[SDWAN] Overlay Management Protocol (OMP) - Part 1 (English)

In the previous article, I introduced the operation of the components in SDWAN Controller, in this article, I will introduce the important protocol in Cisco SDWAN, which is OMP (Overlay Management Protocol).

1. What is OMP?

• OMP is a protocol that works over TCP (same as BGP), which was established to maintain a "control-plane" in SDWAN networks.
• OMP is established between Edge Routers and vSmart controllers, and between vSmart controllers.
• OMP undertakes the following main tasks:

- Distribution Transport Locators (TLOCs) between sites in the SDWAN domain.

- Allocating service-side connection information (LAN side).

- Allocate data-plan security parameters, VPN labels, and crypto keys (used to establish tunnels between Edges.

- In addition, there are other items that will be detailed in the next articles.

• When first joining the SDWAN network, cEdges will automatically establish an OMP connection with vSmart controllers. The important point is that establishing this connection uses System-IP, just like peering in BGP between two neighbors using the Loopback Interface. It helps vEdges automatically establish an OMP connection to vSmarts using all existing physical connections (WAN links) by using System-IP as the connection address.

OMP solves the scaling problem in IGP by establish only cEdges control-plane connections with vSmarts and no need to form the connections with other cEdges like IGP (example BGP peering neighbors).

This helps SDWAN to expand the connection scheme easily,
it's convenient for control plan management through vSmart
and minimize routing calculations (in control-plan)
for cEdge routers in the network. (vSmart will take care of this).        

See you in the next parts.