ZyWALL 70 User’s Guide
104
Chapter 5 Bridge Screens
5.2.1 Rapid STP
The ZyWALL uses IEEE 802.1w RSTP (Rapid Spanning Tree Protocol) that allow faster
convergence of the spanning tree (while also being backwards compatible with 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.
5.2.2 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 from the root bridge to 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 next 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.
5.2.3 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.
Table 21
STP Path Costs
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 ZyWALL 70
Страница 1: ...ZyWALL 70 Internet Security Appliance User s Guide Version 3 64 3 2005 ...
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Страница 38: ...ZyWALL 70 User s Guide 38 List of Figures ...
Страница 46: ...ZyWALL 70 User s Guide 46 List of Tables ...
Страница 74: ...ZyWALL 70 User s Guide 74 Chapter 2 Introducing the Web Configurator ...
Страница 92: ...ZyWALL 70 User s Guide 92 Chapter 3 Wizard Setup ...
Страница 102: ...ZyWALL 70 User s Guide 102 Chapter 4 LAN Screens ...
Страница 108: ...ZyWALL 70 User s Guide 108 Chapter 5 Bridge Screens ...
Страница 130: ...ZyWALL 70 User s Guide 130 Chapter 6 Wireless LAN ...
Страница 136: ...ZyWALL 70 User s Guide 136 Chapter 7 WAN Screens Figure 45 WAN General ...
Страница 155: ...ZyWALL 70 User s Guide Chapter 7 WAN Screens 155 Figure 55 Dial Backup Setup ...
Страница 188: ...ZyWALL 70 User s Guide 188 Chapter 10 Firewall Screens Figure 71 Creating Editing A Firewall Rule ...
Страница 193: ...ZyWALL 70 User s Guide Chapter 10 Firewall Screens 193 Figure 76 My Service Rule Configuration ...
Страница 234: ...ZyWALL 70 User s Guide 234 Chapter 13 Introduction to IPSec ...
Страница 246: ...ZyWALL 70 User s Guide 246 Chapter 14 VPN Screens Figure 112 VPN Rules IKE Gateway Policy Edit ...
Страница 252: ...ZyWALL 70 User s Guide 252 Chapter 14 VPN Screens Figure 113 VPN Rules IKE Network Policy Edit ...
Страница 275: ...ZyWALL 70 User s Guide Chapter 15 Certificates 275 Figure 125 My Certificate Details ...
Страница 294: ...ZyWALL 70 User s Guide 294 Chapter 16 Authentication Server Figure 136 Local User Database ...
Страница 314: ...ZyWALL 70 User s Guide 314 Chapter 17 Network Address Translation NAT ...
Страница 318: ...ZyWALL 70 User s Guide 318 Chapter 18 Static Route ...
Страница 324: ...ZyWALL 70 User s Guide 324 Chapter 19 Policy Route ...
Страница 340: ...ZyWALL 70 User s Guide 340 Chapter 20 Bandwidth Management ...
Страница 376: ...ZyWALL 70 User s Guide 376 Chapter 22 Remote Management ...
Страница 390: ...ZyWALL 70 User s Guide 390 Chapter 24 Logs Screens Figure 194 Log Settings ...
Страница 413: ...ZyWALL 70 User s Guide Chapter 25 Maintenance 413 Figure 216 Restart Screen ...
Страница 414: ...ZyWALL 70 User s Guide 414 Chapter 25 Maintenance ...
Страница 440: ...ZyWALL 70 User s Guide 440 Chapter 28 WAN and Dial Backup Setup ...
Страница 456: ...ZyWALL 70 User s Guide 456 Chapter 31 DMZ Setup ...
Страница 460: ...ZyWALL 70 User s Guide 460 Chapter 32 Route Setup ...
Страница 470: ...ZyWALL 70 User s Guide 470 Chapter 33 Remote Node Setup ...
Страница 522: ...ZyWALL 70 User s Guide 522 Chapter 39 System Information Diagnosis ...
Страница 538: ...ZyWALL 70 User s Guide 538 Chapter 40 Firmware and Configuration File Maintenance ...
Страница 550: ...ZyWALL 70 User s Guide 550 Chapter 42 Remote Management ...
Страница 558: ...ZyWALL 70 User s Guide 558 Chapter 43 IP Policy Routing ...
Страница 573: ...ZyWALL 70 User s Guide Chapter 45 Troubleshooting 573 Figure 360 Java Sun ...
Страница 574: ...ZyWALL 70 User s Guide 574 Chapter 45 Troubleshooting ...
Страница 582: ...ZyWALL 70 User s Guide 582 Appendix B Removing and Installing a Fuse ...
Страница 602: ...ZyWALL 70 User s Guide 602 Appendix D IP Subnetting ...
Страница 608: ...ZyWALL 70 User s Guide 608 Appendix F PPTP ...
Страница 626: ...ZyWALL 70 User s Guide 626 Appendix H Triangle Route ...
Страница 656: ...ZyWALL 70 User s Guide 656 Appendix K Importing Certificates ...
Страница 658: ...ZyWALL 70 User s Guide 658 Appendix L Command Interpreter ...
Страница 664: ...ZyWALL 70 User s Guide 664 Appendix M Firewall Commands ...
Страница 668: ...ZyWALL 70 User s Guide 668 Appendix N NetBIOS Filter Commands ...
Страница 674: ...ZyWALL 70 User s Guide 674 Appendix P Brute Force Password Guessing Protection ...
Страница 696: ...ZyWALL 70 User s Guide 696 Appendix R Log Descriptions ...