Extreme Networks ExtremeWare Command Reference Manual page 1059

ELSM uses two types of hello packets to communicate the health of the network to other ELSM ports.
• Hello+ — The device receives a hello from the neighbor device, and no problem is detected
• Hello- — The device does not receive a hello from the neighbor device, or the device has
experienced a critical event.
Use the following command to specify the time, in seconds, between consecutive ELSM hellos:
configure elsm hellotime <1-128> ports <portlist>
Table 18 describes the ELSM timers that are derived from other timers and are not user-configurable.
Table 18: Derived timers
Timer Description
Down Specifies the time it takes for the ELSM receive port to cycle through the following states:
•
•
•
If the Hello timer is set to 1 seconds, it takes 4 seconds for the ELSM receive port to cycle through
the states.
After the timer expires, the port checks the number of Hello+ packets against the hold threshold. If
the number of Hello+ packets received is greater than or equal to the configured hold threshold, the
ELSM receive port moves from the Down-Wait state to the Up state.
If the number of Hello(+) packets received is less than the configured hold threshold, the ELSM
receive port moves from the Down-Wait state to the Down state.
The down timer is 4 times the Hello timer.
Up When an ELSM-enabled port enters the Up state, the Up timer begins. The timer restarts each time
the port receives a Hello+ packet. The Up timer is 6 times the Hello timer.
HelloRx Specifies the time in which a Hello packet is expected, otherwise the ELSM transmit state changes
from HelloRx+ to HelloRx-. The HelloRx timer is 6 times the Hello timer.
The ELSM receive port receives hello messages from its peer. The ELSM receive states are:
• Down—Port is down.
When you enable ELSM, the starting state is Up. If it does not receive a Hello message from its
neighbor before the Up timeout, it transitions to the Down state. When ELSM is down, data packets
are neither received nor transmitted out of that port.
• Down-Wait—Transitional state.
When the port enters the Down-Wait state, the Down timer begins. After the timer expires, the port
checks the number of Hello+ packets received against the configured down threshold. If the Hello+
packets are greater than or equal to the threshold, the port transitions to the Up state. If the Hello+
packets are less than the threshold, the port returns to the Down state and begins the process again.
• Up—Beginning state, port is up.
If ELSM is enabled and the port enters the Up state, the Up timer begins. Each time the port receives
a Hello+ packet, the timer restarts and remains in the Up state.
If the port no longer receives hello packets for Up-timer seconds, or receives a hello- packet, the port
transitions to either the Down or Down-Stuck state.
ExtremeWare Software 7.3.0 Command Reference Guide
Down
Down-Wait
Up
configure elsm hold-threshold
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