Internet Lab (iLab1) Basics Lars Wstrich ilab1@net.in.tum.de - - PowerPoint PPT Presentation

▶
internet lab ilab1 basics
SMART_READER_LITE
LIVE PREVIEW

Internet Lab (iLab1) Basics Lars Wstrich ilab1@net.in.tum.de - - PowerPoint PPT Presentation

Apr 11, 2023 20 likes •248 views

Chair of Network Architectures and Services Department of Informatics Technical University of Munich Internet Lab (iLab1) Basics Lars Wstrich ilab1@net.in.tum.de Chair of Network Architectures and Services Department of Informatics

slide-1
SLIDE 1

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Internet Lab (iLab1) Basics

Lars Wüstrich ilab1@net.in.tum.de

Chair of Network Architectures and Services Department of Informatics Technical University of Munich

Lab 1 – WiSe 2019/20

slide-2
SLIDE 2

Outline

Internet protocol architecture MAC addresses Internet protocol L3 address resolution

1/20

slide-3
SLIDE 3

Outline

Internet protocol architecture MAC addresses Internet protocol L3 address resolution

2/20

slide-4
SLIDE 4

Layer model

application presentation session transport network data link physical application transport network link 7. 6. 5. 4. 3. 2. 1. ISO/OSI concept Internet example protocols DNS, DHCPv6, HTTP , Tor, . . . TCP , UDP IPv6, ICMP , IPSec Ethernet, WLAN

3/20

slide-5
SLIDE 5

Example: HTTP communication in a local area network

browser TCP IP Ethernet driver HTTP server TCP IP Ethernet driver

HTTP protocol TCP protocol IP protocol Ethernet protocol

Ethernet

4/20

slide-6
SLIDE 6

Example: two networks connected with a router

wireless LAN browser TCP IP HTTP server TCP IP Ethernet driver WLAN driver IP Ethernet driver WLAN driver

HTTP protocol TCP protocol IP protocol IP protocol Ethernet protocol WLAN protocol

Ethernet router

5/20

slide-7
SLIDE 7

Encapsulation of data in the protocol stack

user data application header user data TCP header application data IP header TCP header application data

Ethernet header

IP header TCP header application data

Ethernet trailer

segment/datagram packet/datagram frame 6/20

slide-8
SLIDE 8

Terminology

IP header network layer SDU

Ethernet header

data link layer SDU

Ethernet trailer

network layer PDU data link layer PDU

  • Protocol Data Unit
  • Service Data Unit
  • Interface: service access point (SAP)

7/20

slide-9
SLIDE 9

Design decisions

  • no state between sender and destination
  • end-to-end principle
  • separation of packet forwarding and routing

8/20

slide-10
SLIDE 10

Destinations

  • unicast
  • broadcast
  • multicast

9/20

slide-11
SLIDE 11

Outline

Internet protocol architecture MAC addresses Internet protocol L3 address resolution

10/20

slide-12
SLIDE 12

Layer 2 addresses/frame

  • MAC addresses, “physical address”
  • specific for medium
  • Ethernet/WLAN: 48 bit
  • 1 bit invividual/group (multicast or broadcast)
  • 1 bit globally (factory default)/locally administered
  • vendor and product information
  • not hierarchical

Why are MAC addresses not used for addressing devices on the Internet?

11/20

slide-13
SLIDE 13

Ethernet layer 2

15 16 31

destination address source address type service data unit

❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤ ❤

. . .

                        

46-1500

  • ctets

frame check sequence

12/20

slide-14
SLIDE 14

Layer 2 traffic

PC 0 PC 1 PC 2 switch A B C

PC 0 transmits:

  • 1. destination MAC PC 1
  • 2. destination MAC FF:FF:FF:FF:FF:FF

13/20

slide-15
SLIDE 15

Layer 2 traffic

PC 0 PC 1 PC 2 switch A B C

switch table:

port address A MAC PC 0

13/20

slide-16
SLIDE 16

Outline

Internet protocol architecture MAC addresses Internet protocol L3 address resolution

14/20

slide-17
SLIDE 17

Internet Protocol

  • packet switched
  • best effort
  • connectionless
  • unreliable
  • no flow control

15/20

slide-18
SLIDE 18

IPv6 header

3 4 11 12 15 16 23 24 31

version traffic class flow label payload length next header hop limit source destination extension headers or payload

16/20

slide-19
SLIDE 19

IPv4 header

3 4 11 12 15 16 23 24 31

version hdr len DSCP/ECN total length identification flags fragment offset time to live protocol header checksum source address destination address

  • ptions or payload

Flags will be used for fragmenting packets.

17/20

slide-20
SLIDE 20

Internet control message protocol

7 8 15 16 31

type code checksum depends

  • IPv6 next header: 58
  • IPv4 protocol: 1
  • similarities between ICMPv6 and ICMPv4
  • kind of on L3

purpose, e.g.,

  • destination unreachable
  • time to live exceeded
  • neighbor discovery

18/20

slide-21
SLIDE 21

Outline

Internet protocol architecture MAC addresses Internet protocol L3 address resolution

19/20

slide-22
SLIDE 22

Neighbor Discovery Protocol

PC 0 2001:DB8::1 PC 1 2001:DB8::2 PC 2 2001:DB8::3 A B C

Request/response protocol flow

  • Neighbor Solicitation (NS): What is the MAC of 2001:DB8::2?
  • Neighbor Advertisement (NA): MAC of 2001:DB8::2 is MACPC1.

20/20