The Hybrid Wireless Mesh Protocol (HWMP), part of IEEE 802.11s, is a basic routing protocol for a wireless mesh network.
[1] It relies on a Peer Link Management protocol by which each Mesh Point discovers and tracks neighboring nodes.
If any of these are connected to a wired backhaul, there is no need for HWMP, which selects paths from those assembled by compiling all mesh point peers into one composite map.
[2] In contradiction with classic IP based (OSI layer 3, network) routing, the HWMP protocol is based on MAC addresses (layer 2, data link).
HWMP is intended to displace proprietary protocols used by vendors like Meraki for the same purpose, permitting peer participation by open source router firmware.