Introduction to IPv6 NSS Wing,BSNL Mobile Services, Ernakulam
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IP Network Addressing IPv6 Internet: Worlds largest public data
network doubling its size in every nine months Internet Protocol
(IP) makes internet work Current version- IPv4 defines a 32 bit
addressing scheme. Thus 2 32 or 4,294,967,296 addresses available.
The main problem with IPv4 is eventual depletion of the IP address
space. Traditional model of classful addressing does not allow the
address space to be used to its maximum potential 2
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Techniques to reduce address shortage in IPv4 IPv6 Subnetting
CIDR -Classless Inter Domain Routing NAT Network Address
Translation 3
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Subnetting IPv6 Three level hierarchy- Network, Subnet and Host
The extended-network-prefix is composed of the classful
network-prefix and the subnet-number The extended-network-prefix
has traditionally been identified by the subnet mask 4
Network-Prefix Subnet-Number Host-Number
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CIDR IPv6 Eliminates traditional classful IP routing. Supports
the deployment of arbitrarily sized networks Routing information is
advertised with a bit mask/prefix length specifies the number of
leftmost contiguous bits in the network portion of each routing
table entry Example: 192.168.0.0/21 5
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NAT IPv6 Each organization- single Public IP address Within
organisation each host with IP unique to the organisation, from
reserved set of IP addresses (Private IP Address) IP:Port is
translated both way for inbound and outbound traffic. 6
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IPv6 Very large address space- 128 bit addressing scheme. New
header format Efficient and hierarchical addressing and routing
infrastructure Stateless and stateful address configuration
Built-in security Better support for quality of service (QoS)
Extensibility 7
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IPv6 address format IPv6
3FFE:085B:1F1F:0000:0000:0000:00A9:1234 8 groups of 16-bit
hexadecimal numbers separated by : Leading zeros can be removed eg:
3FFE:85B:1F1F::A9:1234 :: = all zeros in one or more group of
16-bit hexadecimal numbers (can be used once) 8
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IPv6: New header format IPv6 Fixed length main header
Non-essential and optional headers moved to extension header Easy
processing in intermediate devices. No backward compatibility with
IPv4 9
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IPv6: Efficient and hierarchical addressing and routing
infrastructure IPv6 IPv6 designed to create an efficient,
hierarchical, and summarizable routing infrastructure that
addresses the common occurrence of multiple levels of Internet
service providers On the IPv6 Internet, backbone routers have much
smaller routing tables. 10
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IPv6: Stateless and Stateful Address Autoconfiguration IPv6
Stateful Autoconfiguration: In the presense of a DHCP server
Stateless Autoconfiguration: Without help of a DHCP server. Hosts
in the same link can themselves configure IP Address and
communicate 11
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IPv6: Built-in-Security IPv6 Use of IPSec is mandatory 12
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IPv6: Better Support of QoS IPv6 New field in IPv6 header
defines how traffic is identified and handled. Flow label in the
header filed identifies traffic. 13
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IPv6: Extensibility IPv6 IPv6 can be extended for new features
by adding extension headers after the IPv6 header. Unlike the IPv4
header, which can only support 40 bytes of options, the size of
IPv6 extension headers is only constrained by the size of the IPv6
packet. 14