AT-S63 Management Software Features Guide
Section III: Snooping Protocols
211
Overview
Ethernet Protection Switching Ring is a feature found on selected Allied
Telesis products, such as the AT-x900 Advanced Layer 3 Switches. It
offers an effective alternative to spanning tree based options when using
ring based topologies to create high speed resilient networks.
EPSR consists of a master node and a number of transit nodes in a ring
configuration. The master node monitors the health of the ring by
transmitting healthcheck messages from a primary port at regular intervals
over a control VLAN, and watching for the messages on a secondary port.
If the healthcheck messages fail to arrive, the master node commences
fault recovery of the ring by activating the secondary port so that
connectivity between the transit nodes is maintained through the master
node. When the integrity of the ring is restored, and the healthcheck
messages can again traverse the entire ring, the master switch returns the
secondary port to the blocking state.
Note
For background information and configuration examples of EPSR,
refer to the
AlliedWare OS Software Reference Guide
.
EPSR snooping gives the AT-9400 Switch the ability to function as a
transit node of a ring, but with restrictions, as explained in the next section.
The switch can forward healthcheck messages over the control VLAN
from the master node and respond appropriately when notified of a ring
fault by the master node.
The master node generates a variety of messages over the control VLAN
for monitoring the health of the ring and for notifying the nodes of changes
to the ring’s status. Two of these messages are the Ring-Down-Flush-FDB
and Ring-Up-Flush-FDB messages. The first message notifies the nodes
of a ring fault condition and the second signals the reestablishment of the
ring.
The AT-9400 Switch and EPSR snooping react to these messages by
flushing the addresses learned on the two ring ports of the control VLAN
from the forwarding database, so that the switch can relearn the
addresses. These are the only two EPSR messages that EPSR snooping
can react to. It should be noted that EPSR snooping cannot generate any
EPSR messages itself.
To configure the AT-9400 Switch as a transit node you need to create the
control and data VLANs of the individual ring domains. As explained in the
EPSR chapter in the
AlliedWare OS Software Reference Guide
, several
domains can share the same physical network, but they must operate as
logically separate VLAN groups. For information on VLANs, refer to
Chapter 24, “Port-based and Tagged VLANs” on page 269.
Содержание AT-S63
Страница 14: ...Figures 14 ...
Страница 18: ...Tables 18 ...
Страница 28: ...28 Section I Basic Operations ...
Страница 58: ...Chapter 1 Overview 58 ...
Страница 76: ...Chapter 2 AT 9400Ts Stacks 76 Section I Basic Operations ...
Страница 96: ...Chapter 5 MAC Address Table 96 Section I Basic Operations ...
Страница 114: ...Chapter 8 Port Mirror 114 Section I Basic Operations ...
Страница 116: ...116 Section II Advanced Operations ...
Страница 146: ...Chapter 12 Access Control Lists 146 Section II Advanced Operations ...
Страница 176: ...Chapter 14 Quality of Service 176 Section II Advanced Operations ...
Страница 196: ...196 Section III Snooping Protocols ...
Страница 204: ...Chapter 18 Multicast Listener Discovery Snooping 204 Section III Snooping Protocols ...
Страница 216: ...Chapter 20 Ethernet Protection Switching Ring Snooping 216 Section III Snooping Protocols ...
Страница 218: ...218 Section IV SNMPv3 ...
Страница 234: ...234 Section V Spanning Tree Protocols ...
Страница 268: ...268 Section VI Virtual LANs ...
Страница 306: ...Chapter 27 Protected Ports VLANs 306 Section VI Virtual LANs ...
Страница 320: ...320 Section VII Internet Protocol Routing ...
Страница 360: ...Chapter 30 BOOTP Relay Agent 360 Section VII Routing ...
Страница 370: ...Chapter 31 Virtual Router Redundancy Protocol 370 Section VII Routing ...
Страница 372: ...372 Section VIII Port Security ...
Страница 402: ...Chapter 33 802 1x Port based Network Access Control 402 Section VIII Port Security ...
Страница 404: ...404 Section IX Management Security ...
Страница 436: ...Chapter 36 PKI Certificates and SSL 436 Section IX Management Security ...
Страница 454: ...Chapter 38 TACACS and RADIUS Protocols 454 Section IX Management Security ...
Страница 462: ...Chapter 39 Management Access Control List 462 Section IX Management Security ...
Страница 504: ...Appendix B SNMPv3 Configuration Examples 504 Security Model Security Level Storage Type SNMPv3 Parameters Continued ...
Страница 532: ...Appendix D MIB Objects 532 ...