Border Gateway Protocol (BGP) makes core routing decisions. It includes a table of IP networks or prefixes which designate network reachability among autonomous systems.
An underlying connection between two BGP speakers is established before any routing information is exchanged. Keep alive messages are sent out by the BGP speakers in order to keep this relationship alive. Once the connection is established, the BGP speakers exchange routes and synchronize their tables.
To setup BGP the process is (nearly) identical on both ESGs and DLRs (there is an assumption here that the ESG and DLR is configured with IPs and subnets and interfaces and the global routing configuration is in place etc. etc.):
1. Log in to the vSphere Web Client.
2. Click Networking & Security and then click NSX Edges.
3. Double-click an NSX Edge.
4. Click Manage then Routing and then click BGP.
5. Click Edit.
6. In the Edit BGP Configuration dialog box, click Enable BGP.
7. Check the “Enable BGP” and type the Local AS. This is advertised when BGP peers with routers in other autonomous systems (AS). The path of ASs that a route traverses is used as one metric when selecting the best path to a destination.
8. Click Save.
9. In Neighbours, click the Add icon.
10. Type the IP address of the neighbour.
11. Type the remote AS.
12. Edit the default weight for the neighbour connection if required.
13. Hold Down Timer displays interval (180 seconds) after not receiving a keep alive message that the software declares a peer dead. Edit if required.
14. Keep Alive Timer displays the default frequency (60 seconds) with which the software sends keep alive messages to its peer. Edit if required.
15. If authentication is required, type the authentication password. Each segment sent on the connection between the neighbours is verified. MD5 authentication must be configured with the same password on both BGP neighbours, otherwise, the connection between them will not be made.
16. To specify route filtering from a neighbour, click the Add icon in the BGP Filters area.
17. Select the direction to indicate whether you are filtering traffic to or from the neighbour.
18. Select the action to indicate whether you are allowing or denying traffic.
19. Type the network in CIDR format that you want to filter to/from the neighbour.
20. Type the IP prefixes that are to be filtered and click OK.
21. Click Publish Changes.