ELSM works between two connected ports (peers), and each ELSM instance
is based on a single port. The Layer 2 connection between the ports determines the peer. You
can have a direct connection between the peers or hubs that separate peer ports. In the
first instance, the peers are also considered neighbors. In the second instance, the peer is
not considered a neighbor.
Enable ELSM on one or more ports with the
When you enable ELSM on a port, ELSM immediately
blocks the port and it enters the Down state. When the port detects an ELSM-enabled peer, the
peer ports exchange ELSM hello messages. At this point, the ports enter the transitional
Down-Wait state. If the port receives Hello+ messages from its peer and does not detect a
problem, the peers enter the Up state. If a peer detects a problem or there is no peer port
configured, the port enters the Down state.
For more information about the types of ELSM
hello messages, see ELSM Hello Messages. For
information about configuring the ELSM hello timer, see the next section.