3Com 4510G, Руководство по настройке

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4-3
State Indicates…
Disable
A port enters this state when:
z
A unidirectional link is detected.
z
The contact with the neighbor in enhanced mode gets lost.
In this state, the port does not receive or send packets other than
DLDPDUs.
DelayDown
A port in the Active, Advertisement, or Probe DLDP link state
transits to this state rather than removes the corresponding
neighbor entry and transits to the Inactive state when it detects a
port-down event. When a port transits to this state, the DelayDown
timer is triggered.
DLDP timers
Table 4-2 DLDP timers
DLDP timer Description
Active timer
Determines the Interval for sending Advertisement packets with RSY
tags, which defaults to 1 second. That is, a device in the active DLDP
link state sends one Advertisement packet with RSY tags every second
by default. The maximum number of advertisement packets with RSY
tags that can be sent successively is 5.
Advertisement timer
Determines the interval to send advertisement packets, which defaults
to 5 seconds.
Probe timer
Determines the interval to send Probe packets, which defaults to 0.5
seconds. That is, a device in the probe state sends two Probe packets
every second by default. The maximum number of Probe packets that
can be sent successively is 10.
Echo timer
This timer is set to 10 seconds and is triggered when a device transits
to the Probe state or an enhanced detect is launched. When the Echo
timer expires and no Echo packet has been received from a neighbor
device, the state of the link is set to unidirectional and the device
transits to the Disable state. In this case, the device sends Disable
packets, prompts the user to shut down the port or shuts down the port
automatically (depending on the DLDP down mode configured), and
removes the corresponding neighbor entries.
Entry timer
When a new neighbor joins, a neighbor entry is created and the
corresponding entry timer is triggered. When a DLDP packet is
received, the device updates the corresponding neighbor entry and the
entry aging timer.
In the normal mode, if no packet is received from a neighbor when the
corresponding entry aging timer expires, DLDP sends advertisement
packets with RSY tags and removes the neighbor entry.
In the enhanced mode, if no packet is received from a neighbor when
the Entry timer expires, DLDP triggers the enhanced timer.
The setting of an Entry timer is three times that of the Advertisement
timer.
Enhanced timer
In the enhanced mode, this timer is triggered if no packet is received
from a neighbor when the entry aging timer expires. Enhanced timer is
set to 1 second.
After the Enhanced timer is triggered, the device sends up to eight
probe packets to the neighbor at a frequency of one packet per second.