1. Chapter Overview IP
IPX
NetBEUI
AppleTalk

2. Network Layer Protocols
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)

3. IP Encapsulation

4. IP Functions Encapsulation Addressing Routing Fragmentation
Protocol identification

5. The IP Datagram Format

6. IP Addresses
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.
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.

7. End Systems and Intermediate Systems

8. Fragmentation
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.
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.

9. Fragmentation (Cont.)

10. Protocol Field Values IP 1 ICMP 3 Gateway-to-Gateway Protocol (GGP) 6IP 1
ICMP 3
Gateway-to-Gateway Protocol (GGP) 6
TCP 8
Exterior Gateway Protocol (EGP) 17
UDP

11. The IPX Standard Developed by Novell for use with NetWare
Proprietary; never published as a public standard
Reverse engineered by Microsoft to create NWLink

12. IPX Functions
Routing
Addressing
Protocol identification

13. The IPX Header Format

14. IPX Addressing Internet Packet Exchange (IPX) uses Network addresses
Separate node and network addresses
Network interface adapter hardware addresses for node addresses
Network addresses
Are assigned by administrators
Do not need to be registered

15. NetBEUI Characteristics
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

16. NetBIOS Names 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)

17. The NBF Protocol Format

18. Protocols Using NBF Name Management Protocol (NMP)
Session Management Protocol (SMP)
User Datagram Protocol (UDP)
Diagnostic and Monitoring Protocol (DMP)

19. AppleTalk Data-Link Layer Options
LocalTalk
EtherTalk
Fast EtherTalk
TokenTalk
FDDITalk

20. Datagram Delivery Protocol
AppleTalk’s network layer protocol
Provides packet addressing, routing, and protocol identification
Has short-format and long-format packet headers

21. AppleTalk Addressing
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.

22. AppleTalk Addressing (Cont.)
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.

23. Chapter Summary
Network layer protocols are responsible for end-to-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.