Dual Attachment Connections - Cisco 7000 Hardware Installation And Maintenance

Dual Attachment Connections

A FIP that is connected as a dual attachment station (DAS) connects to both the primary and
secondary rings. The signal for each ring is received on one physical interface (PHY A or PHY B)
and transmitted from the other. The standard connection scheme (which is shown in Figure 3-11) for
a DAS dictates that the primary ring signal comes into the FIP on the PHY A receive port and returns
to the primary ring from the PHY B transmit port. The secondary ring signal comes into the FIP on
the PHY B receive port and returns to the secondary ring from the PHY A transmit port. Failure to
observe this relationship will prevent the FDDI interface from initializing. Figure 3-14 shows the
connections for a dual attachment that uses both multimode and single-mode fiber.
Figure 3-11
Depending on whether you are connecting to a single-mode or multimode fiber network, connect the
FIP as follows:
•
Single-mode—Observe the standard connection scheme described previously, and refer to
Figure 3-12 while you connect the interface cables as follows:
— Connect the cable coming in from the primary ring (from PHY B at the primary ring
— Connect the cable going out to the primary ring (to PHY A at the primary ring downstream
— Connect the cable coming in from the secondary ring to the FIP PHY B receive port.
— Connect the cable going out to the secondary ring to the FIP PHY A transmit port.
•
Multimode—Each of the integrated transmit/receive multimode interface cables attaches to both
the primary and secondary ring; each one receives the signal from one ring and transmits to the
other ring. (See Figure 3-13.) To help avoid confusion, use the receive label on the cable MIC
connector as a key and connect the cables to the FIP ports as follows:
— Connect the cable coming in from the primary ring to the PHY A receive port. This also
— Connect the cable coming in from the secondary ring to the PHY B receive port. This also
If you are connecting an optical bypass switch, proceed to the next section. Otherwise, proceed to
the section "Connecting the Console Terminal" later in this chapter.
FDDI DAS Ports
Secondary
TX
PHY
A
Primary
RX
upstream station) to the FIP PHY A receive port.
station) to the FIP PHY B transmit port.
connects the signal going out to the secondary ring to the PHY A transmit port.
connects the signal going out to the primary ring to the PHY B transmit port.
Secondary
RX
PHY
B
Primary
FORMAC
TX
Connecting Interface Cables
Installing the Router 3-133