In the context of Juniper Networks’ high-end routing platforms, particularly the PTX Series Packet Transport Routers and the MX Series Universal Routing Platforms, the term "Ren 2 Link" refers to a critical internal interconnect used within a multi-chassis system. The "Ren" stands for "Rendezvous" — a designated point where data and control traffic meet and are distributed across different components or chassis.
show system alarms: Many REN 2 issues first appear as a minor alarm: "Redundancy link degraded."You won't see interface ren-2/0/0 in a standard show interfaces terse. Instead, use these operational commands: juniper ren 2 link
ren0 or ren2, visible in the CLI).Critical Note: The REN 2 link is not the same as the out-of-band management Ethernet ports (fxp0, em0, or re0:mgmt-*). Those are for external management. REN 2 is strictly internal for RE-to-RE communication. Understanding the Juniper Ren 2 Link: High-Speed Chassis
The Juniper EX4300 series, specifically when evaluated in the context of the "Juniper R2" release cycle (Junos OS 15.1R2), represents a pivotal moment in campus and data center switching. While the hardware itself—specifically the EX4300-48P—remains a workhorse in many enterprise environments, the "R2" firmware iteration introduced critical feature sets, most notably Juniper Fusion. This review assesses the hardware capabilities alongside the specific stability and feature implementations of the R2 software build. How to Check the Status of Your REN
show fabric statistics
On modular systems, this shows the fabric planes. A failed "REN 2" might appear as Plane 2: Link status: Down.