Specifications

26 Installing the S25P
While the diagram, above, shows A-B port connections, the ports are bi-directional, so you can connect A
to A and/or B to B, as shown below in examples of two-switch (Figure 16 on page 26) and three-switch
(Figure 17 on page 27) ring topologies.
Figure 15 shows the use of 24G stacking ports in each of the two rear modules to create a ring. Of course,
this topology does not allow the use of the rear modules for XFP ports. A cascade topology, removing the
stack port modules in the B slots of switches 1 and 2, would free those slots for use by XFP modules.
Figure 15 Stacking Topology Using 24G Single-port Modules
Connecting Two Switches
Insert one end of the special stacking cable into a stack port, and insert the other end into a stack port of the
adjacent switch. Optionally, insert a second cable into the other open stack port, as shown in Figure 14.
The second cable provides both backup connectivity and increased data transfer between the units.
Figure 16 Stack Ports of Two S25P Switches Connected in a Ring
Note: These diagrams and instructions use “Stack Port A” and “Stack Port B” for clarifying the
connections, but the modules are not labeled.
Switch 1
Switch 2
Module A
Switch 3
A
A
A
Ring topology
using two
B
B
Module B
24Gig modules
B
per unit
fn00151s25P-1
Stack Port B Stack Port A
STACK STACK
STACKSTACK