November 29, 2004 Prof. Paul Lin 1 CPET 355 16. Internetworking, Addressing, and Routing Paul I-Hai...

November 29, 2004November 29, 2004 Prof. Paul LinProf. Paul Lin 11

CPET 355 CPET 355

16. 16.

Internetworking, Addressing, and Internetworking, Addressing, and RoutingRouting

Paul I-Hai Lin, Professor Paul I-Hai Lin, Professor Electrical and Computer Engineering TechnologyElectrical and Computer Engineering Technology

Purdue University, Fort Wayne CampusPurdue University, Fort Wayne Campus


Network Layer - an OverviewNetwork Layer - an Overview

Getting data packets from the source Getting data packets from the source all the way to the destinationall the way to the destination

Dealing with end-to-end transmissionDealing with end-to-end transmission Need to knowNeed to know

• Topology of the communication subnet Topology of the communication subnet (routers)(routers)

• Chose paths (routing algorithms)Chose paths (routing algorithms)


Position of Network LayerPosition of Network Layer

Courtesy - From Fig. 1, Page 467, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill


Network Layer DutiesNetwork Layer Duties

Courtesy - From Fig. 2, 68, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill


Network LayerNetwork LayerTopics of DiscussionTopics of Discussion

Network Layer Design IssueNetwork Layer Design Issue• Services to the TCP LayerServices to the TCP Layer

Connectionless Services (Datagram)Connectionless Services (Datagram) Connection-Oriented Services (Virtual Connection-Oriented Services (Virtual

Circuit)Circuit)

• SubnetsSubnets Internetworking Internetworking AddressingAddressing RoutingRouting


InternetworksInternetworks

Courtesy - From Fig. 19.1, Page 471, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

Host A -> Host D• 4 LANS, 1 WAN• S1, S2, S3: Switch or Router• f1, f2: Interface• Three links: S1 -> S2 -> s3


Links in an InternetworkLinks in an Internetwork

Courtesy - From Fig. 19.2, Page 472, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill


Network Layer in an InternetworkNetwork Layer in an Internetwork

Courtesy - From Fig. 19.3 Page 473, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill


Network Layer at the SourceNetwork Layer at the Source


• Creating Source and Destination Address, Fragmentation


Network Layer at Router or SwitchNetwork Layer at Router or Switch


• Routing Table, Fragmentation


Network Layer at DestinationNetwork Layer at Destination

Courtesy - From Fig. 196 Page 475, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

• Corrupted packet, Fragments


Quality of ServiceQuality of ServiceRequirementsRequirements

From Fig. 5-30, Page 397, Computer Networks, 4th edition, Andrew S. Tanenbaum, Prentice Hall


Packet-Switched Network - InternetPacket-Switched Network - Internet


• Packets – Variable Length Data Blocks; Node to Node Delivery

• Virtual Circuit – WAN, Frame Relaying, ATM applications, call setup a single route


Packet-Switched Network - InternetPacket-Switched Network - Internet


• Datagram Approach – no fixed path, routing, out of order

• Packets == Datagrams


AddressingAddressing Internet Address – IP Address

• Classful addressing – original architecture Class A, B, C, D, and E

• Classless addressing – mid 1990s IPv4

• 32-bit binary number• Dotted-Decimal Notation 128.11.3.31 255.255.255.0

IPv6 - 128-bit


Addressing – IPV4Addressing – IPV4


• Network ID, Host ID

• Class A – 128 blocks (First Byte), 16,777,216 hosts

• Class B – 16,384 blocks (First & Second Byte), 65536 hosts

• Class C – 2,097,152 blocks (First, Second, Third byte), 256 hosts

• Class D – 1 block, Multicasting


Finding the ClassFinding the Class



Netid and HostidNetid and Hostid



Classes and Blocks - Netid 73Classes and Blocks - Netid 73


128 Blocks; 16,777,216 Hosts


Blocks in Class B NetworkBlocks in Class B Network


16384 Blocks; 65536 Hosts


Blocks in Class C NetworkBlocks in Class C Network


2,097,152 Blocks; 255 Hosts


Network AddressNetwork Address


• An address defines a network with all host-id = 0


Sample InternetSample Internet



SubnettingSubnetting


• Class B – 1 block, 65536 hosts (16-bit)

• Subnets

• 2 sub-blocks (1-bit), 36768 hosts (15-bit)

• 4 sub-blocks (2-bit), 18384 hosts (14-bit)

• …

• 128 sub-blocks (7-bit), 512 host (9-bit)


Subnetting – 3 Level HierarchySubnetting – 3 Level Hierarchy


• Three levels: Site, Subnet, Host


A Network With and Without SubnettingA Network With and Without Subnetting



MasksMasks

Courtesy - From Table 19.1 Page 489, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

ClassClass In BinaryIn BinaryIn Dotted-In Dotted-DecimalDecimal

Using SlashUsing Slash

AA 11111111 00000000 00000000 0000000011111111 00000000 00000000 00000000 255.0.0.0255.0.0.0 /8/8

BB 11111111 11111111 00000000 0000000011111111 11111111 00000000 00000000 255.255.0.0255.255.0.0 /16/16

CC 11111111 111111111 11111111 0000000011111111 111111111 11111111 00000000 255.255.255.0255.255.255.0 /24/24


SupernettingSupernetting An organization can combine several

class C block to form a larger range of addresses


Classless AddressingClassless Addressing Variable-Length Block (2, 4, 128, etc) Mask Finding the Network Address Subnetting CIDR (Classes InterDomain Routing)


Dynamic Address ConfigurationDynamic Address Configuration DHCP (Dynamic Host Configuration

Protocol)• Database 1 (static) - Physical addresses to

IP addresses• Database 2 (dynamic) – Available IP, Lease

Time


Network Address TranslationNetwork Address Translation

Courtesy – Table 19.2 Page 494, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

RangeRange TotalTotal

10.0.0.0 10.0.0.0 to to 10.255.255.255 10.255.255.255 222424

172.16.0.0 172.16.0.0 toto 172.31.255.255 172.31.255.255 222020

192.168.0.0 192.168.0.0 toto 192.168.255.255 192.168.255.255 221616

• Internally, a large set of addresses

• Externally, one address, or a small set of addresses


A NAT ExampleA NAT Example

Courtesy – Fig 19.25 Page 495, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

• Private address: 172.18.0.0 to 172.18.255.255

• NAT Router address: 200.24.5.8


Address TranslationAddress Translation

Courtesy – Fig. 19.25 Page 495, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

• Private address: 172.18.0.0 to 172.18.255.255

• NAT Router address: 200.24.5.8


Address Translation (cont.)Address Translation (cont.)



Translation TableTranslation Table

Courtesy – Table 19.3 Page 497, Data Communications and Networks, 3rd edition, Forouzan, McGrawHill

Private Private AddressAddress

Private Private PortPort

ExternalExternalAddressAddress

External External PortPort

TransportTransportProtocolProtocol

172.18.3.1172.18.3.1 14001400 25.8.3.225.8.3.2 8080 TCPTCP

172.18.3.2172.18.3.2 14011401 25.8.3.225.8.3.2 8080 TCPTCP

...... ...... ...... ...... ......


Routing TechniquesRouting Techniques Routing Tables Next-Hop Routing Network-Specific Routing Host-Specific Routing Default Routing


Translation TableTranslation Table



Next-Hop RoutingNext-Hop Routing



Network-Specific RoutingNetwork-Specific Routing



Host-Specific RoutingHost-Specific Routing



Default RoutingDefault Routing



More on Routing More on Routing Static vs Dynamic

• Static Routing Table• Dynamic Routing Table and Protocols

RIP – Routing Information Protocol OSPF – Open Shortest Path First BGF – Border Gateway Protocol

Routing Tables• For Classful Addressing• For Classless Addressing (CIDR)

November 29, 2004 Prof. Paul Lin 1 CPET 355 16. Internetworking, Addressing, and Routing Paul I-Hai...

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