| title | datePublished | cuid | slug | cover | tags |
|---|---|---|---|---|---|
How IP Addresses are Assigned in Load Balancing |
Thu Aug 17 2023 09:32:03 GMT+0000 (Coordinated Universal Time) |
clleyq16g000309mqclanf6mo |
how-ip-addresses-are-assigned-in-load-balancing |
security, devops, networking, load-balancing, ip-address |
In load balancing, IP addresses are assigned to a group of servers or instances to distribute the workload across them. There are different methods for assigning IP addresses to servers in load balancing, depending on the type of load balancing used.
Round-robin DNS: This method uses a Domain Name System (DNS) server to distribute incoming requests to a pool of servers in a round-robin fashion. When a client makes a request to a domain, the DNS server returns the IP address of one of the servers in the pool. The next request will be directed to a different server in the pool, and so on. See fig1.1
![DNS Round Robin](https://www.askapache.com/s/u.askapache.com/2009/04/round-robin-dns.png align="center")
Fig 1.1
IP hashing: In this method, the IP address of the client making the request is hashed to generate a unique identifier. This identifier is then used to determine which server in the pool should handle the request. This ensures that all requests from a particular client are always directed to the same server. See fig1.2
![What is Load Balancing? How does it work?](https://afteracademy.com/images/what-is-load-balancing-hashing-example-f4db92bfeed1747a.png align="center")
Fig 1.2
Virtual IP (VIP) address: A VIP address is a single IP address that is shared by multiple servers in a pool. When a client makes a request to the VIP address, the load balancer directs the request to one of the servers in the pool based on a pre-defined algorithm. This method provides a transparent failover mechanism, as the load balancer can easily switch traffic to another server in the pool if one server fails. See fig1.3
![ILB Operation Modes - Managing Oracle Solaris 11.1 Network Performance](https://docs.oracle.com/cd/E26502_01/html/E28993/figures/DSR-diagram1.png align="center")
Fig 1.3
Network Address Translation (NAT): In NAT-based load balancing, the load balancer intercepts incoming traffic and replaces the source IP address of the client with its own IP address. The load balancer then forwards the traffic to one of the servers in the pool. When the server responds, the load balancer replaces the destination IP address with the IP address of the client and forwards the response back to the client. See fig1.4
![What is a NAT firewall, How Does it Work and When Do You Need One?](https://cdn.comparitech.com/wp-content/uploads/2019/03/Network_Address_Translation_file1.jpg align="center")
Fig 1.4
Anycast: This method allows multiple servers in different locations to share a single IP address. When a client makes a request to the anycast IP address, the request is routed to the nearest server in the pool based on network topology. See fig1.5
![What is an Anycast? How does the network work? ⚙️](https://assets.website-files.com/5ff66329429d880392f6cba2/60b8ae7c17dcb99f633ac4a1_What%20is%20Anycast.png align="center")
Fig 1.5
In summary, IP addresses can be assigned to servers in the load balancing using various methods, such as round-robin DNS, IP hashing, VIP addresses, NAT, and anycast. Each method has its own advantages and disadvantages, and the choice of method will depend on the specific needs of the application and the network environment.