16-8

Catalyst2950 and Catalyst2955 Switch Software Configuration Guide
78-11380-10
Chapter16 Configuring Optional Spanning-Tree Features
Understanding Optional Spanning-Tree Features
Connecting the Stack Ports

A fast transition occurs across the stack of switches if the multidrop backbone connections are a

continuous link from one GigaStack GBIC module to another as sh own in t he t o p half of Figu re 16-6.

The bottom half of Figure 16-6 shows how to connect the GigaStack GBIC module to achieve a normal

convergence time.

You should follow these guidelines:

A switch supports only one stack port.
Do not connect alternate stack-root ports to stack ports.
Connect all stack ports on the switch stack to the multidrop backbone.
You can connect the open ports on the top and bottom GigaStack GBIC modules within the same

stack to form a redundant link.

Figure16-6 GigaStack GBIC Module Connections and Spanning-Tree Convergence
Catalyst 2950G-24
SPEED
SYSTEM
RPS
STATUS
MODEUTIL
DUPLX
Catalyst 3500 XL
78
3
2
1
12

Catalyst 2950G-12

1
1X
2X
11X
12X
2 3 4 5 6 78 9 10 1112
56
4
2
1
12

Catalyst 3508G XL

GigaStack GBIC connection for fast convergence

GigaStack GBIC connection for normal convergence

SPEED
SYSTEM
RPS
STATUS
UTIL
DUPLX
Catalyst 3500
12

Catalyst 3550-12T

MODE
1 1 1 1 1 1 1 1 1 1
SPEED
SYSTEM
RPS
STATUS
UTIL
DUPLX
Catalyst 3500
12

Catalyst 3550-12T

MODE
1 1 1 1 1 1 1 1 1 1
2
1
1
1
12
12
Catalyst 2950G-24
1
1X
2X
11X
12X
13X
14X
15X
16X
2 3 4 5 6 78 9 10 1112 1314 1516 1718 19 20 2122 2324
2
1
12
12

Catalyst 2950G-12

1
1X
2X
11X
12X
2 3 4 5 6 78 9 10 1112
2
1
12
Catalyst 2950G-24

Catalyst 2950G-48

SPEED
DUPLX
UTIL
STATUS
RPS
SYSTEM
Catalyst 2950
MODE

Catalyst 2950G-48

1
1X
2X
11X
12X
13X
14X
15X
16X
2 3 4 5 6 78 9 10 1112 1314 1516 1718 19 20 2122 2324
65276
RPS
SYST
STATUTILDUPLXSPEED
Catalyst 2950
MODE
RPS
SYST
STATUTILDUPLXSPEED
Catalyst 2950
Catalyst 2950
MODE
RPS
SYST
STATUTILDUPLXSPEED
MODE
1
1X
2X
11X
12X
2 3 4 56 7 8 9 10 910 910 910 1
1X
2X
11X
12X
2 3 4 56 7 8 9 10 910 910 910 1
1X
2X
2 34 5 6 78 9 10 910 910 910
1
1
12
SPEED
DUPLX
UTIL
STATUS
RPS
SYSTEM
Catalyst 2950
MODE
1
1X
2X
11X
12X
2 3 4 56 7 8 9 10 910 910 910 1
1X
2X
11X
12X
2 3 4 56 7 8 9 10 910 910 910 1
1X
2X
2 34 5 6 78 9 10 910 910 910
2
1
12
1
1X
2X
11X
12X
13X
14X
15X
16X
2 3 4 5 6 78 9 10 1112 1314 1516 1718 19 20 2122 2324
RPS
SYST
STATUTILDUPLXSPEED
Catalyst 2950
Catalyst 2950
MODE
RPS
SYST
STATUTILDUPLXSPEED
MODE