drcl.inet.transport
Class TCP

java.lang.Object
  drcl.DrclObj
      drcl.comp.Component
          drcl.net.Module
              drcl.inet.Protocol
                  drcl.inet.transport.TCP

All Implemented Interfaces:

ActiveComponent, java.lang.Cloneable, drcl.inet.transport.Connection, InetConstants, ObjectCloneable, ObjectDuplicable, java.io.Serializable, TCPConstants

Direct Known Subclasses:

TCPb

public class TCP

extends Protocol

implements TCPConstants, drcl.inet.transport.Connection, ActiveComponent

This component implements the single-session sender TCP. Only one TCP session is handled in this component. Open and close of the connection is not implemented, nor is the 3-way handshaking.

Several variants of TCP are implemented: Tahoe, Reno, New-Reno ([Fall96]) and Vegas ([Brakmo95]). Each can be used with the SACK option. Currently only New-Reno takes advantage of the SACK blocks in an ACK. To specify the implementation, use setImplementation(String) with "Tahoe", "Reno", "New-Reno" or "Vegas" as argument. To enable SACK, use setSackEnabled(boolean).

The initial sequence number is set as 0, instead of a random value suggestted in [TCPILL2]

For Tahoe and Reno, the RTT and RXT timer base estimation is based on [TCPILL2]. The sending time of a segment is recorded as ts_ in the TCP header (similar to the timestamp option in the real TCP header) and returned by the corresponding acknowledgment packet. ts_ is set to -1 if the segment is a retransmitted one, so no RTT estimation is performed for retransmitted segments. The algorithm is described in [RFC793] and [TCPILL1].

        SampleRTT = current time - ts_;
        SmoothedRTT[new] = 7/8*SmoothedRTT[old] + 1/8*SampleRTT;
        Delta = |SampleRTT - SmoothedRTT[old]|;
        RTTVariance[new] = 3/4*RTTVariance[old] + 1/4*Delta;
        and the retransmission timer base is 
        RTO[new] = SmoothedRTT[new] + 4*RTTVariance[new].

The exception is that for the first acknowledgment received:

        SampleRTT = current time - ts_;
        SmoothedRTT[new] = SampleRTT;
        RTTVariance[new] = SampleRTT/2;
        and the retransmission timer base is 
        RTO[new] = SmoothedRTT[new] + 4*RTTVariance[new].

Additional usage infomation:

1. The "maxburst" option, use setMaxburstEnabled(boolean). This option restricts the maximum number of bytes that can be sent in response to a single ACK to be one segment during Reno-style fast recovery, and two segments otherwise. This is based on [RFC2018] and is different from similar setting in [Fall96]. For Vegas, only two segments restriction applies since Vegas does not have fast recovery.
2. To change TTL value, use setTTL(int).
3. To change MSS value, use setMSS(int).
4. To change timer tick, use setTick(double).

References:

• [TCPILL1] W. Stevens, TCP/IP Illustrated vol.1: The Protocols, Addison-Wesley,1994.
• [TCPILL2] G. Wright and W. Stevens, TCP/IP Illustrated vol.2: The Implementation, Addison-Wesley,1995
• [RFC793] J. Postel, Transmission Control Protocol, September 1981.
• [RFC2018] M. Mathis, J. Mahdavi, S. Floyd and A. Romanow, TCP Selective Acknowledgment Options, Octobor 1996.
• [RFC2581] M. Allman, V. Paxson and W. Stevens, TCP Congestion Control, April 1999.
• [Fall96] K. Fall and S. Floyd, Simulation-based Comparisons of Tahoe, Reno and SACK TCP, Computer Comm. Review, V. 26 N. 3, July 1996, pp. 5-21.
• [Brakmo95] L. S. Brakmo and L. L. Peterson, TCP Vegas: End to End Congestion Avoidance on a Global Internet, IEEE Journal on Selected Areas in Communication, Vol 13, No. 8 (October 1995) pages 1465-1480.

Author:

Yuan Gao, Yung-ching Hsiao, Hung-ying Tyan

See Also:

TCPPacket, TCPSink, Serialized Form

Nested Class Summary

static class

TCP.VegasVariables Stores variables for implementing TCP-VEGAS.

Nested classes inherited from class drcl.comp.Component

Component.Locks

Field Summary

static int	AWND_DEFAULT Default advertisement window size (unit of MSS bytes).
static int	DEBUG_ACK
static int	DEBUG_DUPACK
static java.lang.String[]	DEBUG_LEVELS
static int	DEBUG_RTT
static int	DEBUG_SACK
static int	DEBUG_SAMPLE
static int	DEBUG_SEND
static int	DEBUG_TIMEOUT
static int	DEBUG_VEGAS
static int	INIT_SS_THRESHOLD Initial slow-start threshold (unit of MSS bytes).
static int	MAXCWND_DEFAULT Default maximum congestion window size (unit of MSS bytes).
static boolean	NS_COMPATIBLE Sets to true to make TCP ns compatible
static int	NUMDUPACKS Number of duplicate ACKs to trigger fast RXT as specified in [RFC2581] (for Reno, Tahoe).
int	state FSM State of this TCP component.

Fields inherited from class drcl.net.Module

downPort, PortGroup_DOWN, PortGroup_UP, upPort

Fields inherited from class drcl.comp.Component

FLAG_COMPONENT_NOTIFICATION, FLAG_DEBUG_ENABLED, FLAG_DIRECT_OUTPUT_ENABLED, FLAG_ENABLED, FLAG_ERROR_ENABLED, FLAG_EVENT_ENABLED, FLAG_GARBAGE_DISPLAY_ENABLED, FLAG_GARBAGE_ENABLED, FLAG_PORT_NOTIFICATION, FLAG_STARTED, FLAG_STOPPED, FLAG_TRACE_ENABLED, FLAG_UNDEFINED_START, id, infoPort, locks, name, parent, PortGroup_DEFAULT_GROUP, PortGroup_EVENT, PortGroup_SERVICE, Root, Trace_DATA, Trace_SEND

Fields inherited from interface drcl.inet.transport.TCPConstants

ACK_EVENT, ACK_PORT_ID, CLOSE_WAIT, CLOSED, CLOSING, CWND_EVENT, CWND_PORT_ID, DEFAULT_PID, DELAY_ACK, ESTABLISHED, ESTABLISHED_FIN, ESTABLISHED_OVER, FIN_WAIT_1, FIN_WAIT_2, LAST_ACK, LISTEN, LISTEN1, LISTEN2, NEW_RENO, PRE_CLOSED, PRE_LAST_ACK, PRE_SYN_SENT, RECEIVE, RENO, RTT_EVT, RTTVAR_EVENT, RTTVAR_PORT_ID, RXT_EVT, SEND, SEQNO_EVENT, SEQNO_PORT_ID, SEQNO_RCV_EVENT, SEQNO_RCV_PORT_ID, SEQNO_SENT_EVENT, SEQNO_SENT_PORT_ID, SRTT_EVENT, SRTT_PORT_ID, SST_EVENT, SST_PORT_ID, STATES, SYN_RCVD, SYN_SENT, TAHOE, TIME_WAIT, TIMEOUT_TYPES, VEGAS

Fields inherited from interface drcl.inet.InetConstants

BYTE_MODE, DEFAULT_BANDWIDTH, DEFAULT_BUFFER_SIZE, DEFAULT_MTU, EVENT_ID_CHANGED_PORT_ID, EVENT_IDENTITY_ADDED, EVENT_IDENTITY_REMOVED, EVENT_IF_NEIGHBOR_DOWN, EVENT_IF_NEIGHBOR_UP, EVENT_IF_PORT_ID, EVENT_LINK_BROKEN, EVENT_LINK_BROKEN_PORT_ID, EVENT_MCAST_HOST_PORT_ID, EVENT_PKT_ARRIVAL, EVENT_PKT_ARRIVAL_PORT_ID, EVENT_RT_ENTRY_ADDED, EVENT_RT_ENTRY_MODIFIED, EVENT_RT_ENTRY_REMOVED, EVENT_RT_MCAST_CHANGED_PORT_ID, EVENT_RT_UCAST_CHANGED_PORT_ID, EVENT_VIF_NEIGHBOR_DOWN, EVENT_VIF_NEIGHBOR_UP, EVENT_VIF_PORT_ID, HOST_ENTRY_EXT, ID_CSL, ID_TRACE_RT, MCAST_QUERY_PORT_ID, PACKET_MODE, PID_AODV, PID_DV, PID_DVMRP, PID_HELLO, PID_IGMP, PID_OSPF, PID_RSVP, PID_TCP, PID_TRACE_RT, PID_UDP, SERVICE_CONFIGSW_PORT_ID, SERVICE_ID_PORT_ID, SERVICE_IF_PORT_ID, SERVICE_MCAST_PORT_ID, SERVICE_RT_PORT_ID, UCAST_QUERY_PORT_ID

Constructor Summary

TCP()

TCP(java.lang.String id_)

Method Summary

java.lang.String	configInfo()
void	configureRTT(double tick_, double srtt_init_, double rttvar_init_, double basertt_init_, double maxrto_) Configures RTT parameters.
void	duplicate(java.lang.Object source_) Duplicates the content of source_, including ID, name, child components and connections among them, to this component.
double	getBASERTT_INIT() Returns the initial value of baseRTT (in second).
java.lang.String[]	getDebugLevelNames() Returns the names of defined debug levels; subclasses should override this method if debug levels are defined.
java.lang.String	getImplementation()
long	getLocalAddr() Returns the local address.
int	getLocalPort() Returns the local port.
int	getMAXCWND()
double	getMAXRTO() Returns the maximum retr timeout (in second).
int	getMSS()
java.lang.String	getName() Returns the (informational) name of the component.
long	getNumBytesRetransmitted() Returns # of bytes retransmitted.
int	getNumTimeouts() Returns # of coarse-grained timeouts.
long	getPeer() Returns the peer address.
int	getRemotePort() Returns the peer port.
double	getRTTVAR_INIT() Returns the initial value of rttvar (in second).
double	getSRTT_INIT() Returns the initial value of srtt (in second).
int	getState()
double	getTick()
int	getTTL()
java.lang.String	info() Returns information regarding this component.
boolean	isMaxburstEnabled()
boolean	isSackEnabled()
void	reset() Resets the component for being used anew.
void	setBASERTT_INIT(double v_) Sets the initial value of baseRTT (in second).
void	setImplementation(java.lang.String impl_)
void	setMaxburstEnabled(boolean maxburst_)
void	setMAXCWND(int max_)
void	setMAXRTO(double v_) Sets the maximum retr timeout (in second).
void	setMSS(int mss) Sets the maximum segment size.
void	setPeer(long peer_)
void	setRTTVAR_INIT(double v_) Sets the initial value of rttvar (in second).
void	setSackEnabled(boolean sack_)
void	setSRTT_INIT(double v_) Sets the initial value of srtt (in second).
void	setTick(double tick_) Sets the clock tick for RTT estimation.
void	setTTL(int ttl)

Methods inherited from class drcl.inet.Protocol

broadcast, broadcast, broadcast, broadcast, broadcast, broadcast, broadcast, createConfigSwitchPort, createIDChangedEventPort, createIDServicePort, createIFEventPort, createIFQueryPort, createLinkBrokenEventPort, createMcastHostEventPort, createMcastQueryPort, createMulticastRTChangedEventPort, createPktArrivalEventPort, createRTServicePort, createUcastQueryPort, createUnicastRTChangedEventPort, createVIFEventPort, forward, forward, forward, forward, forward, forward, LinkBrokenEventHandler

Methods inherited from class drcl.net.Module

cancelTimeout, setTimeout, setTimeoutAt

Methods inherited from class drcl.comp.Component

addComponent, addComponent, addEventPort, addEventPort, addForkPort, addPort, addPort, addPort, addPort, addPort, addPort, addPort, addPort, addServerPort, addServerPort, cancelFork, connect, containsComponent, containsComponent, containsPort, debug, disconnectAll, disconnectAllPeers, disconnectAllPorts, drop, drop, error, error, expose, exposeEventPorts, exposePort, exposePort, exposePort, exposePort, exposePort, findAvailable, findAvailable, findAvailable, fork, forkAt, getAllComponents, getAllPorts, getAllPorts, getAllWiresInside, getAllWiresInsideOut, getAllWiresOut, getComponent, getComponentFlag, getComponentFlag, getContract, getContractHT, getContractHT, getDebugFlagsInBinary, getID, getParent, getPort, getPort, getRoot, getTime, iduplicate, isAncestorOf, isContainer, isDebugEnabled, isDebugEnabledAt, isDirectlyRelatedTo, isDirectOutputEnabled, isEnabled, isErrorNoticeEnabled, isEventExportEnabled, isGarbageDisplayEnabled, isGarbageEnabled, isPortRemovable, isStarted, isStopped, isTraceEnabled, lock, notify, notifyAll, operate, reboot, removeAll, removeAllComponents, removeAllPorts, removeAllPorts, removeComponent, removeComponent, removePort, removePort, removePort, resume, run, sduplicate, send, sendAt, setComponentFlag, setComponentFlag, setDebugEnabled, setDebugEnabled, setDebugEnabledAt, setDebugEnabledAt, setDebugEnabledAt, setDirectOutputEnabled, setDirectOutputEnabled, setEnabled, setErrorNoticeEnabled, setErrorNoticeEnabled, setEventExportEnabled, setEventExportEnabled, setExecutionBoundary, setGarbageDisplayEnabled, setGarbageDisplayEnabled, setGarbageEnabled, setGarbageEnabled, setID, setID, setName, setPort, setPort, setTraceEnabled, setTraceEnabled, sleepFor, sleepUntil, stop, toString, unexpose, unlock, useLocalForkManager, useLocalForkManager, wait

Methods inherited from class drcl.DrclObj

clone

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

NS_COMPATIBLE

public static boolean NS_COMPATIBLE

Sets to true to make TCP ns compatible

AWND_DEFAULT

public static int AWND_DEFAULT

Default advertisement window size (unit of MSS bytes).

MAXCWND_DEFAULT

public static int MAXCWND_DEFAULT

Default maximum congestion window size (unit of MSS bytes).

INIT_SS_THRESHOLD

public static int INIT_SS_THRESHOLD

Initial slow-start threshold (unit of MSS bytes).

NUMDUPACKS

public static int NUMDUPACKS

Number of duplicate ACKs to trigger fast RXT as specified in [RFC2581] (for Reno, Tahoe).

DEBUG_LEVELS

public static final java.lang.String[] DEBUG_LEVELS

DEBUG_ACK

public static final int DEBUG_ACK

See Also:

Constant Field Values

DEBUG_DUPACK

public static final int DEBUG_DUPACK

See Also:

Constant Field Values

DEBUG_SEND

public static final int DEBUG_SEND

See Also:

Constant Field Values

DEBUG_TIMEOUT

public static final int DEBUG_TIMEOUT

See Also:

Constant Field Values

DEBUG_RTT

public static final int DEBUG_RTT

See Also:

Constant Field Values

DEBUG_SACK

public static final int DEBUG_SACK

See Also:

Constant Field Values

DEBUG_SAMPLE

public static final int DEBUG_SAMPLE

See Also:

Constant Field Values

DEBUG_VEGAS

public static final int DEBUG_VEGAS

See Also:

Constant Field Values

state

public transient int state

FSM State of this TCP component.

Constructor Detail

TCP

public TCP()

TCP

public TCP(java.lang.String id_)

Method Detail

getDebugLevelNames

public java.lang.String[] getDebugLevelNames()

Description copied from class: Component

Returns the names of defined debug levels; subclasses should override this method if debug levels are defined.

Overrides:

getDebugLevelNames in class Component

getName

public java.lang.String getName()

Description copied from class: Component

Returns the (informational) name of the component.

Overrides:

getName in class Component

reset

public void reset()

Description copied from class: Component

Resets the component for being used anew. All the internal variables must be set to the initial state. All the ports and child components are reset as well.

Overrides:

reset in class Component

duplicate

public void duplicate(java.lang.Object source_)

Description copied from class: Component

Duplicates the content of source_, including ID, name, child components and connections among them, to this component. Subclasses need to override this method to copy its own variables.

Specified by:

duplicate in interface ObjectDuplicable

Overrides:

duplicate in class Protocol

getState

public int getState()

setPeer

public void setPeer(long peer_)

getPeer

public long getPeer()

Description copied from interface: drcl.inet.transport.Connection

Returns the peer address.

Specified by:

getPeer in interface drcl.inet.transport.Connection

setTTL

public void setTTL(int ttl)

getTTL

public int getTTL()

setMSS

public void setMSS(int mss)

Sets the maximum segment size. This method initializes this TCP component. Should not be called during simulation.

getMSS

public int getMSS()

setMAXCWND

public void setMAXCWND(int max_)

getMAXCWND

public int getMAXCWND()

setTick

public void setTick(double tick_)

Sets the clock tick for RTT estimation.

getTick

public double getTick()

setSRTT_INIT

public void setSRTT_INIT(double v_)

Sets the initial value of srtt (in second).

getSRTT_INIT

public double getSRTT_INIT()

Returns the initial value of srtt (in second).

setRTTVAR_INIT

public void setRTTVAR_INIT(double v_)

Sets the initial value of rttvar (in second).

getRTTVAR_INIT

public double getRTTVAR_INIT()

Returns the initial value of rttvar (in second).

setBASERTT_INIT

public void setBASERTT_INIT(double v_)

Sets the initial value of baseRTT (in second).

getBASERTT_INIT

public double getBASERTT_INIT()

Returns the initial value of baseRTT (in second).

setMAXRTO

public void setMAXRTO(double v_)

Sets the maximum retr timeout (in second).

getMAXRTO

public double getMAXRTO()

Returns the maximum retr timeout (in second).

getNumBytesRetransmitted

public long getNumBytesRetransmitted()

Returns # of bytes retransmitted.

getNumTimeouts

public int getNumTimeouts()

Returns # of coarse-grained timeouts.

configureRTT

public void configureRTT(double tick_,
                         double srtt_init_,
                         double rttvar_init_,
                         double basertt_init_,
                         double maxrto_)

Configures RTT parameters.

Parameters:

tick_ - time unit for RTT variables.

srtt_init_ - initial value of srtt.

rttvar_init_ - initial value of rttvar.

basertt_init_ - initial value of baseRTT.

maxrto_ - maximum retrx timeout.

setImplementation

public void setImplementation(java.lang.String impl_)

getImplementation

public java.lang.String getImplementation()

setSackEnabled

public void setSackEnabled(boolean sack_)

isSackEnabled

public boolean isSackEnabled()

setMaxburstEnabled

public void setMaxburstEnabled(boolean maxburst_)

isMaxburstEnabled

public boolean isMaxburstEnabled()

getLocalPort

public int getLocalPort()

Description copied from interface: drcl.inet.transport.Connection

Returns the local port.

Specified by:

getLocalPort in interface drcl.inet.transport.Connection

getRemotePort

public int getRemotePort()

Description copied from interface: drcl.inet.transport.Connection

Returns the peer port.

Specified by:

getRemotePort in interface drcl.inet.transport.Connection

getLocalAddr

public long getLocalAddr()

Description copied from interface: drcl.inet.transport.Connection

Returns the local address.

Specified by:

getLocalAddr in interface drcl.inet.transport.Connection

info

public java.lang.String info()

Description copied from class: Component

Returns information regarding this component. Subclasses should override this method to provide useful information at run time.

Overrides:

info in class Component

configInfo

public java.lang.String configInfo()