817708-B21 HPE 2 Port Eth 10/25GB 631FLR Pci Express 3.0 X8 SFP28 Adapter

HPE 817708-B21 High-Speed Network Adapter

The HPE 817708-B21 Ethernet adapter is designed to enhance server networking capabilities with fast data throughput and dependable connectivity. Built for enterprise environments, this adapter supports demanding workloads and scalable infrastructures.

Manufacturer Information

• Brand: Hewlett Packard Enterprise (HPE)
• Part Number: 817708-B21
• Category: Server Network Interface Card (NIC)

Form Factor and Bus Interface

• Internal plug-in expansion card
• PCI Express Gen3 x8 compatibility
• Seamless integration into HPE server platforms

Port Configuration

• Two SFP28 fiber ports
• Supports 10 Gigabit Ethernet connections
• Flexible deployment for multi-network environments

Connectivity and Protocol Support

• Wired Ethernet communication
• 10GbE data link protocol
• Compatible with advanced switching technologies

Supported IEEE Standards

• IEEE 802.3 Ethernet
• IEEE 802.1Q VLAN tagging
• IEEE 802.1P traffic prioritization
• IEEE 802.3X flow control
• IEEE 802.3ad link aggregation (LACP)
• IEEE 802.3AE high-speed Ethernet
• IEEE 802.1AB LLDP discovery
• IEEE 802.1QAU congestion management

Data Transfer Speed

• Up to 10 Gbps per port
• Consistent throughput for demanding applications
• Ideal for virtualization and large data workloads

Smart Networking Functions

• Wake-on-LAN (WOL) capability
• PXE boot support for remote deployment
• Enhanced system management and automation

Key Benefits

• High-speed dual-port Ethernet connectivity
• Broad IEEE compliance for network compatibility
• Reliable Intel-based processing
• Efficient jumbo frame handling
• Advanced boot and power features

HPE 817708-B21 10/25GbE SFP28 Adapter Category

This category of adapters represents a pivotal step in the network evolution path, sitting between the widely deployed 10GbE and the emerging 100GbE standards. SFP28, standing for Small Form-factor Pluggable 28 Gigabit, is a physical form factor that supports single-lane 25 Gb/s speeds, as well as backward-compatible 10 Gb/s. Adapters like the HPE 817708-B21 are engineered to capitalize on this, providing a crucial balance of performance, density, and cost-effectiveness. The transition to 25GbE is driven by several factors. The exponential growth of data from cloud applications, big data analytics, and software-defined storage (SDS) has saturated traditional 10GbE links. Furthermore, the economics are compelling: a single 25GbE connection often provides 2.5x the bandwidth of 10GbE at a marginal cost increase, offering a superior return on investment. For hyper-converged infrastructure (HCI) deployments, where network traffic combines storage, compute, and management, the low latency and high throughput of 25GbE are essential for maintaining cluster performance and stability.

Integrated Features and Management

HPE’s 631 series adapters, including the 817708-B21, are part of HPE's "FlexLOM" (Flexible Lan on Motherboard) ecosystem. This architecture provides a modular approach to server networking, allowing this adapter to be installed in the dedicated FlexibleLOM slot of compatible HPE servers. This integration offers a cleaner, more optimized solution than a standard PCIe riser card, leveraging HPE's firmware and management integration with iLO. To truly appreciate its capabilities, one must examine the detailed engineering of this network interface card (NIC). Each specification is a carefully chosen component of a holistic performance solution.

Port Configuration and Physical Interface

The adapter features two SFP28 ports. This dual-port design is ideal for critical applications requiring redundancy (link aggregation, failover) or for segregating traffic types (e.g., separating storage network traffic from virtual machine traffic). The SFP28 cages accept industry-standard SFP28 optical transceivers or Direct Attach Copper (DAC) cables, providing immense flexibility in connectivity choices based on distance, cost, and infrastructure.

Host Interface: PCI Express 3.0 x8

The PCIe 3.0 x8 host interface is a critical specification. PCIe 3.0 offers a data rate of 8 GT/s per lane. With eight lanes, this provides a total theoretical bidirectional bandwidth of approximately 16 GB/s. This massive pipe ensures that the adapter's dual-port 25GbE potential (up to 6.25 GB/s aggregated) will never be bottlenecked by the connection to the server's motherboard, allowing for full utilization of network bandwidth.

NVGRE and VXLAN Offloads

For modern, overlay-based cloud networks, the adapter includes offloads for NVGRE and VXLAN encapsulation/decapsulation. This task, if performed by the server CPU, is computationally expensive. Offloading it to the adapter's ASIC frees up CPU cycles for applications and improves overall network throughput in software-defined data center environments. The HPE 817708-B21 supports SR-IOV (Single Root I/O Virtualization). This allows the physical adapter to be partitioned into multiple virtual functions (VFs) that can be assigned directly to virtual machines (VMs). This bypasses the hypervisor's virtual switch, drastically reducing CPU overhead and latency, and providing near-bare-metal network performance to critical VMs.

Strategic Use Cases and Deployment Scenarios

The versatility of the HPE 817708-B21 makes it suitable for a wide array of demanding IT environments. In HCI platforms like HPE or VMware v SAN, network performance is the linchpin. These environments combine compute, storage, and networking on a single x86 platform, generating intense East-West traffic between nodes. The 25GbE throughput and RoCE support of this adapter dramatically reduce data synchronization times, accelerate storage Motion operations, and ensure a responsive, scalable cluster.

High-Performance Database and Analytics Backends

For SQL/NoSQL databases (Microsoft SQL Server, MongoDB, Cassandra) and real-time analytics platforms, low-latency network access to data is paramount. Deploying this adapter with RoCE enables rapid query responses by minimizing network stack overhead, ensuring that data-intensive applications are not waiting on the network.

Tiered Storage Connectivity

The adapter is perfect for connecting application servers to high-speed all-flash storage arrays (like HPE Nimble Storage or HPE Primera) over iSCSI or as an NVMeoF initiator. The 25GbE links provide the necessary bandwidth to fully saturate the high IOPS and low latency of modern flash storage, ensuring the storage network is not the bottleneck.

Virtualized Host and Cloud Gateway

In large-scale virtualization hosts (VMware ESXi, Microsoft Hyper-V, KVM), the adapter’s dual ports can be configured for NIC teaming for increased bandwidth and resilience. SR-IOV functionality allows direct passthrough of adapter ports to high-demand VMs, such as virtual desktop infrastructure (VDI) brokers or video rendering servers, ensuring consistent performance.

Firmware

The adapter's firmware is updated and managed through HPE Integrated Lights-Out (iLO), the server's embedded management processor. This provides a unified interface for network configuration, health monitoring, and firmware updates alongside other server components, simplifying lifecycle management. While designed for use with HPE-branded optics and cables for guaranteed support, the adapter generally follows SFP28 MSA standards. It is compatible with a wide array of SFP28 transceivers (e.g., HPE 838893-B21 25GbE SR) and DAC cables for cost-effective, short-reach connections within a rack.

Balancing Traffic and Queue Depths

When configuring the adapter for a specific workload (e.g., storage vs. VM traffic), tuning interrupt moderation, receive/transmit queue depths, and buffer sizes within the driver settings can yield significant performance improvements. Utilizing the latest HPE-provided drivers and network configuration utilities is essential.

Network Infrastructure Readiness

Deploying 25GbE adapters necessitates a compatible network fabric. This means ensuring upstream switches (ToR - Top of Rack) have corresponding 25GbE SFP28 ports and are configured to support features like Data Center Bridging (DCB) for lossless RoCE traffic and appropriate MTU sizes for large frames (often 9000+ bytes for storage and RDMA traffic).

Thermal and Power Planning

While the FlexibleLOM form factor is designed for efficient cooling, high-continuous throughput in dense server configurations requires adequate airflow. The adapter’s power draw is managed by the server, but it's prudent to account for it in overall power and cooling capacity planning for the rack. Investing in the HPE 817708-B21 is not just about solving today's bandwidth constraints; it's a strategic step toward future architectures.

Pathway to 50GbE and 100GbE

The 25GbE standard is the foundational building block for higher speeds. 50GbE is often achieved by bonding two 25GbE lanes, and 100GbE switches often use four 25GbE lanes internally. By establishing a 25GbE server edge today, organizations are building a compatible foundation that can aggregate into faster spine layers in the future, protecting their infrastructure investment.

Enabling Next-Generation Storage Protocols

The low-latency, high-throughput characteristics of this adapter, especially with RoCE, are prerequisites for the widespread adoption of NVMe-oF. This protocol is set to revolutionize networked storage by extending the ultra-low latency of local NVMe SSDs across the network. Deploying 25GbE Ro CE-capable adapters prepares the server fleet for this next wave of storage performance. the HPE 817708-B21 2 Port Eth 10/25GB 631FLR-SFP28 PCIe Adapter is a sophisticated, ecosystem-optimized component that delivers critical network performance for the most demanding modern workloads. Its combination of high-speed ports, intelligent offloads, and deep HPE integration makes it an indispensable tool for IT architects building agile, high-performance, and software-defined data centers.

Compatibility 

As a genuine HPE part, the 817708-B21 is designed for seamless integration, which is a key differentiator from generic PCIe cards. The adapter is qualified for a broad range of HPE ProLiant Gen9, Gen10, and Gen10 Plus servers, as well as HPE Synergy compute modules. It installs into the dedicated Flexible LOM slot, which is powered and configured directly by the server's integrated management. This ensures optimal thermal fit, power delivery, and firmware compatibility.