The Network is slow !

by Johannes Helmig [Published on 31 Oct. 1997 / Last Updated on 31 Oct. 1997]

You have installed your new network (or expanded your existing configuration) and expect a "fast" communication (like a "cheetah):

but the connection is not that fast, it appears to be "very slow"/"dead-slow" (crawling slowly as a caterpillar):


(if it is TCP/IP and fast in one direction,but slow in the other, it could be the Registry)
Lets have a look, on how a "healthy" network should work:
(this is an animated GIF, which takes a while to load):

Since animated GIF's don't "print" very well (and I intend to use printouts of these pages as training material), lets have a more static look at the communication process:

The Client has a REQUEST (could be to list a directory, open a file, read/write a file, make a print,..)
The REQUEST is put into a Network-"Envelope"
The "Envelope" is transmitted as an electrical signal on the Ethernet-cable to the "server" system.
The "server" receives the "envelope"
The "server" executes the requests and generates an answer
The answer is put in an "envelope"
The "envelope" with the "answer" is send back to the client
The client receives the "envelope", opens it and has his "answer".


But due to a problem on the wiring, you are getting:
(this is another animated GIF, taking even longer to load):

Again, lets look a more "static" loop at all the steps:

The Client has a REQUEST (could be to list a directory, open a file, read/write a file, make a print,..)
The REQUEST is put into a Network-"Envelope"
The "Envelope" is transmitted as an electrical signal on the Ethernet-cable to the "server" system, but gets "damaged".
The "server" receives the "envelope", but due to the "damage" is not able to understand the "request" and does therefor NOT generate an "answer"
Since the "server" did not understand the "request", no answer came back, so finally (after a some waiting), the "Client" assumes: "the envelope was lost"
(Time-out)
The "client" repeats the "request".


Due to the "waiting" time ( until the "Time-out" on the Client ) and the time to re-transmit, the networks appears to be : SLOW !
In such cases, make the statistical check with:
NET DIAG /STATUS (Is the Network-Connection "healthy" ?)

Ethernet Packets ("envelopes") get usually damaged due to bad hardware:
- bad NIC (Network Interface card)
- missing/bad terminators/hub-ports
- cable too long
- bad T-connectors
But there is also a possibility to slow down the network with Registry settings:
- TCP/IP Registry settings

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