Networks - Chapter 5

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111 2004, Cisco Systems, Inc. All rights reserved.

Address Class Prefixes


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Network and Host Division


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Class A Address


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Class B Address


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Class C Address


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Class D Address Architecture


7/77777 2004, Cisco Systems, Inc. All rights reserved.

Class E Address Architecture



IP Address Range



Network Address



Broadcast Address



Network Address



Unicast Transmission



Broadcast Address



Broadcast Transmission



Required Unique Address



Private IP Addresses



IPv4 Address Allocation



IPv4 and IPv6



IPv4 and IPv6 Addresses


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Subdividing the Host Octets of a Class CAddress


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Subdividing the Host Octets of a Class BAddress


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Subdividing the Host Octets of a Class AAddress


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Subnetting Chart (Bit Position and Value)


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Subnetting Chart (Subnet Mask Identifier)


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Subnetting


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Subnetting Chart


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Subnetting Scheme


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Subnetting Chart


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Subdividing the Host Octets of a Class BNetwork


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Subdividing the Host Octets of a Class ANetwork


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Subnetting


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Data Encapsulation


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Routing


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Network Layer Devices in Data Flow


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Router Protocol Stripping


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Connectionless Network Services


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Network Layer Fields


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The Network Layer


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The Network Layer


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Layer 2 Switching and Layer 3 Routing


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ARP Tables and Routing Tables


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Router and Switch Features Comparison


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Routed Protocol


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Routing Protocol


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Path Determination


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The Routing Process


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Routing Algorithms and Metrics


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Autonomous Systems


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Interior and Exterior Gateway Protocols


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Routing Protocols


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Classes of Routing Protocols


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Distance Vector Network Discovery

O i Di V R i P l


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Operation Distance Vector Routing Protocols

Each node (router or host) exchange information with neighboringnodes. Neighbors are both directly connected to same network

Node maintains vector of link costs for each directly attachednetwork and distance and next-hop vectors for each destination

Used by Routing Information Protocol (RIP)

Requires transmission of lots of information by each router

Distance vector to all neighborsContains estimated path cost to all networks in configuration

Changes take long time to propagate


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Example on RIP Routing

C f D V R


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Concept of Distance Vector Routing


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Distance Vector Routing Table

R utin Table Initial States


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Routing Table Initial States

U d ti R ti T bl f R t A


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Updating Routing Table for Router A

F l R bl


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Final Routing Tables

h E l RIP O i


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All nodes of the graph represent Routers. In this example, router A receives the routing

tables of its neighboring routers: A,I,H,K Router A computes its routing table based onthe tables of its neighbors plus the delays it has with each of the four

routers( JA: 8, JI: 10, JH: 12, JK: 6)

Another Example on RIP Operation


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Link-State Concepts


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Link-State Network Discovery

k l h


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Link-State Topology Changes

L k C


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Link-State Concerns

Link State Routing Protocols:


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L gOpen Shortest Path First (OSPF)

Replace Routing Information Protocol (RIP)

Uses link state routing strategy

Each router keeps list of state of local links to network

Transmits update state information to all other routers

Little traffic as messages are small and not sent often

Route computed on least cost based on user cost metric


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Example on OSPF Routing


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Concept of Link State Routing


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Link State Advertisement Packet Format


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Routing Table for Router A


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Dijkistra Algorithm ( (

1. Start with the local node (router): the root

of the tree.

2. Assign a cost of 0 to this node and make it

the first permanent node.

3. Examine each neighbor node of the node that

was the last permanent node.

4. Assign a cumulative cost to each node and make

it tentative.

5. Among the list of tentative nodes

5.1. Find the node with the smallest cumulative

cost and make it permanent.

5.2. If a node can be reached from more than

one direction

5.2.1. Select the direction with the shortest

cumulative cost.

6.Repeat steps 3 to 5 until every node becomes

permanent.


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Summary


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Summary

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Networks - Chapter 5