Download Colorful Spring Flowers

Document related concepts

Piggybacking (Internet access) wikipedia , lookup

Distributed firewall wikipedia , lookup

Network tap wikipedia , lookup

Computer network wikipedia , lookup

Wake-on-LAN wikipedia , lookup

Airborne Networking wikipedia , lookup

Dynamic Host Configuration Protocol wikipedia , lookup

List of wireless community networks by region wikipedia , lookup

I²C wikipedia , lookup

Recursive InterNetwork Architecture (RINA) wikipedia , lookup

Cracking of wireless networks wikipedia , lookup

Zero-configuration networking wikipedia , lookup

Transcript
Network Addressing
CS.457 Network Design And Management
Page 1
Page 2
Two Key Network-Layer Functions
Page 3
Router Architecture Overview
Page 4
Page 5
IP Fragmentation & Reassembly
Page 6
IP datagram format
CS.319 Computer Network
Page 7
Network Layer Functions
• Addressing
– Each equipment on the path between
source and destination must have an
address
– Internet Addresses
– Assignment of addresses
– Translation between network layer
addresses and other addresses (address
resolution)
Page 8
Types of Addresses
Page 9
Assignment of Addresses
• Application Layer address (URL)
– For servers only (clients don’t need it)
– Assigned by network managers and placed in configuration
files.
– Some servers may have several application layer addresses
• Network Layer Address (IP address)
– Assigned by network managers, or by programs such as
DHCP, and placed in configuration files
– Every network on the Internet is assigned a range of possible
IP addresses for use on its network
• Data Link Layer Address (MAC address)
– Unique hardware addresses placed on network interface
cards by their manufacturers ( based on a standardized
scheme)
– Servers have permanent addresses, clients usually do not
Page 10
Internet Addresses
• Managed by ICANN
– Internet Corporation for Assigned Names and
Numbers
– Manages the assignment of both IP and
application layer name space (domain names)
• Both assigned at the same time and in groups
• Manages some domains directly (e.g., .com, .org, .net)
and
• Authorizes private companies to become domain name
registrars as well
• Example: kasem bundit university
– IP addresses of kbu.ac.th is 203.149.0.3,
Page 11
IPv4 Addresses
• 4 byte (32 bit) addresses
– Strings of 32 binary bits
• Dotted decimal notation
– Used to make IP addresses easier to
understand for human readers
• Breaks the address into four bytes and
writes the digital equivalent for each
byte
Page 12
Classfull Adressing
Page 13
Subnets
Page 14
Subnets: Example
Page 15
Subnet Masks
• Used to make it easier to separate the subnet
part of the address from the host part.
• Example
– Subnet: 149.61.10.x
– Subnet mask: 255.255.255.0 or in binary
11111111.11111111.11111111.00000000
• Example
– Subnets: 149.61.x.x
– Subnet mask 255.255.0.0 or, in binary:
11111111.11111111.00000000.00000000
Page 16
Page 17
Network and Host Addresses
Page 18
Page 19
A Network with Two Levels of Hierarchy
Page 20
A Network with Three Levels of Hierarchy
Page 21
Page 22
IP addresses
Page 23
Dynamic Addressing
Page 24
Programs for Dynamic Addressing
• Bootstrap Protocol (bootp)
• Dynamic Host Control Protocol (DHCP)
• Different approaches, but same basic operations:
– A program residing in a client establishes connection to
bootp or DHCP server
– A client broadcasts a message requesting an IP address
(when it is turned on and connected)
– Server (maintaining IP address pool) responds with a
message containing IP address (and its subnet mask)
– IP addresses can also be assigned with a time limit (leased
IP addresses)
– When expires, client must send a new request
Page 25
DHCP: Dynamic Host Configuration Protocol
Page 26
DHCP client-server scenario
Page 27
DHCP client-server scenario
Page 28
Handling IP Address Depletion
• Variable Length Subnet Mask
(VLSM)and Classless Interdomain
Routing (CIDR)
• Network Address Translation (NAT)
• IPv6
Page 29
CIDR: Classless InterDomain Routing
• subnet portion of address of arbitrary
length
• address format: a.b.c.d/x, where x is #
bits in subnet portion of address
Page 30
Q: How does network get subnet part of IP address?
Page 31
Page 32
CS.319 Computer Network
Page 33
Page 34
Hierarchical addressing: route aggregation
Page 35
Page 36
CS.319 Computer Network
Page 37
NAT: Network Address Translation
• Motivation: local network uses just one IP
address as far as outside world is concerned:
– range of addresses not needed from ISP: just one
IP address for all devices
– can change addresses of devices in local network
without notifying outside world
– can change ISP without changing addresses of
devices in local network
– devices inside local net not explicitly addressable,
visible by outside world (a security plus).
Page 38
NAT : Network Address Translation
• Assign private addresses to the internal
systems
• Router translate the addresses
Page 39
NAT: Network Address Translation
Page 40
NAT: Network Address Translation
Page 41
Using Illegal Addresses with NAT
Page 42
IPv6 is…
• IP with:
– Larger address fields (128 bits)
– Yes, that’s a VERY big number!
– Smaller number of header fields
– Altered support for header extensions
– Addition of a flow label header field
Page 43
IPv6
• What has not changed
– Almost everything!
– IPv6 is a connectionless datagram delivery
service using end-to-end address identifiers
and end-to-end signalling with TCP and
UDP transport services.
• So is IPv4.
Page 44
IPv6 Strengths
• Larger Addresses mean no forced Network
Address Translators
– Eliminate NAT architectures as a means of
address scaling
– Allow coherent end-to-end packet delivery
– Improve the potential for use of end-to-end security
tools for encryption and authentication
– Allow for widespread deployment peer-to-peer
applications
• SIP, IMM, …
Page 45
What’s good about IPv6
• Larger Address space
– 128 bit: 3.4ื10^38
• IPv6 can not easily solve (same as IPv4);
– (Security,Multicast,Mobile,QoS)
• Re-design to solve the current problems such
as;
–
–
–
–
Routing
Security
Auto-configuration
Plug & Play
Page 46
IPv6
• Initial motivation: 32-bit address space
soon to be completely allocated.
• Additional motivation:
– header format helps speed
processing/forwarding
– header changes to facilitate QoS IPv6
datagram format:
– fixed-length 40 byte header
– no fragmentation allowed
Page 47
IPv6 Header (Cont)
Page 48
Ipv6 and IPv4 Header Format
Page 49
IPv6 Address
Page 50
IPv6 address notation
• Basic rules “:” in every 2 bytes,Hex digits
example
• 3ffe:0501:0008:0000:0260:97ff:fe40:efab
– 3ffe:501:8:0:260:97ff:fe40:efab
– 3ffe:501:8::260:97ff:fe40:feab
• ff02:0000:0000:0000:0000:0000:0000:0001
– ff02:0:0:0:0:0:0:1
– ff02::1
Page 51
Transition From IPv4 To IPv6
• Not all routers can be upgraded
simultaneous
– no “flag days”
– How will the network operate with mixed
IPv4 and IPv6 routers?
• Tunneling: IPv6 carried as payload in
IPv4 datagram among IPv4 routers
Page 52
Tunneling
Page 53
Tunneling
Page 54
Tunneling
Page 55
Question ?
Page 56