16-12
Spanning Tree Protocol (STP)
How STP Operates
S
pan
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ng Tr
ee P
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STP Operation with 802.1Q VLANs
As recommended in the IEEE 802.1Q VLAN standard, when spanning tree is
enabled on the switch, a single spanning tree is configured for all ports across
the switch, including those in separate VLANs (that is, single-instance STP,
which generates untagged BPDUs). This means that if redundant physical
links exist in separate VLANs, spanning tree will block all but one of those
links. However, if you need to use STP on the Switch 4108GL in a VLAN
environment with redundant physical links, you can prevent blocked redun-
dant links by using a port trunk. The following example shows how you can
use a port trunk with 802.1Q (tagged) VLANs and STP without unnecessarily
blocking any links or losing any bandwidth.
Figure 16-4. Example of Using a Trunked Link with STP and VLANs
For more information, refer to “Spanning Tree Protocol Operation with
VLANs” on page 14-27.
Problem:
STP enabled with 2
separate (non-trunked)
links blocks a VLAN link.
Solution:
STP enabled with
one trunked link.
Nodes 1 and 2 cannot
communicate because
STP is blocking the link.
Nodes 1 and 2 can communicate
because STP sees the trunk as a
single link and 802.1Q (tagged) VLANs
enable the use of one (trunked) link
for both VLANs.
Summary of Contents for ProCurve 4108gl Bundle
Page 1: ...hp procurve switch 4108gl management and configuration guide www hp com go hpprocurve ...
Page 2: ......
Page 40: ...2 16 Using the Menu Interface Where To Go From Here Using the Menu Interface ...
Page 154: ...8 24 Time Protocols SNTP Messages in the Event Log Time Protocols ...
Page 350: ...14 44 Port Based Virtual LANs VLANs and GVRP GVRP Port Based Virtual LANs VLANs and GVRP ...
Page 383: ...16 13 Spanning Tree Protocol STP How STP Operates Spanning Tree Protocol STP ...
Page 384: ...16 14 Spanning Tree Protocol STP How STP Operates Spanning Tree Protocol STP ...
Page 442: ...18 30 Troubleshooting Restoring a Flash Image Troubleshooting ...
Page 466: ...B 6 MAC Address Management Determining MAC Addresses MAC Address Management ...
Page 470: ......
Page 481: ...Index 11 Index write memory effect on menu interface 2 13 X Xmodem OS download A 6 ...
Page 482: ......