Advantages

Traffic Balance

It supports HTTP and TCP protocols and will send business traffic to back-end hosts according to their needs.

Health Examination

It will examine back-end servers according to their needs and automatically separate hosts if there should be need to do so. Once a problem is detected, it will quickly switch off the problematic host to a good host, thus ensuring the stable and constant usability of services.

Conversation Persistence

It offers an HTTP conversation persistence function. Once the function started, it will send all users' requests to specific hosts in line with their characteristics. Matched users will be bound with this host in subsequent requests. It supports two-way cookies inserted from the client or selected by the user.

Data Monitoring

On the load-balancing level, new connections per second and bandwidth (to and from) can be monitored in real-time, while on the back-end server level, connections per second and bandwidth (to and from) can be monitored as well.

Security and Stability

It employs hot standby switch and distributed framework to ensure the high usability of the ULB itself.

Features

Supports X-Forwarded-Proto header

Biding SSL certificate, and the ULB can decode the source HTTP protocol data and transfer it into HTTP protocol data and then send it to back-end server.The back-end server can decide source data protocol according to HTTP data head of X-Forwarded-Proto: · X-Forwarded-Proto: http HTTP Data； · X-Forwarded-Proto: https HTTPS Data； Example：you can apply for ULB and create two VServers with front-end ports named 80/443 respectively, and then add the same back-end servers in the two VServers but only to monitor port 80. Bind SSL certificates to the VServers with 443 front-end port so that the back-end server will get the original protocol according to X-Forwarded-Proto Header's judgement and adjust accordingly.

Supports Client Connection Timeout when Idle:

You can set your own parameter for idle time-out via ULB. Example: under some circumstances, it costs a lot to build a TCP connection, e.g. mobile client, and needs to keep free connection. Because of unstable mobile connectivity, it takes a lot of time and resources to reconnect. But now you can contact UCloud to change idle time-out parameters of ULD clients to avoid constant re-connection. At present, you can set it as from 1 to 86400 seconds.

Supports WebSocket:

ULB supports WebSocket service as a way to connect a load-balancing's back-end. With duplex connection, it is convenient for WebSocket to push service information, which is very popular now. Example: ULB supports all type WebSocket and its duplex communication modes.

Suitable Settings

To Increase Business Usability

Usually we will deploy multiple hosts to increase service usability together with the cloud host and ULB. Highly usable solutions can be achieved without any program change. ULB can separate irregular servers by examining the back-end service and ensuring to switch the host if any fault occurs; when this server gets fixed, the connection will be restored automatically.

Seamless Business Scalability Service

Our Seamless Business Scalability Service is available through the virtual IP of load balancing. When business increases, it can create hosts in the back-end server pool to enhance its performance, and vise-versa when business reduces. Since the service's virtual IP doesn't change, the whole scaling process won't influence any relevant call or visitor.

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