652500-B21 HPE 1GB 2-Port 361FLB Ethernet Adapter

Details of HPE 652500-B21 1GB 2-Port PCIE 2.1 Adapter 

The HPE Ethernet 1Gb 2-Port 361FLB Adapter (652500-B21) is a high-performance dual-port network interface solution designed to deliver stable, efficient, and scalable wired connectivity for enterprise environments. Built for modern server infrastructures, this adapter ensures smooth Gigabit Ethernet communication with optimized throughput and advanced networking capabilities.

General Information

• Manufacturer: HPE
• Part Number: 652500-B21
• Product Type: Network Adapter

Technical Specifications

• Bus Interface: PCI Express 2.1 x4
• Connectivity Technology: Wired Ethernet
• Data Link Protocol: Gigabit LAN
• Data Transfer Rate : 1 Gbps
• Compatible Slot Type: FlexibleLOM

Supported Advanced Functions

• Wake on LAN (WoL) support
• Jumbo Frames compatibility for large data packets
• PXE boot support for remote operating system deployment
• Large Send Offload (LSO) for optimized data processing

Supported IEEE Standards

• IEEE 802.3 – Ethernet standard compliance
• IEEE 802.1Q – VLAN tagging support
• IEEE 802.1P – Traffic prioritization
• IEEE 802.3x – Flow control mechanisms
• IEEE 802.3ad – Link aggregation (LACP)
• IEEE 802.1AS – Time synchronization protocol

The HPE 652500-B21 Ethernet 1GB 2-Port Adapter Card

The HPE 652500-B21 Ethernet 1Gb 2-Port PCI Express 2.1 x4 network adapter belongs to a specialized class of enterprise-grade server networking components designed to deliver stable, high-reliability connectivity in modern data center environments. Developed within the ecosystem of this adapter is engineered to support mission-critical workloads where predictable network performance, low latency communication, and hardware-level optimization are essential. The adapter’s architecture is based on the PCI Express 2.1 x4 interface and integrates seamlessly into HPE ProLiant servers featuring FlexibleLOM slots, particularly the 361FLB-compatible configurations that enable modular networking expansion without occupying traditional PCIe slots.

PCIE 2.1 x4 Interface

The PCI Express 2.1 x4 interface used in the HPE 652500-B21 adapter provides a balanced data pathway between the server motherboard and network controller. With four lanes dedicated to simultaneous transmission and reception, the architecture ensures that each Gigabit Ethernet port receives sufficient bandwidth headroom to maintain consistent 1Gbps throughput without congestion at the bus level. Even in scenarios involving heavy virtualization workloads or simultaneous multi-stream traffic, the PCIe 2.1 standard ensures that latency remains predictable and packet delivery is stable. Unlike lower-lane configurations that may introduce bottlenecks during peak traffic, the x4 architecture supports parallel data movement, enabling efficient handling of packet queues, interrupt moderation, and DMA operations. This is particularly important in enterprise environments where deterministic network behavior is preferred over burst-based performance fluctuations.

Packet Processing Optimization

The adapter incorporates hardware acceleration techniques that reduce CPU overhead by offloading key networking tasks such as checksum computation, segmentation, and interrupt handling. These offloads allow server processors to dedicate more cycles to application workloads rather than network stack processing. In virtualization-heavy deployments, this results in improved VM density and better resource allocation efficiency across compute nodes.

Flexiblelom Slot Architecture

The HPE 652500-B21 adapter is designed specifically for FlexibleLOM (Flexible LAN-on-Motherboard) slots, particularly the 361FLB interface used in select HPE ProLiant servers. FlexibleLOM is a modular networking design that allows organizations to customize server connectivity without occupying standard PCIe expansion slots. This design is particularly advantageous in dense server configurations where expansion space is limited and efficient hardware utilization is critical. By leveraging FlexibleLOM architecture, IT administrators can upgrade or replace network adapters without full system downtime or major hardware reconfiguration. This modularity supports long-term infrastructure evolution strategies where networking requirements may change over time without requiring full server replacement.

Hot-Plug Flexibility

In supported environments, FlexibleLOM-based adapters can be replaced or upgraded as part of planned maintenance cycles. This flexibility reduces operational disruption and enhances lifecycle management efficiency. The ability to adapt networking capabilities without invasive hardware changes contributes significantly to reduced total cost of ownership in enterprise data centers.

Dual-Port 1GbE Connectivity

The dual-port configuration of the HPE 652500-B21 enables network redundancy and load balancing across two independent Gigabit Ethernet channels. This architecture ensures continuous network availability even if one port or connected switch path experiences failure. In mission-critical environments, such redundancy is essential to maintaining uptime guarantees and service continuity. Load balancing across both ports allows traffic distribution based on configured bonding or teaming modes at the operating system or hypervisor level. This enhances throughput efficiency for applications that can parallelize network traffic, such as distributed storage systems, backup operations, and clustered application services.

1Gbps Data Transfer Rate Performance

While theoretical maximum bandwidth is 1Gbps per port, real-world performance is influenced by packet size, protocol overhead, and network configuration. The HPE 652500-B21 adapter is optimized to sustain near-line-rate throughput under typical enterprise workloads, including file serving, directory services, and application hosting. Its controller architecture minimizes jitter and ensures consistent packet delivery even under mixed traffic conditions.

Server Compatibility

Designed within the broader ecosystem of ProLiant servers, the 652500-B21 adapter is validated for compatibility with multiple generations of rack-mounted and tower server platforms. This ensures predictable behavior across firmware versions and system BIOS configurations, reducing deployment complexity for IT administrators managing large-scale infrastructures. The adapter is often deployed in environments where standardized hardware configurations are required across multiple server nodes. This consistency simplifies network policy enforcement, driver management, and troubleshooting procedures.

RJ-45 Ethernet Support

The HPE 652500-B21 adapter typically supports RJ-45 copper Ethernet connections, making it compatible with widely deployed Category 5e, Category 6, and Category 6a cabling infrastructures. This ensures easy integration into existing enterprise networks without requiring fiber optic upgrades. Copper-based connectivity is particularly beneficial in office environments, edge data centers, and departmental server rooms where cost efficiency and simplicity are prioritized over long-distance transmission capabilities.

Hardware-Assisted Security Processing

Network security is enhanced through hardware-assisted processing that supports secure packet handling and reduces exposure to CPU-level vulnerabilities. By isolating network processing within dedicated hardware components, the adapter contributes to a more secure server architecture.

Multi-Platform Driver Compatibility

The HPE 652500-B21 adapter supports a range of enterprise operating systems including major Linux distributions, Windows Server environments, and virtualization hypervisors. This broad compatibility ensures flexibility in heterogeneous data center environments where multiple platforms coexist.

Backup and Storage Network Optimization

The adapter is frequently used in backup networks where consistent throughput is required for large data transfers. Dual-port redundancy ensures that backup operations continue uninterrupted even in the event of network path failures.