virtual-channel

Function

The virtual-channel command configures a ring auto protection switching protocol data unit (R-APS PDU) transmission mode for a sub-ring.

The undo virtual-channel enablecommand restores the default configuration.

By default, R-APS PDUs on sub-rings are transmitted in non-virtual channel (NVC) mode.

Format

virtual-channel { disable | enable }

undo virtual-channel enable

Parameters

Parameter	Description	Value
disable	Disables the VC mode for R-APS PDU transmission on a sub-ring, which means the NVC mode is used.	-
enable	Enables the VC mode for R-APS PDU transmission on a sub-ring.	-

Parameter

Description

Value

disable

Disables the VC mode for R-APS PDU transmission on a sub-ring, which means the NVC mode is used.

enable

Enables the VC mode for R-APS PDU transmission on a sub-ring.

Views

ERPS ring view

Default Level

2: Configuration level

Task Name and Operations

Task Name	Operations
erps	write

Usage Guidelines

Usage Scenario

To specify whether to use VCs or NVCs to transmit R-APS PDUs on sub-rings, run the virtual-channel command.
ERPSv2 supports single and multi-ring topologies.
In multi-ring topologies, sub-rings either have VCs or NVCs to transmit R-APS PDUs.
With VCs: R-APS PDUs on sub-rings are transmitted to the major ring through interconnection nodes. The ring protection link (RPL) owner port of a sub-ring blocks both R-APS PDUs and data traffic.
With NVCs: R-APS PDUs on sub-rings are terminated on the interconnection nodes. The RPL owner port blocks data traffic but not R-APS PDUs on each sub-ring.

Prerequisites

ERPSv2 has been configured using the version v2 command, and the ERPS ring has been configured as a sub-ring using the sub-ring command.

Configuration Impact

If a sub-ring uses VCs to transmit R-APS PDUs, you must run the virtual-channel disable command to restore the R-APS PDU transmission mode to NVC before running the undo sub-ring command to restore the sub-ring to a major ring.

If the VC mode is used for sub-ring R-APS PDU transmission, it is recommended that the major ring's VLAN with an ID same as that of the sub-ring's control VLAN transmit only sub-ring R-APS PDUs. If this major ring's VLAN also transmits data packets, attackers may construct bogus sub-ring R-APS PDUs, causing sub-ring loops or even a major ring failure.

Example

# Configure the sub-ring ERPS ring 5 to use VCs to transmit R-APS PDUs.

<HUAWEI> system-view
[~HUAWEI] erps ring 5
[*HUAWEI-erps-ring5] version v2
[*HUAWEI-erps-ring5] sub-ring
[*HUAWEI-erps-ring5] virtual-channel enable