Arista DCS-7280SR3-40YC6-R — 40×25GbE SFP + 6×100GbE Switch Router with Rear-to-Front Airflow
The
Arista DCS-7280SR3-40YC6-R is a 1RU switch router in the 7280R3 Series, delivering
800 Gbps of non-blocking switching capacity with
40 × 25GbE SFP ports (25G/10G/1G configurable) and
6 × 100GbE QSFP28 uplinks. Built on a next-generation VOQ ASIC platform with
2 GB of packet buffer memory (HBM2) and
3.8 µs store-and-forward latency, the 7280SR3-40YC6 provides comprehensive Layer 2/3 switch router capabilities — full BGP routing, MPLS, Segment Routing, EVPN, VXLAN, and 512-way ECMP — with fiber access ports for long-reach, noise-immune deployments. The “
-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, see the
DCS-7280SR3-40YC6-F.
Key Features at a Glance
- 40 × 25GbE SFP ports supporting 25G, 10G, and 1G speeds — configurable in groups of 4 for maximum flexibility
- 6 × 100GbE QSFP28 uplinks supporting breakout to 4×25GbE or 4×10GbE — up to 24 × 25G or 24 × 10G additional ports
- 800 Gbps non-blocking switching capacity with 1.0 Bpps (billion packets per second) forwarding rate
- 3.8 µs store-and-forward latency with 2 GB HBM2 packet buffer — eliminates head-of-line blocking
- Full Layer 3 switch router: BGP, OSPF, IS-IS, MPLS (LDP, RSVP-TE, BGP-LU), SR-TE, EVPN, VXLAN, 512-way ECMP
- Over 2M IPv4 LPM routes, over 1.4M IPv6 LPM routes, 384K MAC addresses — full Internet routing table support with hardware acceleration
- Quad-core x86 CPU with 8 GB DRAM (64 GB optional) running Arista EOS
- IEEE 1588v2 PTP with Synchronous Ethernet (SyncE) and telecom-grade timing (G.8275.1, G.8275.2, G.8261, G.8264)
- Telemetry: LANZ, Accelerated sFlow, Advanced Event Management (AEM), DANZ, INT, IPFIX, gNMI streaming
- CloudVision integration, Zero-Touch Provisioning (ZTP), Python/Bash scripting, NETCONF/RESTCONF, OpenConfig
- Hot-swappable dual PSU (1+1) and N+1 fan trays; rear-to-front (-R) airflow
- 1RU form factor — typical power draw with dual hot-swap redundant supplies
- BrightStar Systems: Supplied fully tested, reset to factory defaults, and backed by a 1-year in-house warranty
800 Gbps Non-Blocking VOQ Architecture
The DCS-7280SR3-40YC6-R delivers
800 Gbps of full-duplex, non-blocking throughput — (40 × 25 Gbps) + (6 × 100 Gbps) in both directions simultaneously. The
Virtual Output Queue (VOQ) ASIC architecture maintains separate queues for each input-to-output port pair, eliminating head-of-line blocking. With a
1.0 Bpps forwarding rate, the switch operates at full line rate across all port combinations regardless of traffic mix or packet size distribution. The
2 GB HBM2 (High Bandwidth Memory) packet buffer is integrated on the switching ASIC, providing substantial burst absorption capacity and latency-optimized buffering. Unlike shared-memory switches with smaller buffer pools, the VOQ deep buffer architecture handles transient congestion, TCP incast events, and bursty traffic patterns without triggering early packet drops or ECN marking — delivering higher effective throughput in oversubscribed topologies.
3.8 µs Store-and-Forward Latency
The 7280SR3-40YC6-R operates in store-and-forward mode with a measured latency of
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 trades the sub-microsecond latency of cut-through architectures for the ability to buffer, inspect, and apply policy at every forwarding decision, while maintaining sub-10-microsecond performance suitable for enterprise, service provider, and data center applications.
Port Configuration and Optics
The 7280SR3-40YC6-R provides 40 × 25GbE SFP access ports and 6 × 100GbE QSFP28 uplink ports:
- 40 × 25GbE SFP (25G/10G/1G configurable): Fiber-based SFP ports with speed negotiation in groups of 4. Supports 25GBASE-SR, LR, ER, ZR and 10GBASE-SR, LR, ER, ZR optics, plus direct attach copper (DAC) cables.
- 6 × 100GbE QSFP28: Support for 100GBASE-SR4, LR4, DR, FR, CWDM4, ZR/ZR+, and DAC/AOC cables. Breakout to 4×25GbE or 4×10GbE via standard breakout cables.
- Management: 1 × 100/1000 Mbps out-of-band management port + 1 × RS-232 RJ-45 console port, independent of the forwarding plane.
- Maximum port configurations: Up to 64 × 25GbE ports (40 SFP + 24 via QSFP28 breakout), or 6 × 100GbE + 40 × 25GbE in the base configuration.
Layer 2/3 Switch Router Capabilities
The 7280SR3-40YC6-R operates as a unified switch router with full Layer 2 and Layer 3 feature sets:
- BGP Full-Table Routing: Over 2M IPv4 unicast LPM routes and over 1.4M IPv6 LPM routes (FlexRoute) in the hardware FIB. Supports MP-BGP, BGP graceful restart, BGP FlowSpec, BGP Monitoring Protocol (BMP), BGP RPKI, and 512-way ECMP for load balancing across equal-cost paths.
- MPLS: Line-rate MPLS label switching with LDP, RSVP-TE with Fast Reroute (FRR), and BGP Labeled Unicast (BGP-LU) for carrier-grade MPLS networks and VPN services.
- Segment Routing: SR-TE and Topology Independent Loop-Free Alternate (TI-LFA) for simplified traffic engineering and rapid failover without per-path LSP state in the network core.
- EVPN and VXLAN: VXLAN Tunnel Endpoint (VTEP) and EVPN control plane with Integrated Routing and Bridging (IRB) for multi-tenant overlay networks, data center interconnect, and MAC mobility over both VXLAN and MPLS transports.
- Routing Protocols: OSPF, OSPFv3, IS-IS, RIPv2, VRF, BFD, Micro BFD, uRPF, VRRP, VRRP v3, VARP, and Policy-Based Routing (PBR) with Prefix-Independent Convergence (PIC) for rapid failure recovery.
- Layer 2: 802.1w/s Spanning Tree, RPVST+, 4096 VLANs, Q-in-Q, 802.3ad LACP (256 ports/channel, 2048 groups), MLAG (512 ports per MLAG), Jumbo Frames (9216 bytes), IGMP and PIM multicast snooping.
Telemetry, Monitoring, and Analytics
- LANZ (Latency Analyzer): 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: Hardware-accelerated traffic sampling for flow analysis and capacity planning. Integrates with third-party collectors (Kentik, Splunk, Solarwinds).
- In-band Network Telemetry (INT): Packet-level telemetry for hop-by-hop latency, queue depths, and switch-local state information embedded in packet headers.
- IPFIX (IP Flow Information Export): NetFlow v10 standards-based flow data export for third-party analysis and capacity planning.
- 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: Arista’s telemetry fabric for advanced mirroring (14 sessions), port mirroring, SPAN/TAP M:N aggregation, and L2/3/4 filtering.
- IEEE 1588v2 PTP: Hardware-assisted Precision Time Protocol for synchronized network timing, supporting Boundary Clock and Transparent Clock modes with sub-microsecond accuracy.
EOS Automation and Provisioning
The 7280SR3-40YC6-R runs
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.
- CloudVision: 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: Native on-box scripting with full Linux shell access for custom event handlers and automation workflows.
- eAPI (JSON-RPC): RESTful programmatic interface to all configuration and operational commands. Integrates with Ansible, Terraform, and custom orchestration.
- NETCONF and RESTCONF: Standards-based configuration protocols for vendor-neutral device management.
- OpenConfig and gNMI: Vendor-neutral data models and high-performance streaming RPC for configuration and telemetry.
Security
- Control Plane Policing (CoPP): Rate-limiting of CPU-destined traffic to protect routing stability
- ACLs and User-Defined Fields (UDF): Ingress/egress access control lists at L2, L3, and L4 with packet classification — over 100K algorithmic ACL entries enforced in the ASIC at line rate
- TACACS+ and RADIUS: Centralized authentication and accounting for administrative access
- Secure Boot: Cryptographic verification of bootloader and EOS image integrity
- MAC Security, DHCP Relay/Snooping, ARP trapping for Layer 2 security enforcement
Quality of Service (QoS)
- Up to 8 egress queues per port with strict priority, weighted round-robin (WRR), and weighted fair queueing (WFQ)
- 802.1p and DSCP classification and remarking
- ECN (Explicit Congestion Notification) marking for TCP-friendly congestion signaling
- PFC and DCBX (Priority Flow Control and Data Center Bridging Exchange) for converged traffic and Hierarchical QoS (H-QoS) for granular traffic prioritization
- Egress shaping and policing per-interface and per-queue
Physical Specifications and Airflow
The “
-R” airflow configuration provides
rear-to-front (reverse) cooling, where cool air enters from the port side and exhausts from the non-port side. Both -R and
-F (front-to-rear) variants are electrically identical.
- Form Factor: 1RU — 17.3 × 1.72 × 18.46 inches (43.99 × 4.37 × 46.9 cm)
- Weight: Approximately 9.57 kg (21.1 lbs)
- Power: Dual hot-swappable PSU (1+1) redundancy; AC or DC power supplies
- Cooling: Two hot-swappable N+1 redundant fan trays
- Storage: 8 GB Flash, 2 × USB ports
- Compliance: FCC Class A, CE, RoHS, WEEE
Lifecycle and Reliability
- Self-Healing Software: 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: Dual-partition boot with Smart System Upgrade (SSU) and Accelerated Software Update (ASU) for planned upgrades with minimal disruption.
- Configuration Rollback: Instant rollback to previous configuration snapshots via EOS configuration replace.
- BrightStar Systems 1-Year Warranty: Supplied fully tested, reset to factory defaults, and backed by a 1-year in-house warranty.
Scalability and Table Sizes
- MAC Addresses: 384K
- IPv4 Host Routes: 768K
- IPv4 Unicast LPM Routes: Over 2M
- IPv6 Unicast LPM Routes (FlexRoute): Over 1.4M
- Algorithmic ACLs: 100K+
- ECMP: 512-way
System Resources
- CPU: Quad-core x86 processor
- System Memory: 8 GB DRAM (64 GB optional for extended route table support)
- Packet Buffer: 2 GB HBM2 (High Bandwidth Memory) integrated on switching ASIC
- Flash Storage: 8 GB
- USB Ports: 2 × USB for external storage and upgrades
Similar Arista Models to Consider
- DCS-7280SR3K-48YC8-F: Higher-density variant with 48 × 25G SFP and 8 × 100G QSFP28 ports delivering 2 Tbps throughput with 4 GB buffer and 512-way ECMP.
- DCS-7280SRA-48C6-F: First-generation 7280R platform with 48 × SFP+ (1/10G) and 6 × QSFP28 ports featuring AlgoMatch algorithmic traffic management.
- DCS-7280CR3K-32P4-F: High-density 100G/400G variant with 32 × QSFP28 and 4 × OSFP ports for maximum port density and 25.6 Tbps throughput.
Related 7280 Series Resources
For comprehensive technical documentation and comparative model information across the Arista 7280 family, visit
In-depth technical overview of the Arista 7280R series.
Summary
The Arista DCS-7280SR3-40YC6-R is a 1RU switch router combining 40 × 25GbE SFP fiber access ports with 6 × 100GbE QSFP28 uplinks, 800 Gbps non-blocking throughput, 2 GB HBM2 packet buffer, and full Layer 2/3 capabilities including BGP, MPLS, SR-TE, EVPN with IRB, and VXLAN with 512-way ECMP. Running Arista EOS with CloudVision integration, ZTP, and comprehensive telemetry (LANZ, Accelerated sFlow, INT, IPFIX, AEM, DANZ, and hardware PTP), the 7280SR3-40YC6-R is available from BrightStar Systems fully tested, reset to factory defaults, and backed by a 1-year in-house warranty.
