Chapter 8 Wireless Screen
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STP-only aware bridges). Using RSTP topology change information does not have
to propagate to the root bridge and unwanted learned addresses are flushed from
the filtering database. In RSTP, the port states are Discarding, Learning, and
Forwarding.
8.3.5.2 STP Terminology
The root bridge is the base of the spanning tree; it is the bridge with the lowest
identifier value (MAC address).
Path cost is the cost of transmitting a frame onto a LAN through that port. It is
assigned according to the speed of the link to which a port is attached. The slower
the media, the higher the cost - see the following table.
On each bridge, the root port is the port through which this bridge communicates
with the root. It is the port on this switch with the lowest path cost to the root (the
root path cost). If there is no root port, then this bridge has been accepted as the
root bridge of the spanning tree network.
For each LAN segment, a designated bridge is selected. This bridge has the lowest
cost to the root among the bridges connected to the LAN.
8.3.5.3 How STP Works
After a bridge determines the lowest cost-spanning tree with STP, it enables the
root port and the ports that are the designated ports for connected LANs, and
disables all other ports that participate in STP. Network packets are therefore only
forwarded between enabled ports, eliminating any possible network loops.
STP-aware bridges exchange Bridge Protocol Data Units (BPDUs) periodically.
When the bridged LAN topology changes, a new spanning tree is constructed.
Once a stable network topology has been established, all bridges listen for Hello
BPDUs (Bridge Protocol Data Units) transmitted from the root bridge. If a bridge
does not get a Hello BPDU after a predefined interval (Max Age), the bridge
assumes that the link to the root bridge is down. This bridge then initiates
Table 29
STP Path Costs
LINK SPEED
RECOMMENDE
D VALUE
RECOMMENDE
D RANGE
ALLOWED
RANGE
Path Cost
4Mbps
250
100 to 1000
1 to 65535
Path Cost
10Mbps
100
50 to 600
1 to 65535
Path Cost
16Mbps
62
40 to 400
1 to 65535
Path Cost
100Mbps
19
10 to 60
1 to 65535
Path Cost
1Gbps
4
3 to 10
1 to 65535
Path Cost
10Gbps
2
1 to 5
1 to 65535
Содержание NWA-3166
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Страница 15: ...15 PART I Introduction Introduction 17 The Web Configurator 29 Tutorials 33 ...
Страница 16: ...16 ...
Страница 32: ...Chapter 2 The Web Configurator NWA 3166 User s Guide 32 ...
Страница 64: ...Chapter 3 Tutorials NWA 3166 User s Guide 64 ...
Страница 66: ...66 ...
Страница 70: ...Chapter 4 Status Screen NWA 3166 User s Guide 70 ...
Страница 122: ...Chapter 8 Wireless Screen NWA 3166 User s Guide 122 ...
Страница 128: ...Chapter 9 SSID Screen NWA 3166 User s Guide 128 ...
Страница 158: ...Chapter 14 IP Screen NWA 3166 User s Guide 158 ...
Страница 166: ...Chapter 15 Rogue AP Detection NWA 3166 User s Guide 166 ...
Страница 186: ...Chapter 17 Internal RADIUS Server NWA 3166 User s Guide 186 ...
Страница 213: ...Chapter 19 Log Screens NWA 3166 User s Guide 213 ...
Страница 214: ...Chapter 19 Log Screens NWA 3166 User s Guide 214 ...
Страница 235: ...Chapter 20 VLAN NWA 3166 User s Guide 235 ...
Страница 236: ...Chapter 20 VLAN NWA 3166 User s Guide 236 ...
Страница 270: ...Appendix B Wireless LANs NWA 3166 User s Guide 270 ...
Страница 300: ...Appendix D IP Addresses and Subnetting NWA 3166 User s Guide 300 ...
Страница 308: ...Appendix E Text File Based Auto Configuration NWA 3166 User s Guide 308 ...
Страница 314: ...Appendix F How to Access and Use the CLI NWA 3166 User s Guide 314 ...
Страница 326: ...Appendix H Customer Support NWA 3166 User s Guide 326 ...
Страница 332: ...Index NWA 3166 User s Guide 332 ...