Chapter 6 Configuring the System
Configuring STP
6-32
Catalyst 2900 Series XL and Catalyst 3500 Series XL Software Configuration Guide
78-6511-05
Figure 6-7
Cross-Stack UplinkFast Topology
CSUF implements the Stack Membership Discovery Protocol and the Fast Uplink
Transition Protocol. Using the Stack Membership Discovery Protocol, all stack
switches build a neighbor list of stack members through the receipt of discovery
hello packets. When certain link loss or STP events occur (described in the
“Events that Cause Fast Convergence” section on page 6-33
), the Fast Uplink
Transition Protocol uses the neighbor list to send fast-transition requests on the
stack port to stack members.
Switch A
Spanning
tree root
Backbone
Multidrop backbone
(GigaStack GBIC connections)
Stack port
47572
Switch B
Stack port
Fwd
Link A
(Root link)
Link B
(Alternate
redundant
link)
Link C
(Alternate
redundant
link)
100 or 1000 Mbps
100 or 1000 Mbps
100 or 1000 Mbps
Fwd
Fwd
Switch C Stack port
Stack root port
Alternate stack
root port
Alternate stack
root port