Data Center Leaf 400G / 800G Comparison: Cisco Nexus 9332D-GX2B vs HPE Aruba CX 10000-48Y6C vs Juniper QFX5220-32CD vs Arista 7060X6

No. Cisco Nexus 9332D-GX2B and Juniper QFX5220-32CD are direct 400G peers (both 32 x 400G QSFP-DD, 1RU, 12.8 Tbps). Arista 7060X6-64PE is an 800G-class platform on Broadcom Tomahawk 5 at 51.2 Tbps — one generation ahead on silicon. HPE Aruba Networking CX 10000-48Y6C is a 25G ToR with 100G uplinks whose architectural distinction is two embedded Pensando DPUs delivering 800 Gbps of stateful services. Comparing them as raw 400G peers obscures what each is actually built for.

Of this set, only the Arista 7060X6 is positioned as UEC-ready. It is part of Arista’s AI Etherlink portfolio and Arista is a founding member of the Ultra Ethernet Consortium. Cisco Cloud Scale silicon (9332D-GX2B) and Broadcom Tomahawk 3 (QFX5220-32CD) predate UEC 1.0 and do not claim the specification. HPE Aruba Networking has publicly committed to UEC on future CX DC platforms, but the CX 10000-48Y6C 25G SKU is not a UEC 1.0 member platform.

The CX 10000-48Y6C has two AMD Pensando Elba P4-programmable DPUs delivering 800 Gbps aggregate throughput for stateful services at every ToR port: distributed firewall, L4 load-balancer, NAT, DDoS mitigation, and per-session telemetry. Workloads typically steered to an external firewall or service-node tier run on the rack switch itself. Latency is under 1 µs without DPU redirect and under 5 µs when traffic transits the DPU pipeline. This is the CX 10000’s buying decision, not raw 400G port count.

Juniper QFX5220-32CD publishes 750 ns. Arista 7060X6 publishes from 700 ns with a typical ~650 ns under RFC 2544 methodology. HPE Aruba CX 10000-48Y6C is under 1 µs without DPU redirect and under 5 µs with DPU redirect. Cisco Nexus 9332D-GX2B does not publish a port-to-port latency figure on the 9332D-GX2B datasheet reviewed. Federal and financial-trading buyers who require a published latency number in procurement should note the gap.

Cisco Nexus 9332D-GX2B supports MACsec and CloudSec at wire rate on the last 8 of its 32 x 400G ports — not all 32. A MACsec-everywhere requirement should drive a platform reselection within the Cisco Nexus family. MACsec is not listed on the Juniper QFX5220-32CD spec sheet or the Arista 7060X6 datasheet reviewed. MACsec scope on the HPE Aruba CX 10000-48Y6C requires AOS-CX release-note verification per SKU. Buyers with a MACsec-everywhere requirement should confirm per-port scope with each vendor before downselecting.

Cisco Nexus 9332D-GX2B requires NX-OS 10.2(3)F or later. HPE Aruba CX 10000-48Y6C runs on the AOS-CX 10.13 / 10.14 train. Juniper QFX5220-32CD requires Junos EVO 19.3R1 or later (JTI gRPC / gNMI and OpenConfig land from that release). Arista 7060X6 requires EOS 4.32.2 on the 64PE and EOS 4.34.2 on the 32PE. All four should be paired with current operational tooling (Nexus Dashboard, Aruba Central or Fabric Composer, Apstra, CloudVision) rather than legacy CLI-only workflows.

HPE Aruba Networking publishes the clearest documentation in this set: AOS-CX Crypto Module FIPS 140-2 validated (NIST CMVP #3958); 140-3 cert #4876 listed by HPE; JITC tactical interop dated 2024-09-06. A CX 10000-specific 140-3 listing was not confirmed on the NIST CMVP site in sources reviewed. Cisco Nexus 9332D-GX2B, Juniper QFX5220-32CD, and Arista 7060X6 SKU-specific FIPS 140-3 and Common Criteria listings were not publicly documented in the primary sources reviewed — verify through Cisco Trust Portal, Juniper Pathfinder Compliance Advisor, and Arista product certifications indexes respectively before a federal scope.

The Arista 7060X6 datasheet lists UL 62368-1 and IEC 62368-1.

Yes, per standards, but the operational cost is non-trivial. EVPN (RFC 7432) and VXLAN (RFC 7348) are standards; Type 2 and Type 5 EVPN route exchange between Cisco NX-OS, AOS-CX, Junos EVO, and Arista EOS is tested in lab scenarios and deployed in some multi-vendor brownfields. In production, the trade-off is operational: Apstra, Nexus Dashboard Fabric Controller, Fabric Composer, and CloudVision are single-vendor intent engines — mixing vendors forces CLI or OpenConfig operations, and feature parity (EVPN multi-homing ESI behavior, anycast-gateway scale, VXLAN Routing support) diverges across platforms.

Most Fortune 500 deployments standardize one vendor per fabric and bridge fabrics at the DCI layer.

For a greenfield AI or GPU training fabric with 800G uplinks, RoCEv2 at scale, and UEC-forward posture, the Arista 7060X6 is the documented-strongest platform in this set: Tomahawk 5 at 51.2 Tbps, 165 MB shared buffer, Cluster Load Balancing (RDMA-aware), Packet Spraying, Fast Link Failover under 500 ns, 128-way ECMP, and UEC founding-member status. For a 400G east-west leaf in a non-AI estate, the Cisco Nexus 9332D-GX2B or Juniper QFX5220-32CD are the direct peers.

For east-west stateful services at every rack, the HPE Aruba CX 10000-48Y6C with Pensando DPUs is the differentiated choice.

Send the GPU cluster size, collective-communication profile, and uplink plan to produce a written fabric scope.

Data center fabric design, EVPN-VXLAN build-outs, and AI / GPU network scoping fall under data center network services and AI-ready infrastructure engineering. Adjacent comparisons in the vendor comparison library cover the access-layer generations (Wi-Fi 6E and Wi-Fi 7 flagship APs) and campus infrastructure. Campus and branch scoping, structured cabling, SD-WAN, and wireless site survey engagements are in the broader services catalog.

QSFP-DD is backwards-compatible with QSFP28 cages — a QSFP-DD port accepts a QSFP28 100G module (downshift to 100G) in addition to 400G QSFP-DD modules. OSFP is not backwards-compatible with QSFP28 and has a slightly larger envelope with integrated heat-sink, designed for higher-power optics (typical 15W vs QSFP-DD 12-14W).

Cisco Nexus 9332D-GX2B uses QSFP-DD. Arista 7060X6-64PE uses OSFP or QSFP-DD variants (check the -PE vs -DE SKU suffix). Juniper QFX5220-32CD uses QSFP-DD. OSFP is more common in AI training spine roles where 800G and 1.6T modules require the larger heat-dissipation envelope; QSFP-DD is more common in enterprise DC leaf.

400G-FR4 reaches 2 km on duplex singlemode (IEEE 802.3cu) — the common campus-to-DC or DC-to-DC interconnect at 2 km. 400G-DR4 reaches 500 m on 4-pair singlemode with 4x 100G-PAM4 per fiber pair (IEEE 802.3bs) — the default intra-rack or row-to-row DC optic. 400G-LR4 reaches 10 km on duplex singlemode (IEEE 802.3cu).

400G-SR8 and 400G-SR4.2 are the multi-mode short-reach variants (100m on OM4 or OM5). Optic choice drives fiber-plant cost and power: DR4 needs a 4-fiber MPO (MPO-12 with 4 active pairs) which cabling teams often prefer for AI-cluster density, while FR4 / LR4 use standard duplex LC.

NRZ (Non-Return-to-Zero) encodes 1 bit per symbol; PAM4 (Pulse Amplitude Modulation 4-level) encodes 2 bits per symbol. 400G Ethernet is PAM4 at 50 Gbaud or 26.5 Gbaud-per-lane depending on the modulation scheme (8x 50G PAM4 or 4x 100G PAM4). 100G NRZ was the prior generation (4x 25G NRZ for 100G).

PAM4 gets higher throughput per fiber but has lower SNR margin than NRZ — it requires stronger FEC (RS FEC per IEEE 802.3cd / 802.3bs) which adds ~100 ns to the end-to-end latency budget. For ultra-low-latency trading fabrics, NRZ-based 100G is still preferred over PAM4 400G; for AI back-end and mainstream DC, PAM4 400G is the default.

Cisco Nexus 9332D-GX2B: 400G QSFP-DD ports break out into 4x 100G (QSFP-DD-to-4x-QSFP28 breakout) per NX-OS 10.2+ config. Arista 7060X6-64PE: 800G ports break out into 2x 400G or 4x 200G; 400G ports break out into 4x 100G or 2x 200G per Arista 7060X6 data sheet. Juniper QFX5220-32CD: 400G breaks out into 4x 100G per Junos EVO documentation.

HPE Aruba CX 10000-48Y6C carries 6 x 100G QSFP28 uplinks plus 48 x 25G SFP28 downlinks — no 400G breakout on the 48Y6C SKU. Breakout flexibility matters at the leaf when mixed 100G / 400G clients attach to the same switch.

DCQCN (Data Center Quantized Congestion Notification) is the reference congestion-control algorithm for RoCEv2 — ECN marking (RFC 3168) combined with a rate-adjustment loop. Cisco Nexus 9332D-GX2B supports DCQCN via NX-OS PFC / ECN configuration with recommended thresholds from the Cisco RoCE Deployment Guide.

Arista 7060X6 supports DCQCN plus adaptive-routing extensions per the Arista AI Networking reference design. Juniper QFX5220-32CD supports DCQCN via Junos EVO QoS configuration. NVIDIA SN5600 Spectrum-X adds switch-level telemetry + SuperNIC DDP on top of DCQCN to reach ~95 percent effective bandwidth per NVIDIA whitepapers.

AI back-end fabrics push incast bursts during AllReduce — multiple GPUs simultaneously send to the same destination, filling leaf egress buffers. AI-optimized buffer tuning dedicates more buffer to priority queues carrying RoCEv2 traffic (typically PFC class 3) and enables adaptive routing to spread congestion across spine paths.

Cisco Nexus 9332D-GX2B on Cloud Scale ASIC has 40 MB shared buffer. Arista 7060X6-64PE on Tomahawk 5 has 165 MB shared buffer per Arista 7060X6 data sheet. Juniper QFX5220-32CD on Tomahawk 3 has ~64 MB. HPE Aruba CX 10000-48Y6C buffer specs reviewed in primary sources for the 48Y6C SKU should be verified at procurement.

Type 2 (MAC/IP Advertisement per RFC 7432): all four platforms generate Type 2 on every learned host MAC + ARP. Type 3 (Inclusive Multicast Ethernet Tag): all four generate Type 3 for each VNI for BUM (broadcast / unknown-unicast / multicast) handling. Type 5 (IP Prefix route per RFC 9136): all four support Type 5 for prefix-based routing across EVPN fabrics.

Cisco Nexus 9332D-GX2B on NX-OS 10.x: full Type 1-5 support. Arista 7060X6: full Type 1-5 on EOS 4.28+. Juniper QFX5220-32CD: full Type 1-5 on Junos EVO 19.3+. HPE Aruba CX 10000: full Type 2/3/5 on AOS-CX 10.13+. Type 5 is the most common route type for Layer 3 prefix advertisement in modern fabrics.

NVIDIA BlueField-3 is a PCIe SmartNIC (not integrated in the switch) that offloads services on the server side. Arista 7060X6 and Cisco Nexus 9332D-GX2B both work with BlueField-3 via standard RoCEv2 uplinks but do not integrate DPU silicon in the switch ASIC.

HPE Aruba CX 10000-48Y6C is the architectural outlier — two AMD Pensando Elba DPUs are embedded in the switch ASIC path, delivering 800 Gbps of P4-programmable stateful services (firewall, NAT, LB) at every ToR port. That is why the CX 10000 is not a drop-in 400G peer for Nexus / Arista / QFX — it is a different architectural category focused on east-west stateful services, not raw 400G port density.

Yes, but PFC class separation is required. RoCEv2 AI traffic typically runs on PFC priority 3 (lossless, ECN-enabled); NVMe-oF over TCP runs on a best-effort class (standard TCP congestion control). Mixing the two on the same leaf works when PFC is correctly segmented by queue.

Cisco Nexus 9332D-GX2B, Arista 7060X6, and Juniper QFX5220-32CD all support multi-class PFC / ETS per IEEE 802.1Qaz. HPE Aruba CX 10000-48Y6C is commonly paired with distributed storage tiers where Pensando DPU-based storage offload (NVMe-oF / iSCSI) runs at the ToR itself rather than offloading to external storage arrays.

Standard PFC tuning per Mellanox / NVIDIA RoCE tuning guides recommends high-watermark at approximately 80 percent of egress buffer and low-watermark (XON threshold) at approximately 50 percent. Headroom is sized to accommodate in-flight bytes during PFC pause assertion — typically 2x the cable-delay-bandwidth product per priority queue.

Under-tuned PFC causes pause storms (PFC signal propagating upstream and inducing head-of-line blocking); over-tuned PFC (too-low thresholds) causes packet drops before PFC triggers. Each vendor publishes a recommended template; NVIDIA SN5600 ships with auto-tuning, while Cisco / Arista / Juniper require explicit operator config validated against the specific ASIC buffer size.

Arista 7060X6-64PE: ~650 ns typical under RFC 2544 methodology per Arista data sheet. Juniper QFX5220-32CD: 750 ns published per the Juniper data sheet. Cisco Nexus 9332D-GX2B: specific port-to-port latency not published in the primary sources reviewed. HPE Aruba CX 10000-48Y6C: under 1 microsecond without DPU redirect, under 5 microseconds when traffic transits the DPU pipeline.

For AI training, sub-microsecond port-to-port latency is standard across Tomahawk 4 / 5 class silicon; the gap matters at trading-floor tick-to-trade time scales but is noise at AI training AllReduce scale.

Yes. 400G RS-FEC per IEEE 802.3bs is the default for PAM4 optics (100G-DR, 400G-DR4, 400G-FR4, 400G-LR4). Low-latency FEC options are specific to DAC / AOC links within a rack and do not change the standards-mandated RS-FEC on single-mode optics.

Cisco Nexus 9332D-GX2B, Arista 7060X6, and Juniper QFX5220-32CD all support FEC profile selection per port. In an AI fabric, matching FEC profile between both sides of the link is required — mismatched FEC triggers link-down or silent drops depending on the platform.

Arista 7060X6-64PE is already 800G-capable (51.2 Tbps on Tomahawk 5) — the 64x 800G spec is the current shipping ceiling per the 7060X6 data sheet. Cisco Nexus 9000 series has the 9364D-GX2A and upcoming 800G SKUs on Silicon One and follow-on Cloud Scale silicon per Cisco roadmap announcements.

Juniper QFX5240 (successor to QFX5220) is positioned at 800G per Juniper AI cluster announcements (2024+). Follow-on HPE Aruba CX data-center platforms will carry 800G per HPE public roadmap. For greenfield AI leaf builds in 2026, 800G-capable leaf is the forward-looking purchase; 400G is the current cost-optimized floor.

HBM (High-Bandwidth Memory) is typically reserved for spine / deep-buffer router platforms (Arista 7800R3/R4, Cisco 8000-series) not leaf. At the 1RU leaf tier, buffer is SRAM shared across ports. Arista 7060X6-64PE: 165 MB shared SRAM buffer. Cisco Nexus 9332D-GX2B Cloud Scale: 40 MB shared buffer.

Juniper QFX5220-32CD Tomahawk 3: ~64 MB. HPE Aruba CX 10000-48Y6C: buffer specs reviewed at procurement. Deep-buffer (GB-scale HBM-backed) leaf is not the typical 400G leaf pattern — the Arista 7280R4K and Arista 7800R4 are the deep-buffer family at the DC tier for storage / incast-sensitive traffic.

UEC 1.0 was released June 11, 2025. Arista 7060X6 is positioned as UEC-ready and forwards-compatible with UET (Ultra Ethernet Transport) per Arista Etherlink positioning. Cisco is a UEC steering member; upcoming Cisco Nexus platforms on G200 silicon are positioned as UEC-compliant, but the 9332D-GX2B (existing Cloud Scale) is not.

Juniper is a UEC member; the QFX5220 predates UEC 1.0 and is not positioned as a UEC platform — the follow-on QFX on Broadcom Tomahawk 5 / NVIDIA silicon will carry UEC compliance. HPE Aruba has publicly committed to UEC on future CX DC platforms. NVIDIA Spectrum-X is the proprietary alternative to UEC; InfiniBand is outside UEC scope (IBTA-governed).

All four support PTP per IEEE 1588-2019. Cisco Nexus 9332D-GX2B supports PTP with hardware timestamping per NX-OS 10.x. Arista 7060X6 supports PTP with hardware timestamping per EOS 4.28+. Juniper QFX5220-32CD supports PTP per Junos EVO 19.3+.

HPE Aruba CX 10000-48Y6C supports PTP per AOS-CX 10.13+. For trading floors or time-sensitive networking (TSN) workloads, PTP Grandmaster clock selection and BMCA (Best Master Clock Algorithm) tuning matters more than raw platform support.