Summarized on September 30, 2026
OMP (Overlay Management Protocol) establishes reachability across the SD-WAN overlay by advertising two types of routes to the SD-WAN Controller: OMP routes (vRoutes) and TLOC routes [1]. OMP routes are prefixes representing services at data centers, branch offices, or other endpoints, while TLOC routes identify the physical transport locations where WAN interfaces connect to carriers. Each edge device advertises its routes exclusively to the SD-WAN Controller, which then distributes overlay routing information to other edge devices based on policy — edge devices do not exchange OMP routing information directly with each other.
When verifying unicast overlay routing, it is important to confirm that each device is correctly advertising its site-local routes to the SD-WAN Controller. A Cisco IOS XE Catalyst SD-WAN device can advertise the following types of routes into OMP [1]:
- Connected (direct)
- Static
- BGP
- EIGRP
- LISP
- OSPF (inter-area, intra-area, and external)
- OSPFv3 (inter-area, intra-area, and external)
- IS-IS
Each OMP route carries key attributes including the TLOC (system IP, color, and encapsulation type), origin, originator, preference, site ID, tag, and VRF, all of which can be inspected to confirm correct route exchange.
TLOC verification is equally critical, as TLOCs are the only OMP entities visible to the underlying transport network and serve as the next hop for OMP routes. Each TLOC is a 3-tuple of the device's system IP address, a link color (such as mpls, biz-internet, or metro-ethernet), and an encapsulation type (IPsec or GRE) [1]. Confirming that all data center and branch TLOCs are properly distributed by the SD-WAN Controller ensures that Service VPN prefixes resolve correctly and that end-to-end forwarding across the overlay is functional.