network fundamentals: ch2 - communicating over the network

Suez Canal University – Faculty of Computers & Informatics - Cisco Local Academy

Network Fundamentals

CHP2: COMMUNICATING OVER THE NETWORK

Abdelkhalik Elsaid MosaLast Update: 20/9/2010

[email protected]

http://abdelkhalik.staff.scuegypt.edu.eg/

mailto:[email protected]




General Certifications


General Certifications

Certification Path Entry Associate Professional Expert

Design CCENT CCNA & CCDA CCDP CCDE

Routing & Switching CCENT CCNA CCNP CCIE R&S

Security CCENT CCNA Security CCSP – CCNP Security CCIE Security

Storage Networking CCENT CCNA CCNP CCIE SAN

Service Provider CCENT CCNA CCIP CCIE SP

SP Operations CCENT CCNA SP Ops CCNA SP Ops CCIE SP Ops

Voice CCENT CCNA Voice CCVP - CCNP Voice CCIE Voice

Wireless CCENT CCNA Wireless CCNP Wireless CCIE Wireless

In addition to Specialist Certifications in: Advanced Routing and Switching , Collaborations,Data Center , Security, Wireless LAN, Video, and Foundation for Channel Partners


CCNA Course and Exams

• The CCNA certification validates the ability to install, configure, operate, and troubleshoot medium-size routed and switched networks.

• Required Exam(s)640-802 (CCNA).640-822 (ICND1) + 640-816 (ICND2).

• CCNA Academy1.Network Fundamentals.2.Routing Protocols and Concepts.3.Switching and wireless LAN.4.WAN.


Elements of Communication

1. Message source: is the sender.2. Encoder: transforms data from one form to another.3. Transmitter: transmits signals across the transmission medium.4. Transmission Medium: is the communication channel.5. Destination: is the receiver.


Communicating the Messages

• In theory, data could be sent as one massive continuous stream of bits. Problems:

1. No other device on the same network can send while there is one sending.

2. If a link failed, the complete message must be retransmitted.

• Actually, data is divided into smaller pieces “Segmentation” Benefits of segmentation:

1. Multiplexing: Multiple digital data streams are combined into one signal.

2. Reliability: only the missing parts need to be retransmitted.


Communicating the Messages

Downsides of Segmentation and Multiplexing: 1. Complexity.2. Time-consumption.


Computer network

• Group of devices which are connected together to give the user a certain service. These devices can be either End devices “Hosts", Intermediary “Network

devices”, or Peripherals.


End Devices «Hosts»

• are also called Hosts.• can act as client or server or both.• are either the source or destination of a message.• must have logical address (Ex: IP address)• Ex: computers, network printers, VOIP phones, mobile devices.


Intermediary «Network » Devices

• Connect computers and networks together.• Manages data flow through the network.• Classify and direct messages according to QoS priorities.• Regenerate and retransmit data signals.• Permit or deny the flow of data, based on security settings.• Notify other devices of errors and communication failures

Network Access DevicesInternetworking DevicesSecurity DevicesModems


Peripherals

• Don’t have logical address.• Don’t communicate directly in the network.• Rely on their connected host to perform all network operations. • Ex: Attached webcam, local printer, scanner


Network Media

• Provides the channel for message transmission.• Types of network mediaMetallic wires “Copper”: data is

encoded into electrical impulses. Fiber optics: data is encoded into

pulses of light.Wireless: data is encoded into

electromagnetic waves. • Criteria for choosing media

Distance, environment, bandwidth,cost of medium and installation, and cost of connectors and equipment


Importance of Networks

• Software and file sharing• Hardware sharing• Modern Technologies (IP Telephony, Video Conferencing)


Network Types

1. According to Size• LAN “Local Area Network”• MAN “Metropolitan Area Network”• WAN “Wide Area Network”

2. According to Media • Wired• Wireless


LAN

• Usually spans a single geographical area.• Provides services to people within a common organization.• Characterized by high data speeds.• Administered by a single organization• May be a single local network or interconnected local networks.


WAN

• Groups of LANs interconnected within large area.• TSP interconnects theses geographical spanned networks.• Characterized by slow data speeds

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The Internet

• Is a global mesh of interconnected networks• The most well known publicly accessible internetwork.• Is created by the interconnection of networks belonging to ISPs.


Intranet and Extranet

• Intranet Private connection of LANs and WANs that belongs to an

organization. Accessible only by organization’s members, or others with

authorization.

• Extranet Internal network in an organization that also connects to

agents outside of the organization (suppliers, and clients). Accessible to authorized outsiders. A way for business partners to share information.


Network Representations

• Common data network symbols.

Activity


NIC

• NIC “Network Interface Card”, LAN adapter is a printed circuit board that provides network

communication capabilities to and from a personal computer or other host device.

The media plugs directly into the NIC.


Protocol, Protocol Suites and Industry Standards

• Protocol: set of rules that govern communication between devices.

• Protocol Suite: a group of interrelated protocols that are necessary to perform a communication function.

• A Standard: is a process that has been endorsed by the networking industry and ratified by a standards organization, such as IEEE, and IETF.

• Protocols describe only what functions are required of a particular communication rule but not how they are to be carried out


The benefits of using a layered model

1. Assist in protocol design.2. Fosters competition.3. Prevents technology changes in one layer from affecting other layers

above and below.4. Provides a common language to describe networking functions and

capabilities.


Protocol and Reference Models

• Protocol Model: provides a model that closely matches the structure of a particular protocol suite. Ex. TCP/IP model.

• Reference Model: a common reference for maintaining consistency with all types of network protocols and services. Aid in clearer understanding of the functions involved. Used for network design, and troubleshooting. Ex. OSI model.

All People Seem To Need Data Processing


OSI Layers and Corresponding Functions

S/W represents an interface to the network. Everything at this layer is application-specific. Ex: E-mail(SMTP, POP), Web Browser(HTTP), FTP, Telnet

Application

Presents the data in the proper format . Encoding, decoding, compression, decompression, encryption and decryption. Ex: ASCII, AVI, JPG

PresentationSyntax

Establishes, manages and terminates sessions “connections” between applications. Controls dialogs between computers.

Session

Provides reliable/ unreliable transfer of data between end users. Segmentation, sequencing, flow control and error detection. Ex: TCP & UDP

Transport

End-to-end delivery, Logical addressing EX: IP Network

Hop-to hop data delivery, Hop-to-hop addressing, Hop-to-hop error detection, and Hop-to-hop flow control. Ex: Ethernet, FR, DSL, ATM

Data Link

Signaling and Encoding, Physical properties of the network such as Cable length, Cable type, Bit rate, H/W interface types.

Physical


Protocol Data Units and Encapsulation

• Encapsulation: is the process of adding information to the application data at each layer.

• PDU: is the form that a piece of data takes at any layer

• A PDU has different names to reflect its new appearance.Data: Application layer PDU.Segment/ Datagram: Transport Layer PDUPacket: Internet layer PDU.Frame: Network Access layer PDU.Bits: Data actually transmitted over the medium.


Encapsulation


The sending and receiving process


Addressing in the network

• L2 Address “MAC”: Communicatebetween devices on a single network

• L3 Add. “IP” “Logical Address”:move data from network to another.

• L4 Add. “Port No.:Identify the applications or servicesrunning on hosts.

• Ipconfig, Ipconfig /all


Network Devices


Thank You..

network fundamentals: ch2 - communicating over the network

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