Top 10 Instructions for IP address v6

I. Overview

IPv6 can meet the increasing demand for complex and systematic addressing. The transition from IPv4 addressing to IPv6 addressing is frequently occurring. cisco ios supports ipv6from 12.2 (T.

Ii. Advantages of IPv6

1. Provide a larger address space for plug and play and flexible re-addressing
2. the simpler header information enables the router to provide more efficient route forwarding.
3. Compatibility with mobile IP and IP sec for mobility and security
4. provides a wide range of translation and interoperability methods from IPv4 to IPv6. IPsec is mandatory in IPv6.

3. IPv6 addressing

1. Address Space

The address length is bits or 16 bytes.
The number of allocable addresses is to the power of 38.
The number of addresses that each person on earth can possess is: To the power of 5x10.

2. IPv6 address format

32 hexadecimal numbers, each 4 segments, with a total of 8 segments separated:
The leading digit 0 in each segment can be left blank
In the same address, several consecutive 0 segments can be abbreviated ::
IPv6 address example:

2031: 0000: 130f: 0000: 0000: 09c0: 876a: 130b correct
2031: 0: 130f: 0: 0: 09c0: 876a: 130b correct
2031: 0000: 130f: 09c0: 876a: 130b correct
2031: 130f: 09c0: 876a: 130b Error
0: 0: 0: 0: 0: 0: 0: 1 =: 1 correct
0: 0: 0: 0: 0: 0: 0: 0 =: Correct

4. IPv6 multicast

1. IPv6 does not use broadcast communication. Instead, use multicast or anycast to replace broadcast.
2. multicst makes network communication more efficient, and IPv6 has a large multicast address space.
3. anycast introduction:

Multiple routers share the same unicast address (a group of multicast forwarding routers)
All multicast sources send data packets to the unicast address.
The router automatically selects the destination of the nearest multicast forwarding Router

5. IPv6 Address Aggregation

Multiple Address prefixes can be summarized as one address prefix.
Address Aggregation increases the efficiency and scalability of route selection.

6. IPv6 address automatic configuration

Data-link address can be used for addressing
Automatic Configuration of non-conflicting addresses
Plug and play (requests and announcements of address prefixes are automatically made between the host and the router)

VII. IPv6 address update

By modifying the survival time of the old prefix advertised by the router (reducing its survival time), a new prefix is also advertised.
If you change the prefix of the entire network, you may need to change the dns

8. IPv6 frame format

1. simplified and more efficient header information

64-bit header fields, with fewer Fields
Hardware-based and efficient processing
Improve the efficiency, performance, and forwarding rate of Route Selection

2. Comparison of IPv4 and IPv6 Header Information

IPv4 generally uses 12 header fields and 20 bytes. IPv6 uses 8 header fields and 40 bytes. Five fields are the same as IPv4 and three new fields exist.
IPv6 does not perform fragmentation, so there is no IPv4 fragmentation information. IPv6 uses a discovery process to determine and adjust the most appropriate MTU for a session.
The discovery and processing function of the IPv6 sender automatically adjusts the MTU Size Based on the icmp message returned by the network.
IPv6 Header information does not contain header verification fields. It relies on the upper layer and data link layer to ensure data transmission reliability.

3. IPv6 Header Format

Version field: 4 bits
Traffic class field: 8 bits, similar to IPv4 TOS
Flow label field: 20 bits, the new 20bits field.
Payload length field: 16 bits, similar to the IPv4 total length field
Next header field: 8 bits, similar to the IPv4 PROTOCOL field, used to identify the IPv6 upper-layer information type.
Hop limit field: 8 bits, similar to the TTL field of IPv4,
Source address field: 128 bits
Destination address: 128 bits

4. IPv6 extension header information

IPv6 can have many types of extension header information, and multiple types of extension header information can be used at the same time. The application sequence is as follows:

1) IPv6 header
2) hop-by-hop options header
3) destination options header
4) routing header
5) fragment header
6) authentication header
7) encapsulating security payload header
8) destination options header
9) upper-layer header

9. interoperability between IPv6 and IPv4

1. Overview

Extensive conversion methods from IPv4 to IPv6
Use dual stack or 6to4 tunnel for smooth conversion
Use NAT to enable IPv4 and IPv6 nodes to communicate

2. IOS dual stack

Dual stacked: if both IPv4 and IPv6 are configured on an interface, this interface is called dual stacked.
The Cisco router must use the global command: IPv6 unicast routing to enable IPv6.
Use interface commands to assign an IPv6 address: IPv6 address <IPv6-address [/prefix length]>

3. overlay tunnel)

Connect two IPv6 networks through an IPv4 Backbone Network
Encapsulation of IPv6 data packets in IPv4 data packets
Both ends of the tunnel must use the dual-stack interface.
IPv4 and IPv6 addresses must be configured at both ends of the tunnel.

4. Use 6to4 tunnel to connect to the IPv6 network

Use an IPv4 network to connect and transmit IPv6 Packets
Is a method for automatically establishing a tunnel
Both ends of the tunnel must use a fixed IPv6 prefix (IPv4 address of the local border router of 2002 + 2 bytes)
The destination address of the IPv6 packet forwarded by the VBR contains the IPv4 address of the destination VBR.
The local border router automatically retrieves the destination IPv4 address and encapsulates the IPv6 package in the IPv4 packet for forwarding.
The destination VBR unblocks the received IPv4 packet and forwards it to the destination IPv6 host.

10. IPv6 routing protocol and IOS requirements

Integrated isis for IPv6 12.0 (22) s and 12.2 (8) T
BGP for IPv6 12.0 (22) s and 12.2 (2) T
RIP for IPv6 12.0 (22) s and 12.2 (2) T
Static route for IPv6 12.0 (22) s and 12.2 (2) T
Currently, the re-release of IPv4 and IPv6 routing protocols is not supported.