Cisco 4OC3X/POS-MM-MJ-B
GSR 4-port OC3/POS MM Eng3 release B
Product Highlights
Keeping a legacy Cisco GSR 12000 deployment running reliably means having the right spare line cards on hand — especially when the platform has reached end-of-life and new-from-manufacturer inventory is no longer available.
The Cisco 4OC3X/POS-MM-MJ-B is a 4-port OC-3c/STM-1c Packet-over-SONET (POS) line card built on Cisco's Engine 3 IP Services Engine (ISE) architecture. It provides four multimode fiber interfaces with MTRJ connectors, each delivering 155 Mbps of SONET/SDH bandwidth in full-duplex mode. The ISE platform enables a rich set of edge services including MPLS, VPN support, access control lists (ACLs), committed access rate (CAR), and NetFlow — all processed in a distributed fashion on the line card itself, offloading the route processor.
Designed as a plug-in module for the Cisco 12000 Series Gigabit Switch Router family, this card is compatible with chassis models including the 12008, 12012, 12016, 12404, 12406, 12410, and 12416. The multimode optics and MTRJ connector type make it well-suited for short-reach connections within a data center or central office environment.
Whether you need a direct replacement for a failed card or a cold spare to protect against downtime, the 4OC3X/POS-MM-MJ-B keeps your SONET/SDH edge infrastructure operational while you plan a longer-term migration path.
Features & Benefits
Engine 3 ISE Distributed Processing
Built on Cisco's IP Services Engine (ISE) architecture, this line card performs advanced packet processing — including ACLs, CAR, NetFlow, and MPLS — directly on the card. This distributed approach offloads the route processor and delivers consistent, line-rate performance across all four ports.
4-Port OC-3c/STM-1c POS Connectivity
Each of the four ports provides a full-duplex 155 Mbps SONET/SDH concatenated interface using Packet-over-SONET encapsulation. Concatenation eliminates the need to partition bandwidth, improving efficiency for IP traffic transport over SONET rings and point-to-point links.
Multimode Fiber / MTRJ Connectors
The multimode (MM) optics with MTRJ connectors are optimized for short-reach fiber connections typically found within data centers, central offices, and campus environments. MTRJ's small form factor enables higher port density on the faceplate compared to traditional SC connectors.
Online Insertion and Removal (OIR)
The line card supports hot-swap capability, allowing you to insert or remove it from a live Cisco 12000 chassis without impacting traffic on other line card slots. This simplifies maintenance windows and reduces planned downtime.
MPLS and VPN Services
Native support for Multiprotocol Label Switching (MPLS) and VPN enables service providers to deliver managed Layer 3 VPN services at the network edge. The ISE engine handles label imposition and disposition at hardware speed.
Deployment Scenarios
Service Provider SONET/SDH Edge Aggregation
Deploy in a Cisco GSR 12000 router at the service provider edge to aggregate multiple OC-3 customer connections. The ISE engine provides per-interface QoS, traffic policing, and MPLS label switching for managed service delivery.
Legacy Network Maintenance & Spare Inventory
As the Cisco 12000 Series and Engine 3 line cards have reached end-of-life, sourcing tested replacement cards is critical for organizations still operating GSR infrastructure. This card serves as a direct drop-in replacement to restore service after a hardware failure.
Central Office / Data Center Short-Reach Interconnect
The multimode fiber optics are ideal for short-distance connections within a single facility — linking the GSR to SONET ADMs, optical cross-connects, or other routers across a meet-me room or co-location environment.
General
Interfaces & Performance
Optical
Features
Compatibility Notes
Compatible Cisco 12000 Series Router Chassis:
- Cisco 12008
- Cisco 12012
- Cisco 12016
- Cisco 12404
- Cisco 12406
- Cisco 12410
- Cisco 12416
Switch Fabric Requirement: Engine 3 line cards require a minimum of one Clock Scheduler Card (CSC) and three Switch Fabric Cards (SFCs) installed in the chassis.
Note: This is an Engine 3 line card. Engine 6 line cards operate only in Cisco 12800 routers. Verify your chassis model and switch fabric configuration before ordering.
EOL Status: The Cisco GSR 12000 platform and Engine 3 line cards have been announced as end-of-life by Cisco. Cisco has recommended migration to the Cisco XR 12000 Series SPA Interface Processors as replacements.
Downloads & Resources
Frequently Asked Questions
| Part Number | Product | Key Difference |
|---|---|---|
| 4OC3X/POS-IR-LC-B | GSR 4-Port OC-3/POS IR LC Engine 3 B | Single-mode intermediate-reach fiber with LC connectors instead of multimode MTRJ — suited for longer-distance links |
| 8OC3X/POS-MM-MJ-B | GSR 8-Port OC-3/POS MM Engine 3 B | Doubles port density to 8 ports of multimode OC-3/POS on a single line card for higher-density deployments |
| 8OC3X/POS-IR-LC-B | GSR 8-Port OC-3/POS IR LC Engine 3 B | 8-port single-mode intermediate-reach variant with LC connectors — maximum OC-3 density with longer reach |
| 16OC3X/POS-M-MJ-B | GSR 16-Port OC-3/POS MM Engine 3 B | Highest density option with 16 multimode OC-3/POS ports per line card for large-scale aggregation |