Switching

Hi All,

 

I was having some problems connecting to a broadcom NIC with the following settings, 

Scenario 1:

 

NIC: 100/full

Switchport: 100/full

 

The interface does not come up. However then i configured "set interface X/X/X ether-options no-auto-negotiation" the interface is up and running.

This information is discussed in the "Junos Enterprise Switching - O'Reilly" book, pg 148-149

 

 

But just wondering:

 

1) Why is auto-negotiation need to be disabled when we fixed the speed/duplex? Is there any situation when we need to set auto-negotiate and speed/duplex is fixed? I feel that the no-auto-negotiation is redundant in Scenario 1

 

2) In Cisco switches, once auto-negotiate is disabled, auto-mdix on the switchport does not work. In Juniper switches , does it also turn off the auto-mdix function on the switchport once no-auto-negotiation is configure? If yes, that at least we can answer my first question. 

 

Anyone experience this situation before, please share. Thanks.

 

 

 

 

 

 

I believe that setting the speed and duplex while leaving auto-negotaition in place is designed so that the settings you set are the maximum values that will be negotiated.  Turning off the negotation protocol will effectively hard-set the speed and duplex at whatever settings you choose.

 

Ron

Hi,

 

I get only these options --

 

root@switch-ex4500# set interfaces xe-0/0/18 ether-options ?
Possible completions:
> 802.3ad              IEEE 802.3ad
+ apply-groups         Groups from which to inherit configuration data
+ apply-groups-except  Don't inherit configuration data from these groups
  flow-control         Enable flow control
  loopback             Enable loopback
  no-flow-control      Don't enable flow control
  no-loopback          Don't enable loopback

 

 

raj

Raj, You are working on a EX4500, this is a 1G/10G switch, 100M is not working. So even if the interface comes up after Auto-Nego disable you get trouble. Regards, Fabian.