Using TCP/IP and UDP Protocols

TCP/IP and UDP are two network protocols supported in Sheerpower for sending and receiving data between servers and client computers.

TCP/IP is a handshake protocol — data delivery is confirmed, and corrupted packets are re-sent automatically.
UDP is a no-handshake protocol — data is sent without confirmation, and reliability must be handled by the application programmer.

Problem: Programs often need reliable communication between machines, but sometimes performance and low latency are more important than guaranteed delivery.

Solution: Use TCP/IP when you need built-in delivery confirmation and retransmission. Use UDP when speed and reduced overhead matter more, and you can manage delivery rules yourself.

Efficiency: TCP/IP provides safety and confirmation, but incurs more overhead. UDP avoids the handshake, which makes it faster and lighter.

Takeaway: Choose the protocol that best fits your application: TCP/IP for reliability, UDP for speed.

TCP/IP vs UDP Overview

TCP/IP (Handshake)

Reliable, connection-oriented. Each message is confirmed by the receiver, and re-sent if corrupted or missing.

Client ---- SYN ----> Server

Client <--- ACK ---- Server

Client ---- DATA --> Server

Client <--- ACK ---- Server

Guarantees delivery with automatic retransmission.

UDP (No Handshake)

Fast, connectionless. Data is sent and may or may not be received. No built-in confirmation or error checking.

Client ---- DATA ----> Server

      (no ACK, no retry)

Programmer must handle reliability if needed.

TCP/IP Protocol

Format:

open file tcp_ch: name 'tcp://[ip]?[param1=value1]&[param2=value2]', access outin

Example 18-4: Very Simple TELNET Client

// prompt for IP address line input 'IP address of the telnet server': ip$ open file tcp_ch: name 'tcp://' + ip$ + '?port=23', access outin print 'Ready for data...' do // check for data from the server (up to 100 iterations) for idx = 1 to 100 line input #tcp_ch: ip$ if ip$ = '' then exit for ask #tcp_ch, symbol 'data': value rec$ print rec$; next idx // check for data from this client when exception in key input timeout 1, prompt '': dat$ print #tcp_ch: dat$ use end when loop end

Purpose

TCP/IP allows programmers to transmit data back and forth with built-in confirmation of delivery and automatic re-requests if data is garbled.

Description

If an IP address is specified, it denotes the client machine’s destination. If no IP address is specified, the channel acts as a server. Parameters follow the ? and are separated by &. For example:

// specify port 23 open file tcp_ch: name 'tcp://' + '?port=23', access outin

Table 18-3: TCP/IP Protocol Parameters

Parameter	Description	Default
Sockets	number of sockets to use	100
port	port number for data transmission	31111
ipaddress	IP address of the client	none
max_receive_queue	max number of requests that can be received	200
max_send_queue	max number of requests in the send queue	200
maxdupconnections	maximum duplicate connections allowed	3
timeout	timeout length in seconds	50

18.4.2 UDP Protocol

Format:

open file udp_ch: name 'udp://[ip]?[param1=value1]&[param2=value2]', access outin

Description

If an IP address is specified, it denotes the client destination. Without an IP address, the channel is a server. Parameters follow the ? and are separated by &. For example:

// set timeout to 20 seconds open file udp_ch: name 'udp://' + '?timeout=20', access outin

Table 18-4: UDP Protocol Parameters

Parameter	Description	Default
Sockets	number of sockets to use	100
port	port number for data transmission	31111
ipaddress	IP address of the client	none
max_receive_queue	max number of requests that can be received	200
max_send_queue	max number of requests in the send queue	200
maxdupconnections	maximum duplicate connections allowed	3
timeout	timeout length in seconds	50

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