Download on TCP/IP

Module A
Panko and Panko
Business Data Networks and Telecommunications, 8th Edition
© 2011 Pearson Education, Inc. Publishing as Prentice Hall



This module presents additional material
about TCP/IP standards.
Most of the material in this module can be
read after Chapter 2, but some of it is
designed to be covered after Chapter 10.
The material in this module is not designed
to be read front-to-back like a regular
chapter, although it can be covered this way.
© 2011 Pearson Education, Inc. Publishing as Prentice Hall
2
Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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3

IP packets can carry different things in their
data fields.
◦ TCP segments
◦ UDP datagrams
◦ ICMP supervisory messages (later)
◦ RIP messages (later)
IP Data Field
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IP Header
4

We say that IP can multiplex (mix) different
types of traffic in a stream of IP packets.
Single IP Packet
Carrying UDP Datagram
UDP IP-H
TCP IP-H
UDP IP-H
ICMP IP-H
Stream of Arriving or Outgoing IP Packets
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The IP process must pass contents of
arriving IP packets to the correct process
for subsequent handling.
TCP
UDP
UDP IP-H
Arriving
Packets
IP
ICMP
IP Process
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
IP process must also accept messages
from multiple processes and multiplex
them on an outgoing stream.
TCP
IP-H UDP
Outgoing
Packets
UDP
IP
ICMP
IP Process
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Need a way for receiving IP process to know
what is in the data field
◦ So it can pass the contents to the appropriate
process
IP Data Field
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IP Header
8
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IP Header has an 8-bit Protocol field.
◦ Identifies the contents of the data field
 1=ICMP, 8=TCP, 17=UDP, and so on
Version
(4)
Hdr Len
(4)
TOS (8)
Indication (16 bits)
Time to Live (8)
Protocol (8)
Total Length in Bytes (16)
Flags (3)
Fragment Offset (13)
Header Checksum (16)
Source IP Address
Destination IP Address
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9
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Other Messages Have Analogous Fields
◦ Identify contents of data field

TCP and UDP
◦ Have Port number fields
◦ Identify the application process (80=HTTP)
Source Port # (16)
Destination Port # (16)
Sequence Number (32 bits)
Acknowledgement Number (32 bits)
Hdr Len
Reserved (6)
(4)
Flags (6)
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Window Size (16)
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Other Messages Have Analogous Fields
◦ Identify contents of data field

PPP
◦ Protocol field identifies contents of
information field as IP, IPX, a supervisory
message, and so on.
Flag
Addr
Ctrl
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Prot
Info
CRC
Flag
11
Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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12
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TCP is Reliable.
◦ IP packets carrying TCP segments may arrive out
of order.
◦ TCP must put the TCP segments in order.
5
3
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4
2
1
13
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TCP is Reliable.
◦ Each correct TCP segment is acknowledged by the
receiver.
TCP Segment
Source
Transport
Process
Destination
Transport
Process
ACK
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Each TCP segment sent by a side must
have a sequence number.
◦ Simplest: 1,2,3,4,5,6,7
◦ To detect lost or out-of-sequence messages
◦ TCP uses a more complex approach
3?
1
4
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2
5
15
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TCP header has a 32-bit sequence number
field.
Source Port # (16)
Destination Port # (16)
Sequence Number (32 bits)
Acknowledgement Number (32 bits)
Hdr Len
Reserved (6)
(4)
Flags (6)
TCP Checksum (16)
Window Size (16)
Urgent Pointer (16)
Options (if any)
PAD
Data Field
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
Initial Sequence Number is randomly selected
by the sender; say, 79.
Sent in the sequence number field of the first
TCP segment.
TCP Header
79
TCP Data Field
Sequence Number Field
with Initial Sequence Number (79)
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Data octets in data fields of all
segments in a connection are viewed as
a long string.

TCP Segment 1
79 ISN

TCP Segment 2
80
81 3 Octets in Data Field
82
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TCP Segment 3
83 2 Octets in Data Field
84
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Supervisory segments, which contain a
header but no data, are treated as carrying a
single octet of data.

TCP seg 1
898
899
Carries Data

TCP seg 2
900
Supervisory Segment
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TCP seg 3
901
902
…
Carries Data
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Sequence number field gets the value of the
first octet in the data field.
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TCP 1
79
79 is SeqNum Field Value
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TCP 2
80
81
82
80 is SeqNum Field Value
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TCP 3
83
84
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83 is SeqNum Field Value
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Acknowledgement must indicate which TCP
segment is being acknowledged.
TCP Segment
Source
TCP
Process
Destination
TCP
Process
ACK
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TCP header contains a 32-bit
Acknowledgement Number field to
designate the TCP segment being
acknowledged.
Source Port # (16)
Destination Port # (16)
Sequence Number (32 bits)
Acknowledgement Number (32 bits)
Hdr Len
Reserved (6)
(4)
Flags (6)
TCP Checksum (16)
Window Size (16)
Urgent Pointer (16)
Options (if any)
PAD
Data Field
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Acknowledgement Number field contains
the next byte expected—the last byte of the
segment being acknowledged, plus one.

TCP 1
79
80 is AckNum Field Value

TCP 2
80
81
82
83 is AckNum Field Value
83
84
85 is AckNum Field Value

TCP 3
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Quiz: A TCP segment contains the following
data octets:
◦ 567, 568, 569, 570, 571, 572, 573, 574


What will be in the sequence number field of
the TCP segment delivering the data?
What will be in the acknowledgement number
field of the TCP segment acknowledging the
TCP segment that delivers these octets?
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Flow Control
◦ One TCP process transmits too fast.
◦ Other TCP process is overwhelmed.
◦ Receiver must control transmission rate.
◦ This is flow control.
TCP Process
Too Much
Data
TCP Process
Flow Control Message
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A TCP segment has a Window Size field.
◦ Used in acknowledgements
Source Port # (16)
Destination Port # (16)
Sequence Number (32 bits)
Acknowledgement Number (32 bits)
Hdr Len
Reserved (6)
(4)
Flags (6)
TCP Checksum (16)
Window Size (16)
Urgent Pointer (16)
Options (if any)
PAD
Data Field
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A TCP segment has a Window Size field.
◦ Tell how many more octets the sender can send
beyond the segment being acknowledged
Data
TCP Process
TCP Process
Acknowledgement with Window Size Field
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Example
◦ TCP segment contained octets 45–89
◦ Acknowledgement number for TCP segment
acknowledging the segment is 90
◦ If Window Size field value is 50, then
◦ Sender may send through octet 140
◦ Must then stop unless the window has been
extended in another acknowledgement
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Each Acknowledgement extends the window
of octets that may be sent.
◦ Called a sliding window protocol
1–44
45–79
80–419
May send through 480
400
1–44
45–79
80–419
May send through 920
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420–630
420–630
500
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TCP Segments have maximum data field
sizes.
◦ (Size limit details are discussed later.)
◦ What if an application layer message is too large?
Application Layer Message
TCP Data Field Max TCP Header
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Application layer message must be
fragmented.
◦ Broken into several pieces
◦ Delivered in separate TCP segments
App Frag 1
App Frag 2
App Frag 3
TCP Data Field Max TCP Header
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Note that, in TCP fragmentation, the TCP
segment is not fragmented.
◦ The application layer message is fragmented.
App Frag 1
App Frag 2
App Frag 3
TCP Data Field Max TCP Header
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Transport layer process on the source
host does the fragmentation.
◦ Application layer on the source host is not
involved
◦ Transparent to the application layer
Application
Transport
Application Message
TCP Segment
TCP Segment
Internet
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Transport layer process on the
destination host does the reassembly.
◦ Application layer on the destination host is
not involved; gets original application layer
message
Application Message
TCP Segment
TCP Segment
Application
Transport
Internet
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What is the maximum TCP data field size?
◦ Complex

Maximum Segment Size (MSS)
◦ Maximum size of a TCP segment’s data field
◦ NOT maximum size of the segment as its name
would suggest!!!
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MSS Default is 536 octets.
◦ Maximum IP packet size any network must
support is 576 octets.
 Larger IP packets MAY be fragmented
◦ IP and TCP headers are 20 octets each if
there are no options.
◦ This gives the default MSS of 536.
◦ Smaller if there are options in the IP or TCP
header.
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MSS Default is 536 octets.
◦ Suppose the application layer process is
1,000 octets long.
◦ Two TCP segments will be needed to send
the data.
◦ The first can send the first 536 octets.
◦ The second can carry the remaining 464
octets of the application layer message.
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Each side may announce a larger MSS.
◦ An option usually used in the initial SYN message it
sends to the other.
◦ If announces MSS of 2,048, this many octets of data
may be sent in each TCP segment.
◦ 536 is only the default—the value to use if no other
value is specified by the other side.
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38
Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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39
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Masks were introduced in Chapter 9.
IP addresses alone do not tell you the size
of their network or subnet parts.
Network Mask
◦ Has 1s in the network part
◦ Has 0s in the remaining bits

Subnet Mask
◦ Has 1s in the network plus subnet parts
◦ Has 0s in the remaining bits
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Based on Logical AND
◦ Both must be true for the result to be true
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Example
◦ 1010101010
Data
◦ 1111100000
Mask
◦ 1010100000
Result
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Based on Logical AND
◦ If mask bit is 1, get back original data
◦ If mask bit is 0, bet back zero

Example
◦ 1010101010
Data
◦ 1111100000
Mask
◦ 1010100000
Result
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IP packet arrives at a router
◦ Router sees destination IP address
◦ 11111111 01000000 10101010 00000000

Compares to each router forwarding table
row
◦ Address Part in First Entry
◦ 11111111 01000000 00000000 00000000
◦ Mask in First Entry
◦ 11111111 11100000 00000000 00000000
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Mask the IP destination Address
◦ 11111111 01000000 10101010 00000000 (IP address)
◦ 11111111 11100000 00000000 00000000 (mask)
◦ 11111111 01000000 00000000 00000000 (result)

Compare Result with First Entry
Address part
◦ 11111111 01000000 00000000 00000000 (address part)
◦ 11111111 01000000 00000000 00000000 (result)

The Entry is a Match!
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Recap
◦ Read destination IP address of incoming IP packet.
◦ For each entry in the router forwarding table
 Read the mask (prefix).
 Mask the incoming IP address.
 Compare the result with the entry’s IP address part.
 Do they match or not?
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Simple for Computers
◦ Computers have circuitry AND two numbers.
◦ Computers have circuitry to COMPARE two numbers
to see if they are equal or not.
◦ Very computer-friendly, so used on routers.

Difficult for people, unfortunately
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46
Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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47

The dominant version of the Internet Protocol
is Version 4 (v4).
◦ Earlier versions were not implemented

The emerging version is Version 6 (v6).
◦ V5 was defined but not implemented
◦ Informally called IPng (Next Generation)

IPv6 is already defined.
◦ Continuing improvements in V4 may delay its
adoption
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IPv6 raises the size of the Internet address
field from 32 bits to 128 bits.
◦ We are running out of IP V4 addresses.
◦ V6 will solve the problem.
◦ But current work-arounds are delaying the need
for IPv6 addresses—mostly Network Address
Translation.
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Improved Security
◦ But, through IPsec, v4 is being upgraded in security
as well

Improved Quality of Service (QoS)
◦ But, under IETF Differentiated Services (diffserv)
initiative, IPv4 is being upgraded in this area as well
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Extension Headers
◦ IPv4 headers are complex.
◦ IPv6 basic header is simple.
◦ IPv6 uses extension headers for options.
Basic Header
Extension Header 1
Extension Header 2
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Extension Headers
◦ Basic header has 8-bit Next Header field
◦ Identifies first extension header or says that
payload follows
NH
Basic Header
Extension Header 1
Extension Header 2
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Extension Headers
◦ Each extension header also has 8-bit Next
Header field
◦ Identifies next extension header or says that
payload follows
Basic Header
NH
Extension Header 1
Extension Header 2
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
Extension Headers
◦ Next header field is an elegant way to allow
options
◦ Easy to add new extension headers for new needs
Basic Header
NH
Extension Header 1
Extension Header 2
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54
Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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Maximum Transmission Unit (MTU)
◦ Largest IP packet a network will accept
◦ Arriving IP packet may be larger
MTU
IP Packet
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
If IP packet is longer than the MTU, the
router breaks packet into smaller packets.
◦ Called IP fragments
◦ Fragments are still IP packets
◦ Earlier in Mod A, fragmentation in TCP
MTU
IP Packet
3
Fragmentation
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2
1
IP Packets
57
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What is Fragmented?
◦ Only the original data field
◦ New headers are created
MTU
IP Packet
3
Fragmentation
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2
1
IP Packets
58
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What Does the Fragmentation?
◦ The router
◦ Not the subnet
MTU
IP Packet
3
Fragmentation
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2
1
IP Packets
59

Original packet may be fragmented multiple
times along its route.
Source
Host
Internet
Process
Destination
Host
Internet
Process
Fragmentation
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
Internet layer process on destination host
defragments, restoring the original packet.
IP defragmentation only occurs once.
Source
Host
Internet
Process
Destination
Host
Internet
Process
Defragmentation
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More Fragments field (1 bit)
1 if more fragments
0 if not
Source host internet process sets to 0
If router fragments, sets More Fragments field in
last fragment to 0
◦ In all other fragments, sets to 1
◦
◦
◦
◦
0
Original IP Packet
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0
1
1
Fragments
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
IP packet has a 16-bit Identification field.
Version
(4)
Hdr Len
(4)
TOS (8)
Identification(16 bits)
Time to Live (8)
Total Length in Bytes (16)
Flags (3)
Protocol (8)
Fragment Offset (13)
Header Checksum (16)
Source IP Address
Destination IP Address
Options (if any)
PAD
Data Field
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
IP packet has a 16-bit Identification field.
◦ Source host internet process places a number in
the Identification field.
◦ Different for each original (non-fragmented) IP
packet.
Version
(4)
Hdr Len
(4)
TOS (8)
Identification(16 bits)
Time to Live (8)
Protocol (8)
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Total Length in Bytes (16)
Flags (3)
Fragment Offset (13)
Header Checksum (16)
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
IP packet has a 16-bit Identification field.
◦ If router fragments a packet, it places the original
Identification field value in the Identification field of
each fragment.
47
Original IP Packet
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47
47
Fragments
65

Purpose
◦ Allows receiving host’s internet layer process to
know what fragments belong to each original
packet
◦ Works even if an IP packet is fragmented several
times
47
Original IP Packet
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47
47
Fragments
66
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
Fragment offset field (13 bits) is used to
reorder fragments with the same
Identification field.
Contains the data field’s starting point (in
octets) from the start of the data field in the
original IP packet.
Version
(4)
Hdr Len
(4)
TOS (8)
Identification (16 bits)
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Total Length in Bytes (16)
Flags (3)
Fragment Offset (13)
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


Receiving host’s internet layer process
assembles fragments in order of increasing
fragment offset field value.
This works even if fragments arrive out of
order!
It works even if fragmentation occurs
multiple times.
Fragment Offset Field
730
212
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0
68

IP Fragmentation
◦ Data field of a large IP packet is
fragmented.
◦ The fragments are sent into a series of
smaller IP packets fitting a network’s MTU.
◦ Fragmentation is done by routers.
◦ Fragmentation may be done multiple times
along the route.
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
IP Defragmentation
◦ Defragmentation (reassembly) is done once, by
destination host’s internet layer process.
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

All IP packets resulting from the
fragmentation of the same original IP
packet have the same Identification field
value.
Destination host internet process orders all
IP packets from the same original on the
basis of their Fragment Offset field values.
More Fragments field tells whether there
are no more fragments coming.
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Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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
Why Dynamic Routing Protocols?
◦ Each router acts independently, based on
information in its router forwarding table.
◦ Dynamic routing protocols allow routers to share
information in their router forwarding tables.
Router
Forwarding
Table Data
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
Routing Information Protocol (RIP) is the
simplest dynamic routing protocol.
◦ Each router broadcasts its entire routing table
frequently.
◦ Broadcasting makes RIP unsuitable for large
networks.
Routing
Table
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
RIP is the simplest dynamic routing
protocol.
◦ Broadcasts go to hosts as well as to routers.
◦ RIP interrupts hosts frequently, slowing them
down; unsuitable for large networks.
Routing
Table
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
RIP is limited.
◦ RIP routing table has a field to indicate the
number of router hops to a distant host.
◦ The RIP maximum is 15 hops.
◦ Farther networks are ignored.
◦ Unsuitable for very large networks.
Hop
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Hop
76

Is a Distance Vector Protocol
◦ “New York” starts, announces itself with a RIP
broadcast.
◦ “Chicago” learns that New York is one hop away.
◦ Passes this on in its broadcasts.
New York
Chicago
NY is 1
Dallas
1 hop
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
Learning Routing Information
◦ “Dallas” receives broadcast from Chicago.
◦ Already knows “Chicago” is one hop from Dallas.
◦ So New York must be two hops from Dallas.
◦ Places this information in its routing table.
New York
Chicago
1 hop
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NY is 1
1 hop
Dallas
NY is 2
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
Slow Convergence
◦ Convergence is getting correct routing tables after
a failure in a router or link.
◦ RIP converges very slowly.
◦ May take minutes.
◦ During that time, many packets may be lost.
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
Encapsulation
◦ Carried in data field of UDP datagram
 Port number is 520
◦ UDP is unreliable, so RIP messages do not always
get through.
◦ A single lost RIP message usually does little or no
harm.
UDP Data Field
RIP Message
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UDP
Header
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
Link State Protocol
◦ Link is a connection between two routers.
◦ OSPF routing table stores more information about
each link than just its hop count: cost, reliability,
and so on.
◦ Allows OSPF routers to optimize routing based on
these variables.
Link
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
Network is Divided into Areas.
◦ Each area has a designated router
Area
Designated
Router
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
When a router senses a link state change
◦ Sends this information to the designated router
Area
Designated
Router
Notice of
Link State Change
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
Designed router notifies all routers
◦ Within its area
Area
Designated
Router
Notice of
Link State Change
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
Efficient
◦ Only routers are informed (not hosts).
◦ Usually only updates are transmitted, not whole
tables.
Area
Designated
Router
Notice of
Link State Change
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
Fast Convergence
◦ When a failure occurs, a router transmits the
notice to the designated router.
◦ Designated router send the information back out
to other routers immediately.
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
Encapsulation
◦ Carried in data field of IP packet
 Protocol value is 89
◦ IP is unreliable, so OSPF messages do not always
get through.
◦ A single lost OSPF message usually does little or
no harm.
IP Data Field
OSPF Message
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IP
Header
87

Within a network you control, it is your
choice.
◦ Your network is an autonomous system.
◦ Select RIP or OSPF based on your needs.
◦ Interior routing protocol.
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
RIP is fine for small networks.
◦ Easy to implement
◦ 15 hops is not a problem
◦ Broadcasting, interrupting hosts are not too
important
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
OSPF is scalable.
◦ Works with networks of any size
◦ Management complexities are worth the cost in
large networks
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
To connect different autonomous systems
◦ Must standardize cross-system routing
information exchanges
◦ BGP is most popular today
◦ Gateway is the old name for router
◦ Exterior routing protocol
Autonomous
System
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BGP
Autonomous
System
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
Distance vector approach
◦ Number of hops to a distant system is stored in
the router forwarding table

Normally only sends updates
Autonomous
System
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BGP
Autonomous
System
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
Encapsulation
◦ BGP uses TCP for delivery
◦ Reliable
◦ TCP is only for one-to-one connections
◦ If a border router connects to multiple external
routers, must establish a TCP and BGP connection
to each
Autonomous
System
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BGP
Autonomous
System
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Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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
Each host and router on a subnet needs a
data link layer address to specify its address
on the subnet.
◦ This address appears in the data link layer frame
sent on a subnet.
◦ For instance, 48-bit 802.3 MAC layer frame
addresses for LANs.
Subnet DA
DL Frame for Subnet
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
Each host and router also needs an IP
address at the internet layer to designate its
position in the overall Internet.
Subnet
128.171.17.13
Subnet
Subnet
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
IP address
◦ To guide delivery to destination host across the
Internet (across multiple networks)

Subnet Address
◦ To guide delivery between two hosts, two routers,
and a host and router within a single LAN, Frame
Relay network, and so on
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



In a company, each person has a companywide ID number (like IP address).
In a company, each person also has a local
office number in a building.
Paychecks are made out to ID numbers.
For delivery, also need to know office
number.
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
Problem
◦ Router knows that destination host is on its
subnet based on the IP address of an arriving
packet.
◦ Does not know the destination host’s subnet
address, so cannot deliver the packet across the
subnet.
Destination Host
128.171.17.13
Subnet
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Subnet Address?
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
Router creates an ARP Request message to
be sent to all hosts on the subnet.
◦ Address resolution protocol message asks “Who
has IP address 128.171.17.13?”
◦ Passes ARP request to data link layer process for
delivery.
Subnet
ARP Request
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
Data link process of router broadcasts the
ARP Request message to all hosts on the
subnet.
◦ On a LAN, MAC address of 48 ones tells all
stations to pay attention to the frame.
Subnet
ARP Request
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
Host with IP address 128.171.17.13
responds.
◦ Internet process creates an ARP Response
message.
◦ Contains the destination host’s subnet address
(48-bit MAC address on a LAN).
ARP Response
Subnet
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
Router delivers the IP packet to the
destination host.
◦ Places the IP packet in the subnet frame
◦ Puts the destination host’s subnet address in the
destination address field of the frame
Deliver IP Packet
within a Subnet Frame
Subnet
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
ARP Requests and Responses are sent
between the internet layer processes on the
router and the destination host.
Router
Internet
Process
ARP
Request
ARP
Response
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Destination Host
Internet
Process
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
However, the data link processes deliver
these ARP packets.
◦ Router broadcasts the ARP Request.
◦ Destination host sends ARP Response to the
subnet source address found in the broadcast
frame.
Router
Destination Host
Internet
Process
Data Link
Process
Internet
Process
Data Link
Process
Broadcast ARP Request
Direct ARP Response
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Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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


How large is the network part in an IP
address?
Today we use network masks to tell.
Originally, IP had address classes with fixed
numbers of bits in the network part.
◦ Class A: 8 bits (24 bits in local part)
◦ Class B: 16 bits (16 bits in local part)
◦ Class C: 24 bits (8 bits in local part)
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
All Class A IP addresses begin with 0.

7 remaining bits in network part.
◦ Only 128 possible Class A networks.

24 bits in local part.
◦ Over 16 million hosts per Class A network!

All Class A network parts are assigned or
reserved.
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

All Class B IP address begin with 10 (1st zero
in 2nd position).
14 remaining bits in network part
◦ Over 16,000 possible Class B networks

16 bits in local part
◦ Over 65,000 possible hosts


A good trade-off between number of
networks and hosts per network
Most have been assigned
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

All Class C IP address begin with 110 (1st
zero in 3d position).
21 more bits in network part
◦ Over 2 million possible Class C networks!

8 bits in local part
◦ Only 256 possible hosts per Class C network!

Unpopular, because large firms must have
several
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

All Class D IP address begin with 1110.
Used for multicasting, not defining networks.
◦ Sending message to group of hosts
◦ Not just to one (unicasting)
◦ Not ALL hosts (broadcasting)
◦ Say, to send a videoconference stream to a group of
receivers
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
All hosts in a multicast group listen for this
multicast address as well as for their specific
own host IP address.
In Group
Accept
Packets to
Multicast Address
Not in Group
Reject
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In Group
Accept
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
Traditionally, unicasting and broadcasting
◦ Unicasting: send to one host
◦ Broadcasting: send to ALL hosts

Multicasting
◦ Send to SOME hosts
◦ 500 stations viewing a video course
◦ 50 computers getting software upgrades
◦ Standards exist and are improving
◦ Not widely used yet
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
Do not need to send an IP packet to each host
◦ Single packets go out
◦ Only multiplied when necessary
Multiple
Packets
Single
Packet
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Multiplexing
Details of TCP operation
IP mask operations
IP Version 6
IP fragmentation
Dynamic routing protocols
Address Resolution Protocol
IP Address Classes
Mobile IP
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




IP addresses are associated with fixed
physical locations.
Mobile IP is needed for notebooks, other
portable equipment.
Computer still gets a permanent IP address.
When travels, also gets a temporary IP
address at its location.
This is linked dynamically to its permanent
IP address.
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mechanical, photocopying, recording, or otherwise, without the prior written
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Publishing as Prentice Hall
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