After you create a Global Accelerator (GA) instance, you must configure listeners for the GA instance. A listener listens for connection requests and then distributes the requests to endpoints based on the forwarding rules that are defined by a specified scheduling algorithm.

Listener protocols

You can create 10 listeners for each GA instance. The following listener protocols are supported: TCP, UDP, HTTP, and HTTPS. You can select a protocol based on the scenario.
Protocol Description Scenario
TCP
  • A connection-oriented protocol that provides high reliability. A logical connection must be established before data can be transmitted.
  • Session persistence is based on source IP addresses.
  • Source IP addresses are visible at the network layer.
  • Data is transmitted at a slow rate.
  • Applicable to scenarios that require high reliability and data accuracy but can withstand a low transmission speed. These scenarios include file transmission, email sending and receiving, and remote logons.
  • Web applications that do not have custom requirements.
UDP
  • A connectionless and unreliable protocol. Three-way handshakes are not required before UDP packets are transmitted. UDP does not provide error recovery or data retransmission.
  • Data is transmitted at a high rate.
Applicable to scenarios where real-time transmission outweighs reliability, such as video conferencing and real-time quote services.
HTTP
  • A connection-oriented protocol that provides high reliability. A logical connection must be established before data can be transmitted.
  • Data is transmitted at a high rate.
  • Data transmission is not encrypted.
  • Applicable to scenarios where HTTP websites need to be accelerated.
  • Applicable to scenarios where HTTP websites that contain specified domain names or paths need to be accelerated.
HTTPS
  • A connection-oriented protocol that provides high reliability. A logical connection must be established before data can be transmitted.
  • You can bind SSL certificates to servers. This ensures high reliability of data.
    Note For more information about SSL certificates, see What is SSL Certificates Service?.
  • Data transmission is encrypted.
  • Applicable to scenarios where HTTP or HTTPS websites need to be accelerated. This also ensures the network security when clients access HTTP or HTTPS websites.
  • Applicable to scenarios where HTTP or HTTPS websites that contain specified domain names or paths need to be accelerated.

Listener ports

Listener ports are used to receive requests and forward the requests to endpoints. Listeners consist of basic listeners and advanced listeners. Advanced listeners can listen on a large number of ports.
Note If you add listeners that use the same protocol to a GA instance, you must configure different ports for the listeners.
  • Basic listeners
    The following table describes the number of ports that are supported by listeners that use different protocols. For TCP and UDP listeners, you can submit a ticket to increase the quota of gaplus_quota_port_per_listener. For more information, see Manage quotas.
    Listener protocol Listener port range Listener port quota
    TCP 1~65499 30.
    • Separate multiple listener ports with commas (,). Example: 80,90,8080.
    • If you want to specify port ranges, you can use a tilde (~). For example, you can enter 80~83 to specify the ports 80, 81, 82, and 83.
    UDP 1~65499 30.
    • Separate multiple listener ports with commas (,). Example: 80,90,8080.
    • If you want to specify port ranges, you can use a tilde (~). For example, you can enter 80~83 to specify the ports 80, 81, 82, and 83.
    HTTP 1~65499 1.
    HTTPS 1~65499 1.
  • Advanced listeners
    You can specify more than 300 consecutive listener ports for a TCP or UDP listener. Advanced listeners are listeners that each contain more than 300 consecutive listener ports. Advanced listeners have the following limits:
    • By default, you can create advanced listeners only for GA instances that are created after January 8, 2022. If your GA instances were created before this date and you want to create advanced listeners, submit a ticket to upgrade the GA instances.
    • You must specify more than 300 ports for an advanced listener. The number of ports that you specify must not exceed 65,499.
    • You can create only one advanced listener for each GA instance.
    • You can specify only consecutive ports. For example, you can set the port range to 1~350. You cannot set the port range to 1,3~350.
    • If the acceleration region of a GA instance is a point of presence (PoP) node of Alibaba Cloud, you cannot create an advanced listener for the GA instance.
      Note If you want to check whether the acceleration region of a specified GA instance is a PoP node of Alibaba Cloud, refer to ListAvailableBusiRegions.
For example, you want to create the following listeners for a GA instance: a TCP listener whose listener ports are from 1 to 400, a TCP listener whose listener port is 443, a UDP listener whose listener ports are from 200 to 210, and a UDP listener port whose listener ports are from 230 to 240. The TCP listener whose listener ports are from 1 to 400 is an advanced listener. The following figure shows the listeners. Listener Ports