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The Network Layer Chapter 5

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Page 1: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Network Layer

Chapter 5

Page 2: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Highlights

Network Layer Design Issues

Routing Algorithms

Congestion Control Algorithms

Quality of Service

Internetworking

The Network Layer in the Internet(ip)

Page 3: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Network Layer Design Isues

• Store-and-Forward Packet Switching• Services Provided to the Transport Layer• Implementation of Connectionless Service• Implementation of Connection-Oriented Service• Comparison of Virtual-Circuit and Datagram Subnets

Page 4: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Store-and-Forward Packet Switching

The environment of the network layer protocols.

fig 5-1

Page 5: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Services Provided to the Transport Layer

Design Goal:The services should be independent of the router technology.

The transport layer should be shielded from the number, type, and topology of the routers present.

The network addresses made available to the transport layer should use a uniform numbering plan, even across LANs and WANs.

Two classes service:

Connection-Oriented Service (Telephone companies)

Connectionless Service (Internet community)

Page 6: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Implementation of Connectionless Service

Routing within a diagram subnet.

Page 7: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Datagram(2)

B.3 B.2 B.1

C.3 C.2 C.1

C.3 C.1 C.2

B.1B.3

B.2

A

B

C

A 1

2

3

4

5

B

C

B.3 B.2

B.1

C.3 C.2

C.1

Page 8: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Implementation of Connection-Oriented Service

Routing within a virtual-circuit subnet.

Page 9: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Virtual Circuit(2)

1.3 1.2 1.1

2.3 2.2 2.1

2.3 2.2 2.1

1.31.2

1.1

A

B

C

A 1

2

3

4

5

B

C

vc1

vc2

vc1: A--1--2--4--B

vc2: A--1--3--5--C

Page 10: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Comparison of Virtual-Circuit and Datagram Subnets

5-4

Page 11: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Routing Algorithms

• The Optimality Principle• Shortest Path Routing• Flooding• Distance Vector Routing• Link State Routing• Hierarchical Routing

Page 12: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Routing Algorithms(2)

• If the subnet uses datagrams internally, routing decisions are made for every arriving data packet .

• Session Routing If the subnet uses virtual circuits internally, routing decisions are made only when a new virtual circuit is being set up. Thereafter, data packets just follow the previously-established route.

Page 13: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Routing Algorithms(3)

properties are desirable in a routing algorithm:

correctness

simplicity

robustness

stability

fairness

optimality

Page 14: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Routing Algorithms (4)

Conflict between fairness and optimality.

Page 15: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Routing Algorithms(5) Routing algorithms can be grouped into two major classes:

nonadaptive and adaptive.

Nonadaptive algorithms do not base their routing decisions on measurements or estimates of the current traffic and topology. Instead, the choice of the route to use to get from I to J (for all I and J) is computed in advance, off-line, and downloaded to the routers when the network is booted. This procedure is sometimes called static routing.

Adaptive algorithms, in contrast, change their routing decisions to reflect changes in the topology, and usually the traffic as well.

Page 16: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Optimality Principle It states that if router J is on the optimal path from router I to router

K, then the optimal path from J to K also falls along the same route. To see this, call the part of the route from I to Jr1 and the rest of the route r2. If a route better than r2 existed from J to K, it could be concatenated with r1 to improve the route from I to K, contradicting our statement that r1r2 is optimal.

As a direct consequence of the optimality principle, we can see that the set of optimal routes from all sources to a given destination form a tree rooted at the destination. Such a tree is called a sink tree

I

K

Jr1

r2

rx r1+r2 r1+rx

Page 17: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Optimality Principle(2)

(a) A subnet. (b) A sink tree for router B.

The goal of all routing algorithms is to discover and use the sink trees for all routers

Page 18: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Shortest Path Routing

The first 5 steps used in computing the shortest path from A to D. The arrows indicate the working node.

Page 19: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Exampleof SP

Initially

N D(B) D(C) D(D) D(E) D(F) D(G) D(H)

{ A } 2 6 { A, B } 9 4 6

9 6 5

9 6 9

9 8

9 10

{ A, B, E }

{ A, B, E, G }

{ A, B, E, G, F }

{ A, B, E, G, F, H }

{ A, B, E, G, F, H, C } 10

{ A, B, E, G, F, H, C, D }

Page 20: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Example of SP(2)

Shortest Path

Dest Next-hop

B B

C B

D B

B

BBB

E

FGH

Route Table of Node A

A

B C

E F

G H

D

Page 21: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

FloodingNo network info required

Packet sent by node to every neighbor

Incoming packets retransmitted on every link except incoming link

Eventually a number of copies will arrive at destination

Each packet is uniquely numbered so duplicates can be discarded

Nodes can remember packets already forwarded to keep network load in bounds

Can include a hop count in packets

Page 22: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Flooding Example

Page 23: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Properties of FloodingAll possible routes are tried

– Very robustAt least one packet will have taken minimum hop count route

– Can be used to set up virtual circuitAll nodes are visited

– Useful to distribute information (e.g. routing)

Page 24: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distance Vector Routing

Distance Vector: Each router sends a vector of

distances to its neighbors. The vector contains

distances to all nodes in the network.

Page 25: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distance Vector Routing(2)

Each node maintains a set of triples

(Destination, Cost, NextHop)Exchange updates directly connected neighbors

periodically (on the order of several seconds<30s>)

whenever table changes (called triggered update)

Each update is a list of pairs:

(Destination, Cost)Update local table if receive a “better” route

Refresh existing routes; delete if they time out

Page 26: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distance Vector Routing(3)

(a) A subnet. (b) Input from A, I, H, K, and the new routing table for J.

Page 27: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distance Vector Routing (4)

The count-to-infinity problem.

Set infinity to 16

rapidly to good news, but leisurely to bad news.

Page 28: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distance Vector Routing(5)

A

B

C

D

2 B

1 B

0 --

1 D

Dest Dist Nexthop

Route of C

A

B

C

D

1

0

1

Dest Dist

Vector to B

A

B

C

D

1

0

1

Dest Dist

Vector to D

Split Horizon :

A B C D

2

Page 29: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distance Vector Routing(6)

Split Horizon :

A B C D E

1 2 3 4 initially

2 3 4 1 exchange

3 4 2 exchange

4 3 exchange

4 exchange

Page 30: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distance Vector Routing(7)Split Horizon

Page 31: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distance Vector Routing(8)

The problem is that when X tells Y that it has a path somewhere, Y has no way of knowing whether it itself is on the path

Page 32: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Link State Routing

Each router must do the following:

1. Discover its neighbors, learn their network address.

2. Measure the delay or cost to each of its neighbors.

3. Construct a packet telling all it has just learned.

4. Send this packet to all other routers.

5. Compute the shortest path to every other router.

Page 33: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Learning about the Neighbors It accomplishes this goal by sending a special HELLO packet on each point-to-point line. The router on the other end is expected to send back a reply telling who it is. These names must be globally unique

When two or more routers are connected by a LAN, the situation is slightly more complicated

Page 34: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Learning about the Neighbors(2)

(a) Nine routers and a LAN. (b) A graph model of (a).

Page 35: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Measuring Line Cost

The most direct way to determine this delay is to send

over the line a special ECHO packet that the other side

is required to send back immediately. By measuring the

round-trip time and dividing it by two, the sending router

can get a reasonable estimate of the delay

One issue is whether to take the load into account when

measuring the delay

Page 36: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Measuring Line Cost(2)

A subnet in which the East and West parts are connected by two lines.

Page 37: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Building Link State Packets

(a) A subnet. (b) The link state packets for this subnet.

Page 38: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distributing the Link State Packets• Use flooding to distribute LSP• Each LSP labeled with a 32-bits sequence• Each LSP protected by a checksum • Each LSP stamped by a age

Page 39: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distributing the LSPs Some refinements to this algorithm make it more robust. When a link state packet comes in

to a router for flooding, it is not queued for transmission immediately. Instead it is first put in a holding area to wait a short while

Page 40: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Distributing the Link State Packets(2)

The packet buffer for router B (Fig. 5-14).

Page 41: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Computing the New Route Use Dijkstra's algorithm

Page 42: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Examples of Link State Routing

OSPF(Open Shortest Path First)

IS-IS (Intermediate System-Intermediate System),

Page 43: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Hierarchical Routing

Hierarchical routing.

Page 44: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Congestion Control Algorithms

• General Principles of Congestion Control

• Congestion Prevention Policies

• Congestion Control in Virtual-Circuit Subnets

• Congestion Control in Datagram Subnets

• Load Shedding

• Jitter Control

Page 45: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Congestion

When too much traffic is offered, congestion sets in and performance degrades sharply.

Page 46: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Congestion Reason• Burst data

• packets come from different lines are routed to the same output line, have to be queued before sending

• If memory is insufficient, some packets will be lost

• Adding too much memory may gets worse

• Slow processors• Low bandwidth• Congestion tends to be spreaded

Page 47: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Comparison of congestion control and flow control

• Congestion control is a global issue, it concerns the carrying capacity of subnet

• Sometimes use feedback

• Flow control relates to the point-to-point traffic, it make sure that a fast sender cannot continually transmit data faster than the receiver is able to absorb it.

• Always use feedback

• A host can get a “slow down” indication either because of receiver or subnet

Page 48: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

General Principles of Congestion Control

open loop

attempt to solve the problem by good design, in essence, to make sure it does not occur in the first place. Once the system is up and running, midcourse corrections are not made

closed loop

based on the concept of a feedback loop

explicit feedback, implicit feedback

Page 49: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

General Principles of Congestion Control(closed loop)

1. Monitor the system .

– detect when and where congestion occurs.

2. Pass information to where action can be taken.

3. Adjust system operation to correct the problem.

Page 50: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Congestion Prevention Policies (open loop)

Policies that affect congestion.

5-26

Page 51: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Congestion Control in Virtual-Circuit Subnets

(a) A congested subnet. (b) A redrawn subnet, eliminates congestion and a virtual circuit from A to B.

Page 52: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Congestion Control in Datagrams Subnets

• Warning bit• Router in congestion set the warning bit in the packet’s header

• Choke packets• When the source host receive choke, it should reduce the traffic

sharply.

• If no choke packets arrive for a period, the host may increase the flow slowly.

Page 53: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Hop-by-Hop Choke Packets

(a) A choke packet that affects only the source.

(b) A choke packet that affects each hop it passes through.

Page 54: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Loading Shedding

When routers are being inundated by packets that they cannot handle,

they just throw them away.

(old is better than new) is often called wine and (new is better than old) is often called milk.

Page 55: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Jitter Control

The variation in the packet arrival times is called

jitter;

High jitter, for example, having some packets taking

20 msec and others taking 30 msec to arrive will give

an uneven quality to the sound or movie.

Page 56: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Jitter Control(2)

(a) High jitter. (b) Low jitter.

Page 57: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Quality of Service

• Requirements• Techniques for Achieving Good Quality of Service• Integrated Services• Differentiated Services• Label Switching and MPLS

Page 58: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Requirements

How stringent the quality-of-service requirements are.

5-30

Page 59: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Buffering

Smoothing the output stream by buffering packets.

Page 60: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Leaky Bucket Algorithm

(a) Input to a leaky bucket. (b)Output from a leaky bucket.

Page 61: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Leaky Bucket Algorithm

(a) A leaky bucket with water. (b) a leaky bucket with packets.

Page 62: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Traffic Shaping- The Token Bucket Algorithm

(a) A leaky bucket with water. (b) a leaky bucket with packets.

Page 63: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Token Bucket Algorithm

Output from a token bucket with capacities of (c) 250 KB, (d) 500 KB, and (e) 750 KB.

Page 64: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Calculating the length of the maximum rate burst

If we call the burst length S sec, the token bucket capacity C bytes, the token arrival rate bytes/sec, and the maximum output rate M bytes/sec, we see that an output burst contains a maximum of C + S bytes. We also know that the number of bytes in a maximum-speed burst of length S seconds is MS. Hence we have:

C + S = MS

S = C/(M - ). For our parameters of C = 250 KB, M = 25 MB/sec, and =2 MB/sec, we get a burst time of about 11 msec

Page 65: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Leaky Bucket +Token Bucket

Page 66: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Internetworking

• How Networks Differ

• Concatenated Virtual Circuits

• Connectionless Internetworking

• Tunneling

• Internetwork Routing

• Fragmentation

• Firewalls

Page 67: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Connecting Networks

A collection of interconnected networks.

Page 68: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

How Networks Differ

Some of the many ways networks can differ.

Page 69: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

How Networks Can Be Connected

(a) Two Ethernets connected by a switch. (b) Two Ethernets connected by routers.

Page 70: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Concatenated Virtual Circuits

Internetworking using concatenated virtual circuits.

Page 71: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Connectionless Internetworking

A connectionless internet.

Page 72: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Tunneling

Tunneling a packet from Paris to London.

Page 73: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Tunneling (2)

Tunneling a car from France to England.

Page 74: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Internetwork Routing

(a) An internetwork. (b) A graph of the internetwork.

interior gateway protocol

exterior gateway protocol

Page 75: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Fragmentation

(a) Transparent fragmentation. (b) Nontransparent fragmentation.

Page 76: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Fragmentation (2)

Fragmentation when the elementary data size is 1 byte.(a) Original packet, containing 10 data bytes.(b) Fragments after passing through a network with maximum

packet size of 8 payload bytes plus header.(c) Fragments after passing through a size 5 gateway.

Page 77: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Network Layer in the Internet

• The IP Protocol

• IP Addresses

• Subnets

• Internet Control Protocols

• OSPF – The Interior Gateway Routing Protocol

• BGP – The Exterior Gateway Routing Protocol

• CIDR-Classless InterDomain Routing

• IPv6

Page 78: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Design Principles for Internet

1. Make sure it works.

2. Keep it simple.

3. Make clear choices.

4. Exploit modularity.

5. Expect heterogeneity.

6. Avoid static options and parameters.

7. Look for a good design; it need not be perfect.

8. Be strict when sending and tolerant when receiving.

9. Think about scalability.

10. Consider performance and cost.

Page 79: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Collection of Subnetworks

The Internet is an interconnected collection of many networks.

Page 80: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The IP Protocol

The IPv4 (Internet Protocol) header.

Page 81: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The IP Protocol (2)

Some of the IP options.

5-54

Page 82: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

IP Addresses

IP address formats.

Page 83: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

IP Addresses (2)

Special IP addresses.

Page 84: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Subnets

A campus network consisting of LANs for various departments.

Page 85: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Subnets (2)

A class B network subnetted into 64 subnets.

Page 86: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

CIDR – Classless InterDomain Routing

A set of IP address assignments.

5-59

Page 87: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

NAT – Network Address Translation

Placement and operation of a NAT box.

Page 88: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Internet Control Message Protocol

The principal ICMP message types.

5-61

Page 89: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

ARP– The Address Resolution Protocol

Three interconnected /24 networks: two Ethernets and an FDDI ring.

Page 90: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Dynamic Host Configuration Protocol

Operation of DHCP.

Page 91: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

OSPF – The Interior Gateway Routing Protocol

(a) An autonomous system. (b) A graph representation of (a).

Page 92: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

OSPF (2)

The relation between ASes, backbones, and areas in OSPF.

Page 93: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

OSPF (3)

The five types of OSPF messeges.

5-66

Page 94: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

BGP – The Exterior Gateway Routing Protocol

(a) A set of BGP routers. (b) Information sent to F.

Page 95: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

The Main IPv6 Header

The IPv6 fixed header (required).

Page 96: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Extension Headers

IPv6 extension headers.

5-69

Page 97: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Extension Headers (2)

The hop-by-hop extension header for large datagrams (jumbograms).

Page 98: The Network Layer Chapter 5. Highlights Network Layer Design Issues Routing Algorithms Congestion Control Algorithms Quality of Service Internetworking

Extension Headers (3)

The extension header for routing.