Network Slowdown Problem 1

[LloydSev]

Ok.. here's the situation..

I have 2 buildings in which we operate...

I am in building 1.

Building 1 houses all of our servers, and 4 of our closets.

Building 2 houses our PIX, router and about 15-20 computers.

Each building is linked via 4 fiber cables ran underground.

Now here is what is happening.

1) I can ping the router and PIX with absolutely no problem, very low reponse times.
P:\>ping 193.100.1.8

Pinging 193.100.1.8 with 32 bytes of data:

Reply from 193.100.1.8: bytes=32 time<1ms TTL=255
Reply from 193.100.1.8: bytes=32 time<1ms TTL=255
Reply from 193.100.1.8: bytes=32 time<1ms TTL=255
Reply from 193.100.1.8: bytes=32 time<1ms TTL=255

2) I can ping other computers in the other building with very low response times.
P:\>ping pc0103

Pinging pc0103.cssbehavioral.org [193.100.1.138] wi

Reply from 193.100.1.138: bytes=32 time<1ms TTL=128
Reply from 193.100.1.138: bytes=32 time<1ms TTL=128
Reply from 193.100.1.138: bytes=32 time<1ms TTL=128
Reply from 193.100.1.138: bytes=32 time<1ms TTL=128

But if I try to access a file server in Building 1 from Building 2, it takes an unbelievable amount of time to transfer any files.. such as 5 minutes to transfer 200kb.

The 2 switches in the other building are 3Com. The switches in this main closet are Dell.

Anyone have any ideas what could be causing this?

Computer/Network Technician
CCNA

 

[jimbopalmer]

Yes, Those symptoms sound just like a fiber duplex mismatch.

Check to see that all the devices use the same duplex, ideally full everywhere, but if you can't set everything to full, set everything to half.

Any line that contains any fiber anywhere in it has to be set to a known duplex at every point, only all copper runs can do auto-negotiate.

You did not give model numbers, but if all ports are fiber the entire length and all switches are managed, you should be able to set all the fiber ports to Full Duplex. That would be ideal.

If you are using copper to fiber converters or any of the switches have no way to set duplex, you may be able to set all the ports you have control over to half duplex, less ideal but better than a mix.


I tried to remain child-like, all I acheived was childish.

 

[technome]

Try the pathping command to a server. Any packet losses ?

Poor fiber cable termination, are these managed switches, if so you could look for the fiber port details (errors).

 

[LloydSev]

P:\>pathping pc0103

Tracing route to pc0103.cssbehavioral.org [193.100.1.138]
over a maximum of 30 hops:
0 pc0025.cssbehavioral.org [193.100.1.106]
1 pc0103.cssbehavioral.org [193.100.1.138]

Computing statistics for 25 seconds...
Source to Here This Node/Link
Hop RTT Lost/Sent = Pct Lost/Sent = Pct Address
0 pc0025.cssbehavioral.org [193.100.1.106]
0/ 100 = 0% |
1 0ms 0/ 100 = 0% 0/ 100 = 0% pc0103.cssbehavioral.org [193.100.1.138]

Trace complete.

That's to a node in Building 2 from Building 1.. (noticed that the slowdown is only from Building 2 to Building 1.

Computer/Network Technician
CCNA

 

[LloydSev]

Microsoft Windows 2000 [Version 5.00.2195]
(C) Copyright 1985-2000 Microsoft Corp.

P:\>pathping cssnt03

Tracing route to cssnt03.cssbehavioral.org [193.100.1.3]
over a maximum of 30 hops:
0 pc0103.cssbehavioral.org [193.100.1.138]
1 cssnt03.cssbehavioral.org [193.100.1.3]

Computing statistics for 25 seconds...
Source to Here This Node/Link
Hop RTT Lost/Sent = Pct Lost/Sent = Pct Address
0 pc0103.cssbehavioral.org [193.100.1.138]
0/ 100 = 0% |
1 0ms 0/ 100 = 0% 0/ 100 = 0% cssnt03.cssbehavioral.org [193.100.1.3]

Trace complete.

P:\>

And this is from Building 2 to server in building 1 which would take forever to transfer a file from only in building 2.

Computer/Network Technician
CCNA

 

[LloydSev]

OK.. just recently we had purchased some new managed switches to phase out a couple of old/damaged/unmanaged switches we still had..

the switch that the fiber convertor was plugged into was unmanaged. So I plugged it into the, up till now, unused new managed switch, hooked that switch back into our network and low and behold transfer speeds are terrific.

Must have been a duplex mismatch problem. Thanks.

Computer/Network Technician
CCNA