CANOGA PERKINS 9175 Configuration Guide - Manual (Page 47)

CanogaOS Configuration Guide
9-1
9 Configuring ERPS
9.1 Overview
ERPS technology increases the availability and robustness of Ethernet rings. In the
event that a fiber cut occurs, ERPS converges in less than one second, often in less than
50 milliseconds.
The main idea is described as the following. ERPS operates by declaring an ERPS
domain on a single ring. On that ring domain, one switch, or node, is designated the
master node, while all other nodes are designated as transit nodes. One port of the
master node is designated as the master node’s primary port to the ring; another port is
designated as the master node’s secondary port to the ring. In normal operation, the
master node blocks the secondary port for all non-ERPS traffic belonging to this ERPS
domain, thereby avoiding a loop in the ring. Keep-alive messages are sent by the master
node in a pre-set time interval. Transit nodes in the ring domain will forward the ERPS
messages. Once a link failure event occurs, the master node will detect this either by
receiving the link-down message sent by the node adjacent to the failed link or by the
timeout of the keep-alive message. After link failure is detected, master node will open
the secondary port for data traffic to re-route the traffic.
9.2 References
The ERPS module is based on the following RFC:
RFC 3619
ERPS is a soft-state protocol. The main requirement is to enable ERPS on desired
devices, and configure the ERPS information correctly for various network topologies.
This section provides ERPS configuration examples for there typical network topologies.
Note: For details on the commands used in the following examples, refer to the ERPS
Command Reference.
9.3 Configuring ERPS for a Single-Ring Topology
Configure same ERPS domain and ring at switch 1, switch 2 and switch 3. Switch 1 is
configured as ERPS master node and other two switches are configured as ERPS transit
nodes. Interface agg11, which has two members called eth-0-9 and eth-0-10, is
configured as primary interface at switch 1 and eth-0-13 is configured as secondary
interface.
Note:
The ports accessing an ERPS ring must be configured as trunk ports, permitting the
traffic of data VLANs to pass through.
• The ports accessing an ERPS ring must be configured as the members of the
control VLAN, allowing the ERPS packets to be sent and received.
• STP on ports accessing ERPS rings must be disabled.
• Only one node can be configured as master node.
• Control VLAN must not be configured as Layer 3 interface.
• VLAN mapping must not be enabled on the ERPS ports.