BGP Mode

This document describes the network topology of PorterLB in BGP mode and how PorterLB functions in BGP mode.

NOTE

The BGP mode is recommended because it allows you to create a high availability system free of failover interruptions and bandwidth bottlenecks. To use the BGP mode, your router must support BGP and Equal-Cost Multi-Path (ECMP) routing. If your router does not support BGP or ECMP, you can use the Layer 2 mode to achieve similar functionality.

Network Topology

The following figure shows the topology of the network between a Kubernetes cluster where PorterLB is installed and a peer BGP router.

IP addresses and Autonomous System Numbers (ASNs) in the preceding figure are examples only. The topology is described as follows:

• A Service backed by two Pods is deployed in the Kubernetes cluster, and is assigned an IP address 172.22.0.2 for external access.
• PorterLB installed in the Kubernetes cluster establishes a BGP connection with the BGP router, and publishes routes destined for the Service to the BGP router.
• When an external client machine attempts to access the Service, the BGP router load balances the traffic among the master, worker 1, and worker 2 nodes based on the routes obtained from PorterLB. After the Service traffic reaches a node, kube-proxy can further forward the traffic to other nodes for load balancing (both Pod 1 and Pod 2 can be reached over kube-proxy).

PorterLB uses GoBGP (integrated in PorterLB) to establish a BGP connection for route publishing. Two CustomResourceDefinitions (CRDs), BgpConf and BgpPeer, are provided for users to configure the local and peer BGP properties on PorterLB. BgpConf and BgpPeer are designed according to the GoBGP API. For details about how to use BgpConf and BgpPeer to configure PorterLB in BGP mode, see Configure PorterLB in BGP Mode.

Last modified March 31, 2021: Relocated files to adapt to localization and changed links. (6b5fcb1)