NETWORK LAYER PROTOCOLS

dargspurNetworking and Communications

Oct 27, 2013 (3 years and 1 month ago)

92 views

1

NETWORK LAYER
PROTOCOLS




Chapter 5

IP

IPX

NetBEUI

AppleTalk

Chapter 5: NETWORK LAYER PROTOCOLS

2

EXAMPLES OF NETWORK LAYER PROTOCOLS


The Transmission Control Protocol/Internet Protocol
(TCP/IP) suite


Internet Protocol (IP)


Novell’s Internetwork Packet Exchange/Sequenced Packet
Exchange (IPX/SPX) suite


Internetwork Packet Exchange (IPX)


Apple Computer’s AppleTalk suite


Datagram Delivery Protocol (DDP)


Microsoft’s suite


NetBIOS Extended User Interface (NetBEUI)

Chapter 5: NETWORK LAYER PROTOCOLS

3

THE INTERNET PROTOCOL


IP, defined in Request for Comments (RFC) 791, is a
connectionless network layer protocol that provides


Datagram encapsulation


Logical addressing


Fragmentation and reassembly of datagrams


Routing

Chapter 5: NETWORK LAYER PROTOCOLS

4

IP FUNCTIONS


Encapsulation


IP forms a datagram by adding an IP header to information
passed down from the transport layer protocol.


Addressing


Each datagram includes logical source and destination
addresses.


Fragmentation and reassembly


The source host or router divides packets into smaller
datagrams that can be transmitted over the network.


The destination host reassembles fragments when it receives
them.


Routing


The selection of the most efficient path.

Chapter 5: NETWORK LAYER PROTOCOLS

5

DATAGRAM ENCAPSULATION

Chapter 5: NETWORK LAYER PROTOCOLS

6

FRAGMENTATION AND REASSEMBLY


Routers connect networks that support different
-
sized
packets.



The largest packet size supported by a network is called its
maximum transmission unit (MTU).



When a packet is too large to be forwarded to a particular
network, the router splits it into fragments.


Chapter 5: NETWORK LAYER PROTOCOLS

7

FRAGMENTATION AND REASSEMBLY


Each fragment is encapsulated with a header and is
transmitted as a separate packet.



Fragments are not reassembled until they reach their final
destination.



Fragments can themselves be fragmented.


Fragmentation

Chapter 5: NETWORK LAYER PROTOCOLS

8

FRAGMENTATION AND REASSEMBLY

Chapter 5: NETWORK LAYER PROTOCOLS

10

IP HEADER AND FIELDS

Chapter 5: NETWORK LAYER PROTOCOLS

12

Protocol Field Values (The most commonly
used values)

0

IP

1

ICMP

3

Gateway
-
to
-
Gateway Protocol (GGP)

6

TCP (most expected)

8

Exterior Gateway Protocol (EGP)

17

UDP (most expected)


Chapter 5: NETWORK LAYER PROTOCOLS

14

IP ADDRESSING


IP addresses are


Logical network layer addresses used to identify
networks, subnetworks, and hosts


4 bytes (or 32 bits) in length and represented in
dotted decimal notation


The values within each byte range from 0 to 255.


Public or private

Chapter 5: NETWORK LAYER PROTOCOLS

15

DECIMAL AND BINARY NUMBERING


The decimal numbering system uses 10 (base 10)
values to represent numbers.


Uses 0

9


The binary numbering system uses 2 (base 2)
values to represent numbers.


Uses 0 and 1

Chapter 5: NETWORK LAYER PROTOCOLS

16

EXAMPLE OF 8
-
BIT CONVERSION

Chapter 5: NETWORK LAYER PROTOCOLS

17

EXAMPLE OF 16
-
BIT CONVERSION

Chapter 5: NETWORK LAYER PROTOCOLS

18

THREE IP ADDRESS CLASSES

Chapter 5: NETWORK LAYER PROTOCOLS

19

THREE DEFAULT MASKS

Chapter 5: NETWORK LAYER PROTOCOLS

20

IP ADDRESS CLASSES AND PARAMETERS

Chapter 5: NETWORK LAYER PROTOCOLS

21

EXAMPLE OF A CLASS A ADDRESS

Chapter 5: NETWORK LAYER PROTOCOLS

22

EXAMPLE OF A CLASS B ADDRESS

Chapter 5: NETWORK LAYER PROTOCOLS

23

EXAMPLE OF A CLASS C ADDRESS

Chapter 5: NETWORK LAYER PROTOCOLS

24

IP SUBNETTING


Each address class can be divided further to create
subnets.


Subnet bits are borrowed from the available host
bits.


Class A: 24 host bits


Class B: 16 host bits


Class C: 8 host bits


Bits used to define subnets cannot be used to
identify hosts.


Borrowed bits are added to the mask.

Chapter 5: NETWORK LAYER PROTOCOLS

25

CLASS A, CLASS B, AND CLASS C SUBNETTING

Chapter 5: NETWORK LAYER PROTOCOLS

28

CLASS C SUBNETTING EXAMPLE (CONT.)

Chapter 5: NETWORK LAYER PROTOCOLS

29

PRIVATE IP ADDRESSES

Chapter 5: NETWORK LAYER PROTOCOLS

30

INTERNET PROTOCOL VERSION 6 (IPV6)
ADDRESSING


Addresses the depletion of Internet Protocol version
4 (IPv4) addresses


Increases the address space from 32 bits to 128
bits

Chapter 5: NETWORK LAYER PROTOCOLS

31

INTERNET PROTOCOL VERSION 6 (IPV6)
ADDRESSING (CONT.)


Uses six variable
-
length sections:


Format Prefix


Registry ID


Provider ID


Subscriber ID


Subnet ID


Interface ID

Chapter 5: NETWORK LAYER PROTOCOLS

32

EXAMPLE OF AN IPV6 ADDRESS

Chapter 5: NETWORK LAYER PROTOCOLS

34

THE IPX PROTOCOL


Novell’s IPX protocol is a connectionless network
layer protocol that provides


Datagram encapsulation


Logical addressing


Fragmentation and reassembly of datagrams


Routing

Chapter 5: NETWORK LAYER PROTOCOLS

37

IPX ADDRESSING


IPX logical network layer addresses consist of three
parts:


Network


The network portion is four bytes long and is assigned
by an administrator or dynamically during installation.


Node



The node portion is the hardware address of the
interface attached to the network
.


Socket


The socket is a two
-
byte value specifying the
application process.

Chapter 5: NETWORK LAYER PROTOCOLS

38

IPX ADDRESSING

Chapter 5: NETWORK LAYER PROTOCOLS

39

IPX ROUTING PROTOCOLS


There are two routing protocols in the Novell
IPX/SPX suite:


IPX Routing Information Protocol (RIP)


IPX RIP uses broadcasts to learn and advertise routes.


The entire route table is broadcast every 60 seconds.


The maximum number of network hops = 15 (16 is
destination unreachable).


IPX RIP uses two metrics for best path selection: hops
and ticks. (A tick is one
-
eighteenth of a second.)

Chapter 5: NETWORK LAYER PROTOCOLS

40

IPX ROUTING PROTOCOLS (CONT.)


NetWare Link Services Protocol (NLSP)


NLSP is a link state routing protocol.


NLSP does not broadcast; it sends route information
only when there is a change in the network.


The maximum number of hops is 127.


The metric for the best path selection is based on link
parameters, not hops.

Chapter 5: NETWORK LAYER PROTOCOLS

42

THE APPLETALK DATAGRAM DELIVERY
PROTOCOL


The DDP protocol is a connectionless network layer
protocol in the AppleTalk suite that provides


Datagram encapsulation


Logical addressing


Fragmentation and reassembly of datagrams


Routing

Chapter 5: NETWORK LAYER PROTOCOLS

46

NETBEUI


The NetBEUI protocol was developed by IBM and
then adopted by Microsoft.


NetBEUI is a nonroutable protocol used for
delivering NetBIOS data.


NetBEUI does not contain network layer addressing.


The NetBEUI frame format includes two
components:


A data
-
link layer Logical Link Control (LLC) (802.2)
Type II header with control fields


A transport layer NetBIOS programming interface

Chapter 5: NETWORK LAYER PROTOCOLS

49

SUMMARY


Network layer protocols like IP, IPX, and DDP
provide data encapsulation, logical addressing,
fragmentation, and reassembly.


There are three classes of IP addresses: Class A,
Class B, and Class C.


Subnet masks are used to further subdivide Class A,
B, and C networks into subnets.


The NetBEUI protocol is the only network layer
protocol that does not provide logical network layer
addressing and is therefore not routable.