Transcript TCP/IP - MECPS

Networking Basics
TCP/IP Protocols
The Main Protocols of the TCP/IP Suite
Contained within the TCP/IP model are
several protocols that direct how
computers connect and communicate
using TCP/IP.
 Even though the protocol suite is called
TCP/IP, many other protocols are available
besides the TCP and IP protocols.

TCP
Transmission Control Protocol (TCP) is one
of the protocols that the TCP/IP suite is
named for.
 TCP provides a reliable, connection-based
delivery service.
 Successful delivery of packets is
guaranteed by the TCP protocol.
 If a TCP packet is lost or corrupted
during transmission, TCP resends a good
packet.

TCP
TCP requires the recipient to
acknowledge the successful receipt of
data.
 ACKs, generate additional traffic on the
network, which causes a network
slowdown

UDP
User Datagram Protocol (UDP) offers a
connectionless datagram service that is an
unreliable "best effort" delivery.
 UDP does not guarantee the arrival of
datagrams, nor does it promise that the
delivered packets are in the correct
sequence.
 Applications that don’t require an
acknowledgment of receipt of data use
UDP.

ICMP
Internet Control Message Protocol (ICMP)
enables systems on a TCP/IP network to
share status and error information.
 You can use the status information to
detect network trouble.
 ICMP messages are encapsulated within IP
datagrams, so they may be routed
throughout an internetwork.
 Two of the most common usages of ICMP
messages are ping and tracert.

PING
You can use ping to send ICMP Echo
Requests to an IP address and wait for
ICMP Echo Responses.
 Ping reports the time interval between
sending the request and receiving the
response.
 With ping you can determine whether a
particular IP system on your network is
functioning correctly.

TRACERT

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Tracert traces the path taken to a particular
host.
Tracert sends ICMP echo requests to an IP
address while it increments the TTL field in
the IP header by a count of one after
starting at one and then analyzing the ICMP
errors that get returned.
Each succeeding echo request should get
one further into the network before the TTL
field reaches 0 and an ICMP Time Exceeded
error is returned by the router attempting
to forward it.
ARP
 ARP
is used to provide IP-addressto-physical-address resolution for IP
packets.
 To accomplish this feat, ARP sends
out a broadcast message with an ARP
request packet in it that contains the
IP address of the system it is trying
to find.
ARP
All systems maintain an ARP cache that
includes their own IP-address-to-physicaladdress mapping.
 The ARP cache is always checked for an
IP-address-to-physical-address mapping
before initiating a broadcast.

SMTP
Simple Mail Transfer Protocol (SMTP) is a protocol
used to send and receive mail over the Internet.
 In the days of mainframes and terminals,
workstations had continuous connections to the
mainframe; therefore electronic mail could be
sent and received with great assurance.
 Because most computers are stand-alone
workstations, and no longer terminal based, SMTP
cannot provide a high degree of reliability
between the non-permanent connections.

POP3
Post Office Protocol (POP) was designed to
overcome the problem encountered with
SMTP
 A POP3 mail server holds the mail in a
maildrop until the workstation is ready to
receive the mail.

POP3
When you set up a mail account with
your Internet Service Provider (ISP), your
ISP gives you the name of the POP3
server to which you can log in, with the
correct username and password, to
obtain your mail.
 POP is on its third iteration, so now it’s
POP3.

SNMP
Simple Network Management Protocol
(SNMP) is an Internet standard that
provides a simple method for remotely
managing virtually any network device.
 A network device could be a network
card in a server, a program or service
running on a server, or a standalone
network device such as a hub or router.

SNMP
The goal for a management system is to
provide centralized network management.
 Any computer running SNMP
management software is referred to as a
management system
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FTP
File Transfer Protocol (FTP) is a TCP/IP
utility that exists solely to copy files from
one computer to another.
 FTP can establish a connection to a
remote computer using either the host
name or IP address
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FTP
There are a number of third-party
graphical user interface (GUI) FTP clients
for all versions of Windows computers.
 If you use FTP a lot, a GUI FTP client may
save you a lot of time and frustration.

IP
IP is the other protocol that the suite is named
for.
 It is a vital link in the suite because all information
that is sent using the TCP/IP protocol suite must
use it.
 IP provides packet delivery for all other protocols
within the suite. It is a connectionless delivery
system that makes a "best-effort" attempt to
deliver the packets to the correct destination.
 IP does not guarantee delivery, nor does it
promise that the IP packets will be received in the
order they were sent.
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