Internet Anadolu

1
Internet Anadoluda ÇalistayiEgitim Notlari

• Mustafa Akgül, M. Ufuk Çaglayan
• Ethem Derman, Attila Özgit
• 23 Mart 2003, v1.0

2
Genel Bakis

• Egitim 1 Internet Nereden Nereye ve
  Internet Kullanimi I
• Egitim 2 Internet Kullanimi II
• Egitim 3 Internet Teknik Temelleri
• Egitim 4 LINUX ve Internet Servisleri

3
Egitim 1Internet Nereden Nereye ve Internet
Kullanimi I

• Internetin Gelisimi
• Giris Bilgileri
• Web Kullanimi ve Bilgiye Erisim
• Web Temelli Elektronik Ticaret

4
Egitim 2Internet Kullanimi II

• Internet Adresleri, Alan Adi Sistemi
• Elektronik Posta ve Listeler
• Sohbet
• Dosya Aktarimi, Uzaktan Erisim
• Internete Erisim Alternatifleri

5
Egitim 3Internet Teknik Temelleri

• Fiziksel Baglantilar
• Yerel Alan Aglari ve Ethernet
• Internet Mimarisi Katmanlarina Genel Bakis -
  Internet Katmani- Transport Katmani-
  Uygulamalar Katmani

6
Egitim 4LINUX ve Internet Servisleri

• LINUXun Basit Kurulumu
• LINUX ve Internet Servislerinin KullanimiWeb
  Tarayici, Elektronik Posta
• LINUX ve Internet Servislerinin SunumuWeb
  Sunucu, Elektronik Posta
• Örnek bir Uygulama Web ve Veri Tabani

7
Internetin Gelisimi - 1

• Arpanet
• ABD Savunma Bakanligi, Ileri Arastirma Projeleri
  Kurumu, 1957
• Analog telefon iletisimine alternatif olarak
  bilginin sayisal paketler halinde gönderilmesi
  kavrami, 60li yillar (datagram)
• Bilgisayar iletisimi için TCP/IP modelinin
  önerilmesi (1974), askeri projelerde kullanim

8
Internetin Gelisimi - 2

• NSFNET
• ABD, Ulusal Bilim Vakfinin (NSF) 1984de askeri
  proje yapmayan üniversite ve kurumlara ARPANET
  alternatifi sunmasi ve Internet
• Önce 56Kbps ve 1.5Mbps daha sonra 45 Mbps hizinda
  baglantilar, MERIT, MCI, IBM konsorsiyumu
• Ticari ag/IP servisleri, 1990larin basi

9
Internetin Gelisimi - 3

• Web kavraminin bulunmasi, Internet servislerinde
  ve bilgiye erisimde patlama
• Bugünkü Durum
• Internet servislerinin tamamen ticarilesmesi
• Gigabit hizlarinda baglantilar
• Internet II, Yeni Nesil InternetYeni bir
  Internet mimarisi ve çok daha yüksek hizlardaki
  baglantilar için için arastirmalar

10
Internetin Gelisimi - 4

• Türkiyedeki Durum - 1
• X.25/TURPAK, EARN/BITNET
• Internete ilk IP baglantisi ODTÜ/TÜBITAK,
  64Kbps, 12 Nisan 1993
• Bogaziçi, Ege, ITÜ, Bilkent gibi üniversitelerin
  IP baglantilari
• 1996dan bu yana, tüm üniversiteleri birbirine
  baglayan TÜBITAK ULAKNET omurgasi

11
Internetin Gelisimi - 5

• Türkiyedeki Durum - 2
• 1996 - 1999, Türk Telekom TURNET omurgasi
• Ticari Internet Servis Saglayicilar (ISS)in
  ortaya çikmasi, hiz ve erisim problemleri
• Sancili yillar, Internet Üst Kurulu, ISSler
  dernegi, Devletde Internet kullanimi, Kamunet
• 1999dan bu yana Türk Telekom TTNet omurgasi,
  Telekomunikasyon Kurumu, serbest piyasaya geçis
  (2003 sonu)

12
Ilgili Organizasyonlar - 1

• Internet Dernegi (ISOC) www.isoc.org
• Ocak 1992den beri
• Internet Mimarisi Kurulu (Internet Architecture
  Board, IAB) Internet protokollerinin tasarimi,
  mühendisligi ve yönetiminden sorumlu, ama
  Internetin isletilmesinden sorumlu degil
• En önemli alt kurulu - Internet Engineering
  Task Force (IETF)

13
Ilgili Organizasyonlar - 2

• ICANN The Internet Corporation for Assigned
  Names and Numbers, www.icann.org
• 1998den bu yana, Internet adreslerinin tahsisi,
  Alan Adi Sisteminin yönetimi gibi konularda
  kurallari koymakla sorumlu uluslararasi kurum
  (karsiz sirket)
• Isletim, rekabete açik ortamda özel sirketler
  tarafindan

14
Ilgili Belgeler

• Internet Drafts (tartisma amaçli belgeler)
• Request for Comments (RFC, Yorum Talebi)
• 3000den fazla RFChttp//www.rfc-editor.org/rfc.h
  tml
• Internet protokollerinin ve çalisma
  prensiplerinin detayli açiklandigi teknik
  belgeler
• Tüm tartismalar ve belgeler Internet ortaminda

15
Internet (TCP/IP) Mimarisi

• Ag Mimarisi Yazilim katmanlari ve bu katmanlar
  arasindaki iletisim protokolleri
• Internet TCP/IP Mimarisi Dört katmanli mimari
  (ISO OSI Referans Modeli yedi katmanli)
• Varsayim Ag içinde bilgi paketlerinin iletimine
  güvenmemek gerekir..!

16
Internet Mimarisi Katmanlari
Uygulama Katmani Interneti kullanmaya yarayan
programlar
Transport Katmani Internette mesajlarin bir
uçtan bir uca hatasiz ve güvenilir bir sekilde
iletimi
Internet Katmani Paketlerin iletimi,
yönlendirilmesi
Ag Erisim Katmani Paketlerin veri olarak iletimi,
fizksel iletisime erisim
17
Katmanlar Arasi Bilgi Aktarimi
4. Uygulama Katmani, mesaj
DATA
H1 DATA
3. Transport K, segment
H2 H1 DATA
2. IK, paket
H3 H2 H1 DATA Trailer
1. NAL, frame
H Katman basligi (header)
18
Bazi Internet Protokollari - 1

• Ag Erisim
• IP over Ethernet, RFC-894
• IP Over ATM, RFC 1577
• Internet Katmani
• Internet Protocol Sürüm 4 (IPv4), RFC-791
• Internet Protocol Sürüm 6 (IPv6)
• Internet Control Message Protocol (ICMP), RFC-792

19
Bazi Internet Protokollari - 2

• Transport Katmani
• Transmission Control Protocol (TCP), RFC-793
• User Datagram Protocol (UDP), RFC-768
• Real Time Protocol (RTP)
• Uygulama Katmani - Altyapi
• Routing Information Protocol (RIP), RFC-1058
• Border Gateway Protocol (BGP), RFC-1267
• Domain Name System (Alan Adi S.), RFC-1035

20
Bazi Internet Protokollari - 3

• Uygulama Katmani - Kaynak/Bilgi Paylasimi
• Dosya Aktarimi (File Transfer Protocol, FTP),
  RFC-959
• Uzaktan Kullanim (TELNET), RFC-854
• WEB Hypertext Transport Protocol,
  HTTPv1.1.RFC-2616, HTMLv2, RFC-1866
• Simple Mail Transfer Protocol (SMTP),
  RFC-821Post Office Protocol (POP3), RFC-1225
• Mesaj Formatlari, RFC-822. Çogul Ortam Mesajlar
  (Multipurpose Internet Mail Extensions, MIME),
  RFC-1341

21
Internette Bilgiye Ulasim

• Web Erisimi ve Arama Motorlari
• Dosya Aktarimi (ftp)
• Uzaktan Kullanim (telnet)

22
Web - 1

• Web of linked/hypertext documents
• TimBerners-Lee, CERN, 1989 and 1991
• Mosaic browser, Marc Andreessen, NCSA, 1993
  (later Netscape Corp.)
• WWW Consortium (MIT, CERN)

23
Web - 2

• HTML, Hyper Text Markup Language
• HTTP, Hyper Text Transport Protocol
• HTTP Server (Apache, etc.), Web Browsers

24
Web - 3

• Secure Socket Layers (SSL) was developed by
  Netscape Communications
• Secure-HTTP (S-HTTP) running over SSL
• SSL supports several cryptographic algorithms to
  handle authentication and encryption

25
Web - 4

• Writing web pages in HTML
• URLs http//baam.boun.edu.tr/netlab/netlab.gif
• Mark-up commands to describe how a document
  should be formatted
• Headings, paragraphs, lists, fonts, forms, etc.

26
Web - 5

• Web - database interaction
• To enter/retrieve web info to/from databases
• CGI scripts, PERL programming language
• PHP Hypertext Preprocessor is a server-side HTML
  embedded scripting language.

27
Web - 6

• Java Programming Language
• Developed at Sun Microsystems
• applets small Java programs in web pages
• To create active, dynamic web pages
• Object oriented, but simple language
• Many object libraries available
• Java VM. Performance problems

28
Arama Motorlari

• ??

29
Güvenlik Sorunlari

• ??

30
Elektronik Ticaret

• ??

31
Egitim 2Internet Kullanimi II

• Internet Adresleri, Alan Adi Sistemi
• Elektronik Posta ve Listeler
• Sohbet
• Dosya Aktarimi, Uzaktan Erisim
• Internete Erisim Alternatifleri

32
Alan Adi Sistemi (Domain Name System, DNS) - 1

• Bilgisayaralarin sembolik isimleri ile
  numaralari arasindaki iliskiye düzenleyen sistem
• akgul.bilkent.edu.tr sembolik adi 139.179.20.11
  IP nosuna karsilik gelir.
• DNS sistemi düzgün çalismazsa Internet çöker!
• makina isimleri akilda kalir

33
Alan Adi Sistemi - 2

• Makina isimleri - 2
• Her bilgisayarin, insanin, ve nesnenin adresi
  vardir ve bu DNS ile ilintilidir
• Protokoller makina adini sart kosmaz
• makina isimleri IP numaralarina döndürülür

34
Alan Adi Sistemi - 3

• Domain (alan) ve altalanlar - 1
• kavramsal bir birim içindeki makinalari ve
  altbirimleri belirler
• Örgütsel, cografi, ülkesel bölünmeleri gösterir
  .tr, .us. .de . com, edu, org, gov, com.tr,
  bel.tr, k12.tr gibi

35
Alan Adi Sistemi - 4

• Alanlar ve altalanlar - 2
• bir alan kendi altalanlarini istedigi gibi
  olusturmakta tam yetkilidir. Bu bölünme
  fonksiyonel, bölgesel vs olabilir
• Alan ve altalan isimleri de IP ye dönebilir, ama
  asil önemlisi o alan içindeki servisler ve
  makinalar hakkinda bilgi verir

36
Alan Adi Sistemi - 5
Root
JP
GR
TR
UK
USA
gov
com
com
mil
gov
net
edu
metu
boun
cc
cmpe
cc
orfoz
37
Alan Adi Sistemi - 6

• Bir makinanin tam adi (FQDN) ilgili tüm alan ve
  altalan bilgisini içerir palamut.cmpe.boun.edu.
  tr , akgul.bcc.bilkent.edu.tr
• sembolik isimler ilgili IP degisiminden
  bagimsizdir, DNS sistemi bu saklar

38
Alan Adi Sistemi - 7

• isim ?? IP degisimini DNS sistemi NS
  sunuculari ile saglar
• DNS sistemine ek olarak yerel olarak dosyalar ve
  NIS gibi sistemler çalisir
• NS sunuculari hiyararsik bir sekilde sorgular,
  cachede tutar ve bunu paylasirlar

39
Alan Adi Sistemi - 8

• DNS servers (DNSSs) - 1
• A host contacts its immediate DNSS for the
  translation of an arbitrary name, the request is
  routed in the DNSS hierarchy until a DNSS in the
  hierarchy has the proper translation record.

40
Alan Adi Sistemi - 9

• DNS servers (DNSSs) - 2
• Intermediate DNSSs remember (cache) the most
  recent translations
• DNSSs use UDP to talk to each other.

41
Alan Adi Sistemi - 10

• DNS Translation Example
• palamut.cmpe.boun.edu.tr attempts to resolve the
  IP address of, say www.lufthansa.de by contacting
  the DNSS for cmpe or boun domains.

42
Alan Adi Sistemi - 11

• DNS Translation Example (continued)
• Request is routed to tr DNSS, then to one of the
  top level domain DNSSs (in US), then to de DNSS
  (assume it has the record), then all the way back
  to boun DNSS and to palamut.cmpe.boun.edu.tr

43
Electronik Posta - 1

• A very frequently used application
• E-mail clients
• E-mail servers
• E-mail gateways
• Mailboxes on e-mail servers

44
Nesne Adresleri

• URL Uniform Resource Locater
• http//akgul.nom.tr/yazilar/cbt/eturkiye.html
• ftp//akgul_at_inet-tr.org.tr2222/dosya/x.zip
• mailtoakgul_at_bilkent.edu.tr?Subjecthello
• Rsync//rsync.xyz.com897/xyz.ppt
• https//www.nic.tr/cgi-bin/whois?nameak
• Pro//usersifre_at_makinaport/nesne

45
Electronik Posta - 3

• Examples TCP/IP e-mail
• RFC 822 message formats
• SMTP (RFC 821)
• RFC 822 Extensions
• MIME (RFC 1521)
• POP (Post Office Protocol)
• POP3 (RFC 1725)
• IMAP

46
Electronik Posta - 4

• Server software Sendmail, postfix,qmail
• Client software Outlook, Eudora, etc.

47
Electronik Posta - 5

• Two methods of secure electronic mail PGP and
  S/MIME
• PGP Work of a single person, Phil Zimmermann
• Digital signatures DSS/SHA or RSA/SHA
• Encryption CAST or IDEA or Triple DES with
  one-time session key, also DH and RSA
• ZIP and Radix-64 conversion

48
Electronik Posta - 6

• S/MIME Secure/Multipurpose Internet Mail
  Extensions
• A natural follower of RFC822 and MIME
• Envelope Concept
• SHA-1 preferred, also MD5
• Signatures DSS RSA with 512 to 1024 bits
• Message encryption One time keys, Triple DES
  and RC2/40 bits

49
Electronik Posta - 9

• SMTP over TCP/IP, UUCP and local mail are three
  distinct facilities that enable users exchange
  mail messages, but they also create problems
  since they are incompatible mail delivery
  systems.
• sendmail eliminates the confusion created by
  multiple mail delivery systems.

50
Electronik Posta Listeleri - 1

• List servers LISTSERV majordomo
• Special e-mail servers to auto distribute e-mail
  to a large group of users
• subscribe, unsubscribe, distribute, archive
  operations. moderated/not moderated lists
• ???

51
Electronik Posta Listeleri - 2

• ???
• ???

52
Sohbet (Chat) - 1

• ???
• ???

53
Uzaktan Erisim - 1

• For local capture of display, keyboard, mouse
  etc. of a remote host
• rlogin, telnet applications, X-Windows
• rlogin provides interactive access to remote
  hosts similar to telnet.

54
Dosya Aktarimi - 1

• ftp uygulamasi
• Herkese açik dosyalarin anonim FTP ile
  getirilmesi- kullanici adiananymous-
  sifreelektronik posta adresi

55
Dosya Aktarimi - 2

• FTP örnek RFC getirme
• \gt ftp ds.internic.net
• \gt cd rfc
• \gt get rfc-index.txt
• \gt get rfc977.txt
• \gt quit
• RFC web http//www.rfc-editor.org

56
Türkiyede Internete Erisim

• ??
• ??

57
Egitim 3Internet Teknik Temelleri

• Fiziksel Baglantilar
• Yerel Alan Aglari ve Ethernet
• Internet Mimarisi Katmanlarina Genel Bakis -
  Internet Katmani- Transport Katmani-
  Uygulamalar Katmani

58
Fiziksel Baglantilar

• ??
• ??
• ?? - ??- ??

59
Yerel Alan Aglari ve Ethernet

• ??
• ??
• ?? - ??- ??

60
Network Access Layer - 1

• Goal To move IP packets over
• Dial-up or leased telephone lines, wireless
  networks, digital carriers such as E1, T1, SONET
• Public switched packet services such as X.25,
  SMDS, Frame Relay, or ATM
• LANs such as Ethernet, token ring
• Any propriety networks such as SNA, etc.

61
Internet Katmani - 1

• Main Functions
• Provide datagram (packet) service to transport
  layer protocols TCP, UDP and to other protocols
  such as ICMP, PPP etc.
• Routing of packets through the subnet
• Congestion control
• Internetworking Connecting multiple networks

62
Internet Katmani - 2

• Provides only connectionless (datagram) services,
  no VC services..!
• Review of packet switching (vs. message
  switching) (next slide)
• Delivery not guaranteed
• Order of packets not guaranteed
• Packets may take different routes

63
Internet Protocol - 1

• IPv4 packetizes each transport message by adding
  an IP header of min 20, max 60 bytes
• IPv4 Packet Header
• Version , 4 bits (Version 4 and 6)
• Header length, 4 bits.Header length in bytes/4
  (header always multiple of 4)

64
Internet Protocol - 4

• Source/destination addresses IP address
• IP address is for the INTERFACE of a host.
  Multiple interfaces mean multiple IP addresses,
  i.e., routers.
• 32 bit IP address in dotted-decimal (hexadecimal)
  notation for ease of reading, i.e.,
  193.140.195.66 or 0xC1.8C.C3.42
• IP address is divided into a network number and a
  host number.

65
Internet Protocol - 5

• IP address (continued)
• IP address division is determined by the address
  classes A, B, C, D, E.
• High order (leftmost) bits determine the address
  class, hence the number of bits in the network
  address.
• Class A Address begins with bit 0. It has 8 bit
  network number (range 0.0.0.0-to-127.255.255.255),
  24 bit host number.

66
Internet Protocol - 6

• IP address (continued)
• Class B Address begins with bits 10. It has 16
  bit network number (range 128.0.0.0-to-191.255.255
  .255), 16 bit host number.
• Class C Address begins with bits 110. It has 24
  bit network number (range 192.0.0.0-to-223.255.255
  .255), 8 bit host number.

67
Internet Protocol - 7

• IP address (continued)
• Rule Regardless of address class, all hosts on
  a single physical network must have the same
  network number, but different host numbers.
• i.e., 2 hosts with IP addresses 193.140.195.66
  and 193.140.196.67 (C class addresses) on the
  same Ethernet cable/hub (even if on different
  segments separated by repeaters and/or bridges)
  violate the above rule.

68
Internet Protocol - 7

• IP address (continued) Host number assignment
  conventions
• Host number 0 means "this host" or "this network"
  (do not use).
• Host number 1 is used to number gateways (router
  interfaces).
• Host numbers with all bits 1's, e.g., 255 or
  255.255, are used as broadcast addresses.

69
Internet Protocol - 8

• Subnet Addresses and Masks
• IP address can actually be divided into a network
  number, a subnet number and a host number.

70
Internet Protocol - 11

• Basic IP Routing
• Routing of the packets is done only by IP.
• IP routes a packet by looking at only the network
  number part of the address, not the host number.
• Goal is to simplify the routing algorithm and to
  reduce the size of routing tables. Note that all
  hosts connected to the same data link network
  will have the same network number.

71
Internet Protocol - 12

• Basic IP Routing (continued)
• Routing table entries are in the following
  form.ltnetwork number, gateway number, flagsgt193.
  140.192.0 193.140.196.1 U199.144.191.0 193.140.19
  7.1 Udefault 193.140.195.1 U
• A router examines a packet header as it passes
  through. Source and destination IP addresses do
  not change.

72
Internet Protocol - 13

• Basic IP Routing (continued)
• A router decrements the TTL field and if zero,
  discards the packet and sends an ICMP time
  expired message to the source IP address.
• A routing protocol is used to update routing
  tables at each routing node of the network.
  Routing protocol enables routers to find out the
  most effective route to a certain destination
  network.

73
Internet Protocol - 14

• Basic IP Routing (continued)
• Routing protocol (RIP, BGP) is not part of IP. IP
  performs actual routing although IP does not know
  how routing tables are built. Routing protocols
  build routing tables.

74
DHCP

• DHCP Dynamic Host Configuration Protocol,
  RFC2131
• DHCP provides complete network configuration/param
  eters in addition to IP address assignment and
  remote boot of an OS.
• Permanent, time-limited, manual IP addresses
• DHCP server

75
ICMP - 1

• Internet Control Message Protocol, RFC-792. ICMP
  uses IP. About 12 ICMP messages.
• Destination Unreachable Message A router cannot
  locate destination host.
• Time Exceeded Message Routers use it to inform
  hosts about packets discarded when packet TTL
  value reaches 0.

76
ICMP - 2

• Echo Request/Reply, Timestamp Request/Reply
  Messages To check if a host is alive, or to
  measure delays on a route. Basic messages behind
  ping utility.
• High volume of ICMP messages may indicate bad
  network.

77
IPv6 - 1

• Many problems associated with IPv4
• Inefficient address space
• Address space hierarchy
• Problems with multicasting and security
• No service quality parameters
• Mobile hosts

78
IPv6 - 3

• IPv6 Header (continued)
• Source and Destination Addresses Each 128 bits
  (16 bytes). Insufficient address space problem is
  solved.

79
Transport Katmani - 1

• Issues and services
• TL provides end to end services to hosts.
• TL entities exchange segments between socket
  numbers (TSAPs).
• TL enhances the quality of service (QoS) of the
  underlying network layer, namely IP and provides
  flow control and error recovery.
• Connection oriented and connectionless services
  (TCP and UDP)

80
TCP - 1

• TCP Header Fixed 20 bytes
• Source port and destination port numbers,each 16
  bits. First 1024 ports are reserved.
• Segment sequence number, 32 bits.Relative byte
  offset of the first byte of current messsage.
• Segment acknowledgment number, 32 bits.Relative
  byte offset of the last byte of ack'ed messsage.

81
User Datagram ProtocolUDP - 1

• Unlike TCP, UDP is packet oriented, has no ack
  facility, no guarantee of UDP packet delivery or
  ordered delivery.
• Better suited to support client/server model.
• UDP is used by application level protocols and
  services such as Remote Procedure Call (RPC),
  NFS, DNS and RIP.

82
User Datagram ProtocolUDP - 2

• UDP Header Fixed 8 bytes
• Source port and destination port numbers,each 16
  bits.
• Data length, 16 bits.
• Checksum, 16 bits
• UDP data, max 64Kbytes, follow the header.

83
Other Transport Protocols - 1

• Real Time Transport Protocol (RTP)
• RFC 1889
• For real time multimedia applications such as
  Internet radio, television, telephony etc.
• RTP runs over UDP, therefore it is not exactly a
  transport protocol. RTP offers generic,
  application independent services to multimedia
  applications, therefore it could be classified as
  a transport protocol.

84
Protocols A Summary

• Protocol Numbers
• IP 0
• ICMP 1
• IGMP 2
• TCP 6
• UDP 17

85
Ports A Summary

• Port Numbers, a subset
• time 37/tcp time 37/udp
• telnet 23/tcp
• ftp 21/tcp
• smtp 25/tcp
• http 80/tcp

86
TCP/IP Clients - 1

• PCs with Windows
• In Control Panel/Network menu
• Assign an IP number and mask.Example
  193.140.196.93, 255.255.255.0or select auto IP
  assignment (DHCP, WINS)
• Assign a gateway IP number.Example
  193.140.196.1
• Find out and define the IP number of DNS
  servers, i.e.,194.140.192.20 and 194.140.192.21

87
TCP/IP Clients - 2

• UNIX/LINUX Workstations
• inetd daemon for TCP/IP services, inetd.conf
  configuration file.
• ifconfig command for interface configuration.ifco
  nfig le0 displays interface properties
• Assign an IP number, mask, gateway IP number, DNS
  server IP number in a similar manner (very much
  OS dependent).

88
TCP/IP Routing - 1

• Bridges versus routers
• A bridge is transparent to IP
• Two segments joining the bridge create a single
  physical network, i.e., the same IP network
  number, from IP's point of view
• Whether a bridge or router is used significantly
  influences how IP addresses are assigned.

89
TCP/IP Routing Protocols - 1

• RIP, BGP
• Two large groups Interior and exterior
• RIP, an interior protocol mostly in use within
  autonomous systems, uses hop count as the metric
• BGP, an exterior protocol to interconnect large
  networks, uses delay as the metric

90
TCP/IP Routing Protocols - 2
Autonomous System 2
Autonomous System 1
Interior Routing Protocol
Exterior Routing Protocol
91
Multimedia Networking - 1

• Download and play applications, such as MP3, MPEG
  are relatively easy to handle and similar to FTP.
• Real multimedia applications require streaming
  audio and video and sometimes interactivity which
  requires more complex mechanisms to handle on
  best effort networks

92
Multimedia Networking - 2

• Real-time (RT)Application
• Key Issues
• Bandwidth Compression
• Timing Delivery
• Best Effort Networks
• Heterogeneous
• Was not initially designed for RT applications

93
Multimedia Networking - 3

• Problems with the Best Effort Networks
• Packet Loss (up to 20 may be tolerated)
• End-to-end Delay may cause disturbances if it
  exceeds 150 msec for interactive applications
• Packet Jitter can be removed by using sequence
  numbers, time stamps and playout delay

94
Multimedia Networking - 4

• Video Compression standards
• H.261
• H.263
• MJPEG
• MPEG-1, -2, -4
• MPEG-7 making audio-visual material
• as searchable as text is today.

95
Services and Applications
MIME
FTP
SMTP
HTTP
Telnet
SNMP
TCP
UDP
ICMP
IGMP
RSVP
IP
96
TCP/IP Troubleshooting - 1

• Ifconfig (ipconfig in Win NT) to check the
  status of all available network interfaces
• netstat to check the status of all available
  network interfaces example netstat -ain

97
TCP/IP Troubleshooting - 2

• ping to check whether a remote host is
  operational
• nslookup to get information from DNS
• traceroute (tracert in Windows NT) tells the
  route a packet is taking

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Egitim 4LINUX ve Internet Servisleri

• LINUXun Basit Kurulumu
• LINUX ve Internet Servislerinin KullanimiWeb
  Tarayici, Elektronik Posta
• LINUX ve Internet Servislerinin SunumuWeb
  Sunucu, Elektronik Posta
• Örnek bir Uygulama Web ve Veri Tabani

99
LINUXun Basit Kurulumu

• ??

100
LINUX ve Internet Servislerinin Kullanimi

• ??

101
LINUX ve Internet Servislerinin Sunumu

• ??

102
Örnek bir Uygulama

• ??

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Kitaplar Listesi - 1

• A. S. Tanenbaum, Computer Networks, 4th Ed.,
  Prentice-Hall, 2003.
• W. Stallings, Data and Computer Communications,
  6th Ed., Prentice-Hall, 2000.

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Kitaplar Listesi - 2

• LINUX, Microsoft Windows vb rehber kitaplari
• Online "man/help sayfalari
• RFCler ve diger IETF belgeleri

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Egitim Notlari ile ilgili Temas

• M. Ufuk Çaglayan
• Bilgisayar Mühendisligi Bölümü
• Bogaziçi Üniversitesi
• Bebek, Istanbul 34342
• Faks [phone]
• Tel [phone] ext 1698 M. Ufuk Çaglayan
• E-posta caglayan_at_boun.edu.tr
• HTTP netlab.boun.edu.tr