Configuring The Adver_Timer Of Vrrp - 3Com 3C13636 Configuration Manual

3Com Router 3000 Ethernet Family
Configuration Guide
router sends a VRRP packet, it fills the authentication key into the VRRP packet. When
the router receives a VRRP packet, it compares the authentication key in the packet
with the one that it retains. If they are the same, the packet is considered genuine and
legitimate. If otherwise, the packet is considered illegitimate and is discarded.
On an unsafe network, you can set the authentication mode to MD5. This allows the
router to authenticate VRRP packets using the authentication method provided by
authentication header (AH) and the MD5 algorithm. When input in simple text, an
authentication key must be 1 to 8 characters long, for example, 1234567. When input in
cipher text, an authentication key must be 24 characters long, for example,
(TT8F]Y\5SQ=^Q`MAF4<1!!.
The router discards the packets that fail authentication and sends traps.
Perform the following configuration in interface view.
Table 3-5 Configure the authentication mode and authentication key
Configure the authentication mode and
authentication key.
Restore the default.
By default, the router does not authenticate VRRP packets.
Note:
For the standby groups on the same interface, you must set the same authentication
mode and authentication key.

3.2.6 Configuring the Adver_Timer of VRRP

In a VRRP standby group, the master tells other routers that it is alive by sending VRRP
packets regularly. If no VRRP packets are received after a specified period, the backup
assumes the master has failed and changes its state to master. The VRRP packet
sending interval and the state transition of the backup are controlled by two timers:
Adver_Timer and Master_Down_Timer.
The Master_Down_Timer is about three times that of the Adver_Timer. Either
enormous traffic or difference of the timer settings on the routers can result in abnormal
timeout of the Master_Down_Timer, causing state transition. One solution to this
problem is to set Adver_Timer (in seconds) to a greater value and/or configure
preemption delay.
Perform the following configuration in interface view.
Operation
3Com Corporation
3-6
Chapter 3 VRRP Configurations
Command
vrrp authentication-mode { md5 key |
simple key }
undo vrrp authentication-mode