HAProxy

• web interface
• http/tcp

LVS

• high performance (kernel function)
• can synchronize connections between instances in the cluster (if one balancer will go down, another balancer will redirect user to the same backend, but with tcp session recreation)

Nginx

• convenient
• http/tcp

DNS round robin

• no health check
• no geo location

gDNSd

• geo location based
• status check

Elastic Load Balancer Amazon

OpenSIPs

Kamailio