Identify and explain the functions of the core TCP/IP protocols Explain how the TCP/IP protocol correlate to the OSI model Discuss addressing schemes for.
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Transcript Identify and explain the functions of the core TCP/IP protocols Explain how the TCP/IP protocol correlate to the OSI model Discuss addressing schemes for.
Identify and explain the functions of the core
TCP/IP protocols
Explain how the TCP/IP protocol correlate to
the OSI model
Discuss addressing schemes for TCP/IP in IPv4
and IPv6
Describe the purpose and implementation of
DNS (Domain Name System) and DHCP
(Dynamic Host Configuration Protocol)
Identify the well-known ports for key TCP/IP
services
Describe common application layer TCP/IP
protocols
Transmission Control Protocol/Internet
Protocol
◦ Actually a whole suite of Protocols
◦ Developed in the late 1960s by the
Department of Defense
◦ Popularity due to
Low costs
Communicate between dissimilar platforms
Open Source
Uses routable protocols
Very flexible – can run on any network
Has several “core” protocols
Source Port
Destination Port
Sequence Number
Acknowledgement Number
TCP Header Length
Reserved
Flags
URG
ACK
PSH
RST
SYN
FIN
Sliding Window Size
Checksum
Urgent Pointer
Options
Data
◦ Three-way Handshake
SYN –
synchronization
request for a
connection
SYN-ACK –
synchronization1
acknowledgement
confirmation that the
distant end node is
willing to make the
connection
ACK –
acknowledgement
3
acknowledges the
SYN-ACK
◦ Connection Established
SYN with SEQ# 558
SYN-ACK with SEQ# 669/ACK with SEQ# 559
ACK with SEQ# 559/ACK with SEQ# 670
Connection Established!
2
Has only 4 field in its header
Source port
Destination port
Length
Checksum
Layer 4 protocol
More efficient that TCP
Used for live audio or video
transmissions
No acknowledgements
UDP Header
Network Layer protocol
Contains information on how and where
data should be delivered including the
source and destination IP addresses
Subprotocol that allows TCP/IP to traverse
more than one LAN segment and more than
one type of network through a router
Version
Internet Header Length
Differentiated Services
Total Length
Identification
Flags
Fragment Offset
Time To Live
Protocol
Header Checksum
Source IP
Destination IP
Options
Padding
Data
Layer 3 protocol
Reports success or failure of data delivery
Only provides error detection not correction
Aids in troubleshooting
Ping Command
Layer 3 Protocol
Manages multicasting
Multicasting allows one node to send traffic
destined for multiple nodes
Routers use this protocol to determine
which multicasting group other nodes
belong to
Layer 3 Protocol
Maps the unknown MAC address to the known
IP address of a given node
The requesting node send a broadcast message that
states; “I have this IP address, if this is your IP
address please send me your MAC address.”
The node with that IP address replies with its MAC
address in a broadcast message
The requesting node then places this information in
its ARP table/cache
Two types of ARP table/cache entries
Dynamic – created when the makes an ARP request that
cannot be satisfied by searching the ARP table
Static – entries that someone has entered manually into
the ARP table
Layer 3 protocol
Used in earlier networks when workstations did
not have the memory or processing power of
today’s machines
Maps an unknown IP address to a known MAC
address
The RARP request is sent to a RARP server that
maintains a table of MAC-to-IP address maps
The server queries the RARP table to find the IP
address of the associated MAC address
The server then returns the IP address to the
requesting node
IP address is a 32 bit number divided into 4
bytes each and separated by periods
192.168.1.10
Each byte equals 8 bits therefore each byte is
referred to as an octet
Although 8 bits have 256 possible combinations
only 254 numbers can be used
The number 0 is a reserved placeholder and represents
the entire network address
The number 255 is reserved for broadcast
transmissions
◦ There are 5 different classes
◦ The first three classes are used for LANs
◦ The other 2 classes are reserved for multicasting
and experimental use
10.0.0.0 – 10.255.255.255 – Private networks
127.0.0.0 – 127.255.255.255 – Loopback
addresses
169.254.0.0 – 169.254.255.255 – Automatic
Private IP Addressing
172.16.0.0 -172.31.255.255 – Private networks
192.168.0.0 -192.168.255 – Private networks
From a Windows OS
Open a command prompt – Start button > All
Programs > Accessories > Command Prompt
Type the command ipconfig /all and press enter
◦ From a UNIX or Linux OS
Open a terminal window (shell)
◦ Type ifconfig –a at the shell prompt
◦ The most common way to express an IP address
◦ A decimal number from 0-255 (256 possibilities)
represents each binary octet
◦ Example:
131.65.10.36
Each dotted decimal notation number has a
binary equivalent
◦ When we take our example IP address –
136.65.10.36
◦ The first octet 136 is converted as follows
The other octets are converted in the same way
The IP address expressed in binary is:
10000011 01000001 00001010 00100100
32 bit number that identifies the network segment or
subnet and informs the rest of the network about the
segment/subnet (subnet is the common name for
network segment)
Used in conjunction with the IP address and is assigned
manually or automatically through DHCP (covered in a
later slide)
Can be expressed with either binary or dotted decimal
notation
Example
255.255.255.0
All of the bits in the first three octets are turned on or have a
value of 1 and represents the network portion of the subnet
The last octet has no bits turned on or a value of 0 and
represents the host portion of the subnet
Every node on the LAN or network must
have a unique IP address assigned
Can be done manually or automatically
Manual configuration (Static IP address)
Automatic configuration (DHCP)
Older protocol developed in the mid 1980s
Application Layer protocol
Used a central list of IPs and the associated MAC
address of each device and assigned IPs automatically –
dynamically assigns the IP address also called dynamic
IP
When a BOOTP client connects
The client sends a broadcast message that contains its MAC
address to the BOOTP server requesting an IP address
The BOOTP server looks up the client’s MAC address in ts
BOOTP table
The BOOTP server responds with
Client’s IP address
Server IP address
Server’s host name
Default router IP address
Application Layer protocol
Developed by the IETF to replace BOOTP
Dynamically assigns IP addresses
Does not use an IP address table like BOOTP
Does require a DHCP server to be configured
Reasons to use DHCP
Reduce management time on assigning and
planning IP addresses
Reduce potential errors
Enables flexibility in client’s location
Makes IP addressing transparent to users
Client request an IP address in a UDP DHCP discover packet broadcast message
All DHCP servers on the network get the broadcast
All DHCP servers respond with an available IP address and
reserves this IP information so that other clients can’t get it
The response message contains
The IP address
Subnet mask
IP address of the DHCP server
Lease duration
The client accepts the first IP address it receives
And responds with another broadcast message confirming
the IP address
All other DHCP servers receive the message and release their
IP addressed reserved for the client back to their DHCP pool
Windows OS feature that assigns an IP address
in the range of 169.254.0.0 – 169.254.255.255
and a subnet mask of 255.255.0.0
Allows communication only with nodes on the
same LAN and hare automatically assigned an
address in the APIPA address range
Used when DHCP services are temporarily
unavailable
When DHCP services are restored the APIPA
address is released
Advantages over IPv4
More efficient header than IPv4
Better security
Better prioritization provisions
128 bits long increase amount of addresses to 296 (4
billion x 4 billion x 4 billion)
Expressed in 8 hexadecimal 16 bit fields separated
by a (:)
Example – F:F:0:0:0:0:3012:0CE3
Can be written in shorthand – all multiple fields
that have a value of 0 can be abbreviated with a
(::)
IPv6 Loopback is 0:0:0:0:0:0:0:1
Shortened IPv6 Loopback is ::1
Unicast – an address that represents a
single interface – Prefix: FEC0 or FE80
Multicast – represents multiple interfaces
normally on multiple devices…point-tomultipoint – Prefix: FF0x where x is a
number that corresponds to a group scope
ID – global multicast prefix : FF0E
Anycast – represents any one interface from
a group of interfaces and any interface in
that group can act on the message
Sockets represent a single connection
between two network applications. A socket
is the process port number and the host
machines IP address
An example is The Telnet port number, 23,
and the host machines IP address
131.10.25.5 with the port number following
the IP address and a colon (:)
The above example is written as follows :
131.10.25.5:23
Simplifies TCP/IP and
ensures that data
transmitted is
transmitted to the
correct application
Port numbers range 0 to
65535
Well known ports range
from 0 to 1023
Registered ports range
1024 to 49151
Dynamic or Private
ports range 49152 to
65535
Click Here for Well
Known Port List
A hostname is a specific name pointing to a
specific device
A domain name is identifies a domain. A domain
name is usually associated with some type of
organization
Is represented by character strings called label
Each label represents a level in the domain naming
hierarchy and is separated with dots
An example is www.ctcd.edu
“.edu” is the top-level domain
“.ctcd” is the second-level domain
“www” is the third-level domain
Fully Qualified Domain Name (FQDN) the hostname
followed by the domain name separated with a dot
“.”
Predecessor to DNS
An ASCII text file called HOSTS.TXT
Mapped host names to IP addresses
Used in early networks when they were
small
Not practical in large networks or the
Internet
Hierarchal system developed in the mid 1980s that gave
a more automated approach to domain names than the
HOSTS.TXT file
Also known as Domain Name Service
Relies on global DNS servers
All servers are hierarchically related to 13 root servers
Because it is distributed, it cannot fail catastrophically
Divided into 3 components
Resolvers – any host on the Internet that needs to look up
domain name information
Name servers – also called DNS servers contain databases of
associated names and IP addresses and provide this
information to the resolvers
Namespace – refers to the database of Internet IP
addresses and their associated names
DDNS
If IP addresses change frequently DNS becomes
unmanageable
DDNS is a for-fee service that a service provider
runs on the user’s computer that informs the service
provider of an IP change
The service provider’s server launches a routine that
updates the DNS servers
Zeroconf
A collection of protocols that simplify the setup of nodes
on a TCP/IP network
IPv4 Local Link (IPv4LL) is a protocol that automatically
assigns IP addresses on locally connected nodes
Telnet – terminal emulation protocol used to logon
to remote hosts using TCP/IP suite
File Transfer Protocol (FTP) – used to send and
receive files via TCP/IP
Trivial File Transfer Protocol (TFTP) – Simplified
transfer of files using UDP
Network Time Protocol (NTP) – Synchronizes clocks
on computers on a network
Network News Transfer Protocol (NNTP) –
Facilitates the exchange of news group messages
Packet Internet Groper (Ping) – a utility that verifies
that TCP/IP is working, and configured correctly
For more information on this
lesson, See Chapter 4 in the
text book or email the
Professor
**All Slides and graphics were produced by Professor Patrick Hughes**