Example for Configuring ERPS (Intersection Rings)

Owned by Tracy Yang
Jul 18, 2024
8 min read

Networking Requirements

Figure 1.     ERPS Configuration Example

example intersect ring.png

To solve the loop problem caused by redundant links in the network, ERPS protocol can be deployed on the devices that form the ring network. As shown in Figure 1, taking the deployment of the interconnection ERPS ring as an example.

  • Switch A, Switch B, Switch C and Switch D form an ERPS major ring, ring ID is 1 and protected instance is 1; Switch B, Switch C and Switch E form a sub-ring, ring ID is 2 and protected instance is 2.

  • Configure the control VLAN ID of ERPS ring 1 to be 4001 and the control VLAN ID of ERPS ring 2 to be 4002. ERPS ring 1 and ring 2 transmit data packets for the same user VLAN 100 to 200.

  • Users wish to share the forwarding path between the intersecting rings for the data traffic, in such case, it is necessary to configure the control VLANs and data VLANs (VLAN 4001, 4002, 100 to 200) into the same protected instance to achieve data forwarding between the intersecting rings.

  • Configure network topology change notification on intersecting nodes Switch B and Switch C. The following configurations are required:

1. Configure the connect ring for a sub-ring on all intersecting nodes.

set protocols erps ring <ring-id> instance <instance-id> connect ring <ring-id> instance <instance-id>

2. Enable tcn-propagation function to advertise topology changes to the connect ring on all intersecting nodes.

set protocols erps tcn-propagation <true | false>

NOTEs:

  • The ERPS port must be a trunk port and disable spanning tree protocol.

  • Different ERPS ring instances cannot use the same control VLAN.

  • The same control VLAN must be configured for all devices in the same ERPS ring instance.

Procedure

Switch A

Step 1          Disable spanning-tree protocol on the interface before configuring ERPS ring on the interface.

admin@SwitchA# set protocols spanning-tree interface te-1/1/1 enable false admin@SwitchA# set protocols spanning-tree interface te-1/1/2 enable false

Step 2          Configure protected MSTP instance (ERPS protected-instance) and VLAN mapping before configuring ERPS.

NOTE: The ERPS control VLAN must be in one of the protected MSTP instance.

admin@SwitchA# set protocols spanning-tree mstp msti 1 vlan 100-200 admin@SwitchA# set protocols spanning-tree mstp msti 1 vlan 4001

Step 3          Configure VLAN and port mode.

admin@SwitchA# set interface gigabit-ethernet te-1/1/1 family ethernet-switching port-mode trunk admin@SwitchA# set interface gigabit-ethernet te-1/1/1 family ethernet-switching vlan members 100-200,4001 admin@SwitchA# set interface gigabit-ethernet te-1/1/2 family ethernet-switching port-mode trunk admin@SwitchA# set interface gigabit-ethernet te-1/1/2 family ethernet-switching vlan members 100-200,4001

Step 4          Enable ERPS function globally. By default, ERPS is disabled.

Step 5          Create the ERPS ring with a given ID.

Step 6          Configure port0 and port1 of the ERPS ring.

Step 7          Create instance for the ERPS ring.

Step 8          Configure port te-1/1/2 (port1) on Switch A as the RPL Owner Node for ERPS ring 1 instance 1.

Step 9          Configure the control VLAN.

Step 10      Configure the MSTP instance of VLANs that are protected by this ring instance.

Step 11      Commit the configurations.

Switch B

Step 1          Disable spanning-tree protocol on the interface before configuring ERPS ring on the interface.

Step 2          Configure protected MSTP instance (ERPS protected-instance) and VLAN mapping before configuring ERPS.

NOTE: Configure the control VLAN and data VLAN of ring 1 and ring 2 (VLAN 4001, 4002, 100 to 200) into the same protected instance to achieve data forwarding between the intersecting rings.

Step 3          Configure VLAN and port mode.

Step 4          Enable ERPS function globally. By default, ERPS is disabled.

Step 5          Create the ERPS ring 1 and 2, and specify ring 2 as a sub-ring.

Step 6          Configure port0 and port1 of the ERPS ring.

Step 7          Configure port te-1/1/5 (port0) on Switch B as the RPL Owner Node for ERPS ring 2 instance 2.

Step 8          Create instance for the ERPS ring.

Step 9          Configure the control VLAN.

Step 10      Configure the MSTP instance of VLANs that are protected by this ring instance.

Step 11      Configure the connect ring for sub-ring 2, and enable network topology change notification on intersecting nodes Switch B and Switch C.

Step 12      Commit the configurations.

Switch C

Step 1          Disable spanning-tree protocol on the interface before configuring ERPS ring on the interface.

Step 2          Configure MSTP instance (ERPS protected-instance) and VLAN mapping before configuring ERPS.

NOTE: Configure the control VLAN and data VLAN of ring 1 and ring 2 (VLAN 4001, 4002, 100 to 200) into the same protected instance to enable data forwarding between the intersecting rings.

Step 3          Configure VLAN and port mode.

Step 4          Enable ERPS function globally. By default, ERPS is disabled.

Step 5          Create the ERPS ring with a given ID.

Step 6          Configure port0 and port1 of the ERPS ring.

Step 7          Create instance for the ERPS ring.

Step 8          Configure the control VLAN.

Step 9          Configure the MSTP instance of VLANs that are protected by this ring instance.

Step 10      Configure the connect ring for sub-ring 2, and enable network topology change notification on intersecting nodes Switch B and Switch C.

Step 11      Commit the configurations.

Switch D

Step 1          Disable spanning-tree protocol on the interface before configuring ERPS ring on the interface.

Step 2          Configure the protected MSTP instance (ERPS protected-instance) and VLAN mapping before configuring ERPS.

NOTE: The ERPS control VLAN must be in one of the protected MSTP instance.

Step 3          Configure VLAN and port mode.

Step 4          Enable ERPS function globally. By default, ERPS is disabled.

Step 5          Create the ERPS ring with a given ID.

Step 6          Configure port0 and port1 of the ERPS ring.

Step 7          Create instance for the ERPS ring.

Step 8          Configure port te-1/1/2 (port0) on Switch D as the RPL Neighbor port for the ERPS ring 1 instance 1.

Step 9          Configure the control VLAN.

Step 10      Configure the MSTP instance of VLANs that are protected by this ring instance.

Step 11      Commit the configurations.

Switch E

Step 1          Disable spanning-tree protocol on the interface before configuring ERPS ring on the interface.

Step 2          Configure the protected MSTP instance (ERPS protected-instance) and VLAN mapping before configuring ERPS.

Step 3          Configure VLAN and port mode.

Step 4          Enable ERPS function globally. By default, ERPS is disabled.

Step 5          Create the ERPS ring with a given ID.

Step 6          Configure port0 and port1 of the ERPS ring.

Step 7          Create instance for the ERPS ring.

Step 8          Configure port te-1/1/5 (port0) on Switch D as the RPL Neighbor port for the ERPS ring 2 instance 2.

Step 9          Configure the control VLAN.

Step 10      Configure the MSTP instance of VLANs that are protected by this ring instance.

Step 11      Commit the configurations.

Verifying the Configuration

  • The command run show erps brief can be used to check the brief configuration information of the ERPS ring. Take Switch A and Switch B as an example:

  • The command run show erps ring <ring-id> can be used to check the detailed information of the ERPS ring. Take Switch A as an example:

From the show result, we can see that port te-1/1/2 on Switch A is the Owner node in Instance 1, with the ERPS ring in the Idle state, the RPL port blocked, and the non-RPL port state is forwarding.

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