mis 430 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
MIS 430 PowerPoint Presentation
Download Presentation
MIS 430

Loading in 2 Seconds...

play fullscreen
1 / 32

MIS 430 - PowerPoint PPT Presentation


  • 147 Views
  • Uploaded on

MIS 430. Chapter 5 – Network and Transport Layers. I. Overview. Layers are very close – move messages from end to end in a network Transport Layer – accepts outgoing messages from the application layer Packetizes them Addresses them

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'MIS 430' - lok


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
mis 430

MIS 430

Chapter 5 – Network and Transport Layers

Chapter 5

i overview
I. Overview
  • Layers are very close – move messages from end to end in a network
  • Transport Layer – accepts outgoing messages from the application layer
    • Packetizes them
    • Addresses them
  • Network layer – takes messages from the transport layer and routes them through the network
  • Data Link Layer – produces error-free delivery

Chapter 5

introduction
Introduction
  • See fig 5-1 p. 145 for 5 OSI layers
    • Note path of packets
    • Note additional headers added at each layer: encapsulation
    • Remember that each layer “talks to” its counterpart layer at the other end

Chapter 5

ii transport and network protocols
II. Transport and Network Protocols
  • Many similar protocols here can do the same thing: TCP/IP, IPX/SPX, X.25, etc.
  • Multiprotocol stacks (software) will process each protocol’s packets
    • must analyze the packet to determine the protocol

Chapter 5

tcp ip internet standard
TCP/IP: Internet Standard
  • TCP/IP originally developed for ARPANET – DoD network
    • Produce error-free transmissions
    • Compatible with variety of data link protocols
  • TCP/IP is world’s most popular
    • TCP=transmission control protocol (TL)
    • IP=Internet protocol (NL)

Chapter 5

tcp transport control protocol
TCP: Transport Control Protocol
  • Performs packetizing
    • Breaks message into packets
    • Numbers them (for reassembly later)
    • Assures packets are delivered reliably
    • Puts packets in order at destination
  • See figure 5-2 p. 147 for TCP packet: 192-bit header

Chapter 5

ip internet protocol
IP: Internet Protocol
  • Network layer protocol
    • Performs addressing and routing
    • IP SW must be at every node
  • IP packet in figure 5-3 p. 147: 192-bit header
  • IPv4: 32 bits=4.3B IP addresses
  • IPv6: 128 bits=3.4x1038 addresses! Simpler header structure but requires ALL computers be revised (Microsoft has upgrade)

Chapter 5

ipx spx novell
IPX/SPX: Novell
  • ISU still uses IPX/SPX but newer Novell Netware now uses TCP/IP
    • SPX: TL protocol and like TCP
    • IPX: NL protocol and like IP

Chapter 5

x 25 packet switching
X.25 Packet Switching
  • WAN global ITU standard for packet switched networks of common carriers
    • Seldom used in North America
  • Maps to lowest 3 levels of OSI model
  • DTE (data terminal equipment or end devices) vs. DCE (data communications equipment or communications devices)
  • PAD – packet assembler/disassembler
  • X. means digital data carried on digital network in ITU-T notation

Chapter 5

system network architecture sna
System network architecture-SNA
  • IBM standard intended for end to end IBM network
    • Used only on IBM compatible mainframes
    • Uses proprietary protocols: important concept in open standards environment
  • Experts predict SNA will be replaced by TCP/IP and this will decline

Chapter 5

iii transport layer functions
III. Transport Layer Functions
  • Each application layer program has a unique TCP/IP port number
    • 16-bit (2 byte) number up to 65536
    • FTP=21, Telnet=23, HTTP=80, SMTP=25
    • Can choose non standard port numbers and give application program that port #
    • http://someplace.com:4567/index.htm

Chapter 5

packetizing
Packetizing
  • Given maximum packet size, most messages are split into >1 packet
  • Web browsers build page a packet at a time, especially streaming and graphics
  • Email clients wait until all packets have arrived and are reassembled

Chapter 5

connection oriented routing
Connection oriented routing
  • Sets up TCP connection as a virtual circuit between sender and receiver
  • Once established, packets flow in same order until connection is closed
  • Reassembling message is simple here

Chapter 5

connectionless routing
Connectionless routing
  • Each packet is treated separately and could take different paths
  • May arrive out of sequence
  • TCP packet replaced by UDP packet
    • User Datagram Protocol packet is much smaller that TCP packet
  • Often used when entire message fits one packet (control messages)

Chapter 5

quality of service qos routing
Quality of service (QoS) routing
  • Special type of connection oriented routing
    • Different connections are assigned different priorities
    • Email is low priority, videoconferencing high priority to assure smooth images

Chapter 5

iv network addresses
IV. Network Addresses
  • Application Layer URL: misnt.indstate.edu
    • at C:>type Ping misnt.indstate.edu to see if active
  • Network Layer IP: 139.102.31.12
  • Data Link Layer MAC: SMC network card 00-E0-29-92-24-54 (12 hex digits)
    • at C:> type winipcfg (Windows 95, 98, ME)
    • at C:> type ipconfig (Windows NT, 2000, XP)
  • Must have an approved address to attach a computer to the Internet
    • Servers have fixed (static) addresses, clients usually not

Chapter 5

internet addresses
Internet Addresses
  • Network Solutions is the agent that provides domain names (called domain registrar)
    • http://www.networksolutions.com
  • .com, .org, .net, .mil, .gov plus several new extensions (.biz, .info, .bz, and .tv) latter two were originally country codes
  • Country extensions: .us, .ca, .il, .jp, .de, .iq http://www.isi.edu/in-notes/iana/assignments/country-codes

Chapter 5

subnets
Subnets
  • Subnet refers to logical group of computers, often same physical network
  • ISU uses 139.102.x.y Class B addresses
    • X is the subnet and y is the computer
    • SB 403 and servers: 139.102.31.y
    • SB faculty and staff: 139.102.67.y and 139.102.69.y
  • Subnet mask: 255.255.255.0 vs 255.255.0.0 – parts refer to clients on the same subnet
  • Partial-byte subnets: 255.255.255.240 allows for 16 computers per subnet: 11111111 11111111 11111111 11110000

Chapter 5

static vs dynamic addresses
Static vs. Dynamic Addresses
  • Static IP address: always same, coded into the Network TCP/IP properties
  • DHCP and bootp give out dynamic addresses at client boot up time
    • Can reuse dynamic IP addresses
    • In TCP/IP Properties, Obtain an IP address automatically
    • Cannot assign a dynamic address to a server!
    • At ISU, even though we use bootp you always get the same IP address; (ISU is replacing bootp with DHCP for roaming)
      • Register: http://ithelp.indstate.edu/forms/bootp.html

Chapter 5

ip address lease
IP Address Lease
  • Client is given an IP address for a certain length of time
  • After that time expires, the IP address lease expires and someone else can use that IP address
  • At C> prompt, type ipconfig /all to see IP address lease information. (In Windows 9x, type winipcfg)

Chapter 5

address resolution
Address Resolution
  • Server name resolution: DNS stands for Domain Name Service
    • Any time your computer does not know the IP address of a server, it calls the DNS to get it
    • DNS may have to go to root DNS to get IP
    • 139.102.48.35, 139.102.7.102, 139.102.1.10 are ISU DNS
    • Once learned, this address is stored inside your computer until you shut down. Hint: you may need to do a DNS Flush if your computer is acting up. Ask about this in class!
  • DNS name is associated with domain name: www.indstate.edu=139.102.15.15
  • DNS servers replicate automatically

Chapter 5

v routing
V. Routing
  • Process of determining path through network of a message
    • Implement via a Routing Table (for computer B)
    • How many paths from A to G? ABCG, ADEFCG, ADEBCG, ABEFCG,

C

B

A

G

D

F

E

Chapter 5

routing 2
Routing - 2
  • Router points in the general direction of destination
    • Ex: for all IP 126.x.x.x addresses, go here
    • Ex: for all Texas destinations go here, otherwise go there
  • Router contains software and builds routing tables dynamically to accommodate congestion, cuts, etc.
  • Cisco – has best dynamic routing software

Chapter 5

tracing your route rs
Tracing Your Route(rs)

C:\WINDOWS\Desktop>tracert www.kelley.indiana.edu

Tracing route to kelley.iu.edu [129.79.121.231]

over a maximum of 30 hops:

1 27 ms 26 ms 38 ms 139.102.180.1 (this was from my home!)

2 26 ms 33 ms 28 ms 139.102.7.3

3 30 ms 2981 ms 29 ms 139.102.1.254

4 45 ms 2971 ms 54 ms ind-ag-2-atm6-0-1-12m.ind.net [157.91.9.174]

5 1982 ms 2965 ms 69 ms ihets-gw-1-atm-ind-ag-2.ind.net [199.8.76.250]

6 1970 ms * 59 ms iupui-atm6-0-100.ind.net [157.91.6.34]

7 1818 ms 2976 ms 56 ms 156.56.249.13

8 156 ms 2952 ms 148 ms wcc6-gw.ucs.indiana.edu [129.79.8.6]

9 1969 ms 182 ms 140 ms kelley.iu.edu [129.79.121.231]

Trace complete.

Chapter 5

types of routing
Types of Routing
  • Centralized routing: all decisions made by central computer
  • Static routing: all decisions made are fixed. If break in network, messages are held until routes refigured. Good for small networks with few alternative paths.
  • Dynamic: adapts to network conditions in decentralized fashion. Default mode with many paths, but requires lots of calculations by routers including network coordination traffic between routers.

Chapter 5

routing protocols
Routing Protocols
  • How routers exchange information to build, maintain routing tables
  • Autonomous system – network operated by one organization
    • Routing protocols inside such systems are interior routing protocols
    • Routing protocols between autonomous systems are exterior routing protocols

Chapter 5

internet routing protocols
Internet Routing Protocols
  • ICMP-Internet Control Message Protocol
  • RIP-Routing Information Protocol
  • BGP-Border Gateway Protocol
  • OSPF-Open Shortest Path First
  • EIGRP-Enhanced Interior Gateway Routing Protocol
  • For the test: know ICMP and RIP 

Chapter 5

multicasting
Multicasting
  • Unicast message: sent from one client to another client
  • Multicast message: sent from one node to a group of computers at same time
    • Ex: Ghost for imaging hard drives; rebuild all computers with same packets
    • Ex: hearing a broadcast on the Internet – like a seminar or workshop

Chapter 5

vi tcp ip example
VI. TCP/IP Example
  • A computer needs four TCP/IP settings:
    • Its IP address
    • Subnet mask
    • IP address of DNS server
    • IP address of gateway leading outside subnet
  • Can get these values
    • automatically or
    • they can be static values typed into TCP/IP Properties in Network control panel

Chapter 5

example network fig 5 14
Example Network: fig 5-14
  • Four subnets: 98, 95, 50, 75
  • DNS server: 128.192.254.4
  • 4 Gateways, each with at least two IP addresses (internal/external)
    • Bldg A: 128.192.98.1 129.192.254.3 (error)
  • Router: 128.192.254.7 next to Internet cloud

Chapter 5

resolving addresses
Resolving Addresses
  • Known Address, Same Subnet
    • Search IP address table, find
    • Hand to Data Link layer, send packet
  • Known Address, Different Subnet
    • Search IP address table, find
    • Go through gateway to other subnet
  • Unknown Addresses
    • Search IP address table, not found
    • Perform DNS request, return address to table
    • May go through gateway or out via router

Chapter 5

bruce s router
Bruce’s Router
  • My home network has a Belkin wireless router: http://139.102.180.53 with a special TCP port number
  • It has the following ports:
    • WAN (connects to DSL modem)
    • 4 wired LAN ports – inside firewall
    • Wireless LAN ports – inside firewall
  • More in chapters 6-7 with LANs

Chapter 5