Stp

Package: inet.linklayer.ieee8021d.stp

Stp

simple module

The Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free topology for any bridged Ethernet local area network. The basic function of STP is to prevent bridge loops and the broadcast radiation that results from them. Spanning tree also allows a network design to include spare (redundant) links to provide automatic backup paths if an active link fails, without the danger of bridge loops, or the need for manual enabling/disabling of these backup links.

There are various versions of Spanning Tree algorithm and protocol. This module implements it according to the IEEE 802.1D-1998 specification.

STP makes use of per-port configuration data such as cost and priority. They can be set using L2NetworkConfigurator. Port state is kept in the switch's InterfaceTable.

See also: L2NetworkConfigurator, InterfaceTable

Inheritance diagram

The following diagram shows inheritance relationships for this type. Unresolved types are missing from the diagram.

Parameters

Name Type Default value Description
helloTime double 2s

The hello time is the time between each bridge protocol data unit (BPDU) that is sent on a port. This time is equal to 2 seconds (sec) by default, but you can tune the time to be between 1 and 10 sec.

forwardDelay double 15s

The forward delay is the time that is spent in the listening and learning state. This time is equal to 15 sec by default, but you can tune the time to be between 4 and 30 sec.

maxAge double 20s

The max age timer controls the maximum length of time that passes before a bridge port saves its configuration BPDU information. This time is 20 sec by default, but you can tune the time to be between 6 and 40 sec.

bridgePriority int 32768

The bridge priority determines which bridge is elected as the root bridge. If the switch has a bridge priority that is lower than all the other switches, the other switches automatically select the switch as the root switch.

interfaceTableModule string

The path to the InterfaceTable module

macTableModule string

The path to the MacForwardingTable module

visualize bool false

Shows the spanning tree by coloring connections in the network graphics. Label ethernet interface with port role and status. Mark root switch

Properties

Name Value Description
display i=block/network2

Gates

Name Direction Size Description
relayIn input
relayOut output

Scheduled messages (observed)

msgkindctrltagsmsgnamecontext
omnetpp::cMessage0STP_TICK

Direct method calls (observed)

call tofunctioninfo
MessageDispatcherinet::MessageDispatcher::arrivedarrived
MessageDispatcherinet::MessageDispatcher::handleRegisterProtocolhandleRegisterProtocol

Called methods (observed)

functioninfocall from
inet::Stp::handleOperationStagehandleOperationStageScenarioManager

Incoming messages (observed)

gatemsgkindctrlsrcModuletags
relayInPacket0Ieee8022LlcDirectionTag, DispatchProtocolReq, EncapsulationProtocolInd, Ieee802SapInd, InterfaceInd, MacAddressInd, PacketProtocolTag

Outgoing messages (observed)

gatemsgkindctrldestModuletags
relayOutPacket0Ieee8022LlcDispatchProtocolReq, InterfaceReq, MacAddressReq, PacketProtocolTag

Packet operations (observed)

chunkTypepacketAction
BpduBasepeekAtFront
BpduCfginsertAtBack
BpduTcninsertAtBack

Shared Tagging operations (observed)

tagTypetagAction
DispatchProtocolReqaddTag
InterfaceIndgetTag
InterfaceReqaddTag
MacAddressIndgetTag
MacAddressReqaddTag
PacketProtocolTagaddTag

Tagging operations (observed)

tagTypetagAction
inet::Ieee8021dInterfaceDatagetTag, getTagForUpdate

Source code

//
// The Spanning Tree Protocol (STP) is a network protocol that ensures a loop-free
// topology for any bridged Ethernet local area network. The basic function of STP
// is to prevent bridge loops and the broadcast radiation that results from them.
// Spanning tree also allows a network design to include spare (redundant) links to
// provide automatic backup paths if an active link fails, without the danger of
// bridge loops, or the need for manual enabling/disabling of these backup links.
//
// There are various versions of Spanning Tree algorithm and protocol. This module
// implements it according to the IEEE 802.1D-1998 specification.
//
// STP makes use of per-port configuration data such as cost and priority.
// They can be set using ~L2NetworkConfigurator. Port state is kept in the switch's
// ~InterfaceTable.
//
// @see ~L2NetworkConfigurator, ~InterfaceTable
//
simple Stp like ISpanningTree
{
    parameters:

        // The hello time is the time between each bridge protocol data unit (BPDU) that is sent on a port.
        // This time is equal to 2 seconds (sec) by default, but you can tune the time to be between 1 and 10 sec.
        double helloTime @unit(s) = default(2s);

        // The forward delay is the time that is spent in the listening and learning state. This time is equal to 15 sec by default,
        // but you can tune the time to be between 4 and 30 sec.
        double forwardDelay @unit(s) = default(15s);

        // The max age timer controls the maximum length of time that passes before a bridge port saves its configuration BPDU information.
        // This time is 20 sec by default, but you can tune the time to be between 6 and 40 sec.
        double maxAge @unit(s) = default(20s);

        // The bridge priority determines which bridge is elected as the root bridge. If the switch has a bridge priority that is lower than all
        // the other switches, the other switches automatically select the switch as the root switch.
        int bridgePriority = default(32768);

        // The path to the InterfaceTable module
        string interfaceTableModule;

        // The path to the MacForwardingTable module
        string macTableModule;

        // Shows the spanning tree by coloring connections in the network graphics.
        // Label ethernet interface with port role and status. Mark root switch
        bool visualize = default(false);

        @display("i=block/network2");
    gates:
        input relayIn;
        output relayOut;
}

File: src/inet/linklayer/ieee8021d/stp/Stp.ned