Ethernet Link Negotiation on Cisco Meraki APs

This article describes how Cisco Meraki access points set their link speed and duplex settings in different networking environments.

When a Cisco Meraki access point detects an Ethernet link, it first attempts to use auto-negotiation as defined in 802.3 Ethernet standards and subsequent revisions.  This is the only way to achieve gigabit Ethernet speeds, as auto-negotiation is required as part of 1000-BASET Ethernet. 

If auto-negotiation fails, the Cisco Meraki AP will set duplex to "half." This is done because it is not possible to detect duplex settings based on link state, and if the duplex is set to "full" with a switch that is not configured for "full" duplex, all communication will fail. The access point will then determine link speed based on received bitrates, encodings, and voltages.

The following table summarizes how the AP will behave in different scenarios: