Training and Placement

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Chapter 8 Communication Networks and Services
Contained Slides by Leon-Garcia and Widjaja

Chapter 8 Communication Networks and Services
The TCP/IP Architecture The Internet Protocol IPv6 Transport Layer Protocols Internet Routing Protocols Multicast Routing DHCP, NAT, and Mobile IP

Chapter 8 Communication Networks and Services
The TCP/IP Architecture

Why Internetworking?


To build a “network of networks” or internet





operating over multiple, coexisting, different network technologies providing ubiquitous connectivity through IP packet transfer achieving huge economies of scale H

H

Net Net 51
G H

G

Net Net 53
G G

Net Net 55
G

Net Net 52

Net Net 54

G H

Why Internetworking?


To provide universal communication services



independent of underlying network technologies providing common interface to user applications

H

Reliable Stream Service
H

Net Net 51
G H

G

Net Net 53
G G

Net Net 55
G

Net Net 52

Net Net 54

G H

User Datagram Service

Why Internetworking?


To provide distributed applications




Any application designed to operate based on Internet communication services immediately operates across the entire Internet Rapid deployment of new applications  Email, WWW, Peer-to-peer



Applications independent of network technology
 

New networks can be introduced below Old network technologies can be retired

Internet Protocol Approach
  

IP packets transfer information across Internet Host A IP → router→ router…→ router→ Host B IP IP layer in each router determines next hop (router) Network interfaces transfer IP packets across networks Router

Internet Layer Network Interface

Host A
Transport Layer Internet Layer Network Interface

Router
Internet Layer

Host B
Transport Layer Internet Layer
Network Interface

Net Net 51
Router
Internet Layer

Network Interface

Net Net 54

Net Net 52

Network Interface

Net Net 53

TCP/IP Protocol Suite
HTTP Reliable stream service
SMTP DNS Distributed applications TCP UDP RTP

User datagram service

Best-effort connectionless packet transfer Network

IP

(ICMP, ARP)

Network

Network Interface 3

Interface 1

Interface 2

Diverse network technologies

Internet Names & Addresses
Internet Names  Each host has a unique name  Independent of physical location  Facilitate memorization by humans  Domain Name  Organization under single administrative unit  Host Name  Name given to host computer  User Name  Name assigned to user

Internet Addresses


Each host has globally unique logical 32 bit IP address  Separate address for each physical connection to a network  Routing decision is done based on destination IP address  IP address has two parts:  netid and hostid  netid unique  netid facilitates routing  Dotted Decimal Notation: int1.int2.int3.int4 (intj = jth octet) leongarcia@comm.utoronto.ca 128.100.10.13 DNS resolves IP name to IP address

Physical Addresses
 
 

LANs (and other networks) assign physical addresses to the physical attachment to the network The network uses its own address to transfer packets or frames to the appropriate destination IP address needs to be resolved to physical address at each IP network interface Example: Ethernet uses 48-bit addresses   

Each Ethernet network interface card (NIC) has globally unique Medium Access Control (MAC) or physical address First 24 bits identify NIC manufacturer; second 24 bits are serial number 00:90:27:96:68:07 12 hex numbers Intel

Encapsulation
TCP Header contains source & destination port numbers IP Header contains source and destination IP addresses; transport protocol type Ethernet Header contains source & destination MAC addresses; network protocol type Ethernet header IP header

HTTP Request

TCP header

HTTP Request

TCP header

HTTP Request

IP header

TCP header

HTTP Request...
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