Lexmark IBM 9077 - Manual (Page 144)

126 IBM 9077 SP Switch Router: Get Connected to the SP Switch
Configure the FDDI media card for dual attach, but use two single attach
(SAS) cables to connect to two M ports. As shown in Figure 45, the M ports
can be on either one or two FDDI concentrators on the ring.
Figure 45. Dual Homing Configurations
4.4.1 Separate Networks versus Bridging
With all that said, it should be very clear now that every port needs to be
attached to a distinct network, either physical or logical (divided by subnet
masks). This gives you distinct paths to every network and requires setting up
routes.
If you are running a flat FDDI backbone and have the need to connect all four
ports into it, you must configure the card’s interfaces to use transparent
bridging, thus "bundling up" the bandwidth of the four interfaces.
The actual steps to implement bridging will be covered later; refer to Section
4.6, “Configuring Bridging” on page 142.
4.4.2 Naming the FDDI Interfaces
Each interface may be named or numbered in four different ways:
• By its physical location on the FDDI card
• By a site-specified SAS/DAS setting name in the Card profile, single or
dual
A0
B0
A1
B1
FDDI
A0
B0
A1
B1
FDDI
M
M
Concentrator
M Concentrator 2
M
Concentrator 1
Ring
Ring