This article describes that 1G optical transceivers do not support auto-negotiation on some modules and ports.
The existing manual for the EX4400 and EX4100 series has led to some confusion among customers. This guide aims to provide a clearer, more straightforward approach to understanding and configuring these devices, addressing common questions and simplifying the setup process
1G optical transceivers do not support auto-negotiation on the EX4100 1G/10G uplink module (PIC 1/PIC 2) and EX4400 1G/10G interface. 1G-T supports auto-negotiation on these ports.
https://www.juniper.net/documentation/us/en/software/junos/cli-reference/topics/ref/statement/auto-negotiation-edit-interfaces.html
On EX Series switches, an interface configuration that disables autonegotiation and manually sets the link speed to 1 Gbps is accepted when you commit the configuration; however, if the interface you are configuring is a Tri-Rate Ethernet copper interface, the configuration is ignored as invalid and autonegotiation is enabled by default.
To correct the invalid configuration and disable autonegotiation:
Delete the no-auto-negotiation statement and commit the configuration.
no-auto-negotiation
Set the link speed to 10 or 100 Mbps, set no-auto-negotiation, and commit the configuration
2024-10-30 : Article Created
2025-5-22 : Visibility set to public