TCP_UDP

VisualSim Block Documentation ›› Interface and Buses ›› Networking ››

TCPInterfaces and Buses / Networking / TCP_UDP
Block Name: TCP_UDP
Code File Location: VisualSim/actor/lib.networking/TCP_UDP

Description

Used to describe the connectivity and attributes of Transport Layer of the Protocol Stack.
Connections between this layer and the one's above/below can be done using connected wires.

Each VisualSim TCP_UDP is used to Visualise the Transport Layer. It simulates Transmission Control Protocol(TCP) and User Datagram Protocol (UDP).
TCP
Transmission Control Protocol(TCP) is a connection - oriented Communication Protocol that facilitates the exchange of data between computing devices in the network. TCP takes messages from the upper layer and divides them into segments which can then be forwarded by Switches, Routers, Gateways to the Destination. The important features of TCP are Reliability,Flow Control, Congestion Control,Full Duplex, Connection oriented. TCP assigns a sequence number to eack packet transmitted and expects an ACK from the receiving TCP layer. If the ACK is not received within the Retransmission Timeout , the data is retransmitted. The receiving TCP uses the Sequence number to rearrange the TCP segments when they arrive out of order. TCP uses Sliding Window Mechanism for Flow Control. The TCP_UDP in Visualsim uses the Slow Start and Congestion Avoidance for Congestion Control. TCP uses Three- Way Handshake method to create connection between the Nodes.

UDP:
User Datagram Protocol is a connectionless protocol. There is no Flow control, congestion control, reliability in UDP. The UDP has multicast.

Data Structure Fields
TCP_UDP requires certain mandatory Data Strucutres such as

Transport_Protocol
A_Destination
Source
Task_Size
Destination_Port

To illustrate the usage, refer to the following demo model.

TCP_UDP

Parameter	Explanation	Type	Example
Block_num	This is a unique number to each TCP_UDP block in the model.	Integer	Integer Eg: 1
Num_Queues	It is the number of Virtual Connections that can be made from one TCP to another TCP layer.	Integer	Integer Eg: 100
Node_Name	This is the name of the Node to which the TCP_UDP block is connected.	String	String Eg: "TCP_UDP_1"
Window_Size	This is the Size of the Receive Buffer in the TCP_UDP layer. The Window Size is in Bytes.	Integer	Integer Eg: 64000

Port_Name	Description	Type
frm_upper_layer	This is the input to the TCP_UDP from the Upper layers. If connecting to the Layer Protocol , the port should be connected to the ds_dn_output port of the Layer Protocol	General, input port
to_upper_layer	This is the output to the upper layers from TCP_UDP protocol. If connecting to the Layer Protocol, the port should be connected to the ds_up_input port of the Layer Protocol.	General, output port
frm_dn_layer	This is the input to the TCP_UDP from the Network Layer. The port should be connected to the ds_up_output port of the Layer Protocol.	General, input port
to_dn_layer	This is the output port from the TCP_UDP to the Network Layer. The port should be connected to the ds_dn_input port of the Layer Protocol,	General, output port
Latency	This is the output port. This port gives the Latency of the Data to the Upper Layer.	General, output port