Support Support Downloads Knowledge Base Case Manager My Juniper Community

Knowledge Base

Search our Knowledge Base sites to find answers to your questions.

Ask All Knowledge Base Sites All Knowledge Base Sites JunosE Defect (KA)Knowledge BaseSecurity AdvisoriesTechnical BulletinsTechnotes Sign in to display secure content and recently viewed articles

[EX] How to link up Juniper Ethernet switching GbE copper port by RJ45 loopback connector



Article ID: KB22174 KB Last Updated: 05 Mar 2017Version: 2.0

The EX series GbE copper ports has the ability to support 10/100/1000BASE-T. But, by default, the copper port will not link up by inserting a RJ45 loopback connector. This article provides a sample configuration for EX switching and the RJ45 pinout to solve this request.

As the EX GbE copper port supports 10/100/1000M speed, testing whether a port can link up or not through a RJ45 loopback connector, is the easiest way for some customers. This article provides information on how to test a EX GbE copper interface via the RJ45 loopback connector.

Instructions to link up EX GbE copper port in 100M fixed speed.

A 100base-T RJ45 loopback connector, whether made or bought, should look similar to the diagram shown below:

RJ45 loopback connector

To link up a copper GbE interface from EX series, disable auto-negotiation and set the speed to 100Mbps.The excerpt below is a sample configuration to link up ge-0/0/14 with a RJ45 loopback connector:
lab# show interfaces ge-0/0/14 | display set
set interfaces ge-0/0/14 ether-options no-auto-negotiation
set interfaces ge-0/0/14 ether-options link-mode full-duplex
set interfaces ge-0/0/14 ether-options speed 100m
set interfaces ge-0/0/14 unit 0 family ethernet-switching
Comment on this article > Affected Products Browse the Knowledge Base for more articles related to these product categories. Select a category to begin.

Getting Up and Running with Junos

Getting Up and Running with Junos Security Alerts and Vulnerabilities Product Alerts and Software Release Notices Problem Report (PR) Search Tool EOL Notices and Bulletins JTAC User Guide Customer Care User Guide Pathfinder SRX High Availability Configurator SRX VPN Configurator Training Courses and Videos End User Licence Agreement Global Search