IP Networking Part 3- IP Address Management

“A webinar to help you prepare for the CBNE™ Certification”

Wayne M. Pecena, CPBE, CBNE

Texas A&M Information Technology Educational Broadcast Services

IP Networking, Part 3 - IP Address Management “A webinar to help you prepare for the CBNE™ Certification”

Advertised Presentation Scope:

IP Networking Fundamentals for Broadcast Engineers is an intensive instructor-lead workshop focused on major IP networking topics. The goal is to equip the broadcast engineer with the knowledge and understanding of IP networking fundamentals and the ability to apply conceptual theory in a practical manner. The workshop will focus upon the principals of IP Addressing and application of best practices in the design of an IP network address plan.

My Goals & Deliverables for This Afternoon:

- Provide an Awareness of Major IP Networking Topics (broadcast application focused) - Provide an Understanding of IP Addressing Fundamentals - Provide a Foundation for SBE CBNT & CBNE Certification Exams - Provide Reference Material & Resources to Obtain Further Knowledge

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A Poll ?

• My Familiarity & Conformability with IP Addressing is:

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Not at All Somewhat Familiar, But I Struggle At Times Very Comfortable, I Am Here for the Free Lunch

IP Networking, Part 3 - IP Address Management “A webinar to help you prepare for the CBNE™ Certification”

• IP Address Basics (IPv4) • IP Addressing Rules • IP Address Classes • IP Subnetting Fundamentals • The IPv6 Address • Practical Exercises:

– Reverse Engineering an IP Address Plan – Developing an IP Addressing Plan

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REVIEW - Physical & Virtual Addressing • Each Host on an Ethernet Based IP Network Has: • An Unique MAC Address

– Layer 2 Physical Address (local network segment)

• An Unique IP Address – Layer 3 Logical Address (global routed)

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172.15.1.1 172.15.2.2 DATA Trailer00:12:3F:8D:4D:A7FF:FF:FF:FF:FF:FF

DestinationMAC

SourceMAC

DestinationIP

SourceIP

IP Packet

Ethernet Frame

Simplified Representation

The IP Address: • Is a “Logical Address” – OSI Model Layer 3 Function

– Allows Hierarchical Network Addressing Structure • Creates Boundaries Between Networks

– Allows Routing Packets Between Networks

• Must Have a Subnet Mask: – Implied – Explicit

• Address & Mask Defines: – Unique Network ID – Unique Host ID

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The IP Address (IPv4)

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32 Bit Address Yields 4,294,967,296 IPv4 AddressesExpressed in Decimal as (4) 8-bit Octets using “Doted Decimal Notation”

192.168.10.1

11000000.10101000.00001010.00000001

128 64 32 16 8 4 2 1

1 1 0 0 0 0 0 0

128 64 32 16 8 4 2 1

0 0 0 0 0 0 0 1

The IP Address Subnet Mask Each IP Address Must Have a Subnet Mask

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32 Bit Subnet MaskExpressed in Decimal as (4) 8-bit Octets using “Doted Decimal Notation”

255.255.255.192

11111111.11111111.11111111.11000000

128 64 32 16 8 4 2 1

1 1 1 1 1 1 1 1

128 64 32 16 8 4 2 1

1 1 0 0 0 0 0 0

Purpose of the Subnet Mask • Identifies the Network Portion and the Host Portion

of the IP Address – Classful Addressing – Mask is Implied Based Upon Class – Classless Addressing – Mask Must Be Specified

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NET ID HOST ID

Octet 1 Octet 2 Octet 4Octet 3

NET ID HOST ID

HOST IDNET ID

Class A

Class B

Class C

8 Bits 24 Bits

8 Bits24 Bits

16 Bits16 Bits

The Subnet Mask: • Rules:

– If Mask Bit =1 Identifies the Network – If Mask Bit=0 Identifies the Host

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192.168.10.1 255.255.255.192

11000000.10101000.00001010.00000001 Address

11111111.11111111.11111111.11000000 Mask

Network Host

Class Octet 1 Octet 2 Octet 3 Octet 4

A Network Host Host Host

B Network Network Host Host

C Network Network Network Host

IP Address Classes Used to Set Different Network Sizes

• The 1st Octet of an IP Address Determines It’s Class:

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Class First Octet Subnet Mask (implied)

CIDR Maximum # of Networks

# Host Bits

# of Hosts / Network

A 1 - 127 255.0.0.0 /8 127 24 16,777,214

B 128 - 191 255.255.0.0 /16 16,384 16 65,534

C 192 - 223 255.255.255.0 /24 2,097,152 8 254

The 1st Octet of an IP Address Dictates the Class

The 1st Octet of an IP Address Determines It’s Class:

• If First Bit = 0 Class A • If First 2 Bits = 10 Class B • If First 3 Bits – 110 Class C • If First 4 Bits = 1110 Class D • If First 4 Bits = 1111 Class E

• Recognize Class D & E Are “Special”:

– Class D Reserved for Multicast – Class E Reserved for Experimental

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A Quiz!

• What Class Are the Following IP Addresses?

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169.254.0.100 Class A Class B Class C Class D

127.10.0.10 Class A Class B Class C Class D

223.127.169.254 Class A Class B Class C Class E

The Network & Broadcast Addresses

• These Addresses Cannot Be Assigned to a Host! – Network (subnet) Address

• ALL HOST BITS = 0 – Broadcast Address

• ALL HOST BITS = 1

• Network Example: 192.168.1.0 /24 • Broadcast Example: 192.168.1.255 /24

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1 1 1 1 1 1 1 1

0 0 0 0 0 0 0 0

Private vs Public IP Addresses

• RFC 1918 Established “Private” Address Space – Class A: 10.0.0.0 to 10.255.255.255 /8 – Class B: 172.16.0.0 to 172.31.255.255 /16 – Class C: 192.168.0.0 to 192.168.255.255 /24

• Key Points: – Private IP Addresses Are NOT Routable Outside the Local Network or

to the Internet – Widely Used in Home & Industry Networks – May Be Translated With NAT At An Edge Router

• Map Private Address Space to Public Address Space

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CIDR RFC 1517, 1518, 1519, 1520

• Classless Inter-Domain Routing (CIDR) – Simplified Approach to Stating the Subnet Mask – / Notation (slanted notation) Utilized = # Bits That Are 1

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Mask: 255.255.255.240 Expressed in Binary: 11111111.11111111.11111111.11110000 Mask (CIDR): /28

24 Bits

IP Address & Subnet Mask Formats

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Classful Addressing: 165.95.240.136 (Implied Mask 255.255.0.0) VLSM Addressing: 165.95.240.136 255.255.255.192 CIDR Notation : 165.95.240.136 /26

Implied Mask Of a Class B Network

Explicit Mask Must Be Stated

Mask Stated as Number of Subnet Bits

Special Use IP Addresses RFC 5735

• 0.0.0.0/8 Network Address “Wire Address” • 10.0.0.0/8 Private IP Address Space (RFC 1918) • 127.0.0.0/8 Loopback Address • 169.254.0.0/16 IETF Zero Configuration Address Space (RFC 3927) • 172.16.0.0/16 Private IP Address Space (RFC 1918) • 192.168.0.0/16 Private IP Address Space (RFC 1918) • 224.0.0.0/4 Multicast Address Space • 255.255.255.255/32 Broadcast Address

And more special use cases………..yields a little over 3.7m “Useable IPv4 Addresses”

(3,706,650,624 out of 4,294,967,296 possible IPv4 addresses or 86%)

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IP Address Trivia • What is Special About 127.0.0.1 ?

– Actually Any 127.0.0.0/8 Address Works OR the Range of 127.0.0.1 to 127.255.255.255

• Known as a “Loop-Back” Address • Useful For:

– Test Local IP Stack and Network Adapter Test

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IP Address Subnetting • What is a Subnet?

– Logical Subdivision of a Larger Network – Creates New Networks From A Larger Network – Bits Are “Stolen” From the Host Portion

• Each Newer Network Created Has Less Hosts • 2n-2 New Networks Created

where n=number of host bits stolen

• Why Do We Subnet? – Efficient Use of IP Address Space (“Right Size” the Network) – Increase Performance (smaller Broadcast domain) – Enhance Routing Efficiency (reduce Routing Table size) – Network Management Policy and Segmentation

(function, ownership, geo location) – Job Security for Network Engineers!

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4

5

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789

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1516

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Provided IP Address Space: 200.25.0.0/16Represents 4,096 IP Addresses

Or 256 /24 Class “C” Blocks

200.25.16.0/24

200.25.17.0/24

200.25.18.0/24

200.25.31.0/24

200.25.30.0/24

200.25.29.0/24

200.25.23.0/24200.25.24.0/24

Provided IP Address Space: 200.25.0.0/16Represents 4,096 IP Addresses

200.25.16.0/21

200.25.30.0/23

200.25.28.0/23

200.25.24.0/22

A

B

C

D

Subnetting Simply Moves the Boundary between the Network and Host Moves Boundary to the Right

Boundary Position Determined by the Subnet “Netmask”

Subnetting Basics

• Identifies the Boundary Between Network and Hosts • “Subnetting” Simply Moves the Boundary!

– Moves Boundary to the Right – IP Address Subnetting Applies to All Classes – Boundary Position Determined by the Subnet “Netmask”

• Expressed in Several Forms: – Doted Decimal Notation (same as IP address) – Slash Notation (also known as CIDR notation)

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IP Address 165.95.240.100 with Netmask of 255.255.255.0

OR

165.95.240.100 /24

Required Host IP Configuration Information

• IP Address • Address Mask • Gateway Address • DNS Server Address(s)

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Where Do We Get This Information?

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Network Questions to Answer • How Many Subnets Are Available? • How May Hosts per Subnet Are Available? • What Are the Subnets? • What is the Broadcast Address of Each Subnet? • What Are the Valid Hosts in Each Subnet?

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What Must Be Known About a Network?

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IP Address and Mask Provides:

First Network Address

First Network Address Assignable to a Host Last Network Address Assignable to a Host

Broadcast Address

192.168.1.0 /24 Provides: 254 useable IP addresses

Mask: 255.255.255.0

Network Address (Wire Address) 192.168.1.0 First Network Address Assignable to a Host 192.168.1.1 Last Network Address Assignable to a Host 192.168.1.254 Broadcast Address 192.168.1.255

Subnet Calculation Examples

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192.168.1.0 /20

Provides: 4094 useable IP addresses Mask: 255.255.240.0

Network Address (Wire Address) 192.168.0.0 First Network Address Assignable to a Host 192.168.0.1 Last Network Address Assignable to a Host 192.168.15.254 Broadcast Address 192.168.15.255

192.168.1.0 /28

Provides: 14 useable IP addresses Mask: 255.255.255.240

Network Address (Wire Address) 192.168.1.0 First Network Address Assignable to a Host 192.168.1.1 Last Network Address Assignable to a Host 192.168.1.14 Broadcast Address 192.168.1.15

An Exercise? • Is 204.56.198.31 mask 255.255.255.224 a Valid Host IP

Address?

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Yes No It Depends

Lets See!

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204.56.198.31 mask 255.255.255.224

1. Convert Mask to Binary – 255.255.255.224: 11111111.11111111.11111111.11100000

2. Convert Mask to Inverse Mask: 11111111.11111111.11111111.11111111subtract from all 1's 11111111.11111111.11111111.11100000

00000000.00000000.00000000.00011111

3. AND IP Address & Mask: 204.56.198.31 00100100.00111000.11000110.00001111255.255.255.224 11111111.11111111.11111111.11100000

00100100.00111000.11000110.00000000Yields the Network Address: 204.56.198.0

4. OR Inverse Mask to Network Address: 00100100.00111000.11000110.0000000000000000.00000000.00000000.0001111100100100.00111000.11000110.00011111Yields the Broadcast Address: 204.56.198.31

5. Thus: Network: 204.56.198.01st Host: 204.56.198.1Last Host: 204.56.198.30Broadcast: 204.56.198.31

The Answer Is NO 204.56.198.31 is Not a Valid

Host Address (It’s the Broadcast Address)

IPv6 Address Space IETF - RFC 2460

IPv6 Provides Expanded IP Address Space 2128 =

340,282,366,920,938,463,463,374,607,431,768,211,456 (three hundred forty UNDECILLION addresses)

3.4 x 1038

• But, IPv6 is More Than Expanded Address Space:

– An Opportunity to Re-Engineer IPv4 • Improved Support for Multicasting, Security, & Mobile Aps • Multiple Addresses per Interface • Host Auto-Configuration Capability • Security Incorporated • MTU Discovery Incorporated • Traffic Engineering Provisions Incorporate

The IPv6 Address

128-Bit Address Binary Format: 001001100000011110111000000000001111101010100000000000110010000110010101100110001000011110111100010010000010100011110001

Subdivide Into Eight (8) 16-bit Groups: 0010011000000111 1011100000000000 0000111110101010 0000000000000011 0010000110010101 1001100010000111 1011110001001000 0010100011110001

Convert Each 16-bit Group to Hexadecimal:

(separate with a colon)

2607:b800:0faa:0003:2195:9887:bc48:28f1 2607:b800:faa:3:2195:9887:bc48:28f1

Address Summarization 128-Bit Address Represented as a 32 Hexadecimal Digits

Subdivided Into Eight Groups (Chunks, Quads, Quartets) of Four Hexadecimal Digits (separated by colon)

2001:0000:0000:0000:0DB8:8000:200C:417A or

2001:0:0:0:DB8:8000:200C:417A or

2001::DB8:8000:200C:417A

Address Summarization 128-Bit Address Represented as a 32 Hexadecimal Digits

Subdivided Into Eight Groups (Chunks, Quads, Quartets) of Four Hexadecimal Digits (separated by colon)

2001:0000:0000:0000:0DB8:8000:200C:417A or

2001:0:0:0:DB8:8000:200C:417A or

2001::DB8:8000:200C:417A

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An Ipv6 Address You Can Remember

The IPv6 Loopback Address ::1 Summarized from: 0:0:0:0:0:0:0:1

IP Addressing Reverse Engineering “A Useful Troubleshooting Tool”

• Verifying Proper Subnet Configuration When Given an IP Address and Subnet Mask – Determine Subnet Address Range – Determine “Assignable” IP Addresses – Determine Broadcast Address

• Subnetting When Given A Network Requirement • Subnetting When Given A Host Requirement

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You Are Provided: IP Address / IP Mask

IP Address Subnetting Charts

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Subnet Calculation Tools

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Hints for Subnetting

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128 1248163264

128 255254252248240224192VLSMMask

BlockSize

/25 /32/31/30/29/28/27/26 CIDR4th Octect

AND0 00

0 01

1 00

1 11

OR0 00

0 11

1 10

1 11

Remember George Boole

Practical Exercise Reverse Engineering an IP Address Plan

Refer to Exercise Handout

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Practical Exercise #2 Developing an IP Addressing Plan

Refer to Exercise Handout

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32 32 64

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Subnet Number:

Broadcast IP Address:

First IP Address:

Subnet Mask:

Last IP Address:

192.168.100.0

255.255.255.192

192.168.100.62

192.168.100.63

192.168.100.1

Subnet Number:

Broadcast IP Address:

First IP Address:

Subnet Mask:

Last IP Address:

192.168.100.64

255.255.255.224

192.168.100.94

192.168.100.95

192.168.100.65

Subnet Number:

Broadcast IP Address:

First IP Address:

Subnet Mask:

Last IP Address:

192.168.100.96

255.255.255.224

192.168.100.126

192.168.100.127

192.168.100.97

What additional IP configuration information is required to configure

hosts on this network? Default Gateway

The Calculator Approach!

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Web Reference Sources: • Subnet Calculation Tools:

www.subnet-calculator.com www.solarwinds.com/products/freetools/free_subnet_calculator.aspx http://www.pkostov.com/wordpress/?p=66 iOS App $: https://itunes.apple.com/us/app/mask-ipv4-ipv6-

calculator/id329508400?mt=8

• RFC Documents: www.rfc-editor.org

• IP Address Subnet Block Size Chart:

http://img.docstoccdn.com/thumb/orig/14990233.png

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Web Reference Sources continued……. • IP Subnetting – Cisco Networkers “Magic Box” Tutorial:

https://learningnetwork.cisco.com/docs/DOC-5893

– Cisco IP Subnetting Game:

https://learningnetwork.cisco.com/docs/DOC-1802

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CBNE Recommended Study:

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My Favorites:

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Thank You for Attending! Wayne M. Pecena Texas A&M University w-pecena@tamu.edu 979.845.5662

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? Questions ?