Wi-Fi 7 (802.11be) MLO and the Wired Network Impact

Wi-Fi 7 is usually described in radio terms - 320 MHz channels, 4096-QAM, multi-link operation. But most of the failures after a Wi-Fi 7 rollout happen on the wire: an AP with a 2.5G uplink that cannot carry the airtime, a PoE budget that was sized for Wi-Fi 5, or an access switch that was never designed for the burst profile. This is the wired-side checklist.

Multi-Link Operation Changes Traffic Shape

MLO lets a client use two or three radios (2.4, 5 and 6 GHz) simultaneously, either for aggregated throughput or for latency/robustness. From the switch's point of view that means:

• Higher, burstier peak throughput per AP: three links converging on one uplink.
• Latency-sensitive steering between links, which can reorder or duplicate frames - there is no relevance at the switch, but it does mean per-AP throughput is less predictable than before.
• More aggressive airtime use, so a saturated AP now saturates its uplink rather than its channel.

Uplink Sizing: Do the Arithmetic

Worst-case per-AP airtime is a poor guide; use the realistic concurrency model:
  6 GHz radio    : 2x2 @ 320 MHz, ~2.4 Gbps PHY -> ~1.4 Gbps TCP
  5 GHz radio    : 2x2 @ 160 MHz, ~1.2 Gbps PHY -> ~0.7 Gbps TCP
  2.4 GHz radio  : 2x2 @  40 MHz, ~0.29 Gbps PHY

  Downstream peak (all radios at once) ~2.2 Gbps TCP
  Uplink traffic is typically 30-40% of this in office, ~10% in warehouse

Conclusion: 2.5G is workable for a standard office AP on a mixed
endpoint fleet; 5G/10G is where 6 GHz + MLO becomes the norm.

Practical rule: 2.5G is the floor for a Wi-Fi 7 AP, 5G is the realistic target for high-density 6 GHz deployments, and the uplink should never be the first thing that saturates. If your access switch is 1G downlink/uplink only, it is a ceiling on the whole deployment.

Cabling: This Is Where Budgets Break

Multigigabit rates (2.5G/5G/10G) over UTP require Cat 6/6A in good condition. Older Cat 5e runs that have negotiated 1G for a decade often negotiate 2.5G and then throw CRC errors, or negotiate only 1G and quietly cap the AP. Before deployment:

• Test existing runs with a qualified tester, not with a link-up event - the interesting metric is insertion loss and return loss at 100 MHz and above.
• Limit run length and bundle sizes where possible; alien crosstalk is the usual culprit in dense trays.
• Consider fiber-to-the-AP or DAC where the run is longer than 60-90 m or in electrified/industrial environments.

PoE: Still the Hidden Constraint

Wi-Fi 7 APs are typically 802.3bt Type 3 (up to 60 W per port) or even Type 4 (90 W). That changes the maths for the whole switch:

48-port access switch with 40 APs at 45 W average  = 1800 W of PD load
Two 1100 W PSUs in N+1                               = 1100 W usable for PoE
Result: power budget exceeded long before ports are exhausted.

Check three numbers in the datasheet before ordering: total PoE budget per switch, budget with one PSU failed (N+1), and the per-port maximum in your model's class. Then plan per-AP consumption from the actual AP model and antenna configuration, not from the standard.

QoS, VLANs and Roaming

MLO makes 802.11r/OKC fast roaming less critical for some clients but not for others; keep the roaming design in place. On the wired side, the essentials are unchanged and worth re-verifying at Wi-Fi 7 rates:

• AP management VLAN untagged or tagged consistently with a voice/data VLAN plan you can explain.
• DSCP trust on the AP uplink, or the AP's marking is discarded at the first hop.
• IGMP snooping and multicast optimisation - video and mDNS are the top causes of mysterious Wi-Fi congestion.
• Uplink QoS: if the AP is capped by the uplink, shaping at the upstream router is often more effective than policing at the port.

Related reading: multigigabit cabling and deployment for the physical details, 802.11r/OKC fast roaming for the roaming side, and mDNS gateway configuration for the service-discovery problem that follows every VLAN-segmented wireless design.

原文链接：https://www.wi-fi.org/discover-wi-fi/wi-fi-certified-7