Description

This article provides guidance when facing an issue where 1G link in PIC1/PIC2 in EX4400 or EX4100 connecting to a CISCO based device is not working.

Symptoms

1G optical transceivers do not support auto-negotiation on PIC 1/PIC 2.


Despite having the CISCO side as no auto negotiation, the link is still down.

Solution

When this issue is seen, you can make a physical loop to discard issues with the EX4400/EX4100 ports. For example:

 

EX4400-1 ge-0/2/0 ----> ge-0/2/1 EX4400-1

 

set interfaces ge-0/2/0.0 family inet address 1.1.1.1/30

set interfaces ge-0/2/1.0 family inet address 1.1.1.2/30

 

>ping 1.1.1.2 source 1.1.1.1

 

 

If this works, this discards issues with the Juniper ports. If the link is not coming up against the cisco, you will need to make sure the CISCO side has auto negotiation disabled.

 

Commands you may want to check on Cisco:

 

speed 1000 nonegotiate

 

nonegotiate speed

 

Possible solution: 

speed nonegotiate

Modification History

2025-09-15 : Article Created