Dual Attach Connections - Cisco 7000 Series Hardware Installation And Maintenance Manual

Connecting Interface Cables
Figure 3-13
FIP

Dual Attach Connections

A FIP that is connected as a dual-attach 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 3-14) 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 3-17 shows the
connections for a dual attachment that uses both multimode and single-mode fiber.
Figure 3-14
Depending on whether you are connecting to a single-mode or multimode fiber network, connect the
FIP as follows:
•
3-18 Cisco 7010 Hardware Installation and Maintenance
Single Attach Station (SAS), Multimode Fiber Network Connections
FDDI DAS Ports
Secondary TX
PHY
A
Primary
RX
Single-mode—Observe the standard connection scheme described previously, and refer to
Figure 3-15 while you connect the interface cables as follows:
— Connect the cable coming in from the primary ring (from PHY B at the primary ring
upstream station) to the FIP PHY A receive port.
— Connect the cable going out to the primary ring (to PHY A at the primary ring downstream
station) to the FIP PHY B transmit port.
— 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.
TX RX
PHY B
To/from
primary ring
RX Secondary
PHY
B
Primary
FORMAC
TX
Multimode,
single attachment.
TX RX
Use one multimode cable
for a single attachment
connection.
PHY A
MIC