Chapter Overview
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IP
IPX
NetBEUI
AppleTalk
1
Network Layer Protocols
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Responsible for end-to-end communications
on an internetwork
Contrast with data-link layer protocols, which
provide communications on the same local
area network (LAN)
2
IP Encapsulation
3
IP Functions
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Encapsulation – The packaging of the transport
Layer data into a datagram
Addressing – The identification of systems in the
network using IP address
Routing – The identification of the most efficient
path to the destination system through the
internetwork
4
IP Functions (Continue)
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Fragmentation – The division of data into fragments
of an appropiate size for transmission over the
network
Protocol identification – The specification of the
transport layer protocol that generated the data in
the datagram.
5
The IP Datagram Format
6
IP Addresses
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Internet Protocol (IP) is the only network layer protocol
with its own addressing system.
IP addresses are 32 bits long.
IP addresses have two parts: a network identifier and a
host identifier.
IP addresses are assigned to network interface
adapters, not to computers.
7
IP Addresses (Continue)
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The Source IP Address field in the IP header always
identifies the computer that generated the packet.
The Destination IP Address field in the IP header always
identifies the packet’s final destination.
8
End Systems and Intermediate
Systems (IP Routing)
ROUTERS
Source and Final Destination Systems
9
Fragmentation
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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.
10
Fragmentation
Fragmentation
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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.
11
Fragmentation (Cont.)
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)
13
The IPX Standard
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Developed by Novell for use with NetWare
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Proprietary; never published as a public standard
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Reverse engineered by Microsoft to create NWLink
14
IPX Functions
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Routing – Routes traffic between different
types of Networks
Addressing
Protocol identification – Identifies the protocol
that generated the data that it is carrying
15
The IPX Header Format
16
IPX Addressing
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IPX does not have its own addressing system
Internet Packet Exchange (IPX) uses
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Separate node and network addresses
Network interface adapter hardware addresses for node
addresses
Network addresses
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Are assigned by administrators
Do not need to be registered
17
NetBEUI Characteristics
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Original Microsoft Windows default networking
protocol
Designed for small local area networks (LANs)
Does not support Internet communications
Does not need configuration
Can be used to troubleshoot Transmission Control
Protocol/Internet Protocol (TCP/IP) configuration
protocols
18
NetBIOS Names
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Assigned to computers during Windows
installation
Sixteen characters long; the sixteenth
character is a resource identifier
Can identify computers, domain controllers,
users, groups, and other resources
Have no network identifier (which is why
NetBEUI is nonroutable)
19
Comparison
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NetBEUI uses NetBIOS to identify computers
on the Network
IP uses IP addresses to identify computers on
the Network
IPX uses Hardware addresses to identify
computers on the Network
20
The NBF (NetBEUI Frame) Protocol
Format
21
Protocols Using NBF
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Name Management Protocol (NMP)
Session Management Protocol (SMP)
User Datagram Protocol (UDP)
Diagnostic and Monitoring Protocol (DMP)
22
AppleTalk Data-Link Layer Options
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LocalTalk
EtherTalk
Fast EtherTalk
TokenTalk
FDDITalk
23
Datagram Delivery Protocol
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AppleTalk’s network layer protocol
Provides packet addressing, routing, and
protocol identification
Has short-format and long-format packet
headers
24
AppleTalk Addressing
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AppleTalk computers have a unique 8-bit
node ID that is self-assigned.
AppleTalk networks can have no more than
254 nodes.
AppleTalk uses 16-bit network numbers for
routing.
Computers obtain network numbers using the
Zone Information Protocol (ZIP).
Computer processes are identified by 8-bit
socket numbers.
25
AppleTalk Addressing (Cont.)
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Network numbers, node IDs, and socket
numbers are expressed as three decimal
numbers, separated by periods.
AppleTalk computers resolve node IDs into
hardware addresses, using the AppleTalk
Address Resolution Protocol (AARP).
AppleTalk computers also have friendly names
and groups of computers called zones.
26
Chapter Summary
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Network layer protocols are responsible for endto-end communications across the network.
IP is a connectionless protocol that encapsulates
transport layer data into datagrams.
IPX is a proprietary standard that performs
routing, addressing, and protocol identification.
NetBIOS Extended User Interface (NetBEUI) is
used by small Windows networks for LAN
networking.
AppleTalk provides basic networking to small
networks.
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