Cisco NCS 5500 Series Modular Line Card NC55-MOD-A-S

Brand: Cisco | Category: Accessories & Components

SKU: CSC-NC55-MODAS | Part #: NC55-MOD-A-S | MPN: NC55-MOD-A-S

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The NC55-MOD-A-S is a modular line card that handles the actual packet forwarding work inside a Cisco NCS 5500 chassis. In a distributed router architecture, this component is what determines your throughput, latency, and whether your network can scale to handle growth without replacing hardware. This scale variant uses a Broadcom Jericho forwarding ASIC and supports two modular port adapters, making it the right choice when your routing table or ECMP fan-out requirements exceed what smaller line cards can deliver. Network engineers across the GCC and Asia-Pacific regions specify this card when they need to move traffic at 400G+ aggregate speeds while maintaining sub-millisecond convergence on BGP failures.

Cisco designed the NCS 5500 series around a chassis model where line cards are swappable, and the NC55-MOD-A-S fits into any NCS 5504, NCS 5508, or NCS 5516 modular chassis. What sets the NC55-MOD-A-S apart from other line cards in the same family is its enhanced scaling for routing tables and equal-cost multi-path (ECMP) adjacencies. This matters in environments where a single BGP route reflector or border router needs to hold hundreds of thousands of prefixes or where you have dense mesh topologies with dozens of next-hops per destination. The card runs Cisco IOS XR, the same operating system that powers the entire chassis, so you get consistent command syntax, policy language, and troubleshooting tools across your infrastructure.

On the protocol side, the NC55-MOD-A-S is not limited to basic IP forwarding. It supports both IPv4 and IPv6 equally, handles MPLS and segment routing (both SR-MPLS and the newer SRv6), terminates EVPN control plane and data plane, and runs all the convergence mechanisms your network needs: TI-LFA for local repair, IP/LDP fast reroute, and BGP prefix-independent convergence. If you are running L3VPN overlays for multi-tenant data centre isolation, or if you need RSVP-TE for traffic engineering, or if you are building an IS-IS or OSPF backbone, this line card handles all of it in hardware. QoS is not an afterthought either—the card implements hardware-based hierarchical QoS with shaping, policing, and weighted queuing deep in the forwarding pipeline, which means you can enforce service levels at line rate without CPU overhead.

Management and observability have moved beyond SNMP and SSH, and the NC55-MOD-A-S reflects that shift. You interact with this card via NETCONF, RESTCONF, or gRPC using YANG data models, making it fit naturally into infrastructure-as-code and CI/CD pipelines. Model-driven streaming telemetry via gRPC dial-out means you can subscribe to link state, route updates, or QoS counters and receive them continuously without polling, which is essential when you need real-time visibility into a network carrying petabytes of data centre traffic. For high availability, Cisco built in In-Service Software Upgrade (ISSU) so you can patch or upgrade IOS XR without stopping traffic, Stateful Switchover (SSO) for graceful failover between redundant route processors, and Non-Stop Forwarding (NSF) so that traffic keeps moving even during control plane restarts. All of this is transparent to the applications using your network.

Omnixon Global stocks the NC55-MOD-A-S (part number NC55-MOD-A-S) as part of our complete Cisco NCS 5500 inventory. Whether you are a network architect building a high-scale data centre fabric, a systems administrator expanding an existing NCS 5500 deployment, or an AI infrastructure team provisioning dedicated networking for GPU clusters, we can provide this line card with Cisco TAC eligibility and warranty support. Based in Dubai and serving GCC, South Asia, and Europe, Omnixon Global delivers Cisco enterprise routing hardware on the timelines that modern networks demand. Please reach out for a Request for Quote on this product or for assistance specifying the right line card configuration for your chassis and traffic profile.

Performance Specifications & Forwarding Capacity

• Forwarding ASIC: Broadcom Jericho with enhanced routing table and ECMP scale for the -S variant
• Modular Port Adapter bays: 2 MPA slots, supporting up to 400G interfaces depending on adapter choice
• Protocol support: IPv4, IPv6, MPLS, SR-MPLS, SRv6, EVPN, L3VPN, RSVP-TE, IS-IS, OSPF, BGP
• Fast convergence mechanisms: TI-LFA, IP/LDP FRR, BGP PIC Edge for sub-second failure recovery
• QoS architecture: Hardware-based hierarchical QoS with shaping, policing, and weighted queuing at line rate
• Management protocols: NETCONF, RESTCONF, gRPC with YANG data models and model-driven streaming telemetry
• High availability: In-Service Software Upgrade (ISSU), Stateful Switchover (SSO), Non-Stop Forwarding (NSF)