HPE 872725-B21 — InfiniBand EDR 100Gb/s 1-Port 841QSFP28 VPI Adapter (ConnectX-5)
Technical Identity
HPE 841QSFP28 single-port QSFP28 VPI adapter (HPE PN 872725-B21): InfiniBand EDR (100Gb/s) or 100GbE Ethernet, selectable via mlxconfig. Built on Mellanox ConnectX-5 silicon (Mellanox equivalent: MCX555A-ECAT). PCIe 3.0 x16 host interface. HPE ProLiant XL/DL Gen9/Gen10 validated for HPC, storage, and AI fabrics. Condition: Refurbished Grade A.
Specifications

Brand: HPE (Mellanox/NVIDIA silicon)
HPE PN: 872725-B21
HPE model: 841QSFP28 (single-port)
Mellanox equivalent: ConnectX-5 VPI MCX555A-ECAT
Ports: 1× QSFP28 (100Gb/s)
Protocol: VPI dual-protocol — InfiniBand EDR (100Gb/s) or 100GbE Ethernet
Host interface: PCIe 3.0 x16
Qualification: HPE ProLiant XL/DL Gen9/Gen10
HPC offloads: MPI tag matching, rendezvous, adaptive routing on reliable transport
Network offloads: RoCE v2, IB verbs, RDMA, NVMe-oF, SR-IOV, OS bypass
Condition: Refurbished Grade A

What This Is NOT

NOT dual-port. Single QSFP28. For dual-port 841QSFP28, see HPE 872726-B21.
NOT ConnectX-4. 841QSFP28 = ConnectX-5 silicon. The earlier 840QSFP28 (HPE 825110-B21) was ConnectX-4.
NOT HDR. EDR maximum (100Gb/s per port). For HDR 200Gb/s, see ConnectX-6 VPI (HPE P24248-001).
NOT Ethernet-only. VPI dual-protocol — IB EDR or 100GbE selectable via mlxconfig.
NOT supplied with cables or QSFP28 transceivers.

Compatibility

HPE servers: ProLiant DL/XL Gen9 and Gen10 — full iLO and SPP firmware support.
Switches: Pairs with NVIDIA/Mellanox Switch-IB 2 (SB7800/SB7890) EDR fabrics, Quantum HDR switches backward-compatible to EDR, and Spectrum / Spectrum-2 100GbE switches.
Cables & optics: Standard QSFP28 EDR / 100GbE — DAC (Mellanox MCP1600-Exxx), AOC (MFA1A00-Exxx), or 100GbE SR4 transceiver (MMA1B00-E100). Not supplied with the card.
OS: RHEL/CentOS 7+, SLES 12+, Ubuntu 18.04+, Windows Server 2016/2019, VMware ESXi 6.5+. MLNX_OFED and HPE SPP firmware supported.

Frequently Asked Questions (FAQ)
Q. What is the HPE 872725-B21?
HPE 841QSFP28 single-port: InfiniBand EDR 100Gb/s or 100GbE Ethernet via VPI. Built on Mellanox ConnectX-5. ProLiant Gen9/Gen10 qualified.
Q. Is the 872725-B21 ConnectX-4 or ConnectX-5?
ConnectX-5. The HPE 841QSFP28 designation = Mellanox ConnectX-5. The earlier 840QSFP28 (HPE 825110-B21) was ConnectX-4.
Q. Difference between 872725-B21 and 872726-B21?
872725 = single-port. 872726 = dual-port. Both are 841QSFP28 ConnectX-5 VPI EDR.
Q. Is 872725-B21 HDR capable?
No — EDR maximum (100Gb/s per port). For HDR 200Gb/s, see ConnectX-6 VPI (HPE P24248-001).
Q. Can 872725-B21 be used in non-HPE servers?
Physically yes — PCIe 3.0 x16. HPE firmware may restrict some management features in non-HPE chassis. Cross-flashing to standard Mellanox firmware is possible at user's risk.
Q. What condition does T.E.S IT-SOLUTIONS supply?
Refurbished Grade A — EEPROM-verified, link-tested at full EDR rate, cosmetically inspected, EU stock.
Why buy from T.E.S IT-SOLUTIONS
T.E.S IT-SOLUTIONS is a Europe-based data-center networking specialist. Every unit is MPN-identified, EEPROM-verified, and cosmetically inspected before leaving our EU warehouse. Multi-currency invoicing, worldwide express shipping, and free pre-sale technical consultation included.