Tuesday, June 17, 2014

Internetworking with TCP/IP Notes (Chapter 1)

Chapter 1  Introduction and Overview

1.1 Application Level Internet Services

* WWW
* Cloud Access & Remote Desktop
* File Transfer
* Email
* Voice & Video Services

1.2 Network Level Internet Services
* Connectionless Packet Delivery Service

* Reliable Stream Transport Service

1.3 Distinguish between TCP/IP services from others

* Network Technology Independence
* Universal Interconnection
* End-to-End Acknowledgements 
* Application Protocol Standards

Berkeley UNIX created a new operating system abstraction known as a socket to allow applications to access the Internet protocols. A generalization of the UNIX mechanism for I/O, the socket interface has options for other network protocols besides TCP/IP. The introduction of the socket abstraction was important because it allowed programmers to use TCP/IP protocols with little effort.

1.4 Internet Request For Comments (RFCs)
The documentation of protocols, standards, and policies cannot be obtained from a vendor and the IETF manages the standardization process. The resulting protocol documents are kept in an on-line repository and made available at no charge.

1.5 Changes from IPv4 to IPv6
Despite conceptual similarities, IPv6 changes most of the protocol details. The changes introduced by IPv6 can be grouped into seven categories:

Larger Addresses. The new address size is the most noticeable change. IPv6 quadruples the size of an IPv4 address from 32 bits to 128 bits.

Extended Address Hierarchy. IPv6 uses the larger address space to create additional levels of addressing hierarchy 

New Header Format. IPv6 uses an entirely new and incompatible packet format that includes a set of optional headers.

Improved Options. IPv6 allows a packet to include optional control information not available in IPv4.

Provision For Protocol Extension. Instead of specifying all details, the IPv6 extension capability allows the IETF to adapt the protocol to new network hardware and new applications.

Support For Auto-configuration And Renumbering. IPv6 allows a site to change from one ISP to another by automating the requisite address changes.

Support For Resource Allocation. IPv6 includes a flow abstraction and allows differentiated services

1.6 Dual Stack System
Dual-stack systems allow applications to choose whether they will use IPv4, IPv6, or both. Older applications continue to use IPv4. However, a dual-stack mechanism allows an application to choose dynamically, making migration automatic. 

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