network load balancer is a load balancer that distributes traffic across multiple local and wide area networks so that large volumes of user requests are handled in a manner that maximizes performance and reliability.

To review general information about load balancers, see Save 80% Compared to Hardware Load Balancers.

A large network is typically built by connecting multiple smaller networks together. A network can be as small as two computers in a home or as big as the Internet. When the computers, servers, or devices in a network are in close proximity to each other, such as inside a single office or home, the network is referred to as a local area network (LAN). Connecting multiple LANs, usually across a larger geographical area, yields a wide area network (WAN). The Internet itself can be thought of as a WAN that aggregates many smaller WANs.

To handle large traffic volumes at their websites, companies often place a load balancer in front of a group of servers connected to the same LAN and running the same applications (sometimes referred to as a server farm). For even greater redundancy, a company might distribute requests across the servers on multiple LANs aggregated into a WAN. One of the goals of load balancing is to maximize application reliability by eliminating single points of failure. Deploying network load balancers to load balance across servers on multiple LANs or even multiple WANs ensures that even if all servers in a LAN fail (or a network partition isolates the LAN), users don’t experience failure, because traffic is redirected to accessible LANs where servers are still online.

A common type of network load balancer is a global server load balancer (GSLB), which distributes user requests across multiple geographically distributed groups of servers. Users experience fast responses to their requests because servers are nearby (either geographically or in terms of network hops), and companies can be confident in the high availability of their websites in all but the most extreme cases of network and server failure.

How Can NGINX Plus Help?

NGINX PlusとNGINXは、クラス最高のロードバランシングソリューションであり、Dropbox、Netflix、Zyngaなどの高トラフィックのWebサイトで使用されています。世界中で4.5億以上のWebサイトがNGINX PlusとNGINX Open Sourceを利用しており、迅速かつ確実で安全なコンテンツのデリバリーを実現しています。

NGINX Plusは、DDoS攻撃を防ぐための重要なコンポーネントであり、さまざまなアプリケーションレイヤー攻撃から脆弱なアプリケーションを保護するためのツールを提供します。

DDoS攻撃には、攻撃に使用されているクライアントIPアドレス、リクエストの割合、特定のHTTPヘッダーなど、DDoS攻撃を防ぐために役立つ特徴があります。NGINX Plusには、これらの特徴を利用してDDoS攻撃に対抗したり、攻撃を受けたときにそれを特定したりするのに有効な機能がいくつかあります。

詳しくは、当社ブログ「Mitigating DDoS Attacks with NGINX and NGINX Plus」をご覧ください。