IES-1248-71/73 User’s Guide
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C
H A P T E R
25
Spanning Tree Protocol
This chapter introduces the Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol
(RSTP).
25.1 RSTP and STP
RSTP adds rapid reconfiguration capability to STP. The IES-1248 supports RSTP and the
earlier STP. RSTP and STP detect and break network loops and provide backup links between
switches, bridges or routers. They allow a device to interact with other RSTP or STP-aware
devices in your network to ensure that only one path exists between any two stations on the
network. The Integrated Ethernet Switch uses RSTP by default but can still operate with STP
switches (although without RSTP’s benefits).
The root bridge is the base of the spanning tree. 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, as illustrated in 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 Integrated Ethernet Switch with the lowest path cost to the root (the root
path cost). If there is no root port, then this Integrated Ethernet Switch 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.
After a bridge determines the lowest cost-spanning tree with RSTP, it enables the root port and
the ports that are the designated ports for the connected LANs, and disables all other ports that
participate in RSTP. Network packets are therefore only forwarded between enabled ports,
eliminating any possible network loops.
Table 48
Path Cost
LINK SPEED
RECOMMENDED
VALUE
RECOMMENDED
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 IES-1248-71
Страница 1: ...www zyxel com IES 1248 71 73 ADSL2 IP DSLAM User s Guide Version 3 52 LS 0 TR 0 9 2006 Edition 2 ...
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Страница 8: ...Safety Warnings IES 1248 71 73 User s Guide 8 ...
Страница 38: ...List of Tables IES 1248 71 73 User s Guide 38 ...
Страница 40: ...40 ...
Страница 51: ...Chapter 2 Hardware Installation IES 1248 71 73 User s Guide 51 Figure 6 IES 1248 Frame Ground Frame Ground ...
Страница 52: ...Chapter 2 Hardware Installation IES 1248 71 73 User s Guide 52 ...
Страница 60: ...Chapter 3 Front Panel Connections IES 1248 71 73 User s Guide 60 ...
Страница 68: ...Chapter 4 MDF Connections IES 1248 71 73 User s Guide 68 ...
Страница 74: ...74 ...
Страница 81: ...Chapter 7 Introducing the Web Configurator IES 1248 71 73 User s Guide 81 Figure 30 Logout ...
Страница 82: ...Chapter 7 Introducing the Web Configurator IES 1248 71 73 User s Guide 82 ...
Страница 110: ...Chapter 12 User Account IES 1248 71 73 User s Guide 110 ...
Страница 116: ...Chapter 13 Switch Setup IES 1248 71 73 User s Guide 116 ...
Страница 118: ...Chapter 14 IP Setup IES 1248 71 73 User s Guide 118 ...
Страница 150: ...Chapter 17 xDSL Profiles Setup IES 1248 71 73 User s Guide 150 ...
Страница 158: ...158 ...
Страница 166: ...Chapter 19 VLAN IES 1248 71 73 User s Guide 166 ...
Страница 184: ...Chapter 22 Multicast VLAN IES 1248 71 73 User s Guide 184 ...
Страница 216: ...Chapter 30 2684 Routed Mode IES 1248 71 73 User s Guide 216 ...
Страница 222: ...Chapter 31 PPPoA to PPPoE IES 1248 71 73 User s Guide 222 ...
Страница 226: ...Chapter 32 DSCP IES 1248 71 73 User s Guide 226 ...
Страница 240: ...Chapter 36 Syslog IES 1248 71 73 User s Guide 240 ...
Страница 248: ...Chapter 37 Access Control IES 1248 71 73 User s Guide 248 ...
Страница 250: ...250 ...
Страница 259: ...Chapter 39 Alarm IES 1248 71 73 User s Guide 259 ...
Страница 260: ...Chapter 39 Alarm IES 1248 71 73 User s Guide 260 ...
Страница 276: ...276 ...
Страница 296: ...Chapter 44 Commands IES 1248 71 73 User s Guide 296 ...
Страница 304: ...Chapter 45 Command Examples IES 1248 71 73 User s Guide 304 ...
Страница 320: ...Chapter 47 DHCP Commands IES 1248 71 73 User s Guide 320 ...
Страница 328: ...Chapter 48 IEEE 802 1Q Tagged VLAN Commands IES 1248 71 73 User s Guide 328 ...
Страница 334: ...Chapter 49 MAC Commands IES 1248 71 73 User s Guide 334 ...
Страница 348: ...Chapter 50 IGMP Commands IES 1248 71 73 User s Guide 348 ...
Страница 352: ...Chapter 51 Packet Filter Commands IES 1248 71 73 User s Guide 352 ...
Страница 362: ...Chapter 53 Firmware and Configuration File Maintenance IES 1248 71 73 User s Guide 362 ...
Страница 394: ...Chapter 55 ADSL Commands IES 1248 71 73 User s Guide 394 ...
Страница 418: ...Chapter 56 Virtual Channel Management IES 1248 71 73 User s Guide 418 ...
Страница 424: ...Chapter 57 ACL Commands IES 1248 71 73 User s Guide 424 ...
Страница 436: ...Chapter 58 Troubleshooting IES 1248 71 73 User s Guide 436 ...
Страница 437: ...437 PART VI Appendices and Index Product Specifications 439 Legal Information 449 Index 457 ...
Страница 438: ...438 ...
Страница 448: ...Appendix B Removing and Installing a Fuse IES 1248 71 73 User s Guide 448 ...
Страница 452: ...Appendix C Legal Information IES 1248 71 73 User s Guide 452 ...
Страница 464: ...Index IES 1248 71 73 User s Guide 464 ...