Part 1: Quick notes on Cisco SDWAN

Part 1: Quick notes on Cisco SDWAN

Quick notes allows you to understand the basics and functionality in the Cisco SDWAN solution. What will be taken care in Cisco SDWAN solution like Centralized Policy, DIA policies, OMP Graceful Restart and OMP best Path selection criteria.

We will take localized policies and other things in our second and third part after this.

Fig 1.1- Centralized Policies

Centralized Policy

  • List ( Prefixes, Application/Custom List, TLOC, VPN Info, Site ids, SLA Class, Color, QOS info)
  • Traffic Policy ( APP aware routing, Traffic Data, Cflowd Collector

How to create the Centralized policy

  • Add Policy- create group of Interest ( Application list)
  • Topology ( Hub/Spoke, Mesh & Custom) and VPN Membership info
  • Traffic rules ( app aware routing, traffic Data & CFLOWD)
  • Add Policies to sites and VPN

DIA Policies

  • Application & Policies ( Define Apps- AWS, Concur, drobox with VPNs and SLA)
  • Client Sites
  • Gateways
  • DIA Sites- Site Ids for DIA sites.

OMP Graceful Restart

vEdge is down and its peer vSmart takes the last good configuration of that vEdge and continue sending the L3 routes to the other vEdges which are peer to the vSmart.

Graceful restart for OMP protocol is enabled by default between the peers vSmart and vEdge and the restart time is 12 hours but can be increased up to 7 days.

OMP best Path selection criteria 

  • Next hop TLOC is reachable
  • Prefer Edge-sourced route over vSmart-sourced route
  • Prefer OMP route with lower admin distance
  • Prefer OMP route with higher route preference
  • Prefer OMP route with higher TLOC preference
  • Prefer highest origin (Connected, Static, OSPF Intra, OSPF Inter, OSPF External. iBGP, Unknown/Unset)
  • Prefer route from higher Router-ID (System-IP)
  • Prefer highest TLOC private IP address