IPv6 : Next Generation IP

[smart paper boy]

Presented by:
Minal Mishra

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Agenda
IP Network Addressing
Classful IP addressing
Techniques to reduce address shortage in IPv4
Features of IPv6
Header Comparisons
Extension Headers
Conclusions
IP Network Addressing
INTERNET  world’s largest public data network, doubling in size every nine months
IPv4, defines a 32-bit address - 232 (4,294,967,296) IPv4 addresses available
The first problem is concerned with the 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.
Classful Addressing
When IP was first standardized in Sep 1981, each system attached to the IP based Internet had to be assigned a unique 32-bit address
The 32-bit IP addressing scheme involves a two level addressing hierarchy
Classful Addressing…
Divided into 5 classes
Class A 8 bits N/W id and 24 bits host id and so on B,C.
Wastage of IP addresses by assigning blocks of addresses which fall along octet boundaries
Techniques to reduce address shortage in IPv4
Subnetting
Classless Inter Domain Routing (CIDR)
Network Address Translation (NAT)
Subnetting
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
Subnetting Example
Classless Inter-Domain Routing
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
CIDR Table Entry…
Extract the destination IP address.
Boolean AND the IP address with the subnet mask for each entry in the routing table.
The answer you get after ANDing is checked with the base address entry corresponding to the subnet mask entry with which the destination entry was Boolean ANDed.
If a match is obtained the packet is forwarded to the router with the corresponding base address
Network Address Translation
Each organization- single IP address
Within organization – each host with IP unique to the orgn., from reserved set of IP addresses
NAT Example
Features of IPv6
Larger Address Space
Aggregation-based address hierarchy
– Efficient backbone routing
Efficient and Extensible IP datagram
Stateless Address Autoconfiguration
Security (IPsec mandatory)
Mobility
Major Improvements of IPv6 Header
No option field: Replaced by extension header. Result in a fixed length, 40-byte IP header.
No header checksum: Result in fast processing.
No fragmentation at intermediate nodes: Result in fast IP forwarding.
Extension Headers
Routing – Extended routing, like IPv4 loose list of routers to visit
Fragmentation – Fragmentation and reassembly
Authentication – Integrity and authentication, security
Encapsulation – Confidentiality
Hop-by-Hop Option – Special options that require hop-by-hop processing
Destination Options – Optional information to be examined by the destination node
Stateless Address Autoconfiguration
3 ways to configure network interfaces: Manually, Stateful, Stateless
IPSAA IPv6 addr. Separated into 2 2 parts: network and interface id.
Link- local addresses: prefix FE80::0 + interface identifier (EUI-64 format)
Obtain network id through Router solicitation (RS)
Conclusion
IPv6 is NEW …
– built on the experiences learned from IPv4
– new features
– large address space
– new efficient header
– autoconfiguration
… and OLD
– still IP
– build on a solid base
– started in 1995, a lot of implementations and tests done