50
C
HAPTER
4: U
SING
R
ESILIENCE
F
EATURES
If a link failure is detected, as shown in
Figure 11
, the STP process
reconfigures the network so that traffic from LAN segment 2 flows
through Bridge B.
Figure 11
Traffic flowing through Bridge B
STP determines which is the most efficient path between each bridged
segment and a specifically assigned reference point on the network. Once
the most efficient path has been determined, all other paths are blocked.
Therefore, in
Figure 9
,
Figure 10
, and
Figure 11
, STP initially determined
that the path through Bridge C was the most efficient, and so blocked
the path through Bridge B. After the failure of Bridge C, STP re-evaluated
the situation and opened the path through Bridge B.
How STP Works
When enabled, STP determines the most appropriate path for traffic
through a network. It does this as outlined in the sections below.
STP Requirements
Before it can configure the network, the STP system requires:
■
Communication between all the bridges. This communication is
carried out using Bridge Protocol Data Units (BPDUs), which are
transmitted in packets with a known multicast address.
■
Each bridge to have a Bridge Identifier. This specifies which bridge acts
as the central reference point, or Root Bridge, for the STP system —
the lower the Bridge Identifier, the more likely the bridge is to become
the Root Bridge. The Bridge Identifier is calculated using the MAC
address of the bridge and a priority defined for the bridge. The default
priority of your Switch is 32768.
Содержание 3C17203 - SuperStack 3 Switch 4400
Страница 8: ...GLOSSARY INDEX ...
Страница 14: ...14 ...
Страница 26: ...26 CHAPTER 1 SWITCH FEATURES OVERVIEW ...
Страница 44: ...44 CHAPTER 3 USING MULTICAST FILTERING ...
Страница 55: ...How STP Works 55 Figure 13 STP configurations ...
Страница 58: ...58 CHAPTER 4 USING RESILIENCE FEATURES ...
Страница 84: ...84 CHAPTER 7 STATUS MONITORING AND STATISTICS ...
Страница 92: ...92 CHAPTER 8 SETTING UP VIRTUAL LANS ...
Страница 98: ...98 CHAPTER 9 USING WEBCACHE SUPPORT ...
Страница 120: ...120 CHAPTER 12 POWER MANAGEMENT AND CONTROL ...
Страница 122: ...122 ...
Страница 126: ...126 APPENDIX A CONFIGURATION RULES ...
Страница 134: ...134 APPENDIX B NETWORK CONFIGURATION EXAMPLES ...
Страница 150: ...150 GLOSSARY ...