L2 Network

What is L2 Network?

An L2 network is a layer 2 broadcast domain used for layer 2 isolation. Generally, L2 networks are identified by names of devices on the physical network.

VLAN, VXLAN, and SDN can be used as an L2 network.
An L2 network is used to provide layer 2 isolation for an L3 network.

L2 Network Types

ZStack Cloud supports the following L2 network types:

Type	Description
L2NoVlanNetwork	You must specify the NIC name of the host. The hosts in the cluster to which the L2 network is attached must have NICs that share the same name. When the data packets of VM instances flow out of the host NIC and reach the physical switch, the data packets are not flagged with VLAN tags. Note that the physical switch must be in VLAN Access mode. If you create an L2 network of the L2NoVlanNetwork type, a network bridge is created based on the specified host NIC.
L2VlanNetwork	You must specify the host NIC name and VLAN ID. ZStack Cloud allows you to create virtual NICs and virtual switches, and supports IEEE 802.1Q VLAN trunking. The hosts in the cluster to which the L2 network is attached must have NICs that share the same name. When the data packets of VM instances flow out of the host NIC and reach the physical switch, the data packets are tagged with the specified VLAN ID. If you create an L2 network of the L2VlanNetwork type, a VLAN device is created based on the specified VLAN ID and then a network bridge is created based on the VLAN device. If you attach an L2 network of the L2NoVlanNetwork type and an L2 network of the L2VlanNetwork type or attach multiple L2 networks of the L2VlanNetwork type to a cluster, the physical switch NIC must be in Trunk mode. Besides, the VLAN ID in use must be contained in the Trunk VLAN configurations.
VxlanNetwork	Virtual Extensible LAN (VXLAN) is an overlay technology that allows for the creation of overlaying L2 networks. This technology can support a maximum of 16 million logical networks. VxlanNetwork is an implementation of the software-based VXLAN technology. If you create an L2 network of the VxlanNetwork type, you must specify a software SDN-based VXLAN pool. The L2 network must correspond to a VNI in the pool. The VTEP IPs of the hosts in the cluster to which the L2 network of the VxlanNetwork type is attached must belong to the specified VXLAN pool. When the data packets of VM instances flow out of the host, the host encapsulates VXLAN messages to the data packets and then sends the encapsulated data to the physical switch.
HardwareVxlanNetwork	Virtual Extensible LAN (VXLAN) is an overlay technology that allows for the creation of overlaying L2 networks. This technology can support a maximum of 16 million logical networks. HardwareVxlanNetwork is a solution to the integration with third-party hardware SDN. If you create an L2 network of the HardwareVxlanNetwork type, you must specify a hardware SDN-based VXLAN pool. The L2 network must correspond to a VNI in the pool. When the data packets of VM instances flow out of the host NICs and reach the distributed virtual switches, the data packets are flagged with the specified VLAN ID. The VLAN ID is mapped with VXLAN ID based on the SDN controlled that you add to the Cloud.
L2GeneveNetwork	A ZNS L2 network created through the ZNS SDN controller. It uses Geneve overlay encapsulation to provide L2 isolation. Select a ready ZNS controller and specify a Geneve ID when creating ZNS L3 networks.

Note: For some OSes, the NIC name in the ethX format will be changed after the system reboots. In addition, the NIC sequence will also be randomly changed. We recommend that you change the NIC name of each compute node (especially for VM instances with multiple NICs) to a non-ethX format, such as em01.

L2 Network | Cluster | L3 Network | VM Instance

The relationship between an L2 network and a cluster, an L3 network, a VM instance is as follows:

If you attached an L2 network to a cluster whereas the L2 network was not attached to a host, you could not add the host to the cluster.
If you did not attach an L2 network to a cluster and the L2 network was not attached to a host, you could not attach the L2 network to the cluster.
If you attached an L2 network to a host whereas the corresponding L2 network devices were inconsistently connected to other hosts in a cluster, note that the VM IP that you created would not work properly.
If you delete an L2 network, the corresponding L3 networks and VM NICs that are using these networks will also be deleted.
If you delete an L2 network, the VPC vRouter and vRouter offering that use the L2 network will also be deleted.
If you delete an L2 public network, all network services that are using the network, such as VPC vRouter, vRouter offering, VIP, EIP, port forwarding, load balancing, IPsec tunnel, and Netflow will also be deleted.
You can create multiple VxlanNetworks using a VXLAN Pool. These VxlanNetworks can be applied to flat networks and VPC networks, respectively.
VM instances in an L2 network of the VxlanNetwork type cannot be accessed through the Internet. To access these VM instances through the Internet, use an EIP or port forwarding.
You can use an L2 network to create multiple L3 networks. However, we recommend that unless necessary you do not create multiple L3 networks from an L2 network. This may cause the DHCP services of these L3 networks unable to work as expected.

Create an L2 Network

On the main menu of ZStack Cloud, choose Resource Center > Network Resource > L2 Network Resources > L2 Network. On the L2 Network page, click Create L2 Network. Then, the Create L2 Network page is displayed.

The following lists the L2 networks that you can create:

Create an L2NoVlanNetwork.
Create a VxlanNetwork.
Create an L2VlanNetwork.
Create a HardwareVxlanNetwork.
Create an L2GeneveNetwork

Create an L2NoVlanNetwork

Set the following parameters:

Zone: By default, the current zone is displayed.
Name: Enter a name for the L2 network.
The name must be 1 to 128 characters in length and can contain Chinese characters, letters, digits, spaces, hyphens (-), underscores (_), periods (.), parenthesis (), colons (:), and plus signs (+) and cannot begin or end with spaces.
Description: Optional. Enter a description for the L2 network.
Switch Type: Choose a type of switch.
- Linux Bridge: The Linux Bridge switch type is suitable for small-scale, low-load network environments.
- ZNS: Use a ZNS SDN controller to create an L2 network
Network Type: Select L2NoVlanNetwork.
Cluster: Select the cluster to which the L2 network will be attached.
NIC Name: Select or enter an NIC name for the L2 network, for example, em01.
Note: You can only select or enter an NIC name shared across all hosts in the cluster.

Create an L2VlanNetwork

Set the following parameters:

Zone: By default, the current zone is displayed.
Name: Enter a name for the L2 network.
The name must be 1 to 128 characters in length and can contain Chinese characters, letters, digits, spaces, hyphens (-), underscores (_), periods (.), parenthesis (), colons (:), and plus signs (+) and cannot begin or end with spaces.
Description: Optional. Enter a description for the L2 network.
Switch Type: Choose a type of switch.
- Linux Bridge: The Linux Bridge switch type is suitable for small-scale, low-load network environments.
- ZNS: Use a ZNS SDN controller to create an L2 network
Network Type: Select L2VlanNetwork.
Cluster: Select the cluster to which the L2 network will be attached.
VLAN ID: Specify a VLAN ID that matches the actual network configurations. Valid values: 1 to 4094.
NIC Name: Select or enter an NIC name for the L2 network, for example, em01.
Note: You can only select or enter an NIC name shared across all hosts in the cluster.
PVLAN (Isolated): By default, the switch is disabled. You can specify whether to enable the isolated VLAN function on the Cloud. It is usually used to work with the PVLAN function of the physical switch. When enabled, the VM instances in the L3 network created from this L2 network cannot communicate with each other.
Note:
- Currently, you cannot change the switch status after the creation. Please plan your network in advance.
- The L3 network services are not affected if the L2 network has isolated VLAN enabled.

Create a VxlanNetwork

Set the following parameters:

Zone: By default, the current zone is displayed.
Name: Enter a name for the L2 network.
The name must be 1 to 128 characters in length and can contain Chinese characters, letters, digits, spaces, hyphens (-), underscores (_), periods (.), parenthesis (), colons (:), and plus signs (+) and cannot begin or end with spaces.
Description: Optional. Enter a description for the L2 network.
Switch Type: You can create VxlanNetwork on the Linux Bridge switch.
Network Type: Select VxlanNetwork.
VXLAN Pool: Select a VXLAN pool of the software SDN type.
Note:
- Before you can create a VxlanNetwork, create a VXLAN pool of the software SDN type.
- For more information, see Create Software-SDN VXLAN Pool.
VNI: Optional. Specify a VNI in the VXLAN pool. If not specified, the platform allocates a VNI randomly.

Create a HardwareVxlanNetwork

To create a HardwareVxlanNetwork, make sure a valid SDN network license is added to the platform.

Set the following parameters:

Zone: By default, the current zone is displayed.
Name: Enter a name for the L2 network.
The name must be 1 to 128 characters in length and can contain Chinese characters, letters, digits, spaces, hyphens (-), underscores (_), periods (.), parenthesis (), colons (:), and plus signs (+) and cannot begin or end with spaces.
Description: Optional. Enter a description for the L2 network.
Switch Type: You can create HardwareVxlanNetwork on the Linux Bridge switch.
Network Type: Select HardwareVxlanNetwork.
VXLAN Pool: Select a VXLAN pool of the hardware SDN type.
Note:
- Before you can create a HardwareVxlanNetwork, create a VXLAN pool of the hardware SDN type.
- For more information, see Create Hardware-SDN VXLAN Pool.
- You need to configure the SDN Tenant parameter, if the selected VXLAN Pool is created based on H3C VCFC R6506.
- If the selected VXLAN Pool is created on HUAWEI SDN controller, the VNI parameter will not be displayed. In addition, you need to configure the Remote VPC and VLAN ID parameters.
VNI: Optional. Select a specified VNI in the VXLAN pool.
If not specified, the Cloud allocates a VNI randomly.

Create an L2GeneveNetwork

To create an L2GeneveNetwork, you must install the ZNS Network Service from the application marketplace in advance.

Set the following parameters:

Zone: By default, the current zone is displayed.
Name: Enter a name for the L2 network.
The name must be 1 to 128 characters in length and can contain Chinese characters, letters, digits, spaces, hyphens (-), underscores (_), periods (.), parenthesis (), colons (:), and plus signs (+) and cannot begin or end with spaces.
Description: Optional. Enter a description for the L2 network.
Switch Type: You can create L2GeneveNetworks on the ZNS switch.
Network Type: Select L2GeneveNetwork.
Cluster: Select the cluster to which the L2 network will be attached.
SDN Controller: Select the ZNS SDN controller.
Geneve ID: Enter the Geneve ID.

Manage an L2 Network

On the main menu of ZStack Cloud, choose Resource Center > Network Resource > L2 Network Resources > L2 Network. Then, the L2 Network page is displayed. The following tables list the actions that you can perform on an L2 network.

Action	Description
Create L2 Network	Create an L2NoVlanNetwork or L2VlanNetwork network.
Edit L2 Network	Edit the name and description of the L2 network.
Attach Cluster	Attach the L2 network to a cluster.
Detach Cluster	Detach the L2 network from a cluster. Note: Detaching an L2 network from a cluster also detaches the corresponding VM NIC. Please exercise caution. If an L2 network is not attached to a cluster, you cannot use the corresponding L3 networks to create VM instances.
Set Sharing Mode	Set the sharing mode of a resource. The platform provides the following sharing modes: Share Globally: Shares the resource to all projects and accounts. Share to Specified Projects/Accounts: Shares the resource with specified projects and accounts. Not Share: Revokes the resource from projects and accounts to which the resource is shared. If you set Sharing Mode to Not Share for a resource, other projects and accounts cannot use the resource. Note: If you change the Sharing Mode setting of a resource from Share Globally to Share to Specified Projects/Accounts, the resource is visible only to the specified projects or accounts the resource is shared to. If the resource that you share to the specified projects oraccounts is being used by these projects or accounts and then you change the Sharing Mode of the resource, the change does not take effect on the projects or accounts immediately. They can reverse and use the resource until it is released.
Delete L2 Network	Delete the L2 network. Note: Deleting an L2 network also deletes its L3 networks and associated VPC vRouters, and detaches the corresponding VM NICs. Please exercise caution.
Modify L2 Network type	Modify a L2 Network type to L2VlanNetwork or L2NoVlanNetwork. Note: You can perform this modification on the L2 Network details page by editing the Type parameter. You cannot modify the L2 Network that has PLVAN enabled. You cannot modify the L2 Network that has been attached to a baremetal/elastic baremetal cluster. Modifying the L2 Network type may interrupt VM network connection. We recommend that you perform this modification during off-peak business hours. Please exercise caution.
Modify VLAN ID	Modify the VLAN ID of the L2 Network. Note: You can perform this modification on the L2 Network details page by editing the VLAN ID parameter. You cannot modify the VLAN ID of the L2 network that has been used for management networks or flow networks. You cannot modify the L2 Network that has been attached to a baremetal/elastic baremetal cluster. You cannot modify the VLAN ID of the L2 network that has PVLAN enabled. Modifying the VLAN ID may interrupt VM network connection. We recommend that you perform this modification during off-peak business hours. Please exercise caution.

Action	Description
Create L2 Network	Create a VxlanNetwork network.
Edit L2 Network	Edit the name and description of the L2 network.
Set Sharing Mode	Set the sharing mode of a resource. The platform provides the following sharing modes: Share Globally: Shares the resource to all projects and accounts. Share to Specified Projects/Accounts: Shares the resource with specified projects and accounts. Not Share: Revokes the resource from projects and accounts to which the resource is shared. If you set Sharing Mode to Not Share for a resource, other projects and accounts cannot use the resource. Note: If you change the Sharing Mode setting of a resource from Share Globally to Share to Specified Projects/Accounts, the resource is visible only to the specified projects or accounts the resource is shared to. If the resource that you share to the specified projects oraccounts is being used by these projects or accounts and then you change the Sharing Mode of the resource, the change does not take effect on the projects or accounts immediately. They can reverse and use the resource until it is released.
Delete L2 Network	Delete the L2 network. Note: Deleting an L2 network also deletes its L3 networks and associated VPC vRouters, and detaches the corresponding VM NICs. Please exercise caution.
Modify VNI	Modify the VNI or the L2 network. Note: You can perform this modification on the L2 Network details page by editing the VNI parameter. You cannot modify the VNI of the L2 network that has been used for management networks or flow networks. Modifying the VNI may interrupt VM network connection. We recommend that you perform this modification during off-peak business hours. Please exercise caution.

Action	Description
Create L2 Network	Create HardwareVxlanNetwork network.
Edit L2 Network	Edit the name and description of the L2 network.
Delete L2 Network	Delete the L2 network. Note: Deleting an L2 network also deletes its L3 networks and associated VPC vRouters, and detaches the corresponding VM NICs. Please exercise caution.

Action	Description
Create L2 Network	Create L2GeneveNetworks.
Edit Name and Description	Edit the name and description of the L2 network.
Attach Cluster	Attach the L2 network to a cluster.
Detach Cluster	Detach the L2 network from a cluster. Note: Detaching an L2 network from a cluster also detaches the corresponding VM NIC. Please exercise caution. If an L2 network is not attached to a cluster, you cannot use the corresponding L3 networks to create VM instances.
Set Sharing Mode	Set the sharing mode of a resource. The platform provides the following sharing modes: Share Globally: Shares the resource to all projects and accounts. Share to Specified Projects/Accounts: Shares the resource with specified projects and accounts. Not Share: Revokes the resource from projects and accounts to which the resource is shared. If you set Sharing Mode to Not Share for a resource, other projects and accounts cannot use the resource. Note: If you change the Sharing Mode setting of a resource from Share Globally to Share to Specified Projects/Accounts, the resource is visible only to the specified projects or accounts the resource is shared to. If the resource that you share to the specified projects oraccounts is being used by these projects or accounts and then you change the Sharing Mode of the resource, the change does not take effect on the projects or accounts immediately. They can reverse and use the resource until it is released.
Delete L2 Network	Delete the L2 network. Note: Deleting an L2 network also deletes its L3 networks and associated VPC vRouters, and detaches the corresponding VM NICs. Please exercise caution.

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