11 NETWORK LAYER PROTOCOLS Chapter 5 IP IPX NetBEUI AppleTalk

Chapter 5: NETWORK LAYER PROTOCOLS2 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)  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 PROTOCOLS3 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  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 PROTOCOLS4 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.  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 PROTOCOLS5 DATAGRAM ENCAPSULATION

Chapter 5: NETWORK LAYER PROTOCOLS6 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 PROTOCOLS7 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 PROTOCOLS8 FRAGMENTATION AND REASSEMBLY

Chapter 5: NETWORK LAYER PROTOCOLS9 ROUTER FRAGMENTATION

Chapter 5: NETWORK LAYER PROTOCOLS10 IP HEADER AND FIELDS

Chapter 5: NETWORK LAYER PROTOCOLS11 IP OPTIONS HEADER AND FIELDS

Chapter 5: NETWORK LAYER PROTOCOLS12 Protocol Field Values (The most commonly used values) 0IP 1ICMP 3Gateway-to-Gateway Protocol (GGP) 6TCP (most expected) 8Exterior Gateway Protocol (EGP) 17UDP (most expected)

Chapter 5: NETWORK LAYER PROTOCOLS13 EXAMPLE OF AN IP HEADER

Chapter 5: NETWORK LAYER PROTOCOLS14 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  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 PROTOCOLS15 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  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 PROTOCOLS16 EXAMPLE OF 8-BIT CONVERSION

Chapter 5: NETWORK LAYER PROTOCOLS17 EXAMPLE OF 16-BIT CONVERSION

Chapter 5: NETWORK LAYER PROTOCOLS18 THREE IP ADDRESS CLASSES

Chapter 5: NETWORK LAYER PROTOCOLS19 THREE DEFAULT MASKS

Chapter 5: NETWORK LAYER PROTOCOLS20 IP ADDRESS CLASSES AND PARAMETERS

Chapter 5: NETWORK LAYER PROTOCOLS21 EXAMPLE OF A CLASS A ADDRESS

Chapter 5: NETWORK LAYER PROTOCOLS22 EXAMPLE OF A CLASS B ADDRESS

Chapter 5: NETWORK LAYER PROTOCOLS23 EXAMPLE OF A CLASS C ADDRESS

Chapter 5: NETWORK LAYER PROTOCOLS24 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.  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 PROTOCOLS25 CLASS A, CLASS B, AND CLASS C SUBNETTING

Chapter 5: NETWORK LAYER PROTOCOLS26 CLASS C SUBNETTING EXAMPLE

Chapter 5: NETWORK LAYER PROTOCOLS27 CLASS C SUBNETTING EXAMPLE (CONT.)

Chapter 5: NETWORK LAYER PROTOCOLS28 CLASS C SUBNETTING EXAMPLE (CONT.)

Chapter 5: NETWORK LAYER PROTOCOLS29 PRIVATE IP ADDRESSES

Chapter 5: NETWORK LAYER PROTOCOLS30 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  Addresses the depletion of Internet Protocol version 4 (IPv4) addresses  Increases the address space from 32 bits to 128 bits

Chapter 5: NETWORK LAYER PROTOCOLS31 INTERNET PROTOCOL VERSION 6 (IPV6) ADDRESSING (CONT.)  Uses six variable-length sections:  Format Prefix  Registry ID  Provider ID  Subscriber ID  Subnet ID  Interface ID  Uses six variable-length sections:  Format Prefix  Registry ID  Provider ID  Subscriber ID  Subnet ID  Interface ID

Chapter 5: NETWORK LAYER PROTOCOLS32 EXAMPLE OF AN IPV6 ADDRESS

Chapter 5: NETWORK LAYER PROTOCOLS33 THE NOVELL IPX/SPX PROTOCOL SUITE

Chapter 5: NETWORK LAYER PROTOCOLS34 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  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 PROTOCOLS35 IPX HEADER AND FIELDS

Chapter 5: NETWORK LAYER PROTOCOLS36 EXAMPLE OF AN IPX HEADER

Chapter 5: NETWORK LAYER PROTOCOLS37 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.  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 PROTOCOLS38 IPX ADDRESSING

Chapter 5: NETWORK LAYER PROTOCOLS39 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.)  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 PROTOCOLS40 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.  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 PROTOCOLS41 IPX RIP

Chapter 5: NETWORK LAYER PROTOCOLS42 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  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 PROTOCOLS43 DDP HEADER AND FIELDS

Chapter 5: NETWORK LAYER PROTOCOLS44 EXAMPLE OF A DDP HEADER

Chapter 5: NETWORK LAYER PROTOCOLS45 APPLETALK ADDRESSING

Chapter 5: NETWORK LAYER PROTOCOLS46 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  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 PROTOCOLS47 NETBEUI FRAME FORMAT (NBF)

Chapter 5: NETWORK LAYER PROTOCOLS48 EXAMPLE OF A NETBEUI FRAME

Chapter 5: NETWORK LAYER PROTOCOLS49 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.  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.