248
PowerConnect B-Series FCX Configuration Guide
53-1002266-01
Configuring STP related features
8
FIGURE 42
Link failure in the topology
Switch 1 sets its Port2 into a discarding state.
At the same time, Switch 2 assumes the role of a root bridge since its root port failed and it has no
operational Alternate port. Port3/Switch 2, which currently has a Designated port role, sends an
RST BPDU to Switch 3. The RST BPDU contains a proposal flag and a bridge ID of Switch 2 as its
root bridge ID.
When Port3/Switch 3 receives the RST BPDUs, 802.1W algorithm determines that they are inferior
to those that the port can transmit. Therefore, Port3/Switch 3 is given a new role, that of a
Designated port. Port3/Switch 3 then sends an RST BPDU with a proposal flag to Switch 2, along
with the new role information. However, the root bridge ID transmitted in the RST BPDU is still
Switch 1.
When Port3/Switch 2 receives the RST BPDU, 802.1W algorithm determines that it is superior to
the RST BPDU that it can transmit; therefore, Port3/Switch 2 receives a new role; that of a Root
port. Port3/Switch 2 then sends an RST BPDU with an agreed flag to Port3/Switch 3. Port3/Switch
2 goes into a forwarding state.
When Port3/Switch 3 receives the RST BPDU that Port3/Switch 2 sent, Port3/Switch 3 changes
into a forwarding state, which then completes the full convergence of the topology.
Convergence at link restoration
When Port2/Switch 2 is restored, both Switch 2 and Switch 1 recognize the change. Port2/Switch
1 starts assuming the role of a Designated port and sends an RST BPDU containing a proposal flag
to Port2/Switch 2.
Bridge priority = 1500
Bridge priority = 2000
Bridge priority = 1000
Switch 2
Switch 3
Switch 1
Port2
Port2
Port3
Port3
Port3
Port4
Port4
Port5
Содержание PowerConnect B-FCXs
Страница 1: ...53 1002266 01 18 March 2011 PowerConnect B Series FCX Configuration Guide ...
Страница 136: ...94 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Viewing information about software licenses 4 ...
Страница 228: ...186 PowerConnect B Series FCX Configuration Guide 53 1002266 01 PowerConnect B Series FCX hitless stacking 5 ...
Страница 229: ...PowerConnect B Series FCX Configuration Guide 187 53 1002266 01 PowerConnect B Series FCX hitless stacking 5 ...
Страница 230: ...188 PowerConnect B Series FCX Configuration Guide 53 1002266 01 PowerConnect B Series FCX hitless stacking 5 ...
Страница 248: ...206 PowerConnect B Series FCX Configuration Guide 53 1002266 01 IPv6 management commands 7 ...
Страница 346: ...304 PowerConnect B Series FCX Configuration Guide 53 1002266 01 802 1s Multiple Spanning Tree Protocol 8 ...
Страница 374: ...332 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Jumbo frame support 9 ...
Страница 424: ...382 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Virtual Switch Redundancy Protocol VSRP 10 ...
Страница 568: ...526 PowerConnect B Series FCX Configuration Guide 53 1002266 01 CLI examples 14 ...
Страница 588: ...546 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Sample application 15 ...
Страница 674: ...632 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Enabling or disabling layer 2 switching 19 ...
Страница 684: ...642 PowerConnect B Series FCX Configuration Guide 53 1002266 01 VLAN based mirroring 20 ...
Страница 724: ...682 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Reading CDP packets 23 ...
Страница 768: ...726 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Clearing cached LLDP neighbor information 24 ...
Страница 930: ...888 PowerConnect B Series FCX Configuration Guide 53 1002266 01 26 ...
Страница 948: ...906 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Configuring MLD snooping 27 ...
Страница 962: ...920 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Displaying CPU utilization statistics 28 ...
Страница 1022: ...980 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Displaying OSPF information 29 ...
Страница 1142: ...1100 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Clearing diagnostic buffers 30 ...
Страница 1258: ...1216 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Using Secure copy with SSH2 33 ...
Страница 1314: ...1272 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Displaying port security information 35 ...
Страница 1348: ...1306 PowerConnect B Series FCX Configuration Guide 53 1002266 01 Example configurations 36 ...
Страница 1406: ...1364 PowerConnect B Series FCX Configuration Guide 53 1002266 01 IP source guard 39 ...
Страница 1422: ...1380 PowerConnect B Series FCX Configuration Guide 53 1002266 01 SNMP v3 Configuration examples 40 ...