Resource Location and Traffic Routing
Total Page:16
File Type:pdf, Size:1020Kb
Load more
Recommended publications
-
Introduction to the Ipaddress Module
Introduction to the ipaddress Module An Introduction to the ipaddress Module Overview: This document provides an introduction to the ipaddress module used in the Python language for manipulation of IPv4 and IPv6 addresses. At a high level, IPv4 and IPv6 addresses are used for like purposes and functions. However, since there are major differences in the address structure for each protocol, this tutorial has separated into separate sections, one each for IPv4 and IPv6. In today’s Internet, the IPv4 protocol controls the majority of IP processing and will remain so for the near future. The enhancements in scale and functionality that come with IPv6 are necessary for the future of the Internet and adoption is progressing. The adoption rate, however, remains slow to this date. IPv4 and the ipaddress Module: The following is a brief discussion of the engineering of an IPv4 address. Only topics pertinent to the ipaddress module are included. A IPv4 address is composed of 32 bits, organized into four eight bit groupings referred to as “octets”. The word “octet” is used to identify an eight-bit structure in place of the more common term “byte”, but they carry the same definition. The four octets are referred to as octet1, octet2, octet3, and octet4. This is a “dotted decimal” format where each eight-bit octet can have a decimal value based on eight bits from zero to 255. IPv4 example: 192.168.100.10 Every packet in an IPv4 network contains a separate source and destination address. As a unique entity, a IPv4 address should be sufficient to route an IPv4 data packet from the source address of the packet to the destination address of the packet on a IPv4 enabled network, such as the Internet. -
The Essentials of Computer Organization and Architecture / Linda Null, Julia Lobur
the essentials of Linda Null and Julia Lobur JONES AND BARTLETT COMPUTER SCIENCE the essentials of Linda Null Pennsylvania State University Julia Lobur Pennsylvania State University World Headquarters Jones and Bartlett Publishers Jones and Bartlett Publishers Jones and Bartlett Publishers International 40 Tall Pine Drive Canada Barb House, Barb Mews Sudbury, MA 01776 2406 Nikanna Road London W6 7PA 978-443-5000 Mississauga, ON L5C 2W6 UK [email protected] CANADA www.jbpub.com Copyright © 2003 by Jones and Bartlett Publishers, Inc. Cover image © David Buffington / Getty Images Illustrations based upon and drawn from art provided by Julia Lobur Library of Congress Cataloging-in-Publication Data Null, Linda. The essentials of computer organization and architecture / Linda Null, Julia Lobur. p. cm. ISBN 0-7637-0444-X 1. Computer organization. 2. Computer architecture. I. Lobur, Julia. II. Title. QA76.9.C643 N85 2003 004.2’2—dc21 2002040576 All rights reserved. No part of the material protected by this copyright notice may be reproduced or utilized in any form, electronic or mechanical, including photocopying, recording, or any information storage or retrieval system, without written permission from the copyright owner. Chief Executive Officer: Clayton Jones Chief Operating Officer: Don W. Jones, Jr. Executive V.P. and Publisher: Robert W. Holland, Jr. V.P., Design and Production: Anne Spencer V.P., Manufacturing and Inventory Control: Therese Bräuer Director, Sales and Marketing: William Kane Editor-in-Chief, College: J. Michael Stranz Production Manager: Amy Rose Senior Marketing Manager: Nathan Schultz Associate Production Editor: Karen C. Ferreira Associate Editor: Theresa DiDonato Production Assistant: Jenny McIsaac Cover Design: Kristin E. -
XEP-0347: Internet of Things - Discovery
XEP-0347: Internet of Things - Discovery Peter Waher mailto:peterwaher@hotmail:com xmpp:peter:waher@jabber:org http://www:linkedin:com/in/peterwaher Ronny Klauck mailto:rklauck@informatik:tu-cottbus:de xmpp:TBD http://www-rnks:informatik:tu-cottbus:de/~rklauck 2018-11-03 Version 0.5.1 Status Type Short Name Deferred Standards Track iot-discovery This specification describes an architecture based on the XMPP protocol whereby Things can be in- stalled and safely discovered by their owners and connected into networks of Things. Legal Copyright This XMPP Extension Protocol is copyright © 1999 – 2020 by the XMPP Standards Foundation (XSF). Permissions Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the ”Specification”), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specifi- cation, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or sub- stantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or pub- lisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation. Warranty ## NOTE WELL: This Specification is provided on an ”AS IS” BASIS, WITHOUT WARRANTIES OR CONDI- TIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. -
Chapter 2 Data Representation in Computer Systems 2.1 Introduction
QUIZ ch.1 • 1st generation • Integrated circuits • 2nd generation • Density of silicon chips doubles every 1.5 yrs. rd • 3 generation • Multi-core CPU th • 4 generation • Transistors • 5th generation • Cost of manufacturing • Rock’s Law infrastructure doubles every 4 yrs. • Vacuum tubes • Moore’s Law • VLSI QUIZ ch.1 The highest # of transistors in a CPU commercially available today is about: • 100 million • 500 million • 1 billion • 2 billion • 2.5 billion • 5 billion QUIZ ch.1 The highest # of transistors in a CPU commercially available today is about: • 100 million • 500 million “As of 2012, the highest transistor count in a commercially available CPU is over 2.5 • 1 billion billion transistors, in Intel's 10-core Xeon • 2 billion Westmere-EX. • 2.5 billion Xilinx currently holds the "world-record" for an FPGA containing 6.8 billion transistors.” Source: Wikipedia – Transistor_count Chapter 2 Data Representation in Computer Systems 2.1 Introduction • A bit is the most basic unit of information in a computer. – It is a state of “on” or “off” in a digital circuit. – Sometimes these states are “high” or “low” voltage instead of “on” or “off..” • A byte is a group of eight bits. – A byte is the smallest possible addressable unit of computer storage. – The term, “addressable,” means that a particular byte can be retrieved according to its location in memory. 5 2.1 Introduction A word is a contiguous group of bytes. – Words can be any number of bits or bytes. – Word sizes of 16, 32, or 64 bits are most common. – Intel: 16 bits = 1 word, 32 bits = double word, 64 bits = quad word – In a word-addressable system, a word is the smallest addressable unit of storage. -
Topics Today
CMSC 313 COMPUTER ORGANIZATION & ASSEMBLY LANGUAGE PROGRAMMING LECTURE 01, SPRING 2013 TOPICS TODAY • Course overview • Levels of machines • Machine models: von Neumann & System Bus • Fetch-Execute Cycle • Base Conversion COURSE OVERVIEW CMSC 313 Course Description Spring 2013 Computer Organization & Assembly Language Programming Instructor. Prof. Richard Chang, [email protected], 410-455-3093. Office Hours: Tuesday & Thursday 11:30am–12:30pm, ITE 326. Teaching Assistant. Roshan Ghumare, [email protected] Office Hours: TBA Time and Place. Section 01: Tu - Th 10:00am – 11:15am, ITE 229. Section 02: Tu - Th 1:00pm – 2:15pm, ITE 229. Textbook. • Essentials of Computer Organization and Architecture, third edition, by Linda Null & Julia Lobur. Jones & Bartlett Learning, 2010. ISBN: 1449600069. • Assembly Language Step-by-Step: Programming with Linux, third edition, by Jeff Duntemann. Wiley, 2009. ISBN: 0470497025. Web Page. http://umbc.edu/~chang/cs313/ Catalog Description. This course introduces the student to the low-level abstraction of a computer system from a programmer's point of view, with an emphasis on low-level programming. Topics include data representation, assembly language programming, C programming, the process of compiling and linking, low-level memory management, exceptional control flow, and basic processor architecture. Prerequisites. You should have mastered the material covered in the following courses: CMSC 202 Computer Science II and CMSC 203 Discrete Structures. You need the programming experience from CMSC202. Additional experience from CMSC341 Data Structures would also be helpful. You must also be familiar with and be able to work with truth tables, Boolean algebra and modular arithmetic. Objectives. The purpose of this course is to introduce computer science majors to computing systems below that of a high-level programming language. -
A Survey of DNSSEC Deployment in the US R&E Community
A survey of DNSSEC deployment in the U.S. R&E community Shumon Huque; University of Pennsylvania Bill Owens; NySERNET Joint Techs Conference, Stanford University, July 16th 2012 http://events.internet2.edu/2012/jt-stanford/ 1 Abstract: DNSSEC (DNS Security Extensions) is a system to verify the authenticity of DNS data using public key signatures. Although a small number of institutions in the R&E community have been at the forefront of DNSSEC deployment, the adoption rate in the larger community is still quite low. This talk will present some results of an ongoing project to survey the status of DNSSEC deployment in the US Research & Education and a few other communities. It also surveys the status of several other DNS capabilities, such as availability of the service over IPv6 transport, TCP transport, EDNS0 support, etc. [Joint Techs, Stanford University, Jul 2012] 2 Agenda • DNSSEC deployment monitoring project overview • Live demo of the website • New uses of DNSSEC by applications (DANE/TLSA etc) • (time permitting) [Joint Techs, Stanford University, Jul 2012] 3 DNSSEC at a glance • “DNS Security Extensions” • A system to verify the authenticity of DNS “data” using public key signatures • Specs: RFC 4033, 4034, 4035, 5155 (and more) • Helps detect DNS spoofing, misdirection, cache poisoning .. • Additional benefits: • Ability to store and use cryptographic keying material in the DNS, eg. SSHFP, IPSECKEY, CERT, DKIM, TLSA, etc .. [Joint Techs, Stanford University, Jul 2012] 4 Other surveys • SecSpider • http://secspider.cs.ucla.edu/ -
XEP-0156: Discovering Alternative XMPP Connection Methods
XEP-0156: Discovering Alternative XMPP Connection Methods Joe Hildebrand Peter Saint-Andre Lance Stout mailto:jhildebr@cisco:com mailto:xsf@stpeter:im mailto:lance@andyet:com xmpp:hildjj@jabber:org xmpp:peter@jabber:org xmpp:lance@lance:im http://stpeter:im/ 2020-07-07 Version 1.3.1 Status Type Short Name Draft Standards Track alt-connections This document defines an XMPP Extension Protocol for discovering alternative methods of connecting to an XMPP server using two ways: (1) DNS TXT Resource Record format; and (2) Web Host Metadata Link format. Legal Copyright This XMPP Extension Protocol is copyright © 1999 – 2020 by the XMPP Standards Foundation (XSF). Permissions Permission is hereby granted, free of charge, to any person obtaining a copy of this specification (the ”Specification”), to make use of the Specification without restriction, including without limitation the rights to implement the Specification in a software program, deploy the Specification in a network service, and copy, modify, merge, publish, translate, distribute, sublicense, or sell copies of the Specifi- cation, and to permit persons to whom the Specification is furnished to do so, subject to the condition that the foregoing copyright notice and this permission notice shall be included in all copies or sub- stantial portions of the Specification. Unless separate permission is granted, modified works that are redistributed shall not contain misleading information regarding the authors, title, number, or pub- lisher of the Specification, and shall not claim endorsement of the modified works by the authors, any organization or project to which the authors belong, or the XMPP Standards Foundation. Warranty ## NOTE WELL: This Specification is provided on an ”AS IS” BASIS, WITHOUT WARRANTIES OR CONDI- TIONS OF ANY KIND, express or implied, including, without limitation, any warranties or conditions of TITLE, NON-INFRINGEMENT, MERCHANTABILITY, or FITNESS FOR A PARTICULAR PURPOSE. -
Guidelines for the Secure Deployment of Ipv6
Special Publication 800-119 Guidelines for the Secure Deployment of IPv6 Recommendations of the National Institute of Standards and Technology Sheila Frankel Richard Graveman John Pearce Mark Rooks NIST Special Publication 800-119 Guidelines for the Secure Deployment of IPv6 Recommendations of the National Institute of Standards and Technology Sheila Frankel Richard Graveman John Pearce Mark Rooks C O M P U T E R S E C U R I T Y Computer Security Division Information Technology Laboratory National Institute of Standards and Technology Gaithersburg, MD 20899-8930 December 2010 U.S. Department of Commerce Gary Locke, Secretary National Institute of Standards and Technology Dr. Patrick D. Gallagher, Director GUIDELINES FOR THE SECURE DEPLOYMENT OF IPV6 Reports on Computer Systems Technology The Information Technology Laboratory (ITL) at the National Institute of Standards and Technology (NIST) promotes the U.S. economy and public welfare by providing technical leadership for the nation’s measurement and standards infrastructure. ITL develops tests, test methods, reference data, proof of concept implementations, and technical analysis to advance the development and productive use of information technology. ITL’s responsibilities include the development of technical, physical, administrative, and management standards and guidelines for the cost-effective security and privacy of sensitive unclassified information in Federal computer systems. This Special Publication 800-series reports on ITL’s research, guidance, and outreach efforts in computer security and its collaborative activities with industry, government, and academic organizations. National Institute of Standards and Technology Special Publication 800-119 Natl. Inst. Stand. Technol. Spec. Publ. 800-119, 188 pages (Dec. 2010) Certain commercial entities, equipment, or materials may be identified in this document in order to describe an experimental procedure or concept adequately. -
Data Representation in Computer Systems
© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION There are 10 kinds of people in the world—those who understand binary and those who don’t. © Jones & Bartlett Learning, LLC © Jones—Anonymous & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION CHAPTER Data Representation © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE 2OR DISTRIBUTIONin ComputerNOT FOR Systems SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 2.1 INTRODUCTION he organization of any computer depends considerably on how it represents T numbers, characters, and control information. The converse is also true: Stan- © Jones & Bartlettdards Learning, and conventions LLC established over the years© Jones have determined& Bartlett certain Learning, aspects LLC of computer organization. This chapter describes the various ways in which com- NOT FOR SALE putersOR DISTRIBUTION can store and manipulate numbers andNOT characters. FOR SALE The ideas OR presented DISTRIBUTION in the following sections form the basis for understanding the organization and func- tion of all types of digital systems. The most basic unit of information in a digital computer is called a bit, which is a contraction of binary digit. In the concrete sense, a bit is nothing more than © Jones & Bartlett Learning, aLLC state of “on” or “off ” (or “high”© Jones and “low”)& Bartlett within Learning, a computer LLCcircuit. In 1964, NOT FOR SALE OR DISTRIBUTIONthe designers of the IBM System/360NOT FOR mainframe SALE OR computer DISTRIBUTION established a conven- tion of using groups of 8 bits as the basic unit of addressable computer storage. -
1912 the Pennsylvania State University Obsoletes: 1537 February 1996 Category: Informational
Network Working Group D. Barr Request for Comments: 1912 The Pennsylvania State University Obsoletes: 1537 February 1996 Category: Informational Common DNS Operational and Configuration Errors Status of this Memo This memo provides information for the Internet community. This memo does not specify an Internet standard of any kind. Distribution of this memo is unlimited. Abstract This memo describes errors often found in both the operation of Domain Name System (DNS) servers, and in the data that these DNS servers contain. This memo tries to summarize current Internet requirements as well as common practice in the operation and configuration of the DNS. This memo also tries to summarize or expand upon issues raised in [RFC 1537]. 1. Introduction Running a nameserver is not a trivial task. There are many things that can go wrong, and many decisions have to be made about what data to put in the DNS and how to set up servers. This memo attempts to address many of the common mistakes and pitfalls that are made in DNS data as well as in the operation of nameservers. Discussions are also made regarding some other relevant issues such as server or resolver bugs, and a few political issues with respect to the operation of DNS on the Internet. 2. DNS Data This section discusses problems people typically have with the DNS data in their nameserver, as found in the zone data files that the nameserver loads into memory. 2.1 Inconsistent, Missing, or Bad Data Every Internet-reachable host should have a name. The consequences of this are becoming more and more obvious. -
Dns Applications and Resource Records
10 DNS APPLICATIONS AND RESOURCE RECORDS 10.1 INTRODUCTION DNS inherently lends itself well to “translating” a given piece of information into another related piece of information. This resolution process is the very reason for DNS’s invention, and it has been extended beyond resolving hostnames into IP addresses and vice versa to support a broad variety of applications. Virtually any service or application that requires translation of one form of information into another can leverage DNS. Each resource record configured in DNS enables this lookup function, returning a resolution answer for a given query. The DNS server parses the query from the Question section of the DNS message,* seeking a match within the corresponding domain’s zone file for the query’s QNAME, QCLASS, and QTYPE. Each resource record has a Name (aka Owner) field, Class (Internet class is assumed if not specified), and Type field. The RData field contains the corresponding answer to the query. The resource record type defines the type and format of the question (owner/name field) and corresponding answer (RData field). In some instances, multiple resource records may match the queried name, type, and class. In such cases, all matching records, called a Resource Record Set (RRSet), are returned in the Answer section of the response message. * Refer to Figure 9.12. IP Address Management: Principles and Practice, by Timothy Rooney Copyright Ó 2011 the Institute of Electrical and Electronics Engineers, Inc. 10.1 INTRODUCTION 177 Most, but not all, new applications require new resource record types to enable definition of application-specific information, and these new resource record types are standardized via the IETF RFC process. -
Ipv6 Address Types & Formats
IIPPVV66 -- AADDDDRREESSSS TTYYPPEESS && FFOORRMMAATTSS http://www.tutorialspoint.com/ipv6/ipv6_address_types.htm Copyright © tutorialspoint.com Hexadecimal Number System Before introducing IPv6 Address format, we shall look into Hexadecimal Number System. Hexadecimal is a positional number system that uses radix base of 16. To represent the values in readable format, this system uses 0-9 symbols to represent values from zero to nine and A-F to represent values from ten to fifteen. Every digit in Hexadecimal can represent values from 0 to 15. [Image: Conversion Table] Address Structure An IPv6 address is made of 128 bits divided into eight 16-bits blocks. Each block is then converted into 4-digit Hexadecimal numbers separated by colon symbols. For example, given below is a 128 bit IPv6 address represented in binary format and divided into eight 16-bits blocks: 0010000000000001 0000000000000000 0011001000111000 1101111111100001 0000000001100011 0000000000000000 0000000000000000 1111111011111011 Each block is then converted into Hexadecimal and separated by ‘:’ symbol: 2001:0000:3238:DFE1:0063:0000:0000:FEFB Even after converting into Hexadecimal format, IPv6 address remains long. IPv6 provides some rules to shorten the address. The rules are as follows: Rule.1: Discard leading Zeroes: In Block 5, 0063, the leading two 0s can be omitted, such as 5thblock: 2001:0000:3238:DFE1:63:0000:0000:FEFB Rule.2: If two of more blocks contain consecutive zeroes, omit them all and replace with double colon sign ::, such as 6thand7thblock: 2001:0000:3238:DFE1:63::FEFB Consecutive blocks of zeroes can be replaced only once by :: so if there are still blocks of zeroes in the address, they can be shrunk down to a single zero, such as 2ndblock: 2001:0:3238:DFE1:63::FEFB Interface ID IPv6 has three different types of Unicast Address scheme.