2024 State of Marketing Report – by HubspotMarius Sescu
https://www.hubspot.com/state-of-marketing
· Scaling relationships and proving ROI
· Social media is the place for search, sales, and service
· Authentic influencer partnerships fuel brand growth
· The strongest connections happen via call, click, chat, and camera.
· Time saved with AI leads to more creative work
· Seeking: A single source of truth
· TLDR; Get on social, try AI, and align your systems.
· More human marketing, powered by robots
ChatGPT is a revolutionary addition to the world since its introduction in 2022. A big shift in the sector of information gathering and processing happened because of this chatbot. What is the story of ChatGPT? How is the bot responding to prompts and generating contents? Swipe through these slides prepared by Expeed Software, a web development company regarding the development and technical intricacies of ChatGPT!
Product Design Trends in 2024 | Teenage EngineeringsPixeldarts
The realm of product design is a constantly changing environment where technology and style intersect. Every year introduces fresh challenges and exciting trends that mold the future of this captivating art form. In this piece, we delve into the significant trends set to influence the look and functionality of product design in the year 2024.
How Race, Age and Gender Shape Attitudes Towards Mental HealthThinkNow
Mental health has been in the news quite a bit lately. Dozens of U.S. states are currently suing Meta for contributing to the youth mental health crisis by inserting addictive features into their products, while the U.S. Surgeon General is touring the nation to bring awareness to the growing epidemic of loneliness and isolation. The country has endured periods of low national morale, such as in the 1970s when high inflation and the energy crisis worsened public sentiment following the Vietnam War. The current mood, however, feels different. Gallup recently reported that national mental health is at an all-time low, with few bright spots to lift spirits.
To better understand how Americans are feeling and their attitudes towards mental health in general, ThinkNow conducted a nationally representative quantitative survey of 1,500 respondents and found some interesting differences among ethnic, age and gender groups.
Technology
For example, 52% agree that technology and social media have a negative impact on mental health, but when broken out by race, 61% of Whites felt technology had a negative effect, and only 48% of Hispanics thought it did.
While technology has helped us keep in touch with friends and family in faraway places, it appears to have degraded our ability to connect in person. Staying connected online is a double-edged sword since the same news feed that brings us pictures of the grandkids and fluffy kittens also feeds us news about the wars in Israel and Ukraine, the dysfunction in Washington, the latest mass shooting and the climate crisis.
Hispanics may have a built-in defense against the isolation technology breeds, owing to their large, multigenerational households, strong social support systems, and tendency to use social media to stay connected with relatives abroad.
Age and Gender
When asked how individuals rate their mental health, men rate it higher than women by 11 percentage points, and Baby Boomers rank it highest at 83%, saying it’s good or excellent vs. 57% of Gen Z saying the same.
Gen Z spends the most amount of time on social media, so the notion that social media negatively affects mental health appears to be correlated. Unfortunately, Gen Z is also the generation that’s least comfortable discussing mental health concerns with healthcare professionals. Only 40% of them state they’re comfortable discussing their issues with a professional compared to 60% of Millennials and 65% of Boomers.
Race Affects Attitudes
As seen in previous research conducted by ThinkNow, Asian Americans lag other groups when it comes to awareness of mental health issues. Twenty-four percent of Asian Americans believe that having a mental health issue is a sign of weakness compared to the 16% average for all groups. Asians are also considerably less likely to be aware of mental health services in their communities (42% vs. 55%) and most likely to seek out information on social media (51% vs. 35%).
AI Trends in Creative Operations 2024 by Artwork Flow.pdfmarketingartwork
Creative operations teams expect increased AI use in 2024. Currently, over half of tasks are not AI-enabled, but this is expected to decrease in the coming year. ChatGPT is the most popular AI tool currently. Business leaders are more actively exploring AI benefits than individual contributors. Most respondents do not believe AI will impact workforce size in 2024. However, some inhibitions still exist around AI accuracy and lack of understanding. Creatives primarily want to use AI to save time on mundane tasks and boost productivity.
Organizational culture includes values, norms, systems, symbols, language, assumptions, beliefs, and habits that influence employee behaviors and how people interpret those behaviors. It is important because culture can help or hinder a company's success. Some key aspects of Netflix's culture that help it achieve results include hiring smartly so every position has stars, focusing on attitude over just aptitude, and having a strict policy against peacocks, whiners, and jerks.
PEPSICO Presentation to CAGNY Conference Feb 2024Neil Kimberley
PepsiCo provided a safe harbor statement noting that any forward-looking statements are based on currently available information and are subject to risks and uncertainties. It also provided information on non-GAAP measures and directing readers to its website for disclosure and reconciliation. The document then discussed PepsiCo's business overview, including that it is a global beverage and convenient food company with iconic brands, $91 billion in net revenue in 2023, and nearly $14 billion in core operating profit. It operates through a divisional structure with a focus on local consumers.
Content Methodology: A Best Practices Report (Webinar)contently
This document provides an overview of content methodology best practices. It defines content methodology as establishing objectives, KPIs, and a culture of continuous learning and iteration. An effective methodology focuses on connecting with audiences, creating optimal content, and optimizing processes. It also discusses why a methodology is needed due to the competitive landscape, proliferation of channels, and opportunities for improvement. Components of an effective methodology include defining objectives and KPIs, audience analysis, identifying opportunities, and evaluating resources. The document concludes with recommendations around creating a content plan, testing and optimizing content over 90 days.
How to Prepare For a Successful Job Search for 2024Albert Qian
The document provides guidance on preparing a job search for 2024. It discusses the state of the job market, focusing on growth in AI and healthcare but also continued layoffs. It recommends figuring out what you want to do by researching interests and skills, then conducting informational interviews. The job search should involve building a personal brand on LinkedIn, actively applying to jobs, tailoring resumes and interviews, maintaining job hunting as a habit, and continuing self-improvement. Once hired, the document advises setting new goals and keeping skills and networking active in case of future opportunities.
A report by thenetworkone and Kurio.
The contributing experts and agencies are (in an alphabetical order): Sylwia Rytel, Social Media Supervisor, 180heartbeats + JUNG v MATT (PL), Sharlene Jenner, Vice President - Director of Engagement Strategy, Abelson Taylor (USA), Alex Casanovas, Digital Director, Atrevia (ES), Dora Beilin, Senior Social Strategist, Barrett Hoffher (USA), Min Seo, Campaign Director, Brand New Agency (KR), Deshé M. Gully, Associate Strategist, Day One Agency (USA), Francesca Trevisan, Strategist, Different (IT), Trevor Crossman, CX and Digital Transformation Director; Olivia Hussey, Strategic Planner; Simi Srinarula, Social Media Manager, The Hallway (AUS), James Hebbert, Managing Director, Hylink (CN / UK), Mundy Álvarez, Planning Director; Pedro Rojas, Social Media Manager; Pancho González, CCO, Inbrax (CH), Oana Oprea, Head of Digital Planning, Jam Session Agency (RO), Amy Bottrill, Social Account Director, Launch (UK), Gaby Arriaga, Founder, Leonardo1452 (MX), Shantesh S Row, Creative Director, Liwa (UAE), Rajesh Mehta, Chief Strategy Officer; Dhruv Gaur, Digital Planning Lead; Leonie Mergulhao, Account Supervisor - Social Media & PR, Medulla (IN), Aurelija Plioplytė, Head of Digital & Social, Not Perfect (LI), Daiana Khaidargaliyeva, Account Manager, Osaka Labs (UK / USA), Stefanie Söhnchen, Vice President Digital, PIABO Communications (DE), Elisabeth Winiartati, Managing Consultant, Head of Global Integrated Communications; Lydia Aprina, Account Manager, Integrated Marketing and Communications; Nita Prabowo, Account Manager, Integrated Marketing and Communications; Okhi, Web Developer, PNTR Group (ID), Kei Obusan, Insights Director; Daffi Ranandi, Insights Manager, Radarr (SG), Gautam Reghunath, Co-founder & CEO, Talented (IN), Donagh Humphreys, Head of Social and Digital Innovation, THINKHOUSE (IRE), Sarah Yim, Strategy Director, Zulu Alpha Kilo (CA).
Trends In Paid Search: Navigating The Digital Landscape In 2024Search Engine Journal
The search marketing landscape is evolving rapidly with new technologies, and professionals, like you, rely on innovative paid search strategies to meet changing demands.
It’s important that you’re ready to implement new strategies in 2024.
Check this out and learn the top trends in paid search advertising that are expected to gain traction, so you can drive higher ROI more efficiently in 2024.
You’ll learn:
- The latest trends in AI and automation, and what this means for an evolving paid search ecosystem.
- New developments in privacy and data regulation.
- Emerging ad formats that are expected to make an impact next year.
Watch Sreekant Lanka from iQuanti and Irina Klein from OneMain Financial as they dive into the future of paid search and explore the trends, strategies, and technologies that will shape the search marketing landscape.
If you’re looking to assess your paid search strategy and design an industry-aligned plan for 2024, then this webinar is for you.
5 Public speaking tips from TED - Visualized summarySpeakerHub
From their humble beginnings in 1984, TED has grown into the world’s most powerful amplifier for speakers and thought-leaders to share their ideas. They have over 2,400 filmed talks (not including the 30,000+ TEDx videos) freely available online, and have hosted over 17,500 events around the world.
With over one billion views in a year, it’s no wonder that so many speakers are looking to TED for ideas on how to share their message more effectively.
The article “5 Public-Speaking Tips TED Gives Its Speakers”, by Carmine Gallo for Forbes, gives speakers five practical ways to connect with their audience, and effectively share their ideas on stage.
Whether you are gearing up to get on a TED stage yourself, or just want to master the skills that so many of their speakers possess, these tips and quotes from Chris Anderson, the TED Talks Curator, will encourage you to make the most impactful impression on your audience.
See the full article and more summaries like this on SpeakerHub here: https://speakerhub.com/blog/5-presentation-tips-ted-gives-its-speakers
See the original article on Forbes here:
http://www.forbes.com/forbes/welcome/?toURL=http://www.forbes.com/sites/carminegallo/2016/05/06/5-public-speaking-tips-ted-gives-its-speakers/&refURL=&referrer=#5c07a8221d9b
ChatGPT and the Future of Work - Clark Boyd Clark Boyd
Everyone is in agreement that ChatGPT (and other generative AI tools) will shape the future of work. Yet there is little consensus on exactly how, when, and to what extent this technology will change our world.
Businesses that extract maximum value from ChatGPT will use it as a collaborative tool for everything from brainstorming to technical maintenance.
For individuals, now is the time to pinpoint the skills the future professional will need to thrive in the AI age.
Check out this presentation to understand what ChatGPT is, how it will shape the future of work, and how you can prepare to take advantage.
The document provides career advice for getting into the tech field, including:
- Doing projects and internships in college to build a portfolio.
- Learning about different roles and technologies through industry research.
- Contributing to open source projects to build experience and network.
- Developing a personal brand through a website and social media presence.
- Networking through events, communities, and finding a mentor.
- Practicing interviews through mock interviews and whiteboarding coding questions.
Google's Just Not That Into You: Understanding Core Updates & Search IntentLily Ray
1. Core updates from Google periodically change how its algorithms assess and rank websites and pages. This can impact rankings through shifts in user intent, site quality issues being caught up to, world events influencing queries, and overhauls to search like the E-A-T framework.
2. There are many possible user intents beyond just transactional, navigational and informational. Identifying intent shifts is important during core updates. Sites may need to optimize for new intents through different content types and sections.
3. Responding effectively to core updates requires analyzing "before and after" data to understand changes, identifying new intents or page types, and ensuring content matches appropriate intents across video, images, knowledge graphs and more.
A brief introduction to DataScience with explaining of the concepts, algorithms, machine learning, supervised and unsupervised learning, clustering, statistics, data preprocessing, real-world applications etc.
It's part of a Data Science Corner Campaign where I will be discussing the fundamentals of DataScience, AIML, Statistics etc.
Time Management & Productivity - Best PracticesVit Horky
Here's my presentation on by proven best practices how to manage your work time effectively and how to improve your productivity. It includes practical tips and how to use tools such as Slack, Google Apps, Hubspot, Google Calendar, Gmail and others.
The six step guide to practical project managementMindGenius
The six step guide to practical project management
If you think managing projects is too difficult, think again.
We’ve stripped back project management processes to the
basics – to make it quicker and easier, without sacrificing
the vital ingredients for success.
“If you’re looking for some real-world guidance, then The Six Step Guide to Practical Project Management will help.”
Dr Andrew Makar, Tactical Project Management
2024 State of Marketing Report – by HubspotMarius Sescu
https://www.hubspot.com/state-of-marketing
· Scaling relationships and proving ROI
· Social media is the place for search, sales, and service
· Authentic influencer partnerships fuel brand growth
· The strongest connections happen via call, click, chat, and camera.
· Time saved with AI leads to more creative work
· Seeking: A single source of truth
· TLDR; Get on social, try AI, and align your systems.
· More human marketing, powered by robots
ChatGPT is a revolutionary addition to the world since its introduction in 2022. A big shift in the sector of information gathering and processing happened because of this chatbot. What is the story of ChatGPT? How is the bot responding to prompts and generating contents? Swipe through these slides prepared by Expeed Software, a web development company regarding the development and technical intricacies of ChatGPT!
Product Design Trends in 2024 | Teenage EngineeringsPixeldarts
The realm of product design is a constantly changing environment where technology and style intersect. Every year introduces fresh challenges and exciting trends that mold the future of this captivating art form. In this piece, we delve into the significant trends set to influence the look and functionality of product design in the year 2024.
How Race, Age and Gender Shape Attitudes Towards Mental HealthThinkNow
Mental health has been in the news quite a bit lately. Dozens of U.S. states are currently suing Meta for contributing to the youth mental health crisis by inserting addictive features into their products, while the U.S. Surgeon General is touring the nation to bring awareness to the growing epidemic of loneliness and isolation. The country has endured periods of low national morale, such as in the 1970s when high inflation and the energy crisis worsened public sentiment following the Vietnam War. The current mood, however, feels different. Gallup recently reported that national mental health is at an all-time low, with few bright spots to lift spirits.
To better understand how Americans are feeling and their attitudes towards mental health in general, ThinkNow conducted a nationally representative quantitative survey of 1,500 respondents and found some interesting differences among ethnic, age and gender groups.
Technology
For example, 52% agree that technology and social media have a negative impact on mental health, but when broken out by race, 61% of Whites felt technology had a negative effect, and only 48% of Hispanics thought it did.
While technology has helped us keep in touch with friends and family in faraway places, it appears to have degraded our ability to connect in person. Staying connected online is a double-edged sword since the same news feed that brings us pictures of the grandkids and fluffy kittens also feeds us news about the wars in Israel and Ukraine, the dysfunction in Washington, the latest mass shooting and the climate crisis.
Hispanics may have a built-in defense against the isolation technology breeds, owing to their large, multigenerational households, strong social support systems, and tendency to use social media to stay connected with relatives abroad.
Age and Gender
When asked how individuals rate their mental health, men rate it higher than women by 11 percentage points, and Baby Boomers rank it highest at 83%, saying it’s good or excellent vs. 57% of Gen Z saying the same.
Gen Z spends the most amount of time on social media, so the notion that social media negatively affects mental health appears to be correlated. Unfortunately, Gen Z is also the generation that’s least comfortable discussing mental health concerns with healthcare professionals. Only 40% of them state they’re comfortable discussing their issues with a professional compared to 60% of Millennials and 65% of Boomers.
Race Affects Attitudes
As seen in previous research conducted by ThinkNow, Asian Americans lag other groups when it comes to awareness of mental health issues. Twenty-four percent of Asian Americans believe that having a mental health issue is a sign of weakness compared to the 16% average for all groups. Asians are also considerably less likely to be aware of mental health services in their communities (42% vs. 55%) and most likely to seek out information on social media (51% vs. 35%).
AI Trends in Creative Operations 2024 by Artwork Flow.pdfmarketingartwork
Creative operations teams expect increased AI use in 2024. Currently, over half of tasks are not AI-enabled, but this is expected to decrease in the coming year. ChatGPT is the most popular AI tool currently. Business leaders are more actively exploring AI benefits than individual contributors. Most respondents do not believe AI will impact workforce size in 2024. However, some inhibitions still exist around AI accuracy and lack of understanding. Creatives primarily want to use AI to save time on mundane tasks and boost productivity.
Organizational culture includes values, norms, systems, symbols, language, assumptions, beliefs, and habits that influence employee behaviors and how people interpret those behaviors. It is important because culture can help or hinder a company's success. Some key aspects of Netflix's culture that help it achieve results include hiring smartly so every position has stars, focusing on attitude over just aptitude, and having a strict policy against peacocks, whiners, and jerks.
PEPSICO Presentation to CAGNY Conference Feb 2024Neil Kimberley
PepsiCo provided a safe harbor statement noting that any forward-looking statements are based on currently available information and are subject to risks and uncertainties. It also provided information on non-GAAP measures and directing readers to its website for disclosure and reconciliation. The document then discussed PepsiCo's business overview, including that it is a global beverage and convenient food company with iconic brands, $91 billion in net revenue in 2023, and nearly $14 billion in core operating profit. It operates through a divisional structure with a focus on local consumers.
Content Methodology: A Best Practices Report (Webinar)contently
This document provides an overview of content methodology best practices. It defines content methodology as establishing objectives, KPIs, and a culture of continuous learning and iteration. An effective methodology focuses on connecting with audiences, creating optimal content, and optimizing processes. It also discusses why a methodology is needed due to the competitive landscape, proliferation of channels, and opportunities for improvement. Components of an effective methodology include defining objectives and KPIs, audience analysis, identifying opportunities, and evaluating resources. The document concludes with recommendations around creating a content plan, testing and optimizing content over 90 days.
How to Prepare For a Successful Job Search for 2024Albert Qian
The document provides guidance on preparing a job search for 2024. It discusses the state of the job market, focusing on growth in AI and healthcare but also continued layoffs. It recommends figuring out what you want to do by researching interests and skills, then conducting informational interviews. The job search should involve building a personal brand on LinkedIn, actively applying to jobs, tailoring resumes and interviews, maintaining job hunting as a habit, and continuing self-improvement. Once hired, the document advises setting new goals and keeping skills and networking active in case of future opportunities.
A report by thenetworkone and Kurio.
The contributing experts and agencies are (in an alphabetical order): Sylwia Rytel, Social Media Supervisor, 180heartbeats + JUNG v MATT (PL), Sharlene Jenner, Vice President - Director of Engagement Strategy, Abelson Taylor (USA), Alex Casanovas, Digital Director, Atrevia (ES), Dora Beilin, Senior Social Strategist, Barrett Hoffher (USA), Min Seo, Campaign Director, Brand New Agency (KR), Deshé M. Gully, Associate Strategist, Day One Agency (USA), Francesca Trevisan, Strategist, Different (IT), Trevor Crossman, CX and Digital Transformation Director; Olivia Hussey, Strategic Planner; Simi Srinarula, Social Media Manager, The Hallway (AUS), James Hebbert, Managing Director, Hylink (CN / UK), Mundy Álvarez, Planning Director; Pedro Rojas, Social Media Manager; Pancho González, CCO, Inbrax (CH), Oana Oprea, Head of Digital Planning, Jam Session Agency (RO), Amy Bottrill, Social Account Director, Launch (UK), Gaby Arriaga, Founder, Leonardo1452 (MX), Shantesh S Row, Creative Director, Liwa (UAE), Rajesh Mehta, Chief Strategy Officer; Dhruv Gaur, Digital Planning Lead; Leonie Mergulhao, Account Supervisor - Social Media & PR, Medulla (IN), Aurelija Plioplytė, Head of Digital & Social, Not Perfect (LI), Daiana Khaidargaliyeva, Account Manager, Osaka Labs (UK / USA), Stefanie Söhnchen, Vice President Digital, PIABO Communications (DE), Elisabeth Winiartati, Managing Consultant, Head of Global Integrated Communications; Lydia Aprina, Account Manager, Integrated Marketing and Communications; Nita Prabowo, Account Manager, Integrated Marketing and Communications; Okhi, Web Developer, PNTR Group (ID), Kei Obusan, Insights Director; Daffi Ranandi, Insights Manager, Radarr (SG), Gautam Reghunath, Co-founder & CEO, Talented (IN), Donagh Humphreys, Head of Social and Digital Innovation, THINKHOUSE (IRE), Sarah Yim, Strategy Director, Zulu Alpha Kilo (CA).
Trends In Paid Search: Navigating The Digital Landscape In 2024Search Engine Journal
The search marketing landscape is evolving rapidly with new technologies, and professionals, like you, rely on innovative paid search strategies to meet changing demands.
It’s important that you’re ready to implement new strategies in 2024.
Check this out and learn the top trends in paid search advertising that are expected to gain traction, so you can drive higher ROI more efficiently in 2024.
You’ll learn:
- The latest trends in AI and automation, and what this means for an evolving paid search ecosystem.
- New developments in privacy and data regulation.
- Emerging ad formats that are expected to make an impact next year.
Watch Sreekant Lanka from iQuanti and Irina Klein from OneMain Financial as they dive into the future of paid search and explore the trends, strategies, and technologies that will shape the search marketing landscape.
If you’re looking to assess your paid search strategy and design an industry-aligned plan for 2024, then this webinar is for you.
5 Public speaking tips from TED - Visualized summarySpeakerHub
From their humble beginnings in 1984, TED has grown into the world’s most powerful amplifier for speakers and thought-leaders to share their ideas. They have over 2,400 filmed talks (not including the 30,000+ TEDx videos) freely available online, and have hosted over 17,500 events around the world.
With over one billion views in a year, it’s no wonder that so many speakers are looking to TED for ideas on how to share their message more effectively.
The article “5 Public-Speaking Tips TED Gives Its Speakers”, by Carmine Gallo for Forbes, gives speakers five practical ways to connect with their audience, and effectively share their ideas on stage.
Whether you are gearing up to get on a TED stage yourself, or just want to master the skills that so many of their speakers possess, these tips and quotes from Chris Anderson, the TED Talks Curator, will encourage you to make the most impactful impression on your audience.
See the full article and more summaries like this on SpeakerHub here: https://speakerhub.com/blog/5-presentation-tips-ted-gives-its-speakers
See the original article on Forbes here:
http://www.forbes.com/forbes/welcome/?toURL=http://www.forbes.com/sites/carminegallo/2016/05/06/5-public-speaking-tips-ted-gives-its-speakers/&refURL=&referrer=#5c07a8221d9b
ChatGPT and the Future of Work - Clark Boyd Clark Boyd
Everyone is in agreement that ChatGPT (and other generative AI tools) will shape the future of work. Yet there is little consensus on exactly how, when, and to what extent this technology will change our world.
Businesses that extract maximum value from ChatGPT will use it as a collaborative tool for everything from brainstorming to technical maintenance.
For individuals, now is the time to pinpoint the skills the future professional will need to thrive in the AI age.
Check out this presentation to understand what ChatGPT is, how it will shape the future of work, and how you can prepare to take advantage.
The document provides career advice for getting into the tech field, including:
- Doing projects and internships in college to build a portfolio.
- Learning about different roles and technologies through industry research.
- Contributing to open source projects to build experience and network.
- Developing a personal brand through a website and social media presence.
- Networking through events, communities, and finding a mentor.
- Practicing interviews through mock interviews and whiteboarding coding questions.
Google's Just Not That Into You: Understanding Core Updates & Search IntentLily Ray
1. Core updates from Google periodically change how its algorithms assess and rank websites and pages. This can impact rankings through shifts in user intent, site quality issues being caught up to, world events influencing queries, and overhauls to search like the E-A-T framework.
2. There are many possible user intents beyond just transactional, navigational and informational. Identifying intent shifts is important during core updates. Sites may need to optimize for new intents through different content types and sections.
3. Responding effectively to core updates requires analyzing "before and after" data to understand changes, identifying new intents or page types, and ensuring content matches appropriate intents across video, images, knowledge graphs and more.
A brief introduction to DataScience with explaining of the concepts, algorithms, machine learning, supervised and unsupervised learning, clustering, statistics, data preprocessing, real-world applications etc.
It's part of a Data Science Corner Campaign where I will be discussing the fundamentals of DataScience, AIML, Statistics etc.
Time Management & Productivity - Best PracticesVit Horky
Here's my presentation on by proven best practices how to manage your work time effectively and how to improve your productivity. It includes practical tips and how to use tools such as Slack, Google Apps, Hubspot, Google Calendar, Gmail and others.
The six step guide to practical project managementMindGenius
The six step guide to practical project management
If you think managing projects is too difficult, think again.
We’ve stripped back project management processes to the
basics – to make it quicker and easier, without sacrificing
the vital ingredients for success.
“If you’re looking for some real-world guidance, then The Six Step Guide to Practical Project Management will help.”
Dr Andrew Makar, Tactical Project Management
2. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Principiul comunicării în Internet
• Inspirat din sistemul clasic poştal.
• Drumul între utilizatorii A şi B
trece prin ruterele
IMP3, IMP7, IMP6.
11.03.2013 Protocoale de comunicaţie 2
3. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Reţele
• Modelul unei reţele:
• Nivelurile străbătute de pachete:
11.03.2013 Protocoale de comunicaţie 3
4. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Nivelul reţea
• Funcţiile nivelului reţea:
– dirijarea pachetelor;
– adresarea;
– evitarea congestionării reţelei.
• Aspecte principale:
– servicii:
• orientate pe conexiune;
• ne-orientate pe conexiune.
– organizarea internă:
• datagrame;
• circuite virtuale.
– dirijarea (politici, algoritmi).
11.03.2013 Protocoale de comunicaţie 4
5. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Organizarea internă – datagrame
Folosită de Folosită de
pachetele pachetul 4
1, 2 şi 3
11.03.2013 Protocoale de comunicaţie 5
6. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Organizarea internă – circuit virtual
11.03.2013 Protocoale de comunicaţie 6
7. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Clasificarea algoritmilor de dirijare
• Fără tabele de dirijare: • Cu tabele de dirijare – alte
– inundarea criterii:
– hot potato – criterii de dirijare:
• calea cea mai scurtă;
• Cu tabele de dirijare – criterii
diverse: • întârzierea medie globală;
• folosirea eficientă a
– adaptarea la condiţiile de resurselor;
trafic:
• echitabilitatea.
• statică;
– informaţii schimbate între
• dinamică. noduri:
– locul unde se fac calculele: • starea legăturii;
• descentralizată; • vectorul distanţelor;
• centralizată; – tipul reţelei.
• distribuită.
11.03.2013 Protocoale de comunicaţie 7
8. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Algoritmi de dirijare – Calea cea mai scurtă
• Algoritmul lui Dijkstra:
– nnod: mulţimea nodurilor reţelei;
– sursa: nodul sursă;
– l[i][j]: costul legăturii (i,j), având valorile:
• 0 dacă i = j;
• lungmax dacă i şi j nu sunt adiacente;
• o valoare între 0 şi lungmax în celelalte cazuri;
– D[i]: costul minim al legăturii de la sursă la i;
– S: mulţimea nodurilor deja selectate;
– V: tabloul de dirijare:
• V[i] = vecinul prin care se transmit date de la nodul curent la nodul i.
11.03.2013 Protocoale de comunicaţie 8
9. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Algoritmul lui Dijkstra
void Dijkstra (int sursa)
{
int i, j, k;
for (i=1; i <= nnod; i++)
{
S[i] = 0; // nod neselectat
D[i] = l[sursa][i]; // distantele minime de la sursa
if (D[i] < lungmax)
V[i] = i; // initializeaza vecinii
else
V[i] = 0;
}
S[sursa] = 1; // selecteaza nodul sursa
D[sursa] = 0;
for ( i=1; i < nnod; i++)
{
// gaseste nodul k neselectat cu D[k] minim;
S[k] = 1;
for (j=1; j <= nnod; j++) // recalculeaza distantele
if ((S[j] == 0) && (D[k] + l[k][j] < D[j]))
{
D[j] = D[k] + l[k][j];
V[j] = V[k]; // modifica tabela de dirijare
}
}
}
11.03.2013 Protocoale de comunicaţie 9
10. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Dirijarea centralizată
• Algoritmul lui Floyd:
– Utilizează tabloul distanţelor minime A:
• A[i][j] distanţa minimă de la nodul i la nodul j.
– Iniţial:
• A[i][j] = l[i][j] pentru orice i şi j.
– Calculul drumurilor minime:
• A[i][j]k = min (A[i][j]k-1, A[i][k]k-1 + A[k][j]k-1)
– Deoarece există relaţiile
• A[i][k]k = A[i][k]k-1
• A[k][j]k = A[k][j]k-1
calculul se poate realiza cu o singură copie a tabloului A.
11.03.2013 Protocoale de comunicaţie 10
11. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Algoritmul lui Floyd
void Floyd()
{
int i, j, k;
for (i=1; i <= nnod; i++)
for (j=1; j <= nnod; j++)
{
A[i][j] = l[i][j];
if ( A[i][j] < lungmax)
V[i][j] = j;
}
for (k=1; k <= nnod; k++)
for ( i=1; i <= nnod; i++)
for ( j=1; j <= nnod; j++)
if (A[i][j] > A[i][k] + A[k][j])
{
A[i][j] = A[i][k] + A[k][j];
V[i][j] = V[i][k];
}
}
11.03.2013 Protocoale de comunicaţie 11
12. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Dirijarea distribuită (starea legăturilor)
• C tabloul distanţelor:
– C[d][v] este lungimea (sau costul) drumului de la nodul curent la
nodul destinatar d, prin nodul vecin v.
• D tabloul distanţelor minime:
– D[d] este lungimea drumului minim de la nodul curent la nodul
destinatar d.
• V tabloul de dirijare:
– V[d] este nodul vecin prin care se transmit datele, pe drumul minim,
spre destinatarul d.
• Evenimente tratate:
– adăugarea unei noi legături;
– sesizarea modificării lungimii unei linii;
– primirea unui mesaj de control de la un nod vecin.
11.03.2013 Protocoale de comunicaţie 12
13. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Structuri de date pentru nodul crt
C vecini D V
v
Destinatar
d D[d] V[d]
C[d][v]
11.03.2013 Protocoale de comunicaţie 13
14. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Adaugă legătura crt-m
C vecini D V
m v
Destinatar
d D[d] V[d]
m D[m] V[m]
C[m][m]
11.03.2013 Protocoale de comunicaţie 14
15. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Adaugă legătura crt-m
/* adauga legatura (crt,m), crt = nodul curent*/
void adauga_legatura (int m)
{
C[m][m] = l[crt][m];
calculeaza p pentru care C[m][p]=min C[m][w], dupa w;
V[m]=p;
if (C[m][p] != D[m])
{
D[m] = C[m][p];
transmite mesaj (crt,m,D[m]) tuturor vecinilor;
}
transmite mesajele (crt,a,D[a]),...,(crt,z,D[z]) nodului m
}
11.03.2013 Protocoale de comunicaţie 15
16. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Schimbă cost crt-m cu delta_crt_m
C vecini D V
m
Destinatar
d D[d] V[d]
C[d][m] se modifică pentru toate d
11.03.2013 Protocoale de comunicaţie 16
17. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Schimbă cost crt-m cu delta_crt_m
void schimba_cost (int m, int delta_crt_m)
{
for (toate destinatiile d)
{ C[d][m] += delta_crt_m;
calculeaza p a.i. C[d][p]=min C[d][w], dupa w;
V[d] = p;
if (C[d][p] != D[d])
{
D[d] = C[d][p];
transmite mesaj (crt,d,D[d]) tuturor vecinilor;
}
}
} m
+delta
d
crt
11.03.2013 Protocoale de comunicaţie 17
18. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Schimbă cost crt-m cu delta_crt_m
void receptie_mesaj (int s, int d, int cost_s_d)
{
if (d != crt)
{ C[d][s] = cost_s_d + l[s][crt];
calc p a.i. C[d][p] = min C[d][w], dupa w;
V[d] = p;
if (C[d][p] != D[d])
{D[d] = C[d][p];
transmite mesaj (crt,d,D[d]) tuturor vecinilor;
}
}
}
s
cost_s_d
l[s][crt]
d
crt
11.03.2013 Protocoale de comunicaţie 18
19. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Starea legăturilor – variantă
• Operaţii executate de fiecare ruter:
– Descoperă vecinii şi află adresele de reţea (pachet HELLO).
– Determină costul la fiecare vecin (pachet ECHO).
– Alcătuieşte un pachet cu informaţiile culese:
• identitatea expeditorului.
• număr de secvenţă.
• vârsta.
• listă de <vecin, cost legatura>.
– Transmite pachetul tuturor ruterelor (inundare).
– Calculează cea mai scurtă cale la fiecare ruter (Dijkstra).
11.03.2013 Protocoale de comunicaţie 19
20. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Dirijare folosind vectorul distanţelor
• Următorii vectori au fost primiţi de nodul C (lista include
distanţele la nodurile A, B, C, D, E, F, în această ordine):
– De la B: (5, 0, 8, 12, 6, 2) ;
– De la D: (16, 12, 6, 0, 9, 10);
– De la E: (7, 6, 3, 9, 0, 4).
• Intârzierea măsurată de la C la B, D si E este 6, 3 şi 5 respectiv.
11.03.2013 Protocoale de comunicaţie 20
21. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Dirijare folosind vectorul distanţelor
De la B D E
La
A 5 16 7
B 0 12 6
C 8 6 3
D 12 0 9
E 6 9 0
F 2 10 4
De la C Prin B D E Cost Pas
La min următor
A 5+6 16 + 3 7+5 11 B
B 0+6 12 + 3 6+5 6 B
C - - - 0 -
D 12 + 6 0+3 9+5 3 D
E 6+6 9+3 0+5 5 E
F 2+6 10 + 3 4+5 8 B
11.03.2013 Protocoale de comunicaţie 21
22. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Problema numărării la infinit
• Toate legăturile au cost 1, exceptând (C,D) cu cost 10
• Costurile la ţintă sunt: A B
– D: direct conectată, cost 1
– B: ruta prin D, cost 2 C
– C: ruta prin B, cost 3
– A: ruta prin B, cost 3 D
• Legătura (B,D) cade!!! ţintă
timp ------------------------------------------------------>
D: dir, 1 dir, 1 dir, 1 dir, 1 ... dir, 1 dir, 1
B: unreach C, 4 C, 5 C, 6 C, 11 C, 12
C: B, 3 A, 4 A, 5 A, 6 A, 11 D, 11
A: B, 3 C, 4 C, 5 C, 6 C, 11 C, 12
• Cauza: C alege ruta prin A şi A alege ruta prin C.
• În ultimul pas, C găseşte o cale mai ieftină prin D şi problema se
rezolvă.
• Pentru reţele deconectate, numărarea continuă la infinit.
11.03.2013 Protocoale de comunicaţie 22
23. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Soluţii
• Adoptate în RIP – Routing Information Protocol
– "simple split horizon" omite rutele învăţate de la un vecin în
actualizările timise acestuia
– "split horizon with poisoned reverse" include astfel de rute dar pune
un cost infinit.
• Ideea: în mesajul său către C, A trebuie să informeze că D nu
mai este tangibil
A B
D: dir, 1 dir, 1 dir, 1
B: unreach unreach C, 12
C
C: B, 3 D, 11 D, 11
A: B, 3 unreach C, 12
D
• Protocoale care folosesc split horizon: ţintă
– RIP, Routing Information Protocol;
– IGRP, Interior Gateway Routing Protocol;
– EIGRP, Enhanced Interior Gateway Routing Protocol.
11.03.2013 Protocoale de comunicaţie 23
24. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Dirijare ierarhică
– Reducere număr intrări: 17 -> 7.
– Penalizare la destinaţia 5C.
11.03.2013 Protocoale de comunicaţie 24
25. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Difuzare şi multicast
• Punct la punct – Trimite un pachet fiecărei destinaţii.
• Inundarea:
– Generează prea multe pachete.
– Copiile sunt distruse.
• Dirijarea multidestinaţie:
– Pachetul conţine lista adreselor de destinaţie.
• Arbore de acoperire. <1,2,3,4,5,6>
0 1 2
<2,3,4>
3 <2>
<5,6>
<4>
4
5
<6>
6
11.03.2013 Protocoale de comunicaţie 25
26. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Difuzare – urmărirea căii inverse
• Calea preferată între nodurile I şi X este cea pe care X trimite
pachete lui I.
• Când un pachet ajunge la un ruter:
– Verifică în tabela sa de dirijare dacă a sosit pe calea preferată
• este trimis pe toate celelalte linii dacă da.
• este distrus, altfel.
– Figura:
• (a) O subreţea
• (b) un arbore de acoperire pentru nodul I
• (c) un arbore construit prin algoritmul căilor inverse
11.03.2013 Protocoale de comunicaţie 26
27. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Dirijarea pentru gazde mobile
• Funcţionare:
– Gazda mobilă cere să se înregistreze cu un agent străin (dă adresa
de acasă).
– Agentul străin contactează agentul de acasă (transmite adresa
străină + info securitate).
– Agentul de acasă validează.
– Agentul străin înregistrează gazda mobilă şi o informează.
11.03.2013 Protocoale de comunicaţie 27
28. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Dirijarea în reţele ad hoc
• AODV (Ad hoc On demand Distance Vector) determină ruta la cerere:
– Reţea ad hoc = graf.
– Muchie = conexiune – nodurile pot comunica direct (radio).
• Fiecare nod = ruter + gazdă
• Fiecare nod conţine:
– Tabela dirijare:
• Destinaţie;
• Pas următor;
• Distanţă;
• Număr secvenţă destinaţie;
• Altele.
– Tabela history:
• Identităţile cererilor precedente.
– Tabela reverse route:
• Calea spre sursa unui pachet de cerere.
11.03.2013 Protocoale de comunicaţie 28
29. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Cum funcţionează?
• Exemplu: A vrea sa comunice cu I care nu e în tabela sa ->
trebuie să descopere ruta.
11.03.2013 Protocoale de comunicaţie 29
30. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Pachete ROUTE REQUEST
• A difuzează un pachet ROUTE REQUEST
– Identificat unic prin Source address + Request ID
– Foloseşte Sequence # pentru a deosebi rutele noi de cele vechi
• Prelucrarea ROUTE REQUEST în fiecare nod:
– Verifică duplicat în tabela history locală (Source address + Request
ID);
– Transmite ROUTE REPLY dacă găsit ruta nouă, adică:
• Dest sequence # în routing table > Dest sequence # în packet
– Altfel,
• Incrementează Hop count şi re-difuzează ROUTE REQUEST.
• Memorează informaţia în reverse route table.
– Source sequence # folosit pentru actualizare tabelă dirijare locală.
11.03.2013 Protocoale de comunicaţie 30
31. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Pachete ROUTE REPLY
• I construieşte ROUTE REPLY şi-l trimite pe legătura inversă:
– Source address, dest address, hop count sunt copiate;
– Destination sequence # luat din contorul propriu;
– Lifetime = cât timp rămâne valid,
• Prelucrarea la alte noduri:
– Actualizează tabela dirijare locală;
– Transmite pe legătura inversă;
– Trece prin anumite noduri – celelalte şterg intrarea în reverse route
table.
11.03.2013 Protocoale de comunicaţie 31
32. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Intreţinerea rutelor
• G cade (se defectează, se opreşte).
– D descoperă (se folosesc mesaje Hello periodice).
– D află că G a fost utilizat pe rute către E, G şi I.
– D anunţă vecinii activi (active neighbors) care folosesc G, anume
{A, B}.
– D goleşte intrările pentru E, G şi I din tabela de rutare.
G
11.03.2013 Protocoale de comunicaţie 32
33. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Protocolul IPv4
• Câmpuri: • Câmpuri:
– SERVICE TYPE = – FLAGS:
precedence (3), delay, • DF = Don’t Fragment
throughput, reliability, cost.
• MF = More Fragments
– TYPE = protocol (TCP, UDP,
etc.). – Opţiuni:
– IDENTIFICATION datagrama • Security.
de care aparţine fragmentul. • Strict source routing.
• Loose source routing.
• Record route.
• Timestamp.
11.03.2013 Protocoale de comunicaţie 33
34. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Adrese IP C las e
d e
ad re s e
E (1 / 16)
D (1 / 16)
C (1 / 8)
A (1 / 2)
B (1 / 4)
11.03.2013 Protocoale de comunicaţie 34
35. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Adrese speciale
Prefix Sufix Tip adresă Scop
Toţi 0 Toţi 0 Acest calculator Bootstrap
Network Toţi 0 Network Identificare reţea
Network Toţi 1 Broadcast Broadcast în reţeaua specificată
Toţi 1 Toţi 1 Broadcast Broadcast în reţeaua locală
127 Orice Loopback Testare
Adrese Scop RFC Clasa Număr adrese
0.0.0.0 - 0.255.255.255 Adrese zero RFC 1700 A 16 777 216
10.0.0.0 - 10.255.255.255 Adrese private (locale) RFC 1918 A 16 777 216
127.0.0.0 - 127.255.255.255 Localhost RFC 1700 A 16 777 216
169.254.0.0 - 169.254.255.255 Zeroconf RFC 3330 B 65 536
172.16.0.0 - 172.31.255.255 Adrese private (locale) RFC 1918 B 1 048 576
192.0.2.0 - 192.0.2.255 Documentaţie, exemple RFC 3330 C 256
192.88.99.0 - 192.88.99.255 Ipv6 RFC 3068 C 256
192.168.0.0 - 192.168.255.255 Adrese private (locale) RFC 1918 C 65 536
198.18.0.0 - 198.19.255.255 Benchmark RFC 2544 C 131 072
224.0.0.0 - 239.255.255.255 Multicast RFC 3171 D 268 435 456
240.0.0.0 - 255.255.255.255 Rezervate RFC 1700 E 268 435 456
11.03.2013 Protocoale de comunicaţie 35
36. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Reprezentare pe biţi
Clasa A
0. 0. 0. 0 = 00000000.00000000.00000000.00000000
127.255.255.255 = 01111111.11111111.11111111.11111111
0nnnnnnn.HHHHHHHH.HHHHHHHH.HHHHHHHH
Clasa B
128. 0. 0. 0 = 10000000.00000000.00000000.00000000
191.255.255.255 = 10111111.11111111.11111111.11111111
10nnnnnn.nnnnnnnn.HHHHHHHH.HHHHHHHH
Clasa C
192. 0. 0. 0 = 11000000.00000000.00000000.00000000
223.255.255.255 = 11011111.11111111.11111111.11111111
110nnnnn.nnnnnnnn.nnnnnnnn.HHHHHHHH
Clasa D
224. 0. 0. 0 = 11100000.00000000.00000000.00000000
239.255.255.255 = 11101111.11111111.11111111.11111111
1110XXXX.XXXXXXXX.XXXXXXXX.XXXXXXXX
Clasa E
240. 0. 0. 0 = 11110000.00000000.00000000.00000000
255.255.255.255 = 11111111.11111111.11111111.11111111
1111XXXX.XXXXXXXX.XXXXXXXX.XXXXXXXX
11.03.2013 Protocoale de comunicaţie 36
37. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Algoritm de rutare IP
• Tabela rutare – tipuri intrări:
– <network, 0>: pentru reţele distante
– <this-network, host>: pentru gazde locale
• Tabele rutare separate pentru diferite clase de adrese
• Căutare prin: indexare (A şi B) sau hashing (C)
• Algoritm rutare:
Extrage adresa destinatiei DADR din datagrama
Calculeaza adresa de retea a destinatiei NADR
if NADR apartine unei retele direct conectate
transmite datagrama gazdei de destinatie intr-un frame
else
if DADR apare in tabela dirijare
ruteaza datagrama conform tabelei
else
if NADR apare in tabela dirijare
ruteaza datagrama conform tabelei
else
ruteaza datagrama la un ruter implicit
11.03.2013 Protocoale de comunicaţie 37
38. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Subreţele
• Organizarea în subreţele este invizibilă în afara reţelei.
• Ruterul principal dirijază pachetele spre ruterele de subreţea
(cum?).
• Ruterele de subreţea le livrează gazdelor.
11.03.2013 Protocoale de comunicaţie 38
39. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Adresarea în subreţele
• Exemplu: O reţea de clasă B impărţită în 64 subreţele.
• Tabela de rutare are intrări suplimentare pentru:
– (this-network, subnet, 0)
– (this-network, this-subnet, host)
• Modificare algoritm rutare:
– Foloseşte masca de subreţea pentru a separa reţea+subreţea şi
gazdă.
– Dirijează spre subreţea (subnet).
– Doar în subreţeaua curentă dirijează direct către gazdă (host).
• Elimină limitările schemei de adresare bazată pe clase.
11.03.2013 Protocoale de comunicaţie 39
40. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
CIDR – Classless InterDomain Routing
• Ideea: alocă spaţiul de adrese IP în blocuri de lungimi diferite.
– Notaţia CIDR 194.24.0.0/21 => din cei 32 de biţi ai adresei:
• reţea+subreţea = 21 biţi.
• gazdă = 11 biţi.
• Exemplu:
Adresă Mască
C: 11000010 00011000 00000000 00000000 11111111 11111111 11111000 00000000
E: 11000010 00011000 00001000 00000000 11111111 11111111 11111100 00000000
O: 11000010 00011000 00010000 00000000 11111111 11111111 11110000 00000000
– Alocare adrese: zona de adrese pentru Oxford incepe la o frontieră
de 4096 octeţi.
– Algoritm rutare:
• (Adresa IP AND masca) comparată cu primul câmp al fiecărei intrări;
• La mai multe coincidenţe se alege masca cea mai lungă.
11.03.2013 Protocoale de comunicaţie 40
41. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
CIDR – Classless InterDomain Routing
• Soseşte pachet cu adresa 194.24.17.4:
11000010 00011000 00010001 00000100
• ŞI logic cu masca de la Cambridge:
11000010 00011000 00010000 00000000 -> nepotrivire
• ŞI logic cu masca de la Edinburgh:
11000010 00011000 00010000 00000000 –> nepotrivire
• ŞI logic cu masca de la Oxford:
11000010 00011000 00010001 00000000 -> potrivire
• Dacă nu sunt alte potriviri -> foloseşte intrarea pentru Oxford.
11.03.2013 Protocoale de comunicaţie 41
42. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
CIDR – Classless InterDomain Routing
• Reducere dimensiune tabelă: agregarea intrărilor pentru o
aceeaşi linie de ieşire
Adresă Mască
C: 11000010 00011000 00000000 00000000 11111111 11111111 11111000 00000000
E: 11000010 00011000 00001000 00000000 11111111 11111111 11111100 00000000
O: 11000010 00011000 00010000 00000000 11111111 11111111 11110000 00000000
• Intrare agregată:
Adresă Mască
11000010 00011000 00000000 00000000 11111111 11111111 11100000 00000000
• Corespunde cu 194.24.0.0/19
• Pentru toate adresele din C, E, O, ruterul trimite pe aceeaşi
interfaţă.
11.03.2013 Protocoale de comunicaţie 42
44. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
NAT – Network Address Translation
• O adresă = mai multe calculatoare.
• Foloseşte adrese locale (private sau non-rutabile) pentru o
adresă globală.
• NAT translatează între adresa privată şi adresa globală.
11.03.2013 Protocoale de comunicaţie 44
45. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Principiul NAT
• Foloseşte:
– adresa IP + număr port.
– tabela de translatare.
• Transmisie:
– înlocuieşte adresa IP locală cu o adresă IP globală;
– memorează (in tabela de translatare) corespondenţa şi număr port;
– inlocuieşte număr port cu index în tabela translatare;
– re-compune sumele de control IP şi TCP.
• Recepţie:
– obţine număr port din pachet (index în tabela translatare);
– extrage adresa IP locală şi număr port;
– înlocuieşte adresa IP şi număr port din pachet;
– re-calculează sumele de control IP şi TCP.
11.03.2013 Protocoale de comunicaţie 45
46. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Protocoale de control în Internet
• Rezolvarea adreselor:
– Mapare adresa de protocol şi adresa hardware.
– Tehnici:
• tabele de corespondenţă.
• formule de calcul.
• schimb de mesaje.
• Address Resolution Protocol:
– livrare mesaj ARP
11.03.2013 Protocoale de comunicaţie 46
47. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
ICMP – Internet Control Message Protocol
• ICMP foloseşte IP pentru transmisie <=> IP foloseşte ICMP
pentru raportare de erori.
• Test accesibilitate (ping trimite ICMP Echo şi aşteaptă un timp
răspunsul).
• Trasare (descoperire) rută (traceroute trimite serie de datagrame
cu valori TIME TO LIVE crescătoare şi primeşte mesaje ICMP
Time exceeded din care extrage adresa ruterului).
11.03.2013 Protocoale de comunicaţie 47
48. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Unităţi de date
• MTU – Maximum Transmission Unit:
• Fragmentarea:
• Reasamblarea:
11.03.2013 Protocoale de comunicaţie 48
49. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Folosire ICMP pentru aflare path MTU
• Path MTU = MTU minimă pentru o cale.
• Foloseşte mesaj eroare ICMP = fragmentare cerută dar
nepermisă.
• Sursa trimite probe cu DF în datagrama IP.
• Dacă datagrama > MTU => sursa primeşte eroare ICMP.
• Sursa trimite probe mai scurte.
11.03.2013 Protocoale de comunicaţie 49
50. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Dirijarea în Internet
• Internet = număr mare de Autonomous Systems.
• Două tipuri de protocoale de dirijare:
– IGP – Interior Gateway Protocols (în AS).
• RIP – Routing Information Protocol (Distance vector).
• OSPF – Open Shortest Path First (Link state).
– EGP – Exterior Gateway Protocols (intre ASs).
• BGP – Border Gateway Protocol.
11.03.2013 Protocoale de comunicaţie 50
51. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
OSPF – Open Shortest Path First
• Suportă:
– Linii punct la punct între două rutere.
– LANs.
– WANs.
• Modelul de graf:
11.03.2013 Protocoale de comunicaţie 51
52. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
OSPF
• Fiecare AS are mai multe
zone
• Tipuri de rutere:
– interne
– de coloană vertebrală
– de graniţă zonală
– de graniţă AS
• OSPF foloseşte schimb de
informaţii între rutere
adiacente
• In LAN, un ruter desemnat
este adiacent cu toate
celelalte
11.03.2013 Protocoale de comunicaţie 52
53. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Calcul rute
• Nivel 1 (zona)
– Fiecare ruter din zonă calculează separat căile cele mai scurte pe
baza informaţiilor de la celelalte.
– Mesaje OSPF:
• Hello – descoperă vecinii.
• Actualizare stare legătură – furnizează costul unei legături + nr secv
(mai multe costuri intr-un pachet).
• Confirmare stare legătură – confirmă primirea.
• Descriere bază de date – furnizează toate costurile (vecin nou).
• Cerere stare legătură – cere info de actualizare.
• Nivel 2 (AS)
– Ruterele backbone:
• acceptă info de la area border routers.
• calculateaza cele mai bune rute intre orice ruter backbone şi celelalte
rutere.
• propagă info înapoi la area border routers.
– Area border routers avertizează ruterele din zonă.
– Fiecare ruter selectează cea mai bună ieşire spre backbone.
11.03.2013 Protocoale de comunicaţie 53
54. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
BGP – Border Gateway Protocol
• Algoritmi orientaţi pe aspectele politice, de securitate,
economice.
• Reţea = ASs şi conexiunile.
• Protocol = vectorul distanţelor.
• Tabelele de dirijare conţin şi rutele spre destinaţie.
• Comunică vecinilor căile utilizate efectiv.
11.03.2013 Protocoale de comunicaţie 54
55. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
IPv6
• Motivaţii:
– Spaţiul de adrese
• 32 biţi = peste un milion de reţele
• Dar...multe sunt Clasa C, prea mici pentru multe organizaţii
• 214 adrese de reţea Clasa B, multe folosite
– Tip servicii
• Aplicaţii diferite au cerinţe diferite de livrare, siguranţă şi viteză
• IPv4 are tip de serviciu dar adesea nu este implementat
• Caracterizare:
– format antet
– antete extensii
– support audio şi video
– protocol extensibil
– spaţiu adresa
– multicast
11.03.2013 Protocoale de comunicaţie 55
56. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
IPv6 – format datagramă
• IPv6 format Base header
• Base header:
– lungime fixă = 40 octeţi.
– Prioritate - clasa de trafic.
– FLOW LABEL - asociază
datagramele unui flux.
– Diferenţe circuit virtual:
• două fluxuri cu aceeaşi
etichetă se diferenţiază prin
adresa sursă + adresa
destinaţie.
• aceeaşi pereche sursă +
destinaţie poate avea mai
multe fluxuri.
11.03.2013 Protocoale de comunicaţie 56
57. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
IPv6 – format datagramă
• Conţine mai puţine informaţii decât antetul IPv4:
– Restul de informaţii în extensii.
– NEXT HEADER defineşte tipul datelor (ex. TCP).
– NEXT HEADER defineşte tipul antetului de extensie (ex. route
header).
11.03.2013 Protocoale de comunicaţie 57
58. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
IPv6 – antete extensie
• Hop-by-hop options – info pentru rutere;
– suport datagrame excedând 64K (jumbograme).
• Destination options – info adiţionale pentru destinaţie;
– nefolosit.
• Routing – lista rutere de vizitat.
• Fragmentation – identificare fragmente.
• Authentication – verificare identitate transmiţător.
• Encrypted security payload – informaţii despre conţinut criptat.
11.03.2013 Protocoale de comunicaţie 58
60. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Fragmentarea
• Fragmentarea IPv6 are loc la sursă
– Ruterele ignoră datagramele mai lungi decât MTU
• Sursa:
– Fragmentează pachetele
– Descoperă path MTU
• Caracter dinamic
– calea se poate schimba.
• Eficienţa – antetul nu are spaţiu pierdut.
• Flexibilitate – noi antete pentru noi caracteristici.
• Dezvoltare incrementală – ruterele care tratează anumite antete
coexistă cu altele care le ignoră.
11.03.2013 Protocoale de comunicaţie 60
61. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Adresarea
• Adrese de 128 biţi
– Includ prefix reţea şi suffix gazdă.
• Fără clase de adresă – limita prefix/suffix oriunde.
• Tipuri speciale de adrese:
– unicast;
– multicast;
– cluster – colecţie de calculatoare cu acelaşi prefix; datagrama
livrată unuia din ele (permite duplicare servicii).
• 16 numere
105.220.136.100.255.255.255.255.0.0.18.128.140.10.255.255
• Notaţie hexazecimală
69DC:8864:FFFF:FFFF:0:1280:8C0A:FFFF
• Compresie zerouri
FF0C:0:0:0:0:0:0:B1 ==> FF0C::B1
• Adrese IPv6 cu 96 zerouri prefix sunt interpretate ca adrese IPv4
11.03.2013 Protocoale de comunicaţie 61
62. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
IPv4-IPv6 Co-Existence / Transition
(1) dual-stack techniques, to allow IPv4 and IPv6 to
co-exist in the same devices and networks
(2) tunneling techniques, to avoid order dependencies
when upgrading hosts, routers, or regions
(3) translation techniques, to allow IPv6-only devices
to communicate with IPv4-only devices
11.03.2013 Protocoale de comunicaţie 62
63. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Mobile IP (v4 version)
mobile host
correspondent foreign agent
host
home agent
home location of mobile host
11.03.2013
63 Protocoale de comunicaţie
64. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Mobile IP (v6 version)
mobile host
correspondent
host
home agent
home location of mobile host
11.03.2013
64 Protocoale de comunicaţie
65. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Internetul peste IPv4
Private v4
Public v4
Addresses
Addresses
NAT
Public v4 Addresses
NAT NAT
Private v4 Private v4
Addresses Addresses
11.03.2013
65 Protocoale de comunicaţie
66. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Introducerea IPv6 (Vedere Simplificata)
Public v6
Public v4
Addresses
Addresses
NAT
Public v4 Addresses
NAT NAT
Private v4 Public v6
Addresses Addresses
11.03.2013
66 Protocoale de comunicaţie
67. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Extinderea IPv6 (Vedere Simplificata)
Public v6
Addresses Public v6
Addresses
Public v4
Addresses NAT
Public v4 Addresses
NAT Public v6
Addresses
NAT
NAT
Private v4
Addresses
Public v6 Public v6
Addresses Addresses
11.03.2013
67 Protocoale de comunicaţie
68. Universitatea Politehnica Bucureşti - Facultatea de Automatică şi Calculatoare
Sumar
• Protocolul IPv4:
• Funcţiile nivelului reţea.
– adrese IPv4
• Organizarea internă: – dirijare IP
– datagrame; – CIDR Classless InterDomain Routing
– circuit virtual. – NAT Network Address Translation
• Clasificarea algoritmilor: • Protocoale de control în
– calea cea mai scurtă; Internet
– centralizată; – ARP Address Resolution Protocol.
– distribuită (starea legăturilor); – ICMP Internet Control Message
Protocol.
– vectorul distanţelor;
– ierarhică; – OSPF Open Shortest Path First.
– difuzare şi multicast. – BGP Border Gateway Protocol.
• Dirijarea pentru gazde mobile. • Protocolul IPv6:
– antete extensie;
• Dirijarea în reţele ad hoc.
– fragmentare.
– adrese IPv6.
11.03.2013 Protocoale de comunicaţie 68