3Com WX2200 3CRWX220095A Switch User Manual

Resiliency and Dual-Homing Options for MAPs
MAPs can support a wide variety of resiliency options. Redundancy for
data link connections and for WX services can be provided to the MAP.
PoE redundancy—On MAP models that have two Ethernet ports, you
can provide PoE redundancy by connecting both ports to PoE sources.
PoE can come from a directly connected WX or a PoE injector.
Dual-homing support for PoE is automatically enabled when you
connect both MAP Ethernet ports.
Data link redundancy—You can provide data link redundancy by
connecting both Ethernet ports directly to one WX, two WX switches,
an intermediate Ethernet switch, or a combination of WX and
Ethernet switch. If an intermediate Ethernet connection is used, you
also need a Distributed MAP configuration on a WX somewhere in the
network. Dual-homing support for data link redundancy is
automatically enabled when you connect both MAP Ethernet ports.
WX redundancy—You can provide redundancy of WX services by
dual-homing the MAP to two directly connected WX switches; or by
configuring a Distributed MAP configuration either on two or more
indirectly connected WX switches, or on a combination of a directly
connected WX and one or more indirectly connected WX switches. To
provide WX redundancy on a MAP model that has only one MAP port,
configure a Distributed MAP connection on two or more indirectly
connected WX switches.
Bias On a WX, configurations for MAPs have a bias (low or high)
associated with them. The default is high. A WX with high bias for a MAP
is preferred over a WX with low bias for the MAP
If more than one WX has high bias, or the bias for all connections is the
same, the WX with the greatest capacity to add more active MAPs is
preferred. For example, if one WX has 50 active MAPs while another WX
has 60 active MAPs, and both WX switches are capable of managing 80
active MAPs, the new MAP uses the WX that has only 50 active MAPs.
Bias applies only to WX switches that are indirectly attached to the MAP
through an intermediate Layer 2 or Layer 3 network. A MAP always attempts
to boot on MAP port 1 first, and if a WX switch is directly attached on MAP
port 1, the MAP boots from it regardless of the bias settings.
(To set the bias for a MAP configuration, see “Changing Bias” on
page 227.)