LevelOne GTL-2691 User Manual

Page 466

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C

HAPTER

14

| Basic Administration Protocols

Ethernet Ring Protection Switching

– 466 –

Configuration Guidelines for ERPS

1.

Create an ERPS ring (

Configure Domain – Add

): The ring name is used

as an index in the G.8032 database.

2.

Configure the east and west interfaces (

Configure Domain – Configure

Details

): Each node on the ring connects to it through two ring ports.

Configure one port connected to the next node in the ring to the east

(or clockwise direction) and another port facing west in the ring.

3.

Configure the RPL owner (

Configure Domain – Configure Details

):

Configure one node in the ring as the Ring Protection Link (RPL) owner.

When this switch is configured as the RPL owner, the west ring port is
set as being connected to the RPL. Under normal operations (Idle

state), the RPL is blocked to ensure that a loop cannot form in the ring.

If a signal failure brings down any other link in the ring, the RPL will be

unblocked (Protection state) to ensure proper connectivity among all

ring nodes until the failure is recovered.

4.

Configure ERPS timers (

Configure Domain – Configure Details

): Set the

Guard timer to prevent ring nodes from receiving outdated R-APS

messages, the Hold-off timer command to filter out intermittent link

faults, and the WTR timer command to verify that the ring has

stabilized before blocking the RPL after recovery from a signal failure.

5.

Configure the ERPS Control VLAN (

Configure Domain – Configure

Details

): Specify the control VLAN (CVLAN) used to pass R-APS ring

maintenance commands. The CVLAN must NOT be configured with an

IP address. In addition, only ring ports may be added to the CVLAN

(prior to configuring the VLAN as a CVLAN). No other ports can be

members of this VLAN (once set as a CVLAN). Also, the ring ports of the

CVLAN must be tagged. Failure to observe these restrictions can result

in a loop in the network.

6.

Enable ERPS (

Configure Global

): Before enabling a ring as described in

the next step, first globally enable ERPS on the switch. If ERPS has not

yet been enabled or has been disabled, no ERPS rings will work.

7.

Enable an ERPS ring (

Configure Domain – Configure Details

): Before an

EAPS ring can work, it must be enabled. When configuration is

completed and the ring enabled, R-APS messages will start flowing in

the control VLAN, and normal traffic will begin to flow in the data

VLANs. A ring can be stopped by disabling the Admin Status on any

node.

8.

Display ERPS status information (

Configure Domain – Show

): Display

ERPS status information for all configured rings.

Configuration Limitations for ERPS

The following configuration limitations apply to ERPS:

One switch only supports two ERPS rings – each ring must have one

Control VLAN, and at most 255 Data VLANs.

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