Page 1 Network Addressing CS.457 Network Design And Management
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
Page 1
Network Addressing
CS.457 Network Design And Management
Page 2
Page 3
Two Key Network-Layer Functions
Page 4
Router Architecture Overview
Page 5
Page 6
IP Fragmentation & Reassembly
Page 7
IP datagram format
CS.319 Computer Network
Page 8
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 9
Types of Addresses
Page 10
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 11
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 12
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 13
Classfull Adressing
Page 14
Subnets
Page 15
Subnets: Example
Page 16
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 17
Page 18
Network and Host Addresses
Page 19
Page 20
A Network with Two Levels of Hierarchy
Page 21
A Network with Three Levels of Hierarchy
Page 22
Page 23
IP addresses
Page 24
Dynamic Addressing
Page 25
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 26
DHCP: Dynamic Host Configuration Protocol
Page 27
DHCP client-server scenario
Page 28
DHCP client-server scenario
Page 29
Handling IP Address Depletion
• Variable Length Subnet Mask (VLSM)and Classless Interdomain Routing (CIDR)
• Network Address Translation (NAT)
• IPv6
Page 30
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 31
Q: How does network get subnet part of IP address?
Page 32
Page 33CS.319 Computer Network
Page 34
Page 35
Hierarchical addressing: route aggregation
Page 36
Page 37CS.319 Computer Network
Page 38
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 39
NAT : Network Address Translation
• Assign private addresses to the internal systems
• Router translate the addresses
Page 40
NAT: Network Address Translation
Page 41
NAT: Network Address Translation
Page 42
Using Illegal Addresses with NAT
Page 43
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 44
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 45
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 46
What’s good about IPv6
• Larger Address space– 128 bit: 3.4 ื10^38
• 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 47
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 48
IPv6 Header (Cont)
Page 49
Ipv6 and IPv4 Header Format
Page 50
IPv6 Address
Page 51
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 52
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 53
Tunneling
Page 54
Tunneling
Page 55
Tunneling
Page 56
QuestionQuestion ??
Related Documents
