Your GCP environment should have a default VPC, which can be used for autoscaling. However if you wish, you can also use a separate network for Red5 Pro autoscaling.

To Create a new VPC

• Navigate to VPC network and click on CREATE VPC NETWORK

• Provide appropriate details for the new VPC form

• Name: Specify a name for the VPC such as red5pronetwork.

• Description: Add a description for the VPC.

• Select Automatic subnet creation mode, to generate subnets in all regions.

• Select all essential Firewall rules for your VPC except allow-rdp.

• Select a Dynamic routing mode according to your needs or just leave it to default.

• Click Create to create VPC

Create firewal rules

• Under VPC Network tab -> Firewall Rules, Click on CREATE FIREWALL RULE. Add a new firewall rule to the network profile you wish to use for autoscaling.
• Name: Specify a name for the rule such as red5pro-ports
• Description: Add a description
• Logs: Leave to default (off)
• Network: Make sure default network is selected
• Priority: Leave to default
• Direction of traffic: Leave to default (Ingress)
• Action on match: Leave to default (Allow)
• Targets: All instances in the network
• Source Filter: IP Ranges
• Source IP Ranges: 0.0.0.0/0 (Implies Any)
• Second Source Filter: Leave to default
• Protocols & Ports: Select Specified Protocols & Ports and enter the following ports for mentioned protocols.

TCP: 5080,443,1935,8554,8081,8083,6262,22
UDP: 40000-65535

• Click Create to create rule

NOTE: As of release 5.4.0, websockets automatically use the same ports as http/https as defined in red5.properties, so you do not need to open up ports 8081/8083.