Setting Up ERP Protection

Ethernet Ring Protection (ERP) is a protection mechanism that maintains high availability of Ethernet services for ring topology networks. ERP is based on the ITU-T G.8032 specification.

An ERP ring consists of at least two units: one unit is configured as the owner and a second adjacent unit as the neighbor. Similar to Spanning Tree Protocol (xSTP), ERP implements a mechanism to prevent loops. Thus, although the physical topology is ring, traffic on one of the links is blocked and therefore the actual logical topology is linear. In ERP, the blocked link is the one between the owner and neighbor and is referred to as the Ring Protection Link (RPL). During normal operation, customer traffic does not travel on the RPL. During a failure, the RPL is unblocked and traffic can move between the owner and neighbor; the failed link thus becomes the new RPL.

Switchover to protection is triggered by link failure that can be based on link status or Connectivity Fault Management (802.1ag CFM). ERP protection allows switchover within 50 milliseconds.

You must set up LAG port protection, as described in Setting Up LAG Port Protection on page 216 before setting up ERP protection.

After setting up LAG port protection, you are ready to set up ERP protection.

To set up ERP protection

1. Access the page Protection ▶ERP ▶Configuration.
   A summary of all ERP instances currently set up in the system is displayed.

2. Click the Add button to add a new ERP instance or click the Index of an existing ERP
   instance to edit its settings.

3. Complete the required fields, then click Apply.

For more information on specific parameters, refer to the following tables.

ERP Configuration (Protection ▶ERP ▶Configuration)

Port Configuration

RPL Configuration

ERP Configuration

Viewing ERP Status

You can view a summary of all ERP status or the details of the status of each ERP instance.

To view a summary of the status for all ERP instances

1. Access the page Protection ▶ERP ▶Status.

For more information on specific parameters, refer to the following tables.

To view the detailed status of a specific ERP instance

1. Access the page Protection ▶ERP ▶Status.

2. To view the detailed status of an ERP, select an ERP Index.

For more information on specific parameters, refer to the following tables.

ERP Status (Protection ▶ERP ▶Status)

Alarms

Latest Top Priority Request

Port X

Forcing a Switch to the Standby Port

A forced switch forces the traffic to the standby port. You may need a forced switch in various situations, for example, when you want to add a unit to the ring, or when you want to perform maintenance on the other side of the ring, or for testing purposes.

To force a switch to the standby port

1. Access the page Protection ▶ERP ▶Status.

2. Click the ERP Index of the ring you want to switch.

3. Click the Port x Force Switch button to force a switch from this port to the standby
   port.

Clearing a Forced Switch

You need to clear a forced switched before forcing another switch on the same unit. So, you
cannot force a switch on port 0 and on port 1 at the same time.

To clear a forced switch

1. Access the page Protection ▶ERP ▶Status.

2. Click the ERP Index of the ring for which you want to clear the forced switch.

3. Click the Clear button to clear the forced switch.

Switching Manually to the Standby Port

Traffic can be manually switched to the standby port if the state of the standby port allows the traffic to switch. A manual switch may be required in various situations, for example, for maintenance. The difference from a forced switch is that a signal failure in the ring will override the manual switch. This is to avoid losing traffic when performing maintenance.

To manually switch to the standby port

1. Access the page Protection ▶ERP ▶Status.

2. Click the ERP Index of the ring you want to switch.

3. Click the Port x Manual Switch button to manually switch from this port to the standby
   port.

Viewing ERP Statistics

You can view a summary and details of the statistics for each ERP instance.

To view a summary of the statistics for all ERP instances

1. Access the page Protection ▶ERP ▶Statistics.

For more information on specific parameters, refer to the following table.

To view the detailed statistics of a specific ERP instance

1. Access the page Protection ▶ERP ▶Statistics.

2. Select an ERP Index.

For more information on specific parameters, refer to the following table.

ERP Results (Protection ▶ERP ▶Statistics)

Port X (The results for each port)

Discarded RX APS

Viewing the ERP VLAN Learning Table

You can view a summary or the details of the VLAN database (or VLAN learning table) for each ERP instance. Doing so allows you to see on which port each VLAN is forwarded.

To view a summary of the VLAN database for all ERP

1. Access the page Protection ▶ERP ▶VLAN fdb.

2. To view an ERP's detailed VLAN database, select its Index value from the list.
   Tip: Click Refresh to update the on-screen values. To force updates at a pre-determined interval, enable the Poll Every n Seconds box and enter a value.

For more information on specific parameters, refer to the following table.

ERP VLAN Forwarding Table (Protection ▶ERP ▶VLAN fdb)