User`s guide
Table Of Contents
- User’s Guide
- Introduction and Hardware
- Basic Configuration
- Advanced
- VLAN
- Static MAC Forward Setup
- Filtering
- Spanning Tree Protocol
- 11.1 STP/RSTP Overview
- 11.1.1 STP Terminology
- 11.1.2 How STP Works
- 11.1.3 STP Port States
- 11.1.4 Multiple RSTP
- 11.2 Spanning Tree Protocol Main Screen
- 11.3 Configure Rapid Spanning Tree Protocol
- 11.4 Rapid Spanning Tree Protocol Status
- 11.5 Configure Multiple Rapid Spanning Tree Protocol
- 11.6 Multiple Rapid Spanning Tree Protocol Status
- Bandwidth Control
- Broadcast Storm Control
- Mirroring
- Link Aggregation
- Port Authentication
- Port Security
- Classifier
- Policy Rule
- Queuing Method
- VLAN Stacking
- Multicast
- 22.1 Multicast Overview
- 22.1.1 IP Multicast Addresses
- 22.1.2 IGMP Filtering
- 22.1.3 IGMP Snooping
- 22.2 Multicast Status
- 22.3 Multicast Setting
- 22.4 IGMP Filtering Profile
- 22.5 MVR Overview
- 22.5.1 Types of MVR Ports
- 22.5.2 MVR Modes
- 22.5.3 How MVR Works
- 22.6 General MVR Configuration
- 22.7 MVR Group Configuration
- 22.7.1 MVR Configuration Example
- IP Application
- Management
- Maintenance
- 28.1 The Maintenance Screen
- 28.2 Firmware Upgrade
- 28.3 Restore a Configuration File
- 28.4 Backup a Configuration File
- 28.5 Load Factory Default
- 28.6 Save Configuration
- 28.7 Reboot System
- 28.8 FTP Command Line
- 28.8.1 Filename Conventions
- 28.8.2 FTP Command Line Procedure
- 28.8.3 GUI-based FTP Clients
- 28.8.4 FTP Restrictions
- Access Control
- 29.1 Access Control Overview
- 29.2 The Access Control Main Screen
- 29.3 About SNMP
- 29.3.1 Supported MIBs
- 29.3.2 SNMP Traps
- 29.3.3 Configuring SNMP
- 29.4 SSH Overview
- 29.5 How SSH works
- 29.6 SSH Implementation on the Switch
- 29.6.1 Requirements for Using SSH
- 29.7 Introduction to HTTPS
- 29.8 HTTPS Example
- 29.8.1 Internet Explorer Warning Messages
- 29.8.2 Netscape Navigator Warning Messages
- 29.8.3 The Main Screen
- 29.9 Service Port Access Control
- 29.10 Remote Management
- Diagnostic
- Syslog
- Cluster Management
- MAC Table
- IP Table
- ARP Table
- Routing Table
- Configure Clone
- Maintenance
- CLI and Troubleshooting
- Introducing Commands
- 38.1 Overview
- 38.2 Accessing the CLI
- 38.2.1 The Console Port
- 38.3 The Login Screen
- 38.4 Command Syntax Conventions
- 38.5 Changing the Password
- 38.6 Privilege Levels
- 38.7 Command Modes
- 38.8 Getting Help
- 38.8.1 List of Available Commands
- 38.9 Using Command History
- 38.10 Saving Your Configuration
- 38.10.1 Configuration File
- 38.10.2 Logging Out
- 38.11 Command Summary
- 38.11.1 User Mode
- 38.11.2 Enable Mode
- 38.11.3 General Configuration Mode
- 38.11.4 interface port-channel Commands
- 38.11.5 interface route-domain Commands
- 38.11.6 config-vlan Commands
- 38.12 mvr Commands
- User and Enable Mode Commands
- 39.1 Overview
- 39.2 show Commands
- 39.2.1 show system-information
- 39.2.2 show ip
- 39.2.3 show logging
- 39.2.4 show interface
- 39.2.5 show mac address-table
- 39.3 ping
- 39.4 traceroute
- 39.5 Copy Port Attributes
- 39.6 Configuration File Maintenance
- 39.6.1 Using a Different Configuration File
- 39.6.2 Resetting to the Factory Default
- Configuration Mode Commands
- 40.1 Change the Out of Band Management IP Address
- 40.2 Enabling IGMP Snooping
- 40.3 Configure IGMP Filter
- 40.4 Enabling STP
- 40.5 no Command Examples
- 40.5.1 Disable Commands
- 40.5.2 Resetting Commands
- 40.5.3 Re-enable commands
- 40.5.4 Other Examples of no Commands
- 40.6 Static Route Commands
- 40.7 Enabling MAC Filtering
- 40.8 Enabling Trunking
- 40.9 Enabling Port Authentication
- 40.9.1 RADIUS Server Settings
- 40.9.2 Port Authentication Settings
- Interface Commands
- 41.1 Overview
- 41.2 Interface Command Examples
- 41.2.1 interface port-channel
- 41.2.2 bpdu-control
- 41.2.3 broadcast-limit
- 41.2.4 bandwidth-limit
- 41.2.5 mirror
- 41.2.6 gvrp
- 41.2.7 ingress-check
- 41.2.8 frame-type
- 41.2.9 weight
- 41.2.10 egress set
- 41.2.11 qos priority
- 41.2.12 name
- 41.2.13 speed-duplex
- 41.2.14 test
- 41.3 Interface no Command Examples
- 41.3.1 no bandwidth-limit
- IEEE 802.1Q Tagged VLAN Commands
- 42.1 Configuring Tagged VLAN
- 42.2 Global VLAN1Q Tagged VLAN Configuration Commands
- 42.2.1 GARP Status
- 42.2.2 GARP Timer
- 42.2.3 GVRP Timer
- 42.2.4 Enable GVRP
- 42.2.5 Disable GVRP
- 42.3 Port VLAN Commands
- 42.3.1 Set Port VID
- 42.3.2 Set Acceptable Frame Type
- 42.3.3 Enable or Disable Port GVRP
- 42.3.4 Modify Static VLAN
- 42.3.5 Delete VLAN ID
- 42.4 Enable VLAN
- 42.5 Disable VLAN
- 42.6 Show VLAN Setting
- Multicast VLAN Registration Commands
- Routing Domain Command Examples
- Troubleshooting
- Introducing Commands
- Appendices and Index
Chapter 11 Spanning Tree Protocol
GS-2724 User’s Guide
102
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.
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 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.
11.1.2 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 switches 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 negotiations with other bridges to reconfigure the
network to re-establish a valid network topology.
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