User Manual User Manual
Table Of Contents
- INTRODUCTION
- INSTALLATION
- SWITCH MANAGEMENT
- WEB CONFIGURATION
- Main Web Page
- System
- System Information
- IP Configuration
- IPv6 Configuration
- Users Configuration
- Users Privilege Levels
- NTP Configuration
- UPnP Configuration
- DHCP Relay
- DHCP Relay Statistics
- CPU Load
- _
- System Log
- Detailed Log
- Remote Syslog
- SMTP Configure
- Web Firmware Upgrade
- TFTP Firmware Upgrade
- Configuration Backup
- Configuration Upload
- _
- Factory Default
- _
- System Reboot
- Simple Network Management Protocol
- Port Management
- Link Aggregation
- VLAN
- Spanning Tree Protocol
- Multicast
- Quality of Service
- Access Control Lists
- Access Control List Status
- Access Control List Configuration
- ACE Configuration
- ACL Ports Configuration
- ACL Rate Limiter Configuration
- Understanding IEEE 802.1X Port-Based Authentication
- Authentication Configuration
- Network Access Server Configuration
- Network Access Overview
- Network Access Statistics
- _
- Authentication Server Configuration
- RADIUS Overview
- _
- RADIUS Details
- Windows Platform RADIUS Server Configuration
- 4.11.10 802.1X Client Configuration
- Security
- Address Table
- _
- LLDP
- Network Diagnostics
- Power over Ethernet (GE-DSSG-244-POE / NS3601-24P/4S)
- _
- COMMAND LINE INTERFACE
- Command Line Mode
- _
- System Command
- Stack
- IP Command
- Port Management Command
- MAC Address Table Command
- VLAN Configuration Command
- _
- Private VLAN Configuration Command
- Security Command
- Security Switch User Configuration
- Security Switch User Add
- Security Switch User Delete
- Security Switch Privilege Level Configuration
- Security Switch Privilege Level Group
- Security Switch Privilege Level Current
- Security Switch Auth Configuration
- Security Switch Auth Method
- Security Switch SSH Configuration
- Security Switch SSH Mode
- Security Switch HTTPs Configuration
- Security Switch HTTPs Mode
- Security Switch HTTPs Redirect
- Security Switch Access Configuration
- Security Switch Access Mode
- Security Switch Access Add
- Security Switch Access IPv6 Add
- Security Switch Access Delete
- Security Switch Access Lookup
- Security Switch Access Clear
- Security Switch Access Statistics
- Security Switch SNMP Configuration
- Security Switch SNMP Mode
- Security Switch SNMP Version
- Security Switch SNMP Read Community
- Security Switch SNMP Write Community
- Security Switch SNMP Trap Mode
- Security Switch SNMP Trap Version
- Security Switch SNMP Trap Community
- Security Switch SNMP Trap Destination
- Security Switch SNMP Trap IPv6 Destination
- Security Switch SNMP Trap Authentication Failure
- Security Switch SNMP Trap Link-up
- Security Switch SNMP Trap Inform Mode
- Security Switch SNMP Trap Inform Timeout
- Security Switch SNMP Trap Inform Retry Times
- Security Switch SNMP Trap Probe Security Engine ID
- Security Switch SNMP Trap Security Engine ID
- Security Switch SNMP Trap Security Name
- Security Switch SNMP Engine ID
- Security Switch SNMP Community Add
- Security Switch SNMP Community Delete
- Security Switch SNMP Community Lookup
- Security Switch SNMP User Add
- Security Switch SNMP User Delete
- Security Switch SNMP User Changekey
- Security Switch SNMP User Lookup
- Security Switch SNMP Group Add
- Security Switch SNMP Group Delete
- Security Switch SNMP Group Lookup
- Security Switch SNMP View Add
- Security Switch SNMP View Delete
- Security Switch SNMP View Lookup
- Security Switch SNMP Access Add
- Security Switch SNMP Access Delete
- Security Switch SNMP Access Lookup
- Security Network Psec Switch
- Security Network Psec Port
- Security Network Limit Configuration
- Security Network Limit Mode
- Security Network Limit Aging
- Security Network Limit Agetime
- Security Network Limit Port
- Security Network Limit Limit
- Security Network Limit Action
- Security Network Limit Reopen
- Security Network NAS Configuration
- Security Network NAS Mode
- Security Network NAS State
- Security Network NAS Reauthentication
- Security Network NAS ReauthPeriod
- Security Network NAS EapolTimeout
- Security Network NAS Agetime
- Security Network NAS Holdtime
- Security Network NAS RADIUS_QoS
- Security Network NAS RADIUS_VLAN
- Security Network NAS Guest_VLAN
- Security Network NAS Authenticate
- Security Network NAS Statistics
- Security Network ACL Configuration
- Security Network ACL Action
- Security Network ACL Policy
- Security Network ACL Rate
- Security Network ACL Add
- Security Network ACL Delete
- Security Network ACL Lookup
- Security Network ACL Clear
- Security Network ACL Status
- Security Network DHCP Relay Configuration
- Security Network DHCP Relay Mode
- Security Network DHCP Relay Server
- Security Network DHCP Relay Information Mode
- Security Network DHCP Relay Information Policy
- Security Network DHCP Relay Statistics
- Security Network DHCP Snooping Configuration
- Security Network DHCP Snooping Mode
- Security Network DHCP Snooping Port Mode
- Security Network DHCP Snooping Statistics
- Security Network IP Source Guard Configuration
- Security Network IP Source Guard Mode
- Security Network IP Source Guard Port Mode
- Security Network IP Source Guard Limit
- Security Network IP Source Guard Entry
- Security Network IP Source Guard Status
- Security Network ARP Inspection Configuration
- Security Network ARP Inspection Mode
- Security Network ARP Inspection Port Mode
- Security Network ARP Inspection Entry
- Security Network ARP Inspection Status
- Security AAA Configuration
- Security AAA Timeout
- Security AAA Deadtime
- Security AAA RADIUS
- Security AAA ACCT_RADIUS
- Security AAA TACACS+
- Security AAA Statistics
- Security Switch User Configuration
- Spanning Tree Protocol Command
- STP Configuration
- STP Version
- STP Tx Hold
- STP MaxHops
- STP MaxAge
- STP FwdDelay
- STP CName
- STP BPDU Filter
- STP BPDU Guard
- STP Recovery
- STP Status
- STP MSTI Priority
- STP MSTI Map
- STP MSTI Add
- STP Port Configuration
- STP Port Mode
- STP Port Edge
- STP Port AutoEdge
- STP Port P2P
- STP Port RestrictedRole
- STP Port RestrictedTcn
- STP Port bpduGuard
- STP Port Statistic
- STP Port Mcheck
- STP MSTI Port Configuration
- STP MSTI Port Cost
- STP MSTI Port Priority
- STP Configuration
- Multicast Configuration Command
- Link Aggregation Command
- Link Aggregation Control Protocol Command
- LLDP Command
- LLDPMED Command
- Power over Ethernet Command
- Quality of Service Command
- Mirror Command
- Configuration Command
- Firmware Command
- UPnP Command
- MVR Command
- Voice VLAN Command
- SMTP Command
- Show Command
- Show ACL Configuration
- Show Link Aggregation Configuration
- Show IGMP Configuration
- Show IP Configuration
- Show LACP Configuration
- Show LLDP Configuration
- Show MAC Configuration
- Show Mirror Configuration
- Show PoE Configuration
- Show Port Configuration
- Show Private VLAN Configuration
- Show QoS Configuration
- Show SNMP Configuration
- Show Stack Configuration
- Show System Configuration
- Show VLAN Configuration
- Show STP Configuration
- Show ACL Configuration
- SWITCH OPERATION
- POWER OVER ETHERNET OVERVIEW
- TROUBLE SHOOTING
- APPENDEX A
- APPENDEX B : GLOSSARY
- APPENDIX C: Local User Privilege Level Table
IFS NS3601-24P/4S GE-DSSG-244 and 244-POE User Manual
113
Spanning Tree Protocol
Theory
The Spanning Tree protocol can be used to detect and disable network loops, and to provide backup links between switches,
bridges or routers. This allows the switch to interact with other bridging devices in your network to ensure that only one route exists
between any two stations on the network, and provide backup links which automatically take over when a primary link goes down.
The spanning tree algorithms supported by this switch include these versions:
STP – Spanning Tree Protocol (IEEE 802.1D)
RSTP – Rapid Spanning Tree Protocol (IEEE 802.1w)
MSTP – Multiple Spanning Tree Protocol (IEEE 802.1s)
The IEEE 802.1D Spanning Tree Protocol and IEEE 802.1W Rapid Spanning Tree Protocol allow for the blocking of links between
switches that form loops within the network. When multiple links between switches are detected, a primary link is established.
Duplicated links are blocked from use and become standby links. The protocol allows for the duplicate links to be used in the event
of a failure of the primary link. Once the Spanning Tree Protocol is configured and enabled, primary links are established and
duplicated links are blocked automatically. The reactivation of the blocked links (at the time of a primary link failure) is also
accomplished automatically without operator intervention.
This automatic network reconfiguration provides maximum uptime to network users. However, the concepts of the Spanning Tree
Algorithm and protocol are a complicated and complex subject and must be fully researched and understood. It is possible to cause
serious degradation of the performance of the network if the Spanning Tree is incorrectly configured. Please read the following
before making any changes from the default values.
The Switch STP performs the following functions:
Creates a single spanning tree from any combination of switching or bridging elements.
Creates multiple spanning trees – from any combination of ports contained within a single switch, in user specified
groups.
Automatically reconfigures the spanning tree to compensate for the failure, addition, or removal of any element in the
tree.
Reconfigures the spanning tree without operator intervention.
Bridge Protocol Data Units
For STP to arrive at a stable network topology, the following information is used:
The unique switch identifier
The path cost to the root associated with each switch port
The port identifier
STP communicates between switches on the network using Bridge Protocol Data Units (BPDUs). Each BPDU contains the following
information:
The unique identifier of the switch that the transmitting switch currently believes is the root switch
The path cost to the root from the transmitting port
The port identifier of the transmitting port
The switch sends BPDUs to communicate and construct the spanning-tree topology. All switches connected to the LAN on which the
packet is transmitted will receive the BPDU. BPDUs are not directly forwarded by the switch, but the receiving switch uses the
information in the frame to calculate a BPDU, and, if the topology changes, initiates a BPDU transmission.
The communication between switches via BPDUs results in the following:
One switch is elected as the root switch
The shortest distance to the root switch is calculated for each switch
A designated switch is selected. This is the switch closest to the root switch through which packets will be forwarded to
the root.
A port for each switch is selected. This is the port providing the best path from the switch to the root switch.
Ports included in the STP are selected.
Creating a Stable STP Topology
It is to make the root port a fastest link. If all switches have STP enabled with default settings, the switch with the lowest MAC
address in the network will become the root switch. By increasing the priority (lowering the priority number) of the best switch, STP
can be forced to select the best switch as the root switch.
When STP is enabled using the default parameters, the path between source and destination stations in a switched network might
not be ideal. For instance, connecting higher-speed links to a port that has a higher number than the current root port can cause a
root-port change.
STP Port States
The BPDUs take some time to pass through a network. This propagation delay can result in topology changes where a port that
transitioned directly from a Blocking state to a Forwarding state could create temporary data loops. Ports must wait for new network
topology information to propagate throughout the network before starting to forward packets. They must also wait for the packet
lifetime to expire for BPDU packets that were forwarded based on the old topology. The forward delay timer is used to allow the