ASP.NET SignalR Backplane Overview

SignalR allows developers to create real-time ASP.NET web applications, where the server broadcasts the updates to all registered clients as soon as an update is triggered. This reduces the delay caused by the client requests for updates.

Note

For production use, it is recommended to run the NCache backplane in the same data center as the SignalR app.

A simple example of SignalR implementation is an online chatroom. Multiple clients are connected to multiple web servers in a farm. These clients can be sending messages to each other, where the message content is displayed as soon as it is sent to the receiving client. This eliminates the need to refresh the webpage every time to request new messages, as the server broadcasts the messages to all clients as soon as the client state is updated.

NCache offers support for SignalR by providing an extension to the SignalR provider. All concerned web servers for the application are registered against the provider. Meanwhile, the clients are connected to their respective web servers. In NCache, as soon as a client registers itself against the web server, two key features of NCache come into play:

  1. Custom Events: The provider fires an event as soon as a client performs an operation. This event triggers all web servers to immediately update their clients according to the latest state, thereby cutting down on the waiting duration for a client to check on updates.

  2. CacheItem.Version: As soon as a client is registered against a web server, an item is added to NCache with user specified event key. Every time the client will perform an operation, the version of the cache item is updated, triggering an event registered against the provider. This allows for instant replication of the client state over all clients, which causes the real-time effect.

In This Section

NCache Extension for ASP.NET SignalR Backplane
Explains how NCache's extended method can be used to utilize SignalR in your ASP.NET applications.