How to create and manage a multicast network - Cloud Enterprise Network

This topic describes how to use an Enterprise Edition transit router to create and manage a multicast network.

Background information

Before you create a multicast network, we recommend that you understand how multicast works, the billing rules for multicast, and the limits of multicast. For more information, see Multicast overview.

Step 1: Prepare the environment

Create an Enterprise Edition transit router in the region where you want to create a multicast network, and enable multicast for the transit router. For more information, see Create a transit router.
Important
- Multicast is supported by Enterprise Edition transit routers only in the following regions: China (Hangzhou), China (Shanghai), China (Beijing), China (Shenzhen), China (Chengdu), China (Hong Kong), Japan (Tokyo), Singapore, Germany (Frankfurt), Australia (Sydney), UK (London), US (Virginia), and US (Silicon Valley).
- In regions that support multicast, Enterprise Edition transit routers created before you enable multicast in the regions do not support multicast. To enable multicast, you can delete the transit routers and create a new one. For more information about how to delete an Enterprise Edition transit router, see Delete a transit router.
Use the Enterprise Edition transit router to connect the virtual private clouds (VPCs) for which you want to enable multicast. For more information, see Use Enterprise Edition transit routers to enable intra-region communication between on-premises and cloud networks and Use Enterprise Edition transit routers to connect VPCs across regions and accounts.

Step 2: Create a multicast domain

You must create a multicast domain and associate it with one or more vSwitches to specify the scope of the multicast network. Only resources in the multicast network can transmit and receive multicast packets.

Log on to the CEN console.
On the Instances page, click the ID of the CEN instance that you want to manage.
On the Basic Settings > Transit Router tab, click the ID of the transit router that you want to manage.
On the details page of the transit router, click the Multicast tab, and click Create Multicast Domain.

In the Create Multicast Domain dialog box, set the following parameters and click OK.

Parameter	Description
Transit Router	The ID of the transit router in the selected region is displayed by default.
Multicast Domain Name	Enter a name for the multicast domain.
VPC	Select the VPCs that you want to associate with the multicast domain.
vSwitch	Select the vSwitches that you want to associate with the multicast domain. You can select one or more vSwitches.
Description	Enter a description for the multicast domain.

Step 3: Add a multicast source

After you create a multicast domain, you must add a multicast source and specify a multicast group for the multicast source. After you add a multicast source, it transmits multicast packets to the multicast group. Members in the multicast group can receive multicast packets sent from the multicast source.

Log on to the CEN console.
On the Instances page, click the ID of the CEN instance that you want to manage.
On the Basic Settings > Transit Router tab, click the ID of the transit router that you want to manage.
On the details page of the transit router, click the Multicast tab, and click the ID of the multicast domain in the left-side section on the Multicast tab.
In the Multicast Domain Details section, click the Multicast Groups tab and click Add Multicast Source.

On the Add Multicast Source page, set the following parameters and click OK.

Parameter		Description
Basic information	Transit Router	The ID of the transit router in the selected region is displayed by default.
Basic information	Multicast Domain	The ID of the selected multicast domain is displayed by default.
Multicast Group Info	Multicast Group	Select the multicast group to which you want to add the multicast source. Valid values: Create Multicast Group: If no multicast group is created in the selected multicast domain, you can select this option and enter an IP address. The system automatically creates a multicast group. Note The IP address of the multicast group cannot be modified after the multicast group is created. Select Multicast Group: If you want to use an existing multicast group in the selected multicast domain, select this option and select a multicast group.
	New Multicast Group IP	Enter an IP address for the multicast group to be created. Valid values: 224.0.1.0 to 239.255.255.254. Important 224.0.0.0 to 224.0.0.255 are reserved IP addresses for the system and cannot be used for the multicast group. Each multicast group is identified by its IP address. You must specify an IP address only if you select Create Multicast Group.
	Multicast Group	Select an existing multicast group. The multicast source is added to the selected multicast group. You can select an existing multicast group only if you select Select Multicast Group.
Multicast Source Info	Resource Type	Select the type of multicast source. Default value: ENI. You can specify only elastic network interfaces (ENIs) that are associated with Elastic Compute Service (ECS) instances as multicast sources. The system uses the primary private IP address of the specified ENI to transmit multicast packets to the multicast group. You can specify at most five ENIs as multicast sources at each time.
	vSwitch	Select the vSwitch of the multicast source.
	ENIs	Select an ENI, which is the multicast source. If you select Add as Multicast Member, the ENI is also specified as a multicast member in the multicast group.

Step 4: Add multicast members

If you do not specify a multicast member when you add a multicast source, you can perform the following operations to add multicast members. Only members in the multicast group can receive multicast packets sent from the multicast source. The multicast members receive multicast packets only from the multicast group to which the members belong.

Log on to the CEN console.
On the Instances page, click the ID of the CEN instance that you want to manage.
On the Basic Settings > Transit Router tab, click the ID of the transit router that you want to manage.
On the details page of the transit router, click the Multicast tab, and click the ID of the multicast domain in the left-side section on the Multicast tab.
In the Multicast Domain Details section, click the Multicast Groups tab, and click Add Group Member.

On the Add Group Member page, set the following parameters and click OK.

Parameter		Description
Basic information	Transit Router	The ID of the transit router in the selected region is displayed by default.
Basic information	Multicast Domain	The ID of the selected multicast domain is displayed by default.
Multicast Group Info	Multicast Group	Select the multicast group to which you want to add members. Valid values: Create Multicast Group: If no multicast group is created in the selected multicast domain, you can select this option and enter an IP address. The system automatically creates a multicast group. Note The IP address of the multicast group cannot be modified after the multicast group is created. Select Multicast Group: If you want to use an existing multicast group in the selected multicast domain, select this option and select a multicast group.
	New Multicast Group IP	Enter an IP address for the multicast group to be created. Valid values: 224.0.0.1 to 239.255.255.254. Each multicast group is identified by its IP address. You must specify an IP address only if you select Create Multicast Group.
	Multicast Group	Select an existing multicast group. You can select an existing multicast group only if you select Select Multicast Group.
Group Member Info	Resource Type	Select the type of multicast member. Valid values: ENI: Select the ENIs of vSwitches. This is the default value. You can specify only ENIs that are associated with ECS instances as multicast members. The system uses the primary private IP address of the specified ENI to receive multicast packets. You can click Add ENI to add more ENIs. Inter-region Multicast Domain: Select a multicast domain of a transit router that supports inter-region communication. After you select a multicast domain of a transit router that supports inter-region communication, members in the multicast group that has the same IP address as the current multicast group are added to the current multicast group. For example, Multicast Domain 1 in the China (Hangzhou) region has a multicast group (Group A). Multicast Domain 2 in the China (Shanghai) region also has a multicast group (Group A). Group A in Multicast Domain 1 has the same IP address as Group A in Multicast Domain 2. Group A in Multicast Domain 2 contains members. You want to add members to Group A in Multicast Domain 1. You can set Resource Type to Inter-region Multicast Domain and select Multicast Domain 2 in the China (Shanghai) region. In this case, members of Group A in Multicast Domain 2 are added to Group A in Multicast Domain 1. The members can receive multicast packets from Group A in Multicast Domain 1. Important Before you select Inter-region Multicast Domain, make sure that the following requirements are met: The regions for which you want to enable multicast can communicate with each other over inter-region connections. The local region has a multicast group whose IP address is the same as a multicast group in the peer region. The multicast group in the peer region contains members. You can add multicast members from a different region but you cannot add multicast sources from a different region.
	vSwitch	Select the vSwitch of the multicast member. You must select a vSwitch if you select ENI.
	ENIs	Select ENIs, which are multicast members. You can specify ENIs as multicast members only if you select ENI. If you select Add as Multicast Source, the ENI is also specified as a multicast source in the multicast group. You can specify at most five multicast members at each time. If you select a resource in a VPC that belongs to another Alibaba Cloud account, you can specify one or more ENIs only in one VPC as multicast members. You cannot specify ENIs in different VPCs that belong to another Alibaba Cloud account.
	Transit Router	Select the peer transit router. You must specify a peer transit router only if you select Inter-region Multicast Domain.
	Peer Multicast Domain	Select a peer multicast domain. You must select a peer multicast domain only if you select Inter-region Multicast Domain.

What to do next

Operation	Description and prerequisite	Procedure
Associate with a vSwitch	After you create a multicast domain, you can associate it with one or more vSwitches to specify the scope of the multicast network.	On the details page of the transit router, click the Multicast tab. In the left-side section of the Multicast tab, click the ID of the multicast domain. In the Multicast Domain Details section, click the vSwitch tab and click Associate with vSwitch. In the Associate with vSwitch dialog box, set the VPC and vSwitch parameters and click OK. You can select multiple vSwitches of a VPC. You can repeat the preceding steps to associate the multicast domain with vSwitches of different VPCs.
Disassociate from a vSwitch	If you want to remove a vSwitch from a multicast domain, you can disassociate the vSwitch from the multicast domain. Before you delete a vSwitch, make sure that the following requirements are met: No multicast sources exist in the vSwitch. For more information about how to delete a multicast source, see the Delete a multicast source section in this topic. No multicast members exist in the vSwitch. For more information about how to remove members from a multicast group, see the Remove members from a multicast group section in this topic.	On the details page of the transit router, click the Multicast tab. In the left-side section of the Multicast tab, click the ID of the multicast domain. In the Multicast Domain Details section, click the vSwitch tab, find the vSwitch that you want to manage, and then click Disassociate in the Actions column. In the message that appears, confirm the information and click OK.
Remove members from a multicast group	If you no longer want a member in a multicast group to receive multicast packets, you can remove the member from the multicast group.	On the details page of the transit router, click the Multicast tab. In the left-side section of the Multicast tab, click the ID of the multicast domain. In the Multicast Domain Details section, click the Multicast Groups tab, find the member that you want to remove, and then click Delete in the Actions column. Multicast members are resources whose Group Member Type is Static. In the Remove Group Member message, click OK.
Delete a multicast source	If you no longer want a multicast source to transmit multicast packets, you can delete the multicast source.	On the details page of the transit router, click the Multicast tab. In the left-side section of the Multicast tab, click the ID of the multicast domain. In the Multicast Domain Details section, click the Multicast Groups tab, find the multicast source that you want to delete, and then click Delete in the Actions column. Multicast sources are resources whose Multicast Source Type is Static. In the Delete Multicast Source message, click OK.
Delete a multicast domain	If you no longer need a multicast network, you can delete the multicast domain used by the multicast network. Before you delete a multicast domain, make sure that the following requirements are met: The multicast domain is disassociated from all vSwitches. For more information, see Disassociate from a vSwitch. All multicast sources and members are removed from the multicast domain. For more information, see Delete a multicast source and Remove members from a multicast group.	On the details page of the transit router, click the Multicast tab. In the left-side section of the Multicast tab, click the ID of the multicast domain. In the left-side of the Multicast Domain Details section, click Delete. In the Delete Multicast Domain message, click OK.

References

Management of multicast domains

CreateTransitRouterMulticastDomain: Creates a multicast domain.
ModifyTransitRouterMulticastDomain: Modifies the name and description of a multicast domain.
DeleteTransitRouterMulticastDomain: Deletes a multicast domain.
ListTransitRouterMulticastDomains: Queries multicast domains.
AssociateTransitRouterMulticastDomain: Associates a vSwitch in a VPC with a multicast domain.
DisassociateTransitRouterMulticastDomain: Disassociates a vSwitch from a multicast domain.
ListTransitRouterMulticastDomainAssociations: Queries whether vSwitches in VPCs are associated with a specified multicast domain.
ListTransitRouterMulticastDomainVSwitches: Queries the vSwitches in a VPC that are associated with a multicast domain.

Management of multicast sources and members

RegisterTransitRouterMulticastGroupSources: Adds a multicast source.
DeregisterTransitRouterMulticastGroupSources: Deletes a multicast source.
RegisterTransitRouterMulticastGroupMembers: Adds multicast members to a multicast group.
DeregisterTransitRouterMulticastGroupMembers: Removes multicast members from a multicast group.
ListGrantVSwitchEnis: Queries the ENIs in a VPC that can be specified as multicast sources or members.
ListTransitRouterMulticastGroups: Queries the multicast sources and members in a multicast domain.