1-43
MSTP is capable of detecting link failures and automatically restoring redundant links to the forwarding
state. In CIST, switches use the max age parameter to judge whether or not a received configuration
BPDU times out. Spanning trees will be recalculated if a configuration BPDU received by a port times
out.
The max age is meaningless to MSTIs. The max age configured for the root bridge of the CIST applies
to all switches operating on the CIST, including the root bridge.
As for the configuration of the three time-related parameters (namely, the hello time, forward delay, and
max age parameters), the following formulas must be met to prevent frequent network jitter:
2 × (forward delay – 1 second) >= max age,
Max age >= 2 × (hello time + 1 second).
You are recommended to specify the network diameter of the switched network and the hello time
parameter by using the
stp root primary
or
stp root secondary
command. After that, the three proper
time-related parameters are automatically determined by MSTP.
Related commands:
stp timer forward-delay,
stp timer hello,
stp bridge-diameter
.
Examples
# Set the max age to 1,000 centiseconds.
<Sysname> system-view
System View: return to User View with Ctrl+Z.
[Sysname] stp timer max-age 1000
stp timer-factor
Syntax
stp timer-factor number
undo
stp timer-factor
View
System view
Parameters
number
: Hello time factor to be set, in the range of 1 to 10.
Description
Use the
stp timer-factor
command to set the timeout time of a switch in the form of a multiple of the
hello time.
Use the
undo stp timer-factor
command to restore the hello time factor to the default value.
By default, the hello time factor of the switch is 3.
A switch regularly sends protocol packets to its neighboring devices at the interval specified by the hello
time parameter to test the links. Generally, a switch regards its upstream switch faulty if the former does
receive any protocol packets from the latter in a period three times of the hello time and then initiates the
spanning tree recalculation process.
Spanning trees may be recalculated even in a steady network if an upstream switch is always busy. You
can configure the hello time factor to a larger number to avoid this problem. Normally, the timeout time
Summary of Contents for 5500-EI PWR
Page 43: ...2 6...
Page 76: ...1 17...
Page 228: ...ii stp transmit limit 1 44 vlan mapping modulo 1 45 vlan vpn tunnel 1 46...
Page 477: ...5 24 Sysname vlan 2 Sysname vlan2 service type multicast...
Page 503: ...2 3 System View return to User View with Ctrl Z Sysname dot1x url http 192 168 19 23...
Page 519: ...iii...
Page 597: ...2 2 security policy server 192 168 0 1 user name format without domain...
Page 648: ...1 9 Examples Clear static ARP entries Sysname reset arp static...
Page 663: ...4 3 Sysname resilient arp interface vlan interface 2...
Page 767: ...1 28 From 12 00 Jan 1 2008 to 12 00 Jun 1 2008...
Page 1111: ...ii xmodem get 3 18...
Page 1314: ...A 44 Z...
