Chapter 21: Multiple Spanning Tree Protocol
230 Section V: Spanning Tree Protocols
Figure 26 illustrates the same two AT-9400 Switches and the same two virtual LANs. But in this example, the two switches are running MSTP and the two VLANs have been assigned different spanning tree instances. Now that they reside in different MSTIs, both links remain active, enabling the VLANs to forward traffic over their respective direct link.Figure 26. MSTP Example of Two Spanning Tree Instances FAULT
RPS
MASTER
POWER
CLASS 1
LASER PRODUCT
STATUS
TERMINAL
PORT
1357911
2 4 6 8 10 12
13 15 17 19 21 23R
14 16 18 20 22 24R
AT-9424T/SP Gigabit Ethernet Switch
1357911131517192123R
2 4 6 810 12 14 16 18 20 22 24R
2324
L/A
D/C
D/C
L/A
D/C
L/A
1000 LINK / ACT
HDX /
COL
FDX
10/100 LINK / ACT
PORT ACTIVITY
L/A
1000 LINK / ACT
SFP
SFP
24
SFP
23
FAULT
RPS
MASTER
POWER
GBIC
23
GBIC
24
CLASS 1
LASER PRODUCT
STATUS
TERMINAL
PORT
1357911
2 4 6 8 10 12
13 15 17 19 21 23R
14 16 18 20 22 24R
AT-9424T/GB Gigabit Ethernet Switch
1357911131517192123R
2 4 6 810 12 14 16 18 20 22 24R
2324
L/A
D/C
D/C
L/A
D/C
L/A
1000 LINK / ACT
HDX /
COL
FDX
10/100 LINK / ACT
PORT ACTIVITY
L/A
1000 LINK / ACT
GBIC
Sales
VLAN in
MSTI 1
Production
VLAN in
MSTI 2
Untagged
Ports Untagged
Ports