Transcript COS 338_day20

COS 338
Day 20
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
2
Network Management
Chapter 10
Copyright 2004 Prentice-Hall
Panko’s Business Data Networks and Telecommunications, 5th edition
Cost
Figure 10-1: Network Demand Versus
Budget Trends
Money/
Demand
User Demand
Budget
Time
5
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
6
Figure 10-2: Cost Issues

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
7
Figure 10-2: Cost Issues

Total Cost of Ownership

Fully configured cost of hardware
 Base price plus necessary options
 Often much higher than base price

Fully configured cost of software

Initial installation costs
 Vendor setup costs
 IT and end-user labor
8
Figure 10-2: Cost Issues

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
9
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
15,000 245,000
85,000
9,000
9,000
9,000 112,000
$100,000
10,000
10,000
10,000 130,000
Software Options
50,000
10,000
10,000
10,000
Technology
Subtotal
435,000
44,000
44,000
44,000 567,000
Base Hardware
Hardware Options
Base Software
Total
80,000
10
Figure 10-3: Multiyear Cost Analysis: Total
Cost of Ownership (TCO)
Year 1
Year 2
Year 3
Year 4
Total
Planning and
Development
75,000
75,000
Implementation
50,000
50,000
Ongoing IT Labor
Ongoing User
Labor
Labor Subtotal
Total
100,000
75,000
75,000
75,000
325,000
50,000
25,000
25,000
25,000
125,000
275,000 100,000 100,000 100,000
575,000
710,000 144,000 144,000 144,000 1,142,000
Note: The total cost of ownership is $1,142,000.
11
Network Simulation
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
13
Figure 10-4: Network Simulation

What is: the existing situation
Net 1
Net 4
Utilization in
Peak Hour
95%
Net 2
Net 3
Too high!
Net 5
Net 6
14
Figure 10-4: Network Simulation

What-if: See the Impact of a Change
Net 1
Net 4
Added
Router
Net 2
Net 3
Added
Link
Est.
Utilization in
Peak Hour
70%
Net 5
Net 6
15
Figure 10-4: Network Simulation

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
16
Figure 10-4: Network Simulation

Before the Simulation, Collect Data

Data must be good

Otherwise, GIGO (garbage in, garbage out)

Collect data on the current network

Forecast growth
17
Figure 10-4: Network Simulation

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
18
Figure 10-4: Network Simulation

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)
19
Figure 10-5: OPNET IT Guru Node
Template
20
Figure 10-6: Configuring a Frame Relay
CIR
21
Figure 10-7: Configured Simulation Model
22
Figure 10-8: What-If Analysis
23
IP Subnetting
Figure 10-9: IP Subnetting
Step
Description
1
Total size of IP address
(bits)
2
Size of network part
assigned to firm (bits)
16
8
3
Remaining bits for firm to
assign
16
24
4
Selected subnet/host part
sizes (bits)
32
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.
25
Figure 10-9: IP Subnetting
Step
Description
5
Possible number of
subnets (2^N-2)
254
62
4,094
254
(2^8-2) (2^6-2) (2^12-2) (2^8-2)
6
Possible number of hosts 254
1,022 4,094 65,534
per subnet (2^N-2)
(2^8-2) (2^10-2) (2^12-2) (2^16-2)
Subnet Calculator
http://www.solarwinds.net/free/
26
27
Directory Servers
Store corporate information
Hierarchical organization of content
LDAP standard to access directory servers
Figure 10-10: Hierarchical Directory Server
Name Space
Directory Server with
Hierarchical Object Structure
LDAP Request:
Get e-mail.Brown.faculty.
University of Waikiki (O) CN=Waikiki
business.waikiki
Astronomy Business (OU)
(OU)
LDAP Response:
[email protected]
O=organization
OU=organizational unit
CN=common name
LDAP=Lightweight Directory
Access Protocol
CprSci
(OU)
Staff
Faculty
Routers
Chun
Brown
Ochoa
CN
Brown
E-Mail
Ext
[email protected] x6782
29
Configuring Routers
Needed to set up new routers
Needed to change operation of old routers
Time consuming and an important skill
Figure 10-11: Cisco Internetwork Operating
System (IOS) Command Line Interface (CLI)
Command
Comment
Router>enable[Enter]
Router> is the prompt. The “>” shows
that the user is in non-privileged mode.
Enables privileged mode so that user
can take supervisory actions. User
must enter the enable secret.
All commands end with [Enter]. Enter
is not shown in subsequent commands.
31
Figure 10-11: Cisco Internetwork Operating
System (IOS) Command Line Interface (CLI)
Command
Comment
Router#hostname julia
Prompt changes to “#” to indicate that
user is in privileged mode.
User gives the router a name, julia.
julia#config t
Enter configuration mode. The t is an
abbreviation for terminal.
32
Figure 10-11: Cisco Internetwork Operating
System (IOS) Command Line Interface (CLI)
Command
Comment
julia(config)#int e0
Prompt changes to julia(config) to
indicate that the user is in configuration
mode.
User wishes to configure Ethernet
interface 0. (Router has two Ethernet
interfaces, 0 and 1.)
julia(config-if)#ip address
10.5.0.6 255.255.0.0
User gives the interface an IP address
and a subnet mask. (Every router
interface must have a separate IP
address.) The subnet is 5.
33
Figure 10-11: Cisco Internetwork Operating
System (IOS) Command Line Interface (CLI)
Command
Comment
julia(config-if)#no shutdown This is an odd one. The command to
shut down an interface is “shutdown”.
Correspondingly, “no shutdown” turns
the interface on.
julia(config-if)# Ctrl-Z
User types Ctrl-Z (the key combination,
not the letters) to end the configuration
of e0.
julia(config)#int s1
User wishes to configure serial
interface 1. (Router has two serial
interfaces, 0 and 1.)
34
Figure 10-11: Cisco Internetwork Operating
System (IOS) Command Line Interface (CLI)
Command
Comment
julia(config-if)#ip address
10.6.0.1 255.255.0.0
User gives the interface an IP address
and 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.
35
Figure 10-11: Cisco Internetwork Operating
System (IOS) Command Line Interface (CLI)
Command
Comment
julia#disable
Takes user back to non-privileged
mode. This prevents anyone getting
access to the terminal from making
administrative changes to the router.
julia>
36
Network Management Utilities
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
38
Figure 10-12: Network Management
Utilities

Host Diagnostic Tools

Network Setup Wizard works most of the time; need
tools if it does not

Testing the connection

Open a connection to a website using a browser

Ping a host to see if latency is acceptable
39
Figure 10-12: Network Management
Utilities

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)
40
Figure 10-12: Network Management
Utilities

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
41
Figure 10-13: NIC Configuration Dialog Box
42
Figure 10-12: Network Management
Utilities

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
43
Figure 10-12: Network Management Utilities
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
44
Figure 10-12: Network Management Utilities
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
45
Figure 10-12: Network Management Utilities
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
46
Figure 10-12: Network Management Utilities
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
47
Figure 10-12: Network Management
Utilities

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
48
Figure 10-14: EtherPeek Packet Capture
and Summarization Program
49
Figure 10-12: Network Management
Utilities

Host Diagnostic Tools

Connection analysis

At the command line, Netstat shows active
connections

This can identify problem connections
Spyware running on Port 3290
50
Figure 10-12: Network Management
Utilities

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
250 ms
Tracert
25 ms
75 ms
225 ms
150 ms (Problem?)
51
Figure 10-12: Network Management
Utilities

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)
52
Figure 10-12: Network Management
Utilities
IP Range
to Scan
Type of
Scan
Identified
Host and
Open
Ports
53
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
54
Figure 10-16: Simple Network Management
Protocol (SNMP)
Network Management
Software (Manager)
Managed
Device
Manager manages multiple
managed devices from a central
location
RMON Probe
55
Figure 10-16: Simple Network Management
Protocol (SNMP)
Network Management
Software (Manager)
Network
Management
Agent (Agent),
Objects
Network
Management
Agent (Agent),
Objects
Manager talks to an network
management agent on each
managed device
RMON Probe
56
Figure 10-16: Simple Network Management
Protocol (SNMP)
Network Management
Software (Manager)
Network
Management
Agent (Agent),
Objects
Network
Management
Agent (Agent),
Objects
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.
RMON Probe
57
Figure 10-16: Simple Network Management
Protocol (SNMP)
Network Management
Software (Manager)
Management
Information
Base (MIB)
Management
Information
Base (MIB)
MIB stores data about devices.
MIB on manager stores all.
MIB on device stores local information
Management
Information
Base (MIB)
RMON Probe
58
Figure 10-16: Simple Network Management
Protocol (SNMP)
Network Management
Software (Manager)
Management
Information
Base (MIB)
Simple Network
Management Protocol (SNMP)
Management
Information
Base (MIB)
Command (Get, Set, etc.)
Response
Management
Information
Base (MIB)
Trap
RMON Probe
59
Figure 10-17: SNMP Object Model


SNMP Object Model
Management
Information
Base (MIB)

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)
60
Figure 10-17: SNMP Object Model

SNMP IP Objects
Management
Information
Base (MIB)

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
61
Figure 10-17: SNMP Object Model

SNMP IP Objects (Continued)
Management
Information
Base (MIB)

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
62
Figure 10-17: SNMP Object Model

SNMP TCP Objects
Management
Information
Base (MIB)

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)
63
Figure 10-17: SNMP Object Model


SNMP UDP Objects

Error: no application on requested port

Traffic statistics
Management
Information
Base (MIB)
SNMP ICMP Objects

Number of errors of various types
64
Figure 10-17: SNMP Object Model

Management
Information
Base (MIB)
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.
65
Remote Switch and Router
Management
Figure 10-12: Network Management
Utilities

Remote Switch and Router Management

Telnet

Web interfaces

SSH

TFTP

Saves money compared to traveling to device
67
Figure 10-18: Telnet, Web Management,
SSH, and TFTP

Telnet

Remotely log into managed device as a dumb
terminal

Poor security

Weak password authentication

Passwords are sent in the clear, making them
vulnerable to sniffers

No encryption of traffic
68
Figure 10-18: Telnet, Web Management,
SSH, and TFTP

Web Interfaces

Managed device contains a webserver

Administrator connects to the managed device with
a browser

Can use SSL/TLS but typically does not
69
Figure 10-18: Telnet, Web Management,
SSH, and TFTP

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
70
Figure 10-18: Telnet, Web Management,
SSH, and TFTP

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
71
Figure 10-18: Telnet, Web Management,
SSH, and TFTP

TFTP

No password is needed

Can be used by hackers to download attack
programs

Poor security makes TFTP very dangerous
72
Traffic Management
Figure 10-19: Traffic Management Methods

Traffic Management

Capacity is expensive; it must be used wisely

Especially in WANs
74
Figure 10-19: Traffic Management Methods

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
75
Figure 10-19: Traffic Management Methods

Traditional Approaches

Priority

In Ethernet, assign priority to applications based
on sensitivity to latency

In momentary periods of congestion, send highpriority frames through

Substantial ongoing management labor
76
Figure 10-19: Traffic Management Methods

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
77
Figure 10-19: Traffic Management Methods

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
78
Figure 10-19: Traffic Management Methods

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)
79
Topics Covered
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
81
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
82
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?
 127.0.0.1
 Windows XP: Connection Properties
83
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)
84
Topics Covered

Simple Network Management Protocol (SNMP)

Manager, managed devices, agents

Get and set commands

MIB

RMON probe

SNMP object model (MIB schema)
85
Topics Covered

Remote Switch and Management Utilities

Saves money compared to traveling to device

Telnet

Web interfaces

SSH

TFTP
86
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 traffic
 Drop certain traffic or limit it to a certain amount
87