Introduction to VRRP
1079
master, while the others are the backups. The master sends VRRP
advertisement packets periodically to notify the backups that it is working
properly, and each of the backups starts a timer to wait for advertisement
packets from the master.
■
In preemption mode, when a backup receives a VRRP advertisement packet, it
compares the priority in the packet with that of its own. If its priority is higher,
it becomes the master; otherwise, it remains a backup.
■
In non-preemption mode, the switch in the standby group remains as a master
or backup as long as the master does not fail. The backup will no become the
master even if the former is configured with a higher priority.
■
If the timer of a backup expires but the backup still does not receive any VRRP
advertisement packet, it considers that the master fails. In this case, the backup
switch considers itself as the master switch and sends VRRP advertisements to
start the election process to elect a new master switch for forwarding packets.
VRRP Interface Tracking
The interface tracking function expands the backup functionality of VRRP. It
provides backup not only when the interface to which a standby group is assigned
fails but also when other interfaces on the switch become unavailable. This is
achieved by tracking interfaces. When a monitored interface goes down, the
priority of the switch owning the interface is automatically decreased by a
specified value
,
allowing a higher priority switch in the standby group to become
the master.
VRRP Application
(Taking IPv4-Based VRRP
for Example)
Master/backup
In master/backup mode, only one switch, the master, provides services. When the
master fails, a new master is elected from the original backups. This mode requires
only one standby group, in which each switch holds different priorities and the
one with the highest priority becomes the master, as shown in Figure 322.
Figure 322
VRRP in master/backup mode
At the beginning, Switch A is the master and therefore can forward packets to
external networks, while Switch B and Switch C are backups and are thus in the
state of listening. If Switch A fails, Switch B and Switch C will elect for the new
Host A
Host B
Host C
Switch A
Master
Switch B
Backup
Switch C
Backup
Virtual IP address:
10.1.1.1/24
10.1.1 .2/24
10.1.1 .3/24
10.1.1 .4/24
Network
Содержание 4800G Series
Страница 26: ...26 CHAPTER NETWORKING APPLICATIONS ...
Страница 30: ...30 CHAPTER 1 LOGGING IN TO AN ETHERNET SWITCH ...
Страница 62: ...62 CHAPTER 3 LOGGING IN THROUGH TELNET ...
Страница 70: ...70 CHAPTER 5 LOGGING IN THROUGH WEB BASED NETWORK MANAGEMENT SYSTEM ...
Страница 72: ...72 CHAPTER 6 LOGGING IN THROUGH NMS ...
Страница 82: ...82 CHAPTER 8 CONTROLLING LOGIN USERS ...
Страница 98: ...98 CHAPTER 9 VLAN CONFIGURATION ...
Страница 108: ...108 CHAPTER 10 VOICE VLAN CONFIGURATION ...
Страница 119: ...GVRP Configuration Examples 119 DeviceB display vlan dynamic No dynamic vlans exist ...
Страница 120: ...120 CHAPTER 11 GVRP CONFIGURATION ...
Страница 160: ...160 CHAPTER 17 PORT ISOLATION CONFIGURATION ...
Страница 172: ...172 CHAPTER 19 LINK AGGREGATION CONFIGURATION ...
Страница 196: ...196 CHAPTER 22 DLDP CONFIGURATION ...
Страница 240: ...240 CHAPTER 23 MSTP CONFIGURATION ...
Страница 272: ...272 CHAPTER 27 RIP CONFIGURATION ...
Страница 364: ...364 CHAPTER 29 IS IS CONFIGURATION ...
Страница 426: ...426 CHAPTER 31 ROUTING POLICY CONFIGURATION ...
Страница 442: ...442 CHAPTER 33 IPV6 RIPNG CONFIGURATION ...
Страница 466: ...466 CHAPTER 35 IPV6 IS IS CONFIGURATION ...
Страница 488: ...488 CHAPTER 36 IPV6 BGP CONFIGURATION ...
Страница 498: ...498 CHAPTER 37 ROUTING POLICY CONFIGURATION ...
Страница 540: ...540 CHAPTER 40 TUNNELING CONFIGURATION ...
Страница 552: ...552 CHAPTER 41 MULTICAST OVERVIEW ...
Страница 604: ...604 CHAPTER 43 MLD SNOOPING CONFIGURATION ...
Страница 628: ...628 CHAPTER 46 IGMP CONFIGURATION ...
Страница 699: ...Troubleshooting MSDP 699 4 Verify that the C BSR address is different from the anycast RP address ...
Страница 700: ...700 CHAPTER 48 MSDP CONFIGURATION ...
Страница 812: ...812 CHAPTER 57 DHCP SERVER CONFIGURATION ...
Страница 822: ...822 CHAPTER 58 DHCP RELAY AGENT CONFIGURATION ...
Страница 834: ...834 CHAPTER 61 BOOTP CLIENT CONFIGURATION ...
Страница 850: ...850 CHAPTER 63 IPV4 ACL CONFIGURATION ...
Страница 856: ...856 CHAPTER 64 IPV6 ACL CONFIGURATION ...
Страница 860: ...860 CHAPTER 65 QOS OVERVIEW ...
Страница 868: ...868 CHAPTER 66 TRAFFIC CLASSIFICATION TP AND LR CONFIGURATION ...
Страница 888: ...888 CHAPTER 69 PRIORITY MAPPING ...
Страница 894: ...894 CHAPTER 71 TRAFFIC MIRRORING CONFIGURATION ...
Страница 904: ...904 CHAPTER 72 PORT MIRRORING CONFIGURATION ...
Страница 930: ...930 CHAPTER 74 UDP HELPER CONFIGURATION ...
Страница 990: ...990 CHAPTER 79 FILE SYSTEM MANAGEMENT CONFIGURATION ...
Страница 1000: ...1000 CHAPTER 80 FTP CONFIGURATION ...
Страница 1020: ...1020 CHAPTER 82 INFORMATION CENTER CONFIGURATION ...
Страница 1038: ...1038 CHAPTER 84 SYSTEM MAINTAINING AND DEBUGGING ...
Страница 1046: ...1046 CHAPTER 85 DEVICE MANAGEMENT ...
Страница 1129: ...SSH Client Configuration Examples 1129 SwitchB ...
Страница 1130: ...1130 CHAPTER 88 SSH CONFIGURATION ...
Страница 1160: ...1160 CHAPTER 90 RRPP CONFIGURATION ...
Страница 1180: ...1180 CHAPTER 91 PORT SECURITY CONFIGURATION ...
Страница 1192: ...1192 CHAPTER 92 LLDP CONFIGURATION ...
Страница 1202: ...1202 CHAPTER 93 POE CONFIGURATION ...
Страница 1218: ...1218 CHAPTER 96 HTTPS CONFIGURATION ...