Abstract
Learning for SD-WAN, complementary to my current CCIE “Closing the gaps to the Lab” study I try to force myself to lookup every protocol or application that is part of the SD-WAN solution. This way I can get as much as information possible from various resources to master my SD-WAN skills. Make sure you check “Belt of Heroes” for these resources.
SD-WAN OMP
What’s OMP? What does it stand for? What does it do?
OMP stands for Overlay Management Protocol. It’s a Cisco proprietary protocol that established and maintain the SD-WAN control plane. It runs inside the TLS/DTLS tunnels between vEDGES and vSMARTs and forms the Overlay Network.
It’s enabled by default on all vEDGE routers so you don’t have to explicitly enable it. Without OMP no SD-WAN overlay, no brains in SD-WAN. OMP is comparable with BGP, but still different.
OMP’s main function is to advertise and route IP subnets and TLOC’s to form the Overlay Network and make sure vEDGES are reachable. vEDGES can also be seen as the service side of SD-WAN. The service side advertises routes into OMP towards the vSmarts.
OMP protocol regularly provides updates towards the vSmarts. These updates contain the following:
- Reachability info: IP subnets, TLOC
- Security: Encryption keys
- Policy: Data/App-route policies
OMP never peers with vEDGES directly. Only with vSmart controllers.
Attributes
The most prominent attributes uses:
- TLOC
- Site-ID
- Label
- VPN-ID
- Tag
- Preference
- Orginator System IP
- Origin Protocol
- Origin Metric
OMP uses VPN-id 0 for data plane communications, also known as Transport VPN in some documentations.