Network Protocol Requirements:

 Message encoding (making data proper way)

 Message formatting and encapsulation that includes:
Source IP address
Destination IP address
Start of the message indicator
Encapsulated data
End of a frame
 Message size (bits)
 Message timing that includes:
Flow control (speed of Transmation control)
Response timeout (when will it stop asking)
Access method (WHEN someone can send a message)
 Message delivery options (to who):
Unicast (one end device)
Multicast (more than one end devices)
broadcast (all the end devices in network)

Protocol types:
 Network Communications Protocols (which we use to communicate to one or more
networks):
IP – Internet Protocol, who and to who we are sending message
TCP – Transmission Control Protocol, taking care of if our message was sent
HTTP – HyperText Transfer Protocol, sending demands for someone in network or in the
other network)
 Network Security Protocols (providing authentication, data integrity and data encryption):
SSH – Secure Shell, terminal connections with end devices
SSL – Secure Sockets Layer, reduced version of TLS
TLS – Transport Layer Security, taking care of server, website (HTTP) or sometimes client
authentication
 Routing Protocols (enable routers to exchange route info, compare path info and then
choose the best, the quickest way that data can go):
OSPF – Open Shortest Path first, literal understanding, working inside
BGP – Border Gateway Protocol, same as OSPF, but working outside of the network
 Service Discovery Protocols (automatic detection of devices and services):
DHCP – Dynamic Host Configuration Protocol, discovers services for IP address allocation
DNS – Domain Name System, it performs name-to-IP address translation

Network Protocol functions:

 Addressing (identifies the sender and receiver, Ethernet, IPv4, IPv6)
 Reliability (data not lost or corrupted, TCP)
 Flow control (if there are not any collisions between files and transmissions, TCP)
 Sequencing (taking care of proper order of data if something is not lost, TCP)
 Error Detection (corrupt alarm, Ethernet, IPv4, v6, TCP)
  Application Interface (process-to-process communication between network applications,
HTTP

Protocol Suites:
A protocol suite is a group of inter-related protocols necessary to perform a communication
function.
Protocol suites are sets of rules that work together to help solve a problem.
TCP/IP - Internet Protocol Suite:

Application:

 Name system:
DNS – Domain name system, translates domains into IP addresses
 Host config:
DHCPv4 – Dynamic Host Configuration Protocol for IPv4, dynamically assigns IPv4 addressing
to clients
DHCPv6 – Dynamic Host Configuration Protocol for IPv6, dynamically assigns IPv6 addressing
to clients
SLAAC – StateLess Address AutoConfiguration, allows a device to obtain its IPv6 addressing
information without using a DHCPv6 server
 E-mail:
SMTP – Simple Mail Transfer Protocol, enables clients to send mails to servers, then servers
to servers
POP3 – Post Office Protocol v3, enables clients to retrieve emails from a mail server, and to
download to client’s local mail application
IMAP – Internet Message Access Protocol, enables clients to access email stored on a mail
server and maintaining emails on server
 File transfer
FTP – File Transfer Protocol, enable client send files from one host to another over a
network
SFTP – the same with SecureShell, more established and secure way of FTP
TFTP – Trivial TFP, connectionless, and uses less overhead than FTP
 Web and Web Service
HTTP – Hypertext Transfer Protocol, a set of rules for multimedia files on the www
HTTPS – secure version of HTTP
REST – Representational State Transfer, A web service that uses application programming
interfaces (API) and HTTP requests to create web applications

Transport:

 TCP – Transmission Control Protocol, reliable communication between processes running on

separate hosts and provides secure delivery
 UDP – User Datagram Protocol, no connection, no flow control faster transport protocol,
usually used for videoconferences

Internet:
  Internet Protocol:
IPv4 – receives message segments from the transport layer, packets and addresses packets
for and-to-end delivery over a network. 32-bit address
IPv6 – similar to IPv6, uses 128-bit address
NAT – Network Access Translation, translating from IPv4 to website
 Messaging:
ICMPv4 – Internet Control Message Protocol v4, provides feedback for errors in packet
delivery
ICMPv6 – similar to ICMPv4 but for IPv6
ICMPv6 ND – ICMPv6 Neighbour Discovery, includes four protocol messages that are used
for address resolution and duplicate address detection
 Routing Protocols:
OSPF - Open Shortest Path First, literal understanding, interior gateway
BGP – Border Gateway protocol, exterior gateway routing between ISPs and ISP and their
clients
EIGRP – Enhanced Interior Gateway Routing Protocol, routing protocol by Cisco, uses a
composite metric based on bandwidth, delay, load and reliability

Network Access:

 Address Resolution:
ARP – Address Resolution Protocol, dynamic address mapping between an IPv4 address and
a hardware address (MAC address)
 Data Link Protocols:
Ethernet – rules for wiring and signalling standards of the network access layer
WLAN – Wireless Local Area Network, rules for wireless signalling across the 2.4 GHz and 5
GHz radio frequencies

OSI – Open Systems Interconnection protocols – developed by International Organization for

Standardization (OSI/ISO). OSI original protocols largely have been replaced by TCP/IP protocols

TCP/IP protocol example:

TCP/IP protocol suite:

TCP/IP has two important aspects for vendors and manufacturers:

Open standard protocol suite – freely available to public
Standards-based protocol suite – endorsed by the networking industry and approved by a standards
organization

Standards Organizations:
Internet Standards:
ISOC – Internet Society, open internet development promoting
IAB – Internet Architecture Board, overall management and development of internet standards
IETF – Internet Engineering Task Force, develops, updates and maintains internet and TCP/IP
technologies
IRTF – Internet Research Task Force – long-term internet research and TCP/IP research
ICANN – Internet Corporation for Assigned Names and Numbers, coordinates IP address allocation
and other info provided be TCP/IP protocols
IANA – Internet Assigned Numbers Authority, overseeing and managing IP address allocation,
domain name management and protocol identifiers for ICANN

Electronic and Communications Standards:

IEEE – Institute of Electrical and Electronics Engineers

EIA – Electronic Industries Alliance
TIA – Telecommunications Industry Association
ITU-T - International Telecommunications Union-Telecommunication Standardization Sector

Models
OSI model

TCP/IP model

Data encapsulation:
Segmenting (transmitting in smaller parts) messages benefits:
Increases speed
Increases efficiency

Multiplexing – two hosts want to send info by one channel, segmenting provides no interruption

Sequencing – each packet has number, followed by order of a full message, sequencing provides
“numbering” it, TCP is taking care of that

PDU – the form that a piece of data takes at any layer.

Data access:
Network layer source and destination addresses - Responsible for delivering the IP packet from the
original source to the final destination, which may be on the same network or a remote network.
Data link layer source and destination addresses - Responsible for delivering the data link frame
from one network interface card (NIC) to another NIC on the same network.

IP packets contain source and destination IP address

IP address contains two parts:

Network portion (IPv4) or Prefix (IPv6) - The left-most part of the address that indicates the
network in which the IP address is a member. All devices on the same network will have the same
network portion of the address.

Host portion (IPv4) or Interface ID (IPv6) - The remaining part of the address that identifies a
specific device on the network. This portion is unique for each device or interface on the network.

MAC address – Ethernet Media Access Control address (AA-AA-AA-AA-AA-AA)

Trough different networks, router removes the Layer 2 info, and then adds new data link information
before forwarding out the exit NIC on its way towards the final destination