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-   -   Duplex? (https://www.cableforum.uk/board/showthread.php?t=18366)

ian@huth 07-10-2004 16:43

Re: Duplex?
 
Quote:

Originally Posted by theblueraja
LOL,

The simple fact of the matter is this-

Always run AUTO unless it is specified otherwise or you KNOW that the connected equipment is forced at a specific speed or duplex. In this case your speed and duplex setting should be set to match that of the connected equipment.

I would tend to disagree as using auto on both CM and NIC relies on both of them correctly determining the speed and duplex settings of the other which is not always the case.

New CMs such as the NTL:Home Ambits can be set to any combination of speed and duplex settings and may have been set to something other than auto by the user at some point in time. If the user then fits a NIC that doen't detect the CMs settings correctly on auto then there could be problems as Robin Walker pointed out. I would tend to accept his vast knowledge of the subject over any theory expressed by others.

TheBlueRaja 07-10-2004 17:07

Re: Duplex?
 
So what would you suggest you set it too then?

Matth 07-10-2004 23:27

Re: Duplex?
 
For the Pace STB (1000) 10 half is definitely the answer - if set to FULL, it works, but the netword card control panel counts rather too many errors.

In the old days, Ethernet ran on a dirty great hosepipe of coaxial cable, or on "thinwire" coax for smaller installations (10base5 and 10base2).

Since there was only one cable, it could not be duplex.

The way it worked , was under CSMA/CD (carrier sense multiple access / collision detect).
When an interface had a packet to send, it listened for carrier, and held off if busy.
Then it switched over to transmit, but kept listening - if another interface also switched at the same time, a collision resulted.
On a collision, both interfaces transmiot a collision signal for long enough that it will traverse the maximum permissible network delay due to line length and repeater delay, and then back off for a random interval.

The UTP cables were originally treated in exacly the same way, but then they started using the seperate transmit and receive paths to improve throughput.

But setting full duplex when it's not supported, will cause the full dduplex device to stomp on incoming packets with outgoing ones, since under full duplex, the two channels are assumed to be seperate - that's why mis-setting full duplex causes a loss in performance.

Paul 07-10-2004 23:43

Re: Duplex?
 
Set the CM and the PC to 10/Half and enjoy your error free web browsing. :D

Chrysalis 10-10-2004 23:18

Re: Duplex?
 
well you right auto works ok, but If I set 10/full then it is pretty bad throughput is all over the place, 10/half gives me the best result.

kronas 11-10-2004 00:11

Re: Duplex?
 
something wierd was happening to me when i tried to change settings on my machine due to issues with my connection.

i first tried 10mbit full duplex then 10mbit half duplex, my cm lost the pc light on both occasions, then i tried 100mbit full then half duplex it was still out, i set it to auto and everything started working....

samuelnw53 11-10-2004 11:02

Re: Duplex?
 
I am on 1.5 meg on an NTL 200 modem so would you still set computer at 10/half?

Paul 11-10-2004 11:58

Re: Duplex?
 
Quote:

Originally Posted by samuelnw53
I am on 1.5 meg on an NTL 200 modem so would you still set computer at 10/half?

Yes, set them both to 10/half.

Remember - 10mbps is already over 6 times faster than your internet connection, more than enough.

samuelnw53 11-10-2004 12:03

Re: Duplex?
 
When you say set them both to 1/2 what do you mean , i have gone into network conns and set that to 10 1/2 but what else do i need to do?

Paul 11-10-2004 12:12

Re: Duplex?
 
Quote:

Originally Posted by samuelnw53
When you say set them both to 1/2 what do you mean , i have gone into network conns and set that to 10 1/2 but what else do i need to do?

Set the CM to 10 half as well (it's probably on Auto atm).

samuelnw53 11-10-2004 12:59

Re: Duplex?
 
How do i set the CM to 1/2, im a silver surfer and have little up top?:dunce:

altis 11-10-2004 14:41

Re: Duplex?
 
Follow this: http://root:root@192.168.100.1/

Select 'set ethernet type'

Select 10M half

Click save and reset

samuelnw53 11-10-2004 15:09

Re: Duplex?
 
your follow this ....Page cannot be displayed.

altis 11-10-2004 16:15

Re: Duplex?
 
What model of SACM do you have?

MovedGoalPosts 11-10-2004 17:02

Re: Duplex?
 
What about the cable router between the PCs and Samsung STB?

If, as above, the PCs NIC autodetect may not work correctly, then surely the same issue can happen with the router, or are they more reliable? I cannot see any way of changing the router speed though, mines a D-Link 804V.


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