Switch port Flaps when I configure the speed full duplex...

[formolie.m1]

I am trying to configure VLANID for PPPoE, however, when I try and configure the speed for the port on the switch either using speed auto or speed 1000 the link just flaps constantly and doesn't come up for more than a few seconds.

However, when I force speed to speed 100, it works fine. Any ideas?

P.S - I want to run on full duplex - Half duplex works fine. 

I would appropriate your help.....

Cheers,

[Mark Malone]

whats the far end end device your connected to , does it support 1000 full ? some devices ISPs may only support half dup 100 that could be why its only working at that setting

[pwwiddicombe]

Your provider can tell you what you should/can use; but you might want to do a test.

First, verify your cable to the provider equipment is a quality Cat 6 cable with all 8 pins end-to-end.  100 Meg only needed the "common" Ethernet 4 pins.

Once that's verified, set the interface to AUTO and see what you get.  If the provider is also set to auto, you will negotiate the correct duplex and "maximum" speed available.  If the provider has set to 100Full OR 100 Half, you will end up seeing 100-half, as negotiation will be disabled.

[formolie.m1]

Cheers Pwwiddicombe, 

I will lodge a ticket to our provider and let you know if I face any issue.  I tried changing the interface to auto and full depl it didn't work only half works. 

Cheers// 

[formolie.m1]

thanks for your feedback Mark;

I plugged a TP link device to the switch and from the switch to service provider's NTU. 

Cheers//

[pwwiddicombe]

Which kind of TP device?  Many of those ONLY support auto-negotiation, as there is no management to them; although occasionally there is a button or DIP switch for speed/duplex settings.  This gives you 2 additional potential mismatch points; although it MAY have indicator llights for speed and duplex negotiated ?