10Mb and 100Mb connections to a hub? Since a hub is a repeater, does the 10Mb force all the other connections to drop down to 10Mb. If not how can a 100Mb conection talk to a another 100 Mb when there is a 10Mb pluged into the hub?

 

[jimbopalmer]

Karm

multi speed hubs are often made as two 'port' switches, all the ports at 10 are on one 'port', all the ports at 100 one the other 'port'. So only the packets needing to go from one speed to the other, are seen at the other speed.

Sailugsue

If two switches connected by ports a and A have traffic from ports b and B then there will be traffic from b to a to A to B, but it will not broadcast to other ports on either switch. I love everyone til they prove otherwise, sadly some prove otherwise SO quickly