What is the difference between Azure Application Gateway and Load Balancer?

Azure Application Gateway has the following capabilities:

• URL path-based routing.
  
• Host header support.
  
• Session cookie affinity.
  
• SSL/TLS termination.
  
• End-to-end SSL encryption.
  
• Web application firewall.
  
• Cross-region load balancing.
  
• Visual end-to-end diagnostics.
  

 

 

Whereas Load balancer has only capability to do the load balancing on the basis of IP Address and Port. 

There is this concept of HA ports in LB, which allows to forward all ports to a set of back-ends, rather placing individual rules for each port.