FUJITSU SPARC M4000 - Manual (Page 49)

Chapter 1 XSCF Overview 1-15
XSCF-LAN Redundancy
In the midrange systems, the XSCF-LAN paths can be made redundant (duplicated).
If a LAN failure occurs, it contributes significantly to reducing system availability.
However, in a system equipped with a duplicate LAN, the routes (paths) in the
remaining network can be used even if one subnetwork is faulty. In this way, high
system availability can be achieved.
FIGURE 1-4 shows configurations with a single mounted XSCF Unit: one where the
LAN is not redundant, and the other with a redundant LAN. (In FIGURE 1-4 and
FIGURE 1-5 , the ordinary lines represent subnetwork connections and the thick lines
represent network connections.)
FIGURE 1-4 XSCF-LAN Redundancy (In Midrange Systems)
XSCF
System
Failure of
path or XSCF
a) No redundant LAN
XSCF
System
Failure of a path
b) Redundant LAN
In the configuration with a single XSCF Unit, XSCF-LAN cannot be used by any
XSCF Unit failure even if the XSCF-LANs are redundant (duplicated). In the
configuration example shown in
FIGURE 1-5 , the XSCF-LANs are redundant and the
XSCF Unit is in a redundant configuration. If one subnetwork is faulty, the
remaining path can be used (
FIGURE 1-5 -c). If the active XSCF Unit is faulty, XSCF
initiates failover ( FIGURE 1-5 -d). Therefore, high network availability can be achieved.