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Network PlusIP Addressing Review

IP Address Classes

Reserved IP Addresses Ranges

• Addresses cannot be all “1s”– Considered broadcast

• Loopback address– 127.x.y.z

• Private IP address reserved for LAN, not routable across Internet BGP routers.

Private IP Address Ranges

Subnet Masking

Default Subnet Masks

• Classful Default Masks– Class A: 255.0.0.0– Class B: 255.255.0.0– Class C: 255.255.255.0

• Classless Default Masks– Class A: /8– Class B: /16– Class C: /24

Subnetting• IP Address: 192.168.1.x/24• Default Mask: 255.255.255.0 • Create 3 subnets

– Mask: 255.255.255.224• 11100000 = 128+64+32 = 224

• Subnet numbers:– 001, 010, 100

• Computer address 1 on subnet 001– 192.168.1.33

• Computer address 1 on subnet 010– 192.168.1.65

Super-Netting

• Put more computers on subnet than default mask would allow

• Example: Need 300 computers on 192.168.4.x/24• Subnet Mask (move to the left 1 bit)

– 255.255.254.0 or /23– Computer addresses:

• 192.168.00000100.00000001 – 192.168.4.1• 192.168.00000101.111111110 – 192.168.5.254

Planning IP Addresses

• Necessary IP Address components:– IP Address– Subnet Mask– Default Gateway

IP Configuration

• Gateway and all computers must have same IP network address on the switch

• Gateway has public IP address on Internet port• Computer uses Subnet Mask to check destination

against it’s IP address. If on same network, ARP and get MAC address of receiver. If on different networks, sends packet to the gateway.

Computer IP Configuration Settings

• IP Address: 192.168.4.1• Mask: 255.255.255.0• Default Gateway: 192.168.4.10

IP Assignment Methods

• Static– Used by devices such as Printers, Servers, Routers– Assignment method depends on device or computer

OS• Dynamic

– BootP (Bootstrap Protocol)– DHCP (Dynamic Host Configuration Protocol)– APIPA (Automatic Private IP Addressing)

Static IP Assignment

DHCP

• Client makes requrest.• DHCP Server makes IP lease assignment from a range

of IP addresses called a scope• Lease must be renewed within specified period (days or

hours)• Provides multiple parameters

APIPA

• Automatic Private IP Addressing• Used by Windows when no response from DHCP

server• Microsoft Standard• Apple has similar process called Rendezvous• Address range:

– 169.254.x.y– Does not use Gateway– When you see a computer with this address it may have

experienced problem connecting to DHCP server such as if a users turns on computer before WAP

IPv6 Address Overview• Composed of 8 16-bit fields (128-bits)

• Each 16-bit field represented by 4 Hex digits separated by colons.

• F:F:0:0:0:0:3012:0CE3 same as 000F:000F:0000:0000:0000:0000:3012:0CE3

• A string of “0000” fields may be represented by a double ::

• F:F::3012:CE3 ( in shorthand) • Because there are 8 16 bit fields, it is assumed 4 fields

of 0000 between the “::”

• Loopback address = ::1 (0000:0000:0000:0000:0000:0000:0000:0001)

IPv6 Address Specifications

• Address reflects scope of transmission’s recipients:• First 64 bits is the network and last 64 bits is the host• Unicast address local address

– Starts with – FEC or FE8 – Public Internet start with 2 or 3

• Anycast address – represents any one interface from a group of interfaces

• Multicast address:– Starts with – FF0x “x” is the group id

• Global multicast– Starts with – FF0E

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IPv6 Address Scopes

• Unicast address (link-local)– FE80: … (link-local – packet not routable)

– 1111 1110 10 (“FE8”, “FE9”, “FEA” or “FEB”)

– FEC0:.. (site-local – not routable on public Internet)– 1111 1110 11 (“FEC”, “FED”, “FEE” or “FEF”)

– Nnnn: (Internet)

• Multicast– Send to all computers in a multi-cast group– FF0x: … (x represents the multicast group)

• Anycast address– Standard unicast address assigned to multiple machines– Used with routers to all nearest router to accept the packet– Packet can be accepted by first available device

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IPv6 Address Types

Link Scope

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Aggregatable Global Address

• Used on Public Internet routers • Designed from its foundation to support efficient,

hierarchical addressing and routing– Summarized to produce an efficient routing

infrastructure

• Start with 001 in first three bits. (2:: or 3::)

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IPv6 Subnetting

• Does not use Classes – every IPv6 address is classless– No subnet masks

• First 64-bits network id (Subnet Prefix) and last 64-bits is the interface id.– Interfaces that share subnet prefix on same subnet

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Route Prefix

• Interfaces that belong to same route• Vary in length defined by “/”

– 2608:FE10::/32• Example:

• National NSP assigns regional ISP 32-bit route: 2608:FE10::/32

• Regional ISP assigns a local ISP a 48-bit route block prefix: 2608:FE10:1::/48

• Local ISP assigns business 2608:FE10:1:A::/64

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That’s all folks