Terminology and Definitions

• Domain ID
  A domain is a logical grouping of vEdge routers and Cisco Catalyst SD-WAN Controllers that demarcates the span of control for the Cisco Catalyst SD-WAN Controllers. Each domain is identified by a unique integer, called the domain ID. Currently, you can configure only one domain in a Cisco SD-WAN overlay network.

• OMP Routes
  On Cisco Catalyst SD-WAN Controllers and vEdge routers, OMP advertises to its peers the routes and services that it has learned from its local site, along with their corresponding transport location mappings, which are called TLOCs. These routes are called OMP routes, to distinguish them from standard IP routes. It is through OMP routes that the Cisco Catalyst SD-WAN Controllers learn the network topology and the available services.

• Site ID
  A site is a particular physical location within the Cisco SD-WAN overlay network, such as a branch office, a data center, or a campus. Each site is identified by a unique integer, called a site ID. Each Cisco vEdge device at a site is identified by the same site ID. So within a data center, all the Cisco Catalyst SD-WAN Controllers and any vEdge routers are configured with the same site ID. A branch office or local site typically has a single vEdge router, but if a second one is present for redundancy, both routers are configured with the same site ID.

• System IP Address
  Each vEdge router and Cisco Catalyst SD-WAN Controllers is assigned a system IP address, which identifies the physical system independently of any interface addresses. This address is similar to the router ID on a regular router.​ The system IP address provides permanent network overlay addresses for vEdge routers and Cisco Catalyst SD-WAN Controllers, and allows the physical interfaces to be renumbered as needed without affecting the reachability of the Cisco vEdge device. You write the system IP address as you would an IPv4 address, in decimal four-part dotted notation.

• TLOC
  A TLOC, or transport location, identifies the physical interface where a vEdge router connects to the WAN transport network or to a NAT gateway. A TLOC is identified by a number of properties, the primary of which is an IP address–color pair, which can be written as the tuple {IP-address, color}. In this tuple, IP address is the system IP address and color is a fixed text string that identifies a VPN or traffic flow within a VPN. OMP advertised TLOCs using TLOC routes.