BASE BAND
Priority 7. This column displays, for every single port, the traffic class which a packet with User Priority value equal to 7 is assigned to
C- VID Registration tab
3. In order to modify a parameter, select the box Path Cost relevant to the wished port and set a value between 1 and 200 000 000
4. Press Apply and confirm.
Verify the information stored by every single Switch port (STP/RSTP) User Profile | Read Only, Maint., Read/Write, Admin.
1. Select Base Band > Ethernet > RSTP.
The Port Status tab displays the information stored by every Switch port as regards the STP/RSTP func-tionality.
RSTP contextual area
The contextual area displays the parameters for management of Spanning Tree protocol.
Tabs
Settings tab. Parameters of the STP/RSTP module, used at global level by the Switch and by all its ports.
Port Settings tab. Parameters of the Ethernet ports relevant to STP/RSTP function.
Port Status tab. Information stored by every Switch port as regards the STP/RSTP functionality.
Push-button
Apply. Confirm the changes.
Refresh. Update the context.
Help. Open the help on-line.
See also
RSTP (command) STP/RSTP Protocol (info)
Settings tab
The tab displays the general basic parameters of the STP/RSTP module, used at global level by the Switch and all its ports.
Parameters
GLOBAL CONFIGURATION
System Control. Enabling state, by the control system, of the STP/RSTP function for the Switch:
• Start. The system activates the STP/RSTP function on every Switch port: the necessary memory is allocated for the function.
• Shutdown. The system stops the STP/RSTP function on every Switch port: the allocated memory is made available for other activities.
Default Shutdown.
Enable Ports. Setting of the STP/RSTP function for every Switch port.
The active box ( ) indicates that the STP/RSTP function is set for the port (the port is inserted in the STP/RSTP tables: Port Settings and Port Status); the inactive box ( ) indicates that the STP/RSTP function is not set for the port (the port is not present in the STP/RSTP tables).
The identifier of the port (slot number/port number) and the port name (LAN 1, LAN 2 etc.) is indicated for every port.
By default, all the ports are disabled.
Parameter available only if the System Control parameter has Start value.
Dynamic Path Cost Calculation. State of the path cost dynamic calculation function.
The Path Cost represents the distance between the port Root and the port Designated.
The Path Cost, according to the Specification 802.1d, is calculated dividing the bit rate by the bandwidth of the network portion connected to the port:
• Enable. The Path Cost is calculated according to the bit rate of the ports whose administrative state is active (Enabled) in that moment. The path cost, once calculated, is not changed according to the operating state of the ports.
• Disable. The Path Cost is calculated according to the bit rate of the connection when the port is created.
Default Disable.
Parameter available only if the System Control parameter has Start value.
Status. Enabling state of the STP/RSTP function:
• Enabled. Activates the STP/RSTP function in the Switch: the ports transmit/
receive the BPDU packets.
• Disabled. Disables the STP/RSTP function in the Switch: the ports do not transmit/receive the BPDU packets.
Default Disabled.
Parameter available only if the System Control parameter has Start value.
Dynamic Path Cost Lag-Speed. Parameter not meaningful in the current system ver-sion. For future use.
RSTP CONFIGURATION
Version. Spanning Tree protocol version currently used by the Switch:
• STP Compatible. Spanning Tree Protocol standard IEEE 802.1d.
• RSTP Compatible. Rapid Spanning Tree protocol standard IEEE 802.1D-2004.
Protocol characterized by a greater speed (lower convergence time).
Default RSTP Compatible.
Parameter available only if the System Control parameter has Start value.
Priority. Priority assigned to the Switch. This value is used during the election of the Root.
Values between 0 (highest priority) and 61440 (lowest priority) are available, subdivided in intervals of 4096: 0, 4096 (1), 8192 (2), 12288 (3), 16384 (4), 20480 (5) and so on, up to 61440 (15).
Default 32768 (8).
Parameter available only if the System Control parameter has Start value.
Tx Hold Count. Maximum number of BPDU packets which can be transmitted within a given interval.
Default 6.
Parameter available only if the System Control parameter has Start value.
Max Age.Maximum number of switches which the packet can pass through before ex-piring. The passage from a Switch to another one involves the decrease of 1 second per equipment.
Default 20 seconds.
Parameter available only if the System Control parameter has Start value.
Hello Time. Interval between two consecutive transmissions of the BPDU (Bridge Proto-col Data Unit) packet, generated by the Switch.
Default 2 seconds.
Parameter available only if the System Control parameter has Start value.
Forward Delay. Time interval which passes between the passage between the Discard-ing status and the LearnDiscard-ing status and between the LearnDiscard-ing status and the ForwardDiscard-ing status of the port.
Default 15 seconds.
Parameter available only if the System Control parameter has Start value.
See also
Enable/disable the use of STP/RSTP protocol for the equipment Verify/modify the allocation of memory for the STP/RSTP function Verify/modify the ports set for the STP/RSTP function
Verify/modify the enabling of STP/RSTP function
Verify/modify the dynamic path cost calculation function (STP/RSTP) Verify/modify the version of the protocol (STP/RSTP)
Verify/modify the priority assigned to the Switch (STP/RSTP)
Verify/modify the maximum number of BPDU packets in transmission (STP/RSTP) Verify/modify the parameters for the transmission of BPDU packets (STP/RSTP)
Port Settings tab
The tab displays the parameters of the Ethernet ports in relation to STP/RSTP function.
Table
Every table row corresponds to one port set for the STP/RSTP function (parameter Enable Ports, box active).
The table will be empty if the parameter System Control has value Shutdown or if the parameter Enable Ports has not active values (see Settings tab).
Port. Port identifier. The ID value is a combination of slot number and the port number (slot number/port number).
Read only parameter.
Description. Name of the port:
• LAN 1. First line Ethernet port (electric or optical).
• LAN 2. Second line Ethernet port (electric or optical).
• LAN 3. Third line of Ethernet port (electrical) (management port).
• LAN 4. Fourth line Ethernet port (electrical).
• LAN 5. Fifth line Ethernet port (optical).
• LAN 6. Sixth line Ethernet port (optical).
• ODU A. Ethernet port to the Radio A.
• ODU B. Ethernet port to the Radio B.
Port available only for equipment with more ODU (see Tab.4).
• LAN C. Seventh line Ethernet port (optical).
• LAN D. Eighth line Ethernet port (optical).
Read only parameter.
Port Role. Role assigned by STP/RSTP to the port. The role defines the behaviour of the port according to the state of the Bridge in the network:
• Disabled. Porta disabled manually (state STP/RSTP) or automatically (Link): it will not take part to Spanning Tree process.
• Root. Port offering the best path (lowest cost) to the Bridge elected Root. Eve-ry Bridge can have only one Root port. When the Spanning Tree algorithm is at steady state, every Root port is in state Forwarding.
• Alternate. Port alternative to the Root port, as it offers an alternative path to the Bridge Root with cost higher with respect to the Root port. Generally, the Alternate port is in state Discarding. It is enabled and declared Root if the Root port is in state Discarding.
• Designated. Port which does not offer paths to the Bridge Root and is used to forward the information of the Bridge Root to other Bridges. Every Designated port is in state Forwarding. In every segment, only one port is Designated.
• Backup. Port physically connected to a Lan where a Designated port of the same Bridge is connected. The Backup port is in state Discarding. It is enabled and declared Designated if the current Designated port is in state Discarding.
Read only parameter.
Port Priority. This value is used during the process of selection of the port role (see Port Role).
Values between 0 (highest priority) and 240 (lowest priority) are available, subdivided in intervals of 16: 0, 16 (1), 32 (2), 48 (3), 64 (4), 80 (5) and so on up to 240 (15).
Default 128 (8).
RSTP Status. Port enabling state as regards the operation of STP/RSTP protocol:
• Disable. Protocol operation disabled: the port does not take part to Spanning Tree process and does not receive/transmit BPDU packets.
• Enable. Protocol operation enabled: the port stake part to Spanning Tree pro-cess and is ready to receive/transmit BPDU packets.
Default Enable.
Path Cost. Cost of the network segment directly connected to the port. It represents the distance between the port Root and the port Designated.
The default value is automatically set depending on the port bit rate: 8000 for ODU ports and line ports configured at 2.5 Gb/s, 20000 for 1Gb/s, 200000 for 100Mb/s and 2000000 for 10Mb/s.
The selection of present in the header of each column, shows the following commands:
Sort Ascending. Not available in this context.
Sort Descending. Not available in this context.
Columns. Activate ( ) or deactivate ( ) the display of a column in the table.
See also
Verify/modify the priority of a port (STP/RSTP)
Verify/modify the status of the STP/RSTP function of a port Verify/modify the cost of the a port (STP/RSTP)
Port Status tab
The tab displays the information stored by every Switch port as regards the STP/RSTP functionality.
All the parameters are read-only.
Table
Every table row corresponds to one port set for the STP/RSTP function (parameter Enable Ports, active box).
The table will be empty if the parameter System Control has value Shutdown or if the parameter Enable Ports has not active values (see Settings tab).
Port. Port identifier. The ID value is a combination of slot number and the port number (slot number/port number).
Description. Name of the port:
• LAN 1. First line Ethernet port (electric or optical).
• LAN 2. Second line Ethernet port (electric or optical).
• LAN 3. Third line of Ethernet port (electrical) (management port).
• LAN 4. Fourth line Ethernet port (electrical).
• LAN 5. Fifth line Ethernet port (optical).
• LAN 6. Sixth line Ethernet port (optical).
• ODU A. Ethernet port to the Radio A.
• ODU B. Ethernet port to the Radio B.
Port available only for equipment with more ODU (see Tab.4).
• LAN C. Seventh line Ethernet port (optical).
• LAN D. Eighth line Ethernet port (optical).
Port Role. Role assigned by STP/RSTP to the port. The role defines the behaviour of the port according to the state of the Bridge in the network:
• Disabled. Porta disabled manually (state STP/RSTP) or automatically (Link): it will not take part to Spanning Tree process.
• Root. Port offering the best path (lowest cost) to the Bridge elected Root. Eve-ry Bridge can have only one Root port. When the Spanning Tree algorithm is at steady state, every Root port is in state Forwarding.
• Alternate. Port alternative to the Root port, as it offers an alternative path to the Bridge Root with cost higher with respect to the Root port. Generally, the Alternate port is in state Discarding. It is enabled and declared Root if the Root port is in state Discarding.
• Designated. Port which does not offer paths to the Bridge Root and is used to forward the information of the Bridge Root to other Bridges. Every Designated port is in state Forwarding. In every segment, only one port is Designated.
• Backup. Port physically connected to a Lan where a Designated port of the same Bridge is connected. The Backup port is in state Discarding. It is enabled and declared Designated if the current Designated port is in state Discarding.
Port State. Current state of the port in relation to RSTP functionality.
Designated Root. Univocal identifier of the Bridge registered as Root for the segment of the network which the port is connected to.
Designated Cost. Path Cost of the Designated port of the segment connected to the porta.
Designated Bridge. Univocal identifier of the Bridge which the port considers the Bridge Designated for the segment of the port. The Bridge Designated is the only Bridge allowed to transmit the packets from/to the segment.
Designated Port. Identifier of the port on the Bridge Designated for the relevant seg-ment. It represents the port through which the Bridge Designated forwards/receive the packets to/from the segment.
Type. Operating state of the port in relation to the LAN segment connected to the port:
• SharedLan. The port is treated as connected to a shared connection.
• Point-to-Point. The port is treated as connected to a point-to-point connection.
The selection of present in the header of each column, shows the following commands:
Sort Ascending. Not available in this context.
Sort Descending. Not available in this context.
Columns. Activate ( ) or deactivate ( ) the display of a column in the table.
See also
Verify the information stored by every single Switch port (STP/RSTP) Port status Receive
traffic Forward traffic
Update the Address Table
Unit
Receive/
process BPDU Re-transmit BPDU
Discarding No No No Yes No
Learning Yes No Yes Yes Yes
Forwarding Yes Yes Yes Yes Yes
STP/RSTP Protocol (info)
Spanning Tree Protocol (STP)
Spanning Tree is a protocol for the management of the connections, which supports the redun-dancy of the path avoiding the creation of unwished loops in the network. In order that an Ether-net Ether-network operates correctly, only an active path must exist between two stations. Multiple active paths cause loops in the network and, as consequence, the possible replication of the messages to infinity.
The Spanning Tree protocol constitutes a tree logic network which pass through all the bridges into a complex physical network forcing the possible duplicated paths (possible loops) into a stand-by status.
If a network segment becomes unreachable or if the cost of a path changes, the algorithm of Spanning Tree reconfigures the topology of the network activating an alternative path.
To make this possible, STP needs to know the whole network. The Bridges have to define the main Bridge (Bridge Root) and calculate the role of the ports (Root, Designated, etc.) using the known information. To ensure that every bridge has the information, the Bridges use special packets called Bridge Protocol Data Units (BPDU) for the exchange of information on the ID’s of the Bridges and on the cost of the path from the Root element.
The BPDU packets are periodically exchanged and allow the Switch keeping trace of the network changes to start and stop the transmission of the ports, on demand.
A Bridge sends a BPDU packet using the univocal MAC address of the port as source address and the STP multicast address 01:80:C2:00:00:00 as destination address.
For more information, refer to the standard IEEE 802.1d (Spanning Tree Protocol).
Rapid Spanning Tree Protocol (RSTP)
The protocol Rapid STP decreases, with respect to STP, the time necessary for the re-configu-ration of the active network when the physical topology or the network configure-configu-ration parameters are changed.
The RSTP protocol has been designed to be compatible with the STP protocol.
For more information, refer to the standard IEEE 802.1D-2004 (Rapid Spanning Tree Protocol).
AGS-20
The equipment can be configured to work with the STP protocol or the RSTP protocol (see Verify/
modify the version of the protocol (STP/RSTP)).
The use of the protocol must be enabled at Switch level and at single port level (see Enable/
disable the use of STP/RSTP protocol for the equipment).
Before enabling the protocol, it is suggested to set the relevant configuration parameters. By WEB LCT, it is possible to configure:
PARAMETERSAT SWITCHLEVEL
System Control (see Verify/modify the allocation of memory for the STP/RSTP function).
Enable Ports (see Verify/modify the ports set for the STP/RSTP function).
Dynamic Path Cost Calculation (see Verify/modify the dynamic path cost calcula-tion funccalcula-tion (STP/RSTP).
Status (see Verify/modify the enabling of STP/RSTP function).
Priority (see Verify/modify the priority assigned to the Switch (STP/RSTP).
Tx Hold Count (see Verify/modify the maximum number of BPDU packets in trans-mission (STP/RSTP).
Max Age, Hello Time e Forward Delay (see Verify/modify the parameters for the transmission of BPDU packets (STP/RSTP).
PARAMETERSATPORTLEVEL
Port Priority (see Verify/modify the priority of a port (STP/RSTP).
RSTP Status (see Verify/modify the status of the STP/RSTP function of a port).
Path Cost (see Verify/modify the cost of the a port (STP/RSTP).
LLF
User Profile | Read Only, Maint., Read/Write, Admin.
The command LLF allows configuring the operation of LLF (Link Loss Forwarding) functionality for the equipment.
Operations
Verify the status of the LLF functionality for the Ethernet ports Configure a port for the management of LLF functionality
Remove a port of the switch from the management of LLF functionality Configure the radio circuit for the forwarding of the LOS alarm present on LAN Remove a radio circuit from the management of LLF functionality for a given LAN Enable/disable the LLF functionality for a LAN
Enable/disable the forwarding of LLF alarm on the radio Modify the hysteresis value for the LLF functionality Modify the propagation modality of LLF alarm
Enable/disable the forwarding of LOS alarm of a LAN to the radio
GUI
LLF contextual area
See also
Bidirectional LLF (info)
Verify the status of the LLF functionality for the Ethernet ports User Profile | Read Only, Maint., Read/Write, Admin.