COS 338 Day 20. 2 DAY 19 Agenda Assignment 6 Due Lab 7 due next Monday Assignment 7 Posted Due Dec 1 Capstone Progress reports due Exam 3 on November

COS 338

Day 20

2

DAY 19 Agenda

Assignment 6 Due

Lab 7 due next Monday

Assignment 7 Posted Due Dec 1

Capstone Progress reports due

Exam 3 on November 21 Chap 8&9, open book, open notes, 60 min, 25 M/c questions. Quiz can be taken from anywhere. Availability, time and password will be sent via WebCT e-mail

Today we will do discuss network management

Chapter 10

Copyright 2004 Prentice-HallPanko’s Business Data Networks and Telecommunications, 5th edition

Network Management

Cost

5

Figure 10-1: Network Demand Versus Budget Trends

Money/Demand

Time

User Demand

Budget

6

Figure 10-2: Cost Issues

The Importance of Costs

Exploding demand

Slow budget growth

Falling hardware costs help, but software costs fall more slowly, and labor costs are rising

Select the least expensive technology that will fully meet user needs

7


Non-Technology Costs Labor costs

High, and unit labor costs are rising over time Rising Health Care costs are also a factor

Often dominate total costs

Carrier fees

Recurring contractual charges

8


Total Cost of Ownership Fully configured cost of hardware

Base price plus necessary optionsOften much higher than base price

Fully configured cost of software

Initial installation costsVendor setup costs IT and end-user labor

9


Total Cost of Ownership Ongoing costs

Upgrades

Labor costs often exceed all other costs

Immature products have very high labor costs

Total cost of ownership (TCO): total of all costs over life span

10

Figure 10-3: Multiyear Cost Analysis: Total Cost of Ownership (TCO)

Year 1 Year 2 Year 3 Year 4

$200,000 15,000 15,000 15,000Base Hardware

85,000 9,000 9,000 9,000Hardware Options

Total

245,000

112,000

$100,000 10,000 10,000 10,000Base Software 130,000

50,000 10,000 10,000 10,000Software Options 80,000

435,000 44,000 44,000 44,000 Technology Subtotal

567,000

11

Figure 10-3: Multiyear Cost Analysis: Total Cost of Ownership (TCO)

Year 1 Year 2 Year 3 Year 4

50,000Implementation

100,000 75,000 75,000 75,000Ongoing IT Labor

Total

50,000

325,000

50,000 25,000 25,000 25,000Ongoing UserLabor

125,000

275,000 100,000 100,000 100,000 Labor Subtotal 575,000

710,000 144,000 144,000 144,000Total 1,142,000

Note: The total cost of ownership is $1,142,000.

75,000Planning andDevelopment

75,000

Network Simulation

13

Figure 10-4: Network Simulation

Simulation

Build a model, study its implications

More economical to simulate network alternatives than to build them

Opnet GURU is a Simulation tool

14


What is: the existing situation

Net 1

Net 2

Net 3

Net 4

Net 5

Net 6

Utilization inPeak Hour

95%

Too high!

15


What-if: See the Impact of a Change

Net 1

Net 2

Net 3

Net 4

Net 5

Net 6

Est.Utilization inPeak Hour

70%

AddedRouter

AddedLink

16


Simulation Purposes

Comparing alternatives to select the best one

Base case and sensitivity analysis to see what will happen if the values of variables were varied over a range (+ or –- a certain amount)

Anticipating problems, such as bottlenecks

Planning for growth, to anticipate areas where more capacity is needed

17


Before the Simulation, Collect Data

Data must be good

Otherwise, GIGO (garbage in, garbage out)

Collect data on the current network

Forecast growth

18


The Process (Based on OPNET IT Guru)

Add nodes to the simulation work area (clients, servers, switches, routers, etc.)

Specify the topology with transmission lines (including line speeds)

Configure the nodes and transmission lines (IP Time-to-Live value, etc.)

Add applications, which generate traffic data

19


The Process

Run the simulation for some simulated period of time

Examine the output to determine implications

Validate the simulation (compare with reality if possible to see if it is correct)

What-if analysis

Application performance analysis (OPNET ACE)

20

Figure 10-5: OPNET IT Guru Node Template

21

Figure 10-6: Configuring a Frame Relay CIR

22

Figure 10-7: Configured Simulation Model

23

Figure 10-8: What-If Analysis

IP Subnetting

25

Figure 10-9: IP Subnetting

DescriptionStep

32Total size of IP address(bits)

1

Size of network partassigned to firm (bits)

2 16 8

Remaining bits for firm toassign

3 16 24

Selected subnet/host partsizes (bits)

4 8/8 6/10 12/12 8/16

A firm is given its network size; it chooses its subnet size.Total is 32 bits, so big subnet size gives many subnets but few hosts.

26

Figure 10-9: IP Subnetting

DescriptionStep

Possible number ofsubnets (2^N-2)

5254

(2^8-2)62

(2^6-2)4,094

(2^12-2)254

(2^8-2)

Possible number of hostsper subnet (2^N-2)

6254

(2^8-2)1,022

(2^10-2)65,534

(2^16-2)4,094

(2^12-2)

Subnet Calculatorhttp://www.solarwinds.net/free/

27

Directory Servers

Store corporate information

Hierarchical organization of content

LDAP standard to access directory servers

29

Figure 10-10: Hierarchical Directory Server Name Space

University of Waikiki (O) CN=Waikiki

Astronomy(OU)

Staff

Chun

CNBrown

Extx6782

Directory Server withHierarchical Object Structure

Ochoa

Routers

CprSci(OU)

Brown

Faculty

[email protected]

Business (OU)

LDAP Request:Get e-mail.Brown.faculty.

business.waikiki

LDAP Response:[email protected]

O=organizationOU=organizational unitCN=common nameLDAP=Lightweight Directory Access Protocol

Needed to set up new routers

Needed to change operation of old routers

Time consuming and an important skill

Configuring Routers

31

Figure 10-11: Cisco Internetwork Operating System (IOS) Command Line Interface (CLI)

Command Comment

Router>enable[Enter] Router> is the prompt. The “>” showsthat the user is in non-privileged mode.

Enables privileged mode so that usercan take supervisory actions. Usermust enter the enable secret.

All commands end with [Enter]. Enteris not shown in subsequent commands.

32


Command Comment

Router#hostname julia

Prompt changes to “#” to indicate thatuser is in privileged mode.

User gives the router a name, julia.

julia#config t

Enter configuration mode. The t is anabbreviation for terminal.

33


Command Comment

julia(config)#int e0

Prompt changes to julia(config) toindicate that the user is in configurationmode.

User wishes to configure Ethernetinterface 0. (Router has two Ethernetinterfaces, 0 and 1.)

julia(config-if)#ip address10.5.0.6 255.255.0.0

User gives the interface an IP addressand a subnet mask. (Every routerinterface must have a separate IPaddress.) The subnet is 5.

34


Command Comment

julia(config-if)#no shutdown

This is an odd one. The command toshut down an interface is “shutdown”.Correspondingly, “no shutdown” turnsthe interface on.

julia(config-if)# Ctrl-Z

User types Ctrl-Z (the key combination,not the letters) to end the configurationof e0.

julia(config)#int s1

User wishes to configure serialinterface 1. (Router has two serialinterfaces, 0 and 1.)

35


Command Comment

julia(config-if)#ip address10.6.0.1 255.255.0.0

User gives the interface an IP addressand subnet mask. The subnet is 6.

julia(config-if)#no shutdown Turns on s1.

julia(config-if)# Ctrl-Z Ends the configuration of s1.

julia# router rip

Enables the Router Initiation Protocol(RIP) routing protocol.

36


Command Comment

julia#disable

Takes user back to non-privilegedmode. This prevents anyone gettingaccess to the terminal from makingadministrative changes to the router.

julia>

Network Management Utilities

38

Figure 10-12: Network Management Utilities

Network management utilities are programs to help network managers administer the network

Security

Management tools can be used to make attacks

Policies should limit these tools to certain employees and for certain purposes

Firewalls block many network management tools to avoid attacks

39


Host Diagnostic Tools

Network Setup Wizard works most of the time; need tools if it does not

Testing the connectionOpen a connection to a website using a browserPing a host to see if latency is acceptable

40


Host Diagnostic Tools Loopback testing and ipconfig/winipconfig

Go to the command line

Ping 127.0.0.1. This is the loopback interface (you ping yourself)

For detailed information: ipconfig /all or winipconfig (older versions of Windows)

41


Host Diagnostic Tools Checking the NIC in Windows XP

Right click on a connection and select Properties

Under the name of the NIC, hit the Configuration button

The dialog box that appears will show you the status of the NIC

It also offers a Troubleshooting wizard if the NIC is not working

42

Figure 10-13: NIC Configuration Dialog Box

43


Host Diagnostic Tools Packet capture and display programs

Capture data on individual packets

Allows extremely detailed traffic analysis

Look at individual packet data and summaries

WinDUMP is a popular packet capture and display program on Windows

44


Command prompt>tcpdump www2.pukanui.com

7:50.10.500020 10.0.5.3.62030 >www2.pukanui.com.http: S 800000050:800000050(0) win 4086 <mss1460>

7:50.10.500020 is the time

10.0.5.3.62030 is the source host (62030 is the port number)

www2.pukanui.com.http is the destination host (HTTP)

WinDUMP from Ch. 8a

45


7:50.10.500020 10.0.5.3.62030 > www2.pukanui.com.http: S 800000050:800000050(0) win 4086 <mss1460>

S indicates that the SYN flag is set

800000050:800000050(0) Seq No and length

Win 4086 is the window size (for flow control)

<mss1460> is the option for maximum segment size (size of the TCP data field)

WinDUMP from Ch. 8a

46


7:50.10.500030 www2.pukanui.com.http > 10.0.5.3.62030 : S 300000030:300000030(0) ack 800000051 win 8760 <mss1460>

SYN/ACK from the webserver

7:50.10.500040 10.0.5.3.62030 > www2.pukanui.com.http: . ack 1 win 4086

ACK to finish 3-way open

WinDUMP from Ch. 8a

47


7:50.10.500050 10.0.5.3.62030 > www2.pukanui.com.http: P 1:100(100)

7:50.10.500060 www2.pukanui.com.http > 10.0.5.3.62030 : . ack 101 win 9000

7:50.10.500070 www2.pukanui.com.http > 10.0.5.3.62030 : . 1:1000(999)

7:50.10.500080 10.0.5.3.62030 > www2.pukanui.com.http: . ack 1001 win 4086

WinDUMP from Ch. 8a

48


Host Diagnostic Tools Traffic summarization

Shows statistical data on traffic going into and out of the host

EtherPeek is a popular commercial traffic summarization program

49

Figure 10-14: EtherPeek Packet Capture and Summarization Program

50


Host Diagnostic Tools Connection analysis

At the command line, Netstat shows active connections

This can identify problem connections

Spyware running on Port 3290

51


Route Analysis Tools To test the route to another host Ping tests gives the latency of a whole route Tracert gives latencies to router along the path

Ping 275 ms

Tracert

25 ms 75 ms

250 ms

225 ms

150 ms (Problem?)

52


Network Mapping Tools To understand how the network is organized

Discovering IP addresses with active devices

Fingerprinting them to determine their operating system (client, server, or router)

A popular network mapping program is Nmap (Figure 10-4)

53


IP Range to Scan

Type of Scan

Identified Host and

Open Ports

54

Figure 10-16: Simple Network Management Protocol (SNMP)

Simple Network Management Protocol (SNMP)

Standard for managing remote devices in a network

Collects information from remote devices to give the network administrator an overview of the network

Optionally, allows the network administrator to reconfigure remote devices

Potential for strong labor cost savings

55


Network ManagementSoftware (Manager)

RMON Probe

ManagedDevice

Manager manages multiple managed devices from a central location

56



NetworkManagement

Agent (Agent),Objects

RMON Probe

NetworkManagement


Manager talks to an network management agent on each managed device

57



NetworkManagement


RMON Probe

NetworkManagement


RMON (remote monitoring) probe is a special agent that collects data about multiple devices in a region of in the network. It is like a local manager that can be queried by the main manager.

58


ManagementInformationBase (MIB)




RMON Probe

MIB stores data about devices.MIB on manager stores all.MIB on device stores local information

59






Simple NetworkManagement Protocol (SNMP)

RMON Probe

Command (Get, Set, etc.)

Response

Trap

60

Figure 10-17: SNMP Object Model

SNMP Object Model The MIB database schema

Defines objects (parameters) about which information is stored for each managed device

SNMP System Objects System name System description System contact person System uptime (since last reboot)


61


SNMP IP Objects Forwarding (for routers). Yes if forwarding (routing),

No if not

Subnet mask

Default time to live

Traffic statistics

Number of discards because of resource limitations


62


SNMP IP Objects (Continued) Number of discards because could not find route

Number of rows in routing table

Rows discarded because of lack of space

Individual row data in the routing table


63


SNMP TCP Objects Maximum / minimum retransmission time Maximum number of TCP connections allowed Opens / failed connections / resets Segments sent Segments retransmitted Errors in incoming segments No open port errors Data on individual connections (sockets, states)


64


SNMP UDP Objects Error: no application on requested port

Traffic statistics

SNMP ICMP Objects Number of errors of various types


65


SNMP Interface Objects (One per Port) Type (e.g., 69 is 100Base-FX; 71 is 802.11)

Status: up / down / testing

Speed

MTU (maximum transmission unit—the maximum packet size)

Traffic statistics: octets, unicast / broadcast / multicast packets

Errors: discards, unknown protocols, etc.


Remote Switch and Router Management

67


Remote Switch and Router Management Telnet Web interfaces SSH TFTP Saves money compared to traveling to device

68

Figure 10-18: Telnet, Web Management, SSH, and TFTP

Telnet Remotely log into managed device as a dumb

terminal

Poor securityWeak password authentication

Passwords are sent in the clear, making them vulnerable to sniffers

No encryption of traffic

69


Web Interfaces

Managed device contains a webserver

Administrator connects to the managed device with a browser

Can use SSL/TLS but typically does not

70


SSH

Secure shell protocol

Similar to Telnet but highly secure

Widely installed on Unix computers (including Linux computers)

Software must be added to Windows devices

71


TFTP

Trivial File Transfer Protocol

Similar to file transfer program but simpler

Simple enough to implement on switches and routers

Often used to download configurations to a switch or router from a server

72


TFTP

No password is needed

Can be used by hackers to download attack programs

Poor security makes TFTP very dangerous

Traffic Management

74

Figure 10-19: Traffic Management Methods

Traffic Management

Capacity is expensive; it must be used wisely

Especially in WANs

75


Traditional Approaches Overprovisioning

In Ethernet, install much more capacity than is needed most of the time

This is wasteful of capacity

Does not require much ongoing management labor

76


Traditional Approaches Priority

In Ethernet, assign priority to applications based on sensitivity to latency

In momentary periods of congestion, send high-priority frames through

Substantial ongoing management labor

77


Traditional Approaches QoS Reservations

In ATM, reserve capacity on each switch and transmission line for an application

Allows strong QoS guarantees for voice traffic

Highly labor-intensive

Data gets the scraps—capacity that is not reserved for voice

78


Traffic Shaping The Concept

Control traffic coming into the network at access switches

Filter out unwanted applications

Give a maximum percentage of traffic to other applications

79


Traffic Shaping Advantages and Disadvantages

Traffic shaping alone reduces traffic coming into the network to control costs

Very highly labor intensive

Creates political battles (as do priority and QoS reservations to a lesser degree)

Topics Covered

81

Topics Covered

Cost Exploding demand, slow budget growth Hardware, software, labor costs Fully-configured hardware versus base prices Total cost of ownership: cost over entire life cycle

Network Simulation Model the network on a computer Explore alternatives Cheaper than building alternatives

82

Topics Covered

IP Subnet Planning Organization is given its network part

Divides remaining bits of IP address into subnet and host part

Must balance number of subnets with hosts per subnet

Directory Servers Hierarchical data storage

LDAP

83

Topics Covered

Configuring Routers Time-consuming; important skill

Cisco IOS is the dominant router operating system

Command-line interface (CLI)

Network Management Utilities Both network managers and hackers love them

Host diagnostic tools. Is the connection working?127.0.0.1Windows XP: Connection Properties

84

Topics Covered

Network Management Utilities Packet capture and display programs

Traffic summarization program (Etherpeek)

Netstat to show active connections

Route analysis: Ping and Tracert

Network mapping tools (nmap)

85

Topics Covered

Simple Network Management Protocol (SNMP) Manager, managed devices, agents

Get and set commands

MIB

RMON probe

SNMP object model (MIB schema)

86

Topics Covered

Remote Switch and Management Utilities Saves money compared to traveling to device

Telnet

Web interfaces

SSH

TFTP

87

Topics Covered

Traffic Management Capacity is expensive on WANs

Overprovisioning is too wasteful on WANs

Priority is good but expensive to manage

QoS reservations only allow strong guarantees for some services; rest get the scraps

Traffic shaping: only select certain type of trafficDrop certain traffic or limit it to a certain amount

Documents

COS 338 Day 20. 2 DAY 19 Agenda Assignment 6 Due Lab 7 due next Monday Assignment 7 Posted Due Dec 1 Capstone Progress reports due Exam 3 on November