Topic 2 - Network Protocols and Communications

Cisco Topic 2: Network Protocols and Communication

Introduction to Networks 7.0 (ITN)

• Overview of essential network protocols and communication fundamentals.

Module Objectives

Module Title: Network Protocols and Communication

• Module Objective: Explain how network protocols enable devices to access local and remote network resources.

Topic Objectives

1. The Rules: Describe the types of rules necessary for successful communication.

2. Protocols: Explain the necessity of protocols in network communication.

3. Protocol Suites: Explain the purpose of adhering to protocol suites.

4. Standards Organizations: Explain the role of standards organizations in establishing protocols for network interoperability.

5. Reference Models: Explain how the TCP/IP and OSI models facilitate standardization in communication processes.

6. Data Encapsulation: Explain how data encapsulation enables data transportation across the network.

7. Data Access: Explain how local hosts access local resources on a network.

The Rules

Communications Fundamentals

• Networks vary in size and complexity; connections are not enough without agreement on communication methods.

• Three elements of communication:

  • Source (sender)

  • Destination (receiver)

  • Channel (media/path for communication)

Communications Protocols

• All communications are governed by protocols, which are established rules that differ by the type of protocol utilized.

Rule Establishment

• Established rules or agreements are essential for effective communication:

  • An identified sender and receiver

  • Common language and grammar

  • Speed and timing of delivery

  • Confirmation/acknowledgment requirements

Network Protocol Requirements

• Agreements between common protocols should include:

  • Message Encoding: Process of converting information into a suitable form for transmission.

  • Message Formatting and Encapsulation: Specific formats must be used depending on the message type and delivery channel.

  • Message Size: Proper encoding for mediums and conversion to bits.

  • Message Timing: Includes flow control, response timeouts, and access methods to prevent collisions in transmission.

  • Message Delivery Options: Different types of communication:

    • Unicast: One to one

    • Multicast: One to many

    • Broadcast: One to all (used in IPv4, but not an option for IPv6).

Protocols

Network Protocol Overview

• Protocols define a common set of rules and can be implemented in software, hardware, or both.

• Each protocol has its own functionality, format, and governing rules.

Types of Protocols

1. Network Protocols: Facilitate communication between devices.

2. Network Security Protocols: Ensure authentication, data integrity, and encryption.

3. Routing Protocols: Enable efficient route exchange and path selection.

4. Service Discovery Protocols: Automatically locate devices or services.

Protocol Functions

• Agreed-upon protocols allow devices to communicate:

  • Addressing

  • Reliability

  • Flow Control

  • Sequencing

  • Error Detection

  • Application Interface

Protocol Interaction

• Multiple protocols may operate together:

  • HTTP: Web server/client interaction

  • TCP: Manages conversation and ensures delivery

  • IP: Global message delivery

  • Ethernet: Local message delivery on a LAN.

Protocol Suites

Network Protocol Suites

• Protocols must work together; a protocol suite is a group of interrelated protocols necessary for communication functions.

• Viewed in terms of layers:

  • Higher Layers

  • Lower Layers (data movement and services).

Evolution of Protocol Suites

• Several protocol suites:

  • TCP/IP: Most common, maintained by the IETF.

  • OSI Protocols: Developed by ISO and ITU.

  • AppleTalk: Proprietary protocol suite by Apple Inc.

  • Novell NetWare: Proprietary suite developed by Novell Inc.

TCP/IP Protocol Suite

• TCP/IP operates at application, transport, and internet layers with common LAN protocols like Ethernet and WLAN.

• An open standard protocol suite, freely available and endorsed by the networking industry for interoperability.

Reference Models

Benefits of Layered Model

• Layers assist in protocol design and competition by allowing interoperability among products from different vendors.

• Provides a common language for networking functions and capabilities.

OSI Reference Model

TCP/IP Reference Model

OSI and TCP/IP Model Comparison

• OSI model divides function into more layers compared to TCP/IP, which does not specify transmission protocols.

Data Encapsulation

Protocol Data Units (PDUs)

• Encapsulation involves adding information to data at each stage:

  • DataStream to Segment to Packet to Frame to Bits.

Encapsulation Example

• Encapsulation is a top-down process, interacting through model layers until the final bit stream is created.

De-encapsulation Example

• As data moves up the stack, each layer strips off its header, eventually resulting in data that can be processed by the application.

Data Access

Addresses

• Addresses are crucial for delivering data between source and destination through network and data link layers.

Layer 3 Logical Address

• Source IP Address: Address of the sending device.

• Destination IP Address: Address of the receiving device.

• Each IP address consists of a network portion and a host portion for identification.

Devices on the Same Network

• Devices share the same IP network portion to communicate directly.

Role of Data Link Layer Addresses

• Uses MAC addresses for devices on the same Ethernet network, ensuring local addressing.

Devices on a Remote Network

• Identifies how data is routed when devices are on different networks, utilizing the default gateway for communication.