03-11-2012, 03:24 PM
Introduction to IPv6
IPv61.ppt (Size: 421 KB / Downloads: 94)
ipv6.ppt (Size: 250 KB / Downloads: 47)
ipv62.ppt (Size: 74.5 KB / Downloads: 76)
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
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
Sub netting
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
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
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