IST220 Networking and Telecommunications

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IST220Networkingand Telecommunications

• InstructorDr. George W. Crawford
• Office Frable 201B
• Telephone[phone] (Office)
• 412-741-9643 (home)
• Email gwc2_at_psu.edu

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Course ContentIST 220 is an introduction to
digital networking and telecommunications and
their applications in information systems. It is
a required core course for both the two-year and
four-year IST degrees. The objective of this
class is to provide a basic understanding of the
working of digital networks and the ability to
apply this knowledge to specific applications and
situations.
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Organization of Forouzan Text Part 1 Data
Transmission Part 2 Packet Transmission Part
3 Internetworking Part 4 Networking
Applications
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Complexity in Network Systems

• Internal networks nervous system of
  organizations
• Massive increase in complexity in management
• Biggest Problems
• No uniform standard in equipment design
• No standard in network management (sort of)
• Near exponential growth in Internet growth and
  interconnections

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Complexity in Network Systems

• As the Internet continues to proliferate, it has
  become natural to think of it biologically as a
  flourishing ecosystem of computers or a sprawling
  brain of Pentium, AMD, and Apple powered neurons.
• In the past, scientists treated networks as
  though they were strung together at random,
  giving rise to a homogeneous web in which nodes
  tended to have roughly the same number of links.

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Complexity in Network Systems

• As they come together, many networks seem to
  organize themselves so that most nodes have very
  few links, and a tiny number of nodes, called
  hubs, have many links. The pattern can be
  described by what scientists call a power law.
• This kind of structure may help explain why
  networks are generally very stable and resilient,
  yet prone to occasional catastrophic collapse.
  Since most nodes (molecules, species, computer
  servers) are sparsely connected, little depends
  on them a large fraction can be plucked away and
  the network will endure. But if just a few of the
  highly connected nodes are eliminated, the
  whole system could crash.

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Top 15 Nations in Internet Use at
Year-End 2000 Rank Nation
Internet Users

(millions) Share 1.
United States 135.7 36.2
2. Japan 26.9 7.18
3. Germany 19.1 5.10
4. UK 17.9 4.77
5. China 15.8 4.20
6. Canada 15.2 4.05 7. South
Korea 14.8 3.95
8. Italy 11.6 3.08
9. Brazil 10.6 2.84
10. France 9.0 2.39
11. Australia 8.1 2.16
12. Russia 6.6 1.77
13. Taiwan 6.5 1.73
14. Netherlands 5.4 1.45
15. Spain 5.2 1.39 Worldwide Total 374.9
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Probing the Internet Two tools ping - sends
message that is echoed by remote computer
traceroute - reports path to remote
computer Ping (Packet Internet Groper) example
ping -s www.bucknell.edu 100 5 PING
web.bucknell.edu 100 data bytes 108 bytes
from web.bucknell.edu (134.82.6.6) icmp_seq0.
time8. ms 108 bytes from web.bucknell.edu
(134.82.6.6) icmp_seq1. time5. ms 108
bytes from web.bucknell.edu (134.82.6.6)
icmp_seq2. time3. ms 108 bytes from
web.bucknell.edu (134.82.6.6) icmp_seq3.
time2. ms 108 bytes from web.bucknell.edu
(134.82.6.6) icmp_seq4. time2. ms
----web.bucknell.edu PING Statistics---- 5
packets transmitted, 5 packets received, 0
packet loss round-trip (ms) min/avg/max
2/4/8
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Probing the Internet Two tools Traceroute
example traceroute merlin.cs.purdue.edu tracerout
e to merlin.cs.purdue.edu (128.10.2.3), 30 hops
max, 40 byte packets 1 CCSServC (134.82.7.254)
2 ms 1 ms 1 ms 2 134.82.254.253
(134.82.254.253) 2 ms 2 ms 3 ms 3
12.127.210.89 (12.127.210.89) 22 ms 20 ms 20
ms 4 gr1-a3100s5.wswdc.ip.att.net
(192.205.34.9) 20 ms 20 ms 20 ms 5
Hssi2-1-0.GW1.DCA1.ALTER.NET (157.130.32.21) 20
ms 20 ms 20 ms 6 104.ATM2-0.XR2.DCA1.ALTER.NET
(146.188.161.30) 21 ms 39 ms 20 ms 7
194.ATM2-0.TR2.DCA1.ALTER.NET (146.188.161.146)
20 ms 20 ms 20 ms 8 101.ATM6-0.TR2.CHI4.ALTER.
NET (146.188.136.109) 40 ms 41 ms 56 ms 9
198.ATM7-0.XR2.CHI4.ALTER.NET (146.188.208.229)
41 ms 41 ms 41 ms 10 194.ATM8-0-0.GW1.IND1.ALTE
R.NET (146.188.208.165) 63 ms 66 ms 51 ms 11
purdue-gw.customer.alter.net (157.130.101.106)
56 ms 54 ms 54 ms 12 cisco-cs-atm.gw.purdue.edu
(128.210.252.21) 66 ms 65 ms 63 ms 13
merlin.cs.purdue.edu (128.10.2.3) 68 ms 84 ms
63 ms
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Internet Technology Within Organization
Internet The Internet is what we are accustomed
to talking about when we talk about the World
Wide Web. Intranet An internal internet an
internal system that used Internet technologies
(Web servers, Java, XML, etc.) but is accessed
only within the organization. Extranet A mix
between an intranet and access to the intranet by
selected outside organizations via the Internet.
It needs extensive security measures.
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Homework

• 1) Read the Table of Contents and the Preface for
  the Forouzan book.
• 2) Send me an email using either of the PSU
  systems Eudora or WEBmail
• 3) Get on the Internet and try ping and
  traceroute. You may not be able to get this to
  work on your computer.