OSI%20Seven%20Layer

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OSI Seven Layer
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2
Physical Layer
(1)
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3
Physical Layer
(2) RS-232C
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4
Physical Layer
(3) Manchester
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Physical Layer
(4) Differential Manchester
0. Signal voltage changes in the middle of the
bit Signal voltage changes in the beginning
of the bit 1. Signal voltage changes in the
middle of the bit Signal voltage do not
change in the beginning Control Signal
voltage do not change in the middle of the bit
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Data Link Layer
MAC information http//map-ne.com/Ethernet/v
endor.html

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Network Layer

• Some of the Routing Protocols
• RIP
• RIPv2
• OSPF
• IGRP
• EIGRP
• IS-IS
• BGP

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Network Layer

• Routed Protocols
• IP
• IPX
• Apple Talk
• DecNET

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Network Layer

• Network Layer Address  
• Hierarchical
• Network Number
• Host Number
• Logical Address
• MAC Address  
• Flat
• Physical Address

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TCP/IP Model
DOD Reference Model OSI Model
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TCP/IP Model
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TCP/IP Model
IEEE 802 Standard
802.1 Higher Layer LAN Protocols Working Group
802.2 Logical Link Control Working Group (Inactive)
802.3 Ethernet Working Group
802.4 Token Bus Working Group (Inactive)
802.5 Token Ring Working Group
802.6 Metropolitan Area Network Working Group (Inactive)
802.7 Broadband TAG (Inactive)
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TCP/IP Model
IEEE 802 Standard(Contd)
802.8 Fiber Optic TAG
802.9 Isochronous LAN Working Group
802.10 Security Working Group
802.11 Wireless LAN Working Group
802.12 Demand Priority Working Group
802.13 Not Used
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TCP/IP Model
IEEE 802 Standard(Contd)
802.14 Cable Modem Working Group (Archive information is currently being moved, not available)
802.15 Wireless Personal Area Network (WPAN) Working Group
802.16 Broadband Wireless Access Working Group
802.17 Resilient Packet Ring Working Group
http//grouper.ieee.org/groups/802/dots.html
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Summary

• OSI Model Functions
• Compression/Decompression
• Encryption/Decryption
• Connection Establishing/Terminating
• Segmentation/Reassembly
• Flow Control
• Error Control
• Addressing/Routing

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Summary

• OSI Model Functions (Contd)
• Sequencing
• Encapsulation/Decapsulation
• Encoding/Decoding
• Multiplexing
• Synchronization
• Positive Acknowledgement and
  Retransmission (PAR)
• Windowing

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Internet Protocol
First Octet Rule Default Class First
Octet Range Idea Subnet Mask ------ --------
----- ---------- ----------- -----------------
- A 0xxx xxxx 0127 N.H.H.H 255.0.0.0 B 10xx
xxxx 128191 N.N.H.H 255.255.0.0 C 110x
xxxx 192223 N.N.N.H 255.255.255.0 D for
multicast E for research
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Internet Protocol
Class Networks Nodes in each network A   B   C
128
256 x 256 x 256
64 x 256
256 x 256
32 x 256 x 256
256
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Subnet
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Subnet
Example 1 172.16.40.4 255.255.255.0
10101100.00010000.00101000.00000100 11111111.11111
111.11111111.00000000
AND
10101100.00010000.00101000.00000000
172 . 16 . 40 . 0
Network Number
AND 0 0 0 1 0 0 0 1 0 1 1
1

• . 16 . 40 . 4
• 255 . 255 . 255 . 0
• 172 . 16 . 40 . 0

AND
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Subnet
Example 2 172.16.40.4 255.255.224.0
10101100.00010000.00101000.00000100 11111111.11111
111.11100000.00000000
AND
10101100.00010000.00100000.00000000
172 . 16 . 32 . 0
Network Number
AND 0 0 0 1 0 0 0 1 0 1 1
1

• . 16 . 00101000 . 4
• 255 . 255 . 11100000 . 0
• 172 . 16 . 00100000 . 0

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Subnet
Example 3 172.16.0.0 255.255.224.0
Continuous 0 to 1
11111111.11111111.11100000.00000000 172
. 16 .000xxxxx.xxxxxxxx
.001xxxxx.xxxxxxxx
.010xxxxx.xxxxxxxx
.011xxxxx.xxxxxxxx
.100xxxxx.xxxxxxxx
.101xxxxx.xxxxxxxx
.110xxxxx.xxxxxxxx
.111xxxxx.xxxxxxxx
Subnet Mask
Subnets 23 Valid subnets 23 -2 Total nodes in
each subnet 213 Valid nodes in each subnet 213
-2 Abbreviation 172.16.0.0/19
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Subnet
Example 4 172.16.0.0 / 255.255.255.0
Continuously borrowing bits from the right
11111111.11111111.11111111.00000000 172
. 16 .00000000.xxxxxxxx
.00000001.xxxxxxxx
.00000010.xxxxxxxx
.
.11111111.xxxxxxxx
Subnet Mask
Subnets 28 Total nodes in each subnet
28 172.16.0.0/24
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Subnet
Network Number The first node of each
network Broadcast address The last node of each
network 172.16.0.0/20
172.16.32.0 172.16.47.255 172.16.0.0/24
172.16.15.0 172.16.15.255 172.16.0.0/28
172.16.15.64 172.16.15.79
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Subnet
Class C
Subnet mask Valid Subnets Valid nodes Total valid nodes IP Saving
255.255.255.192 2 62 124  
255.255.255.224 6 30 180  
255.255.255.240 14 14 196 v
255.255.255.248 30 6 180  
255.255.255.252 62 2 124  
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Subnet
Best IP Saving
Class Subnet Mask Total usable nodes
A 255.255.240.0 (212-2) x (212-2)
B 255.255.255.0 (28-2) x (28-2) 2542
C 255.255.255.240 (24-2) x (24-2) 196

• borrowing bits left-over bits

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Subnet
    /17 255.255.128.0 /25 255.255.255.128
/10 255.192.0.0 /18 255.255.192.0 /26 255.255.255.192
/11 255.224.0.0 /19 255.255.224.0 /27 255.255.255.224
/12 255.240.0.0 /20 255.255.240.0 /28 255.255.255.240
/13 255.248.0.0 /21 255.255.248.0 /29 255.255.255.248
/14 255.252.0.0 /22 255.255.252.0 /30 255.255.255.252
/15 255.254.0.0 /23 255.255.254.0    
/16 255.255.0.0 /24 255.255.255.0    
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Subnet
IP 10.128.32.64, Find its broadcast
IP /8 10.255.255.255 /17 10.128.127.255 /25 10.1
28.32.127 /10 10.191.255.255 /18 10.128.63.255 /26
10.128.32.127 /11 10.159.255.255 /19 10.128.63.25
5 /27 10.128.32.95 /12 10.143.255.255 /20 10.128.4
7.255 /28 10.128.32.79 /13 10.135.255.255 /21 10.1
28.39.255 /29 10.128.32.71 /14 10.131.255.255 /22
10.128.35.255 /30 10.128.32.67 /15 10.129.255.255
/23 10.128.33.255 /16 10.128.255.255 /24 10.128.32
.255
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Subnet
Find the broadcast address of the following
IP 128.1.2.3/29 128.1.2.7 16.65.30.1/20 16.65.31
.255 128.5.6.7/28 128.5.6.15 16.65.60.1/19 16.65.6
3.255 128.4.5.6/30 128.4.5.7 16.65.140.1/18 16.65.
191.255 128.3.4.5/26 128.3.4.63 16.65.100.1/17 16.
65.127.255 128.10.15.20/27 128.10.15.31 16.65.1.1/
16 16.65.255.255 128.5.160.3/23 128.5.161.255 16.6
5.0.0/15 16.65.255.255 128.6.7.10/25 128.6.7.127 1
6.65.3.4/14 16.67.255.255 128.7.6.4/22 128.7.7.255
16.65.100.200/13 16.71.255.255 128.6.27.8/21 128.
6.31.255 16.65.128.255/12 16.79.255.255
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Subnet

• IP and Subnet Mask work together to define the
  neighborhood(network range) of that IP
• Router uses routing table to make path decision
• Routing table records the relationship of
  network number and the routers interface
  (port) not the IP to the port
• Intermediate routers forward packets based on
  their destination network number, not the
  destination IP
• The final router uses IP to get the MAC of the
  destination host, then uses the destination MAC
  to deliver the packet (within a frame)

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Private IP
10.0.0.0 1 x 224 224 IP
(10.0.0.010.255.255) 172.1631.0.0 16 x 216
220 IP (172.16.0.0172.31.255.255) 192.168.0.
0 256 x 28 224 IP (192.168.0.0192.168.255.25
5)
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Summary
When IP and its subnet mask are known, the
following can be determined      The subnet
number of this subnet      The broadcast
address of this subnet      The range of this
subnet      The maximum subnets allowed by this
mask      The number of hosts in this subnet
   Borrowing bits and total network bits
(/number) http//www.johnscloset.net/cgi/dictiona
ry.pl?Netmask
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