ECMP Load Balancing in the Service Chain
Traffic flowing through a service chain can be load-balanced by distributing traffic streams to multiple service virtual machines (VMs) that are running identical applications. This is illustrated in Figure 1, where the traffic streams between VM-A and VM-B are distributed between Service VM-1 and Service VM-2. If Service VM-1 goes down, then all streams that are dependent on Service VM-1 will be moved to Service VM-2.
The following are the major features of load balancing in the service chain:
Load balancing can be configured at every level of the service chain.
Load balancing is supported in routed and bridged service chain modes.
Load balancing can be used to achieve high availability—if a service VM goes down, the traffic passing through that service VM can be distributed through another service VM.
A load balanced traffic stream always follows the same path through the chain of service VM.