Topology: The S12708 functions as
the control device, the S5720 functions as the access switch, and policy
association authentication is performed. The terminal is directly connected to
the access switch.
Fault symptom: After the network
cable of the user terminal is removed, run the display access-user command. The access user entry disappears about
10 seconds later.
whether the ARP probe period is configured on the device.
The user-detect command is not
configured on the access switch. The default detection period is 15 seconds and
the number of retransmission times is 3. That is, the terminal is considered
offline only when the detection period is longer than 45 seconds and no
response is received within this period .
In addition, the ARP probe result also needs to be considered when determining
whether a terminal is offline. When the access-user
arp-detect command is configured, the default interval is 300 seconds.
Therefore, a terminal should not be considered offline within such a short
period of time.
terminal is directly connected to the access device. When the terminal is
disconnected from the interface of the access device, the device considers the
interface Down and logs out the user. The intermittent disconnection protection
delay of an interface is 10s. Therefore, the user entry is deleted 10s later.
detection is performed in the non-direct connection scenario, in which the
local interface is unaware that the peer device goes Down, so the detection is
used to keep the peer device alive. In the direct connection scenario, the
local interface can detect if the peer device goes Down.