Switched Mode Operation; Switched Mode Operation And Logical Equivalent - HP StorageWorks 64 - SAN Director Switch Planning Manual

Planning Considerations for Fibre Channel Topologies

Switched Mode Operation

When set to switched mode (default setting), a loop switch enables frame
transmission through multiple point-to-point connected pairs. Switched mode
operation and its simplified logical equivalent are illustrated in
Part (A) of
pair of H_Ports, communicating at 1.0625 Gbps. Server S
D through a second switched pair of H_Ports, also communicating at 1.0625
2
Gbps. Because of opportunistic bandwidth sharing, the two switched pairs
effectively increase the switch bandwidth to 2.125 Gbps. The remaining switch
H_Ports (four ports) are available for switched connection to each other, but
cannot communicate with servers S
Figure 29
S1
Figure 29: Switched mode operation and logical equivalent
Switched mode also allows independent operation of looplets of devices, each
connected through an unmanaged hub, and each attached to a single switch
H_Port.
connected to a pair of devices (16 devices total). Each device pair forms a looplet
that communicates through a hub and connecting H_Port, and because of
opportunistic bandwidth sharing, the looplets effectively increase the switch
bandwidth to 8.5 Gbps.
70
Figure 29 shows server S
shows the logical equivalent of this arbitrated loop.
Loop Switch
D1 S2
Figure 30 shows 8 hubs, each connected to a switch H_Port, and each
connected to device D
1
and S or devices D
1 2
A
Logical Equivalent
H_Ports
S1
D2
SAN High Availability Planning Guide
Figure 29.
through a switched
1
is connected to device
2
and D . Part (B) of
1 2
B
D1 S2 D2