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Setting Up ERP Protection
- 24 Jan 2024
- 9 Minutes to read
- Contributors
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Setting Up ERP Protection
- Updated on 24 Jan 2024
- 9 Minutes to read
- Contributors
- Print
- PDF
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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
Access the page Protection ▶ERP ▶Configuration.
A summary of all ERP instances currently set up in the system is displayed.Click the Add button to add a new ERP instance or click the Index of an existing ERP instance to edit its settings.
Complete the required fields, then click Apply.
For more information on specific parameters, refer to the following tables.
ERP Configuration (Protection ▶ERP ▶Configuration)
| Parameter | Description |
|---|---|
| Index | The unique identifier assigned to the ERP instance once it has been created. You cannot modify this value. Note: The system supports up to eight ERP instances. |
| Name | The name of the ERP instance. |
| Version | The version number assigned to the ERP instance once it has been created. You cannot modify this value. |
Port Configuration
| Parameter | Description |
|---|---|
| LAG Port | The LAG port used by this ERP instance. You must first set this LAG port to ERP status protection mode in the page Port ▶ Configuration. |
| Port 0 | The name of the physical port 0 (depending on which LAG port is selected) used in the ERP. |
| MEP0-idx | The MEP index used for detecting a failure on ring port 0. |
| Port 1 | The name of the physical port 1 (depending on which LAG port is selected) used in the ERP. |
| MEP1-idx | The MEP index used for detecting failure on ring port 1. |
RPL Configuration
| Parameter | Description |
|---|---|
| RPL-Role | The ring protection link role:
|
| RPL-Port | The physical port for the ring protection link. It is useful to know which port to connect to between the owner and its neighbor. Possible values are:
|
| Hold-Off Timer (ms) | The time, expressed in milliseconds, to wait before ERP protection initiates a switch. Waiting before switching may give another protection mechanism time to repair the defect. |
| Revertive | Select this box to enable the revertive mode of operation. Note: Only applies when the RPL-Role is set to Owner. |
| Guard Timer (ms) | The guard timer duration, expressed in milliseconds. |
| WTR Timer (min) | The duration of the Wait To Restore timer, expressed in minutes. Note: Only applies when the RPL-Role is set to Owner. |
ERP Configuration
| Parameter | Description |
|---|---|
| MD Level | The MD level of the ERP messages. |
| VLAN Type | The VLAN Type may be one of the following:
|
| APS-VID | The VLAN used by the APS protocol. Each ERP instance uses a different VLAN. Range: 1–4095. Note: This VLAN must be reserved solely for the APS protocol, otherwise an error will be raised. Furthermore, the VLAN must not be used for any type of customer traffic. |
| VID Set VID-List | The list of VLAN IDs protected by this ERP instance. Only these VLANs can be sent on this ring. |
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
- 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
Access the page Protection ▶ERP ▶Status.
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)
| Parameter | Description |
|---|---|
| Index | The unique identifier assigned to the ERP instance. You cannot modify this value. |
| Name | The name of the ERP instance. |
| Node ID | The MAC address of this unit. |
| State | The state of the ERP instance:
|
| RPL Node ID | The MAC address for the ring protection link port. |
Alarms
| Parameter | Description |
|---|---|
| Version Mismatch | The ERP version of the units in the ring match (Inactive) or do not match (Active). |
| Force Switch | Forced switching of a ring port (Active or Inactive). |
| Manual Switch | Manual switching of a ring port (Active or Inactive). |
| Signal Failed | Signal failure is present (Active) or absent (Inactive). A signal failure triggers a protection switch. |
Latest Top Priority Request
| Parameter | Description |
|---|---|
| Request Node ID | The MAC address of the requested node. |
| Request | The last top priority request that was processed. |
Port X
| Parameter | Description |
|---|---|
| Port X | The name of the physical port used in the ERP. |
| Status | The status of the ring protection link port. |
| State | The state of the port, i.e. Blocked or Forwarding. |
| Force Switch | Click this button to force switching of the ring port. |
| Manual Switch | Click this button to perform a manual switch of the ring port. |
| Clear | Click this button to clear a switch you forced previously. |
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.
CAUTION: Forcing a switch to a port that is in "Protection" state may result in a loss of traffic.
To force a switch to the standby port
Access the page Protection ▶ERP ▶Status.
Click the ERP Index of the ring you want to switch.
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
Access the page Protection ▶ERP ▶Status.
Click the ERP Index of the ring for which you want to clear the forced switch.
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
Access the page Protection ▶ERP ▶Status.
Click the ERP Index of the ring you want to switch.
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
- 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
Access the page Protection ▶ERP ▶Statistics.
Select an ERP Index.
For more information on specific parameters, refer to the following table.
ERP Results (Protection ▶ERP ▶Statistics)
| Parameter | Description |
|---|---|
| Index | The unique identifier assigned to the ERP instance. You cannot modify this value. |
| Name | The name of the ERP instance. |
| Node ID | The MAC address of this unit. |
Port X (The results for each port)
| Parameter | Description |
|---|---|
| Local Clear | The number of the local clears performed. |
| Local FS | The number of local forced switches performed. |
| Local SF | The number of local signal failures. |
| Local MS | The number of local manual switches performed. |
| RX APS(Event) | The number of APS events received (all events of type received). |
| RX APS(FS) | The number of forced-switch events received. |
| RX APS(SF) | The number of signal-failed events received. |
| Rx APS(MS) | The number of manual-switch events received. |
| RX APS(NR,RB) | The number of no-requests and RPL blockages received. |
| RX APS(NR) | The number of no-requests received. |
| TX APS(Event) | The number of APS events transmitted. |
| TX APS(FS) | The number of forced switches transmitted. |
| TX APS(SF) | The number of signal failures transmitted. |
| TX APS(MS) | The number of manual switches transmitted. |
| TX APS(NR,RB) | The number of no-requests and RPL blockages transmitted. |
| TX APS(NR) | The number of no-requests transmitted. |
Discarded RX APS
| Parameter | Description |
|---|---|
| GuardTimer | The number of APS messages blocked by the guard timer. The guard timer blocks outdated APS messages, which prevents the system from acting upon outdated Rx APS messages. |
| Unknown Request Code | Unknown request code received. |
| Version Mismatch | The number of events received with an ERP version that do not match the local version. |
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
Access the page Protection ▶ERP ▶VLAN fdb.
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)
| Parameter | Description |
|---|---|
| Index | The unique identifier assigned to the ERP instance. |
| Name | The name of the ERP instance. |
| Ports | The ports in use and the Flooding VIDs and Flapping VIDs. Each port lists the learned VLAN IDs on this port. VIDs listed for a port are transmitted over this port. The Flooding VIDs list the VLAN IDs that are not presently learned. VIDs listed here are transmitted over the two ports of the ring. The Flapping VIDs list the VLAN IDs that are received too frequently over each port alternatively. This indicates a possible configuration issue for these VLAN IDs. |
| VIDs | The list of VIDs for each port, Flooding VIDs and Flapping VIDs. |
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