3Com CoreBuilder 9000, Руководство пользователя

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LAN Emulation Redundancy 393
LECS Redundancy
Facility —
Configuring the
LECS-Order Database
You provide for LECS redundancy by enabling the LECS in up to five
CoreBuilder 9000 ATM Enterprise Switches in the network. A LECS-order
database with up to five entries is provided in each switch to support
LECS redundancy. The first entry is the normally active LECS and the
others are redundant backup LECS, which are activated according to
order. When you plan out the network, decide which LECS you want to
be active and put it in the first position in the LECS-order database in
each switch in the network.
Normally, only one LECS of the five is active in the network at any time,
fulfilling the LECs join requests. If the switch unit with the active LECS
fails, the next redundant LECS in the LECS-order database is established
as the active LECS by associating its address with the “well-known”
address. Then, a LEC that attempts to establish a connection to the LECS
via the well-known address is redirected to establish a connection to the
newly activated LECS.
Multiple Active LECS in a Large Network
For a large network, you can reduce signaling traffic by having more than
one LECS active in the network at the same time. Then, a LEC that
requests to join a specific ELAN can do it through the nearest active LECS.
Divide the network into parts A, B, C, and so on. Assign LECS 1 to be
active for part A of the network by putting LECS 1 first in the LECS-order
database for all switches in part A; assign LECS 2 to be active for part B
by putting LECS 2 first in the LECS-order database for all switches in part
B, and so on.
For this arrangement to work, all LECS in the network must be configured
with exactly the same ELAN topology database, as discussed in the next
section.
LMA Commands
To display the LECS-order database by LMA, see “Display LECS
Redundancy” on page 234. To enter a LECS into the LECS-order database
see “Add LECS to LECS-Order Database” on page 235.