Arista DCS-7280CR3K-36A-R — 28×QSFP100 + 6×QSFP200 + 2×QSFP-DD Multi-Speed Switch Router with Rear-to-Front Airflow
TheÂ
Arista DCS-7280CR3K-36A-RÂ is a compact, high-performance 1RU switch router from the Arista 7280R3 family. It deliversÂ
2.4 Tbps of wire-speed, non-blocking switching capacity with flexible multi-speed port configuration (28 × QSFP100 + 6 × QSFP200 + 2 × QSFP-DD) supporting 1G, 10G, 25G, 40G, 50G, 100G, 200G, and 400G breakout modes. Built on a high-throughput ASIC platform withÂ
4 GB of packet buffer memory andÂ
3.8 µs store-and-forward latency, the 7280CR3K-36A provides full Layer 2/3 switch router capabilities — comprehensive routing protocols, MPLS, Segment Routing, EVPN, VXLAN, and 512-way ECMP — with exceptional forwarding scale and flexible optics support for diverse network deployments. TheÂ
“K” variant features expanded FlexRoute capacity supportingÂ
5M+ IPv4 routes, enabling unprecedented routing scale for large service provider and hyperscale networks. TheÂ
“A” variant incorporates enhanced AlgoMatch and updated ASIC for improved ACL performance and algorithm matching. TheÂ
“-R” suffix denotes rear-to-front (reverse) airflow, where cool air enters from the port side and exhausts from the non-port side of the chassis. For front-to-rear airflow, theÂ
DCS-7280CR3K-36A-FÂ variant may be available.
Key Features at a Glance
- 28 × QSFP100 + 6 × QSFP200 + 2 × QSFP-DD ports with flexible multi-speed operation: 1G, 10G, 25G, 40G, 50G, 100G, 200G, and 400G breakout modes for optimized port utilization
- 2.4 Tbps non-blocking switching capacity with 1 Bpps forwarding rate
- 3.8 µs store-and-forward latency with 4 GB packet buffer — eliminates head-of-line blocking
- Full Layer 3 switch router:Â BGP, OSPF, OSPFv3, IS-IS, MPLS (LDP, RSVP-TE, BGP-LU), SR-MPLS, SR-TE, EVPN, VXLAN, 512-way ECMP
- Expanded FlexRoute capacity: 5M+ IPv4 routes, supporting hyperscale service provider and cloud deployments
- Enhanced AlgoMatch:Â Optimized ACL and algorithm matching on the A variant for improved packet classification performance
- Eight-Core x86 CPUÂ with 64 GB system memory running Arista EOS
- IEEE 1588v2 PTP, SyncE, G.8275.1/2, G.8261/8264Â for precision timing in synchronization-critical deployments
- Telemetry:Â Accelerated sFlow, Advanced Event Management (AEM), DANZ, Inband Network Telemetry (INT), IPFIX, streaming telemetry via gNMI
- CloudVision integration, Zero-Touch Provisioning (ZTP), Python/Bash scripting, eAPI, NETCONF, RESTCONF, OpenConfig
- Hot-swappable dual PSU (1+1) and dual-fan architecture (1+1); rear-to-front (-R) airflow
- 1RU form factor — compact design with flexible deployment options
- BrightStar Systems:Â Supplied fully tested, reset to factory defaults, and backed by a 1-year in-house warranty
2.4 Tbps Non-Blocking High-Throughput Architecture
The DCS-7280CR3K-36A-R deliversÂ
2.4 Tbps of full-duplex, non-blocking throughput across flexible QSFP100/QSFP200/QSFP-DD ports in the third-generation R3 design. The advanced ASIC architecture maintains separate queues for each input-to-output port pair, eliminating head-of-line blocking. With aÂ
1 Bpps forwarding rate, the switch operates at full line rate across all port combinations regardless of traffic mix, packet size distribution, or speed mix configuration. TheÂ
4 GB packet buffer is architected to handle transient congestion, TCP incast events, and bursty traffic patterns without triggering early packet drops or ECN marking — delivering higher effective throughput in oversubscribed topologies and multi-speed environments. The R3 architecture supports up toÂ
512-way ECMPÂ for advanced load balancing and faster convergence.
3.8 µs Store-and-Forward Latency
The 7280CR3K-36A-R operates in store-and-forward mode with a measured latency ofÂ
3.8 microseconds. The ASIC receives the complete packet, performs a full Layer 2/3 lookup, applies ACLs and QoS policies, and forwards the packet — all within 3.8 µs. This design enables comprehensive policy enforcement and traffic inspection at every forwarding decision while maintaining sub-10-microsecond performance suitable for enterprise, service provider, and data center applications.
Port Configuration and Multi-Speed Flexibility
The 7280CR3K-36A-R provides flexible multi-speed port support with up to 120 maximum interfaces:
- 28 × QSFP100 ports: Support for 100GBASE-SR4, LR4, DR, FR, CWDM4, ZR/ZR+, and DAC/AOC cables with flexible multi-speed modes (1G, 10G, 25G, 40G, 50G, 100G native)
- 6 × QSFP200 ports: Support for 200GBASE multi-speed operation with 50G, 100G, and 200G native modes
- 2 × QSFP-DD ports: Support for 400G operation with optional breakout to 4×100G or 8×50G
- Maximum port density: 2 × 400G, 40 × 100G, 80 × 50G, 36 × 40G, 120 × 25/10G, 24 × 1G depending on configuration
- Management: 1 × 100/1000 Mbps out-of-band management port + 1 × RS-232 RJ-45 console port, independent of the forwarding plane.
- Flexible port configurations: Operators can optimize port density and speed mix based on topology requirements — native configurations or mixed-speed setups for cost-effective deployment.
Expanded FlexRoute IPv4 Capacity (K Variant)
The DCS-7280CR3K-36A-R incorporates the “
K” variant, which expands the routing table capacity to supportÂ
5M+ IPv4 LPM routes in addition to full IPv6 support. This expanded capacity enables deployment in hyperscale environments where service providers and content delivery networks require massive route table sizes without requiring additional ASICs or external routing processors. The K variant maintains the same forwarding rate and latency as standard models while providing unparalleled routing scale.
Enhanced AlgoMatch (A Variant)
The “
A” variant integrates enhanced AlgoMatch functionality with an updated ASIC architecture. This improves packet classification performance for complex ACL policies, traffic engineering rules, and algorithm-based matching operations. The A variant is optimized for environments requiring sophisticated packet filtering, policy-based routing, and multi-field packet classification at wire-speed with minimal performance impact.
Layer 2 Switching Capabilities
The 7280CR3K-36A-R operates as a unified switch router with comprehensive Layer 2 switching features:
- 802.1w/s Spanning Tree:Â RPVST+ for loop prevention and redundancy
- VLAN Support:Â 4096 VLANs with Q-in-Q capabilities for service provider deployments
- Link Aggregation:Â 802.3ad LACP with 256 ports per channel and 2048 groups for high-density bonding
- MLAG (Multi-Chassis LAG):Â Up to 512 ports per MLAG for flexible redundancy across multiple chassis
- Jumbo Frames:Â Support for frames up to 9216 bytes
- IGMP Snooping:Â IP multicast group filtering and management
Layer 3 Routing and Advanced Forwarding
The 7280CR3K-36A-R delivers industry-leading Layer 3 routing capabilities with expanded IPv4 route scale:
- BGP Full-Table Routing:Â 5M+ IPv4 unicast LPM routes in hardware FIB with full IPv6 support. Supports MP-BGP, BGP graceful restart, BGP FlowSpec, BMP, BGP-RPKI, and 512-way ECMP for sophisticated load balancing.
- Interior Gateway Protocols:Â OSPF, OSPFv3, IS-IS, RIPv2 with BFD and Micro BFD for sub-second convergence
- VRF and Policy:Â Virtual Routing and Forwarding (VRF), Policy-Based Routing (PBR), and Prefix Independent Convergence (PIC) for fast reroute
- VRRP and VARP:Â Virtual Router Redundancy Protocol and Virtual ARP for gateway redundancy
- Unicast RPF:Â Reverse path forwarding for source validation and anti-spoofing
MPLS and Segment Routing
The 7280CR3K-36A-R provides carrier-grade MPLS and advanced traffic engineering:
- MPLS Label Switching:Â LDP, RSVP-TE with Fast Reroute (FRR), and BGP Labeled Unicast (BGP-LU) for seamless VPN and carrier services
- BGP-LS:Â BGP Link State for topology discovery and distribution in SDN controllers
- Segment Routing (SR):Â SR-MPLS and SR-TE (Segment Routing Traffic Engineering) for simplified, source-driven path optimization without per-path LSP state in the network core
- TI-LFA:Â Topology-Independent Loop-Free Alternate for sub-50ms local reroute protection
VPN and Overlay Services
The 7280CR3K-36A-R enables flexible VPN deployments across Layer 2 and Layer 3 domains:
- IP-VPN:Â BGP/MPLS IPv4 and IPv6 VPN (RFC 4364/4659) for carrier-grade multi-tenant service delivery
- VPLS:Â Virtual Private LAN Service for Layer 2 VPN connectivity
- EVPN-VXLAN:Â Ethernet VPN with VXLAN Tunnel Endpoints (VTEP) for multi-tenant data center overlays and MAC mobility
- EVPN-MPLS:Â Ethernet VPN over MPLS for carrier-grade Layer 2 services
- EVPN IRB (Integrated Routing and Bridging):Â Seamless Layer 2/3 virtualization for efficient multi-tenant and multi-domain networks
Precision Timing and Synchronization
The 7280CR3K-36A-R includes comprehensive timing support for synchronization-critical deployments:
- IEEE 1588v2 PTP:Â Hardware-assisted Precision Time Protocol for network clock synchronization, supporting Boundary Clock and Transparent Clock modes
- Synchronous Ethernet (SyncE):Â G.8261, G.8262 for frequency synchronization over Ethernet
- Telecom Timing Standards:Â G.8275.1 and G.8275.2 for phase/time synchronization in telecom and financial networks
- G.8264:Â MPLS Section and Span Loss of Signal monitoring for timing chain integrity
Quality of Service (QoS)
The 7280CR3K-36A-R provides advanced QoS for multi-service networks:
- 8 queues per port with strict priority, weighted round-robin (WRR), and weighted fair queueing (WFQ)
- Classification:Â DSCP and 802.1p tag-based priority mapping with remarking support
- ECN (Explicit Congestion Notification):Â DCTCP-friendly congestion signaling for reduced packet loss in oversubscribed networks
- PFC (Priority Flow Control) and DCBX:Â Data Center Bridging Exchange for lossless Ethernet and converged traffic
- Hierarchical QoS (H-QoS):Â Multi-level queue structures for complex traffic policies and SLA guarantees
- Egress shaping and policing per-interface and per-queue
Security
- Control Plane Policing (CPP):Â Rate-limiting of CPU-destined traffic to protect routing stability
- ACLs and User-Defined Fields (UDF):Â Ingress/egress access control lists at L2, L3, and L4 with 100K+ Algorithmic ACL entries enhanced by AlgoMatch on the A variant for sophisticated packet filtering and rate limiting
- TACACS+ and RADIUS:Â Centralized authentication and accounting for administrative access
- Secure Boot:Â Cryptographic verification of bootloader and EOS image integrity
- Layer 2 Security: DHCP Relay/Snooping and ARP trapping for Layer 2 security enforcement (Note: MACsec is supported on M and MK models only — not supported on CR3K models)
Telemetry, Monitoring, and Analytics
The 7280CR3K-36A-R provides comprehensive network visibility:
- LANZ (Latency Analyzer):Â Per-port, real-time microburst detection and queue depth monitoring at microsecond granularity. Records egress port, queue, drop reason, and timestamp for every congestion event.
- Accelerated sFlow v5:Â Industry-standard traffic sampling for flow analysis and capacity planning. Integrates with third-party collectors (Kentik, Splunk, Solarwinds).
- Advanced Event Management (AEM): Programmable event-driven automation within EOS — customize alerts and actions, automate routine tasks, and respond to real-time network conditions.
- DANZ:Â Advanced mirroring and traffic analysis with configurable M:N aggregation and L2/3/4 filtering for deep packet inspection.
- Inband Network Telemetry (INT):Â Embedded telemetry in packet headers for hop-by-hop analytics and performance visibility
- IPFIX:Â IP Flow Information Export for NetFlow-compatible analytics
- Streaming Telemetry:Â Real-time counter and state export via gNMI (gRPC) and Arista eAPI (REST). Supports OpenConfig data models for vendor-neutral management.
EOS Automation and Provisioning
The 7280CR3K-36A-R runsÂ
Arista EOS, a modular operating system built on a standard Linux kernel where each process runs in its own protected memory space and communicates through an in-memory state-sharing database (Sysdb). This architecture enables in-service software updates and self-healing resiliency without data plane interruption. Minimum EOS version: 4.27.2
- CloudVision:Â Centralized configuration management, network-wide change control, topology visualization, and compliance monitoring across multi-site Arista deployments.
- Zero-Touch Provisioning (ZTP): Automatic configuration download on first power-up via DHCP — no manual CLI access required for initial deployment.
- Python and Bash:Â Native on-box scripting with full Linux shell access for custom event handlers and automation workflows.
- eAPI and RESTCONF:Â RESTful and NETCONF programmatic interfaces to all configuration and operational commands. Integrates with Ansible, Terraform, and custom orchestration.
- OpenConfig and gNMI:Â Vendor-neutral data models and high-performance streaming RPC for configuration and telemetry.
Physical Specifications and Airflow
TheÂ
“-R” airflow configuration provides rear-to-front (reverse) cooling, where cool air enters from the port side and exhausts from the non-port side. The compact 1RU form factor enables space-efficient deployment in constrained rack environments. The 7280CR3K-36A-R usesÂ
high-speed forward-airflow fans (FAN-7011H-R)Â optimized for rear-to-front operation. Both -R and -F variants are electrically identical and fully supported.
- Form Factor: 1RU — compact design for flexible deployment
- Dimensions: 17.3 × 1.72 × 18.57 in (43.99 × 4.37 × 47.17 cm)
- Weight:Â 23 lbs (10.47 kg)
- Power Supply:Â Dual hot-swappable PWR-1011 PSU (1+1 redundancy, AC or DC input) for high availability
- Cooling: Dual hot-swappable high-speed fans (FAN-7011H-R, 1+1 redundancy) — rear-to-front airflow
- Power Consumption:Â Typical 262 W / Maximum 437 W
- Storage: 120 GB SSD, 2 × USB ports
- Compliance:Â FCC Class A, CE, RoHS, WEEE
Scalability and Table Sizes
- MAC Addresses:Â Up to configured limit
- IPv4 Unicast LPM Routes:Â 5M+ (FlexRoute K variant)
- IPv6 Unicast LPM Routes:Â Full IPv6 support
- Algorithmic ACL Entries:Â 100K+ (enhanced by AlgoMatch on A variant)
- ECMP:Â 512-way
- EOS License Group:Â Group 3
Lifecycle and Reliability
- Self-Healing Software:Â EOS includes Stateful Fault Repair (SFR) for automatic recovery from software faults without data plane impact, and Stateful Fault Containment (SFC) for fault isolation.
- In-Service Software Updates:Â Dual-partition boot with Smart System Upgrade (SSU) and Accelerated Software Update (ASU) for planned upgrades with minimal disruption.
- Configuration Rollback:Â Instant rollback to previous configuration snapshots via EOS configuration replace.
- BrightStar Systems 1-Year Warranty:Â Supplied fully tested, reset to factory defaults, and backed by a 1-year in-house warranty.
Related 7280 Series Resources
For comprehensive technical documentation and comparative model information across the Arista 7280 family, visitÂ
Arista 7280 Series Overview.
Summary
The Arista DCS-7280CR3K-36A-R is a compact 1RU switch router combining 28 × QSFP100 + 6 × QSFP200 + 2 × QSFP-DD multi-speed ports with 2.4 Tbps non-blocking throughput, 1 Bpps forwarding rate, 4 GB packet buffer, and industry-leading Layer 2/3 capabilities including BGP with 5M+ IPv4 routes (K variant), MPLS, SR-TE, EVPN, VXLAN, and 512-way ECMP. With enhanced AlgoMatch packet classification (A variant), support for precision timing (PTP, SyncE, G.8275), comprehensive telemetry (LANZ, sFlow, AEM, DANZ, INT, IPFIX), and full Arista EOS automation (CloudVision, ZTP, eAPI, gNMI), the 7280CR3K-36A-R with rear-to-front airflow is available from BrightStar Systems fully tested, reset to factory defaults, and backed by a 1-year in-house warranty.
Also available: DCS-7280CR3K-36A-F with front-to-rear airflow.
