AT-S63 Management Software Features Guide
Section VII: Routing
365
Backup Switches
All the other switches participating in the virtual router are designated as
backup switches. A switch can be part of several different virtual routers
on one LAN, provided that all the virtual routers have different virtual router
identifiers.
When a switch functions as a backup for a virtual router, it does the
following:
Receives advertisement packets from the master switch and checks
that the information contained in them is consistent with their own
configuration, ignoring and discarding advertisement packets that do
not match.
Assumes the role of master switch for the virtual router if an
advertisement packet is not received for a given period of time (the
“master-down” period), based on the specified advertisement interval.
The “master-down” time is approximately three times the
advertisement interval.
Assumes the role of master switch if it receives an advertisement
packet from another switch with a lower priority than its own, if preempt
mode is on.
When the master switch fails, the backup switch assumes control and
starts processing traffic.
If a backup switch is about to assume the role of master of the virtual
router because it has not received an advertisement for the “master-down”
period, it first checks the operational status of the interface to which the
virtual router is attached. If the interface is down, it does not enter the
master state. Instead, it says in the backup state and checks the interface
again after another “master-down” period, assuming that it does not
receive an advertisement during that time.
Summary of Contents for AT-S63
Page 14: ...Figures 14 ...
Page 18: ...Tables 18 ...
Page 28: ...28 Section I Basic Operations ...
Page 58: ...Chapter 1 Overview 58 ...
Page 76: ...Chapter 2 AT 9400Ts Stacks 76 Section I Basic Operations ...
Page 96: ...Chapter 5 MAC Address Table 96 Section I Basic Operations ...
Page 114: ...Chapter 8 Port Mirror 114 Section I Basic Operations ...
Page 116: ...116 Section II Advanced Operations ...
Page 146: ...Chapter 12 Access Control Lists 146 Section II Advanced Operations ...
Page 176: ...Chapter 14 Quality of Service 176 Section II Advanced Operations ...
Page 196: ...196 Section III Snooping Protocols ...
Page 204: ...Chapter 18 Multicast Listener Discovery Snooping 204 Section III Snooping Protocols ...
Page 216: ...Chapter 20 Ethernet Protection Switching Ring Snooping 216 Section III Snooping Protocols ...
Page 218: ...218 Section IV SNMPv3 ...
Page 234: ...234 Section V Spanning Tree Protocols ...
Page 268: ...268 Section VI Virtual LANs ...
Page 306: ...Chapter 27 Protected Ports VLANs 306 Section VI Virtual LANs ...
Page 320: ...320 Section VII Internet Protocol Routing ...
Page 360: ...Chapter 30 BOOTP Relay Agent 360 Section VII Routing ...
Page 370: ...Chapter 31 Virtual Router Redundancy Protocol 370 Section VII Routing ...
Page 372: ...372 Section VIII Port Security ...
Page 402: ...Chapter 33 802 1x Port based Network Access Control 402 Section VIII Port Security ...
Page 404: ...404 Section IX Management Security ...
Page 436: ...Chapter 36 PKI Certificates and SSL 436 Section IX Management Security ...
Page 454: ...Chapter 38 TACACS and RADIUS Protocols 454 Section IX Management Security ...
Page 462: ...Chapter 39 Management Access Control List 462 Section IX Management Security ...
Page 532: ...Appendix D MIB Objects 532 ...