Computer Technology and Software Professional Technical Qualification (Level) Examination-Soft Exam Intermediate Network Engineer Notes Six

IPv6

 

Get to know: IPv6 extension header classification

If there are multiple extended headers, the first extended header is the hop-by-hop header. The hop-by-hop option has no specified code, and field 0 is used to indicate the existence of the hop-by-hop header.

 

In IPv6, segmentation can only be performed by the source node, and the intermediate router cannot be segmented. Its purpose is to simplify routing processing.

IPv6 address is expanded to 128 bits, using colon hexadecimal

IPv6 abbreviation rules: the effective zero cannot be simplified, and the double colon can only appear once

The format prefix of an IPv6 address indicates the address type and subnet address.

 

Unicast address:

1. Unknown address (0:0:0:0:0:0:0:0)
2. Loopback address (0:0:0:0:0:0:0:1)
3. Multicast address (no broadcast address)

 

Anycast address

1. Anycast address cannot be used as a source address, only as a destination address.
2. Anycast addresses cannot be assigned to IPv6 hosts, they can only be assigned to IPv6 routers.
3. The subnet prefix must be fixed, and the remaining positions are all "0"

 

 

Similar to 192.168.xx in IPv4

Similar to 169.254.xx in IPv4

 

 

 

 

IPv6 stateful addresses require DHCPv6 server support. The stateless address is generated based on the MAC address.

ICMPv6 replaces ARP function

 

Mobile IP: The mobile host can work online at a remote site away from the home network.

 

IPv4 to IPv6 transition technology

1. 1. Tunnel technology (two IPv6 nodes communicate through the existing IPv4 network) IPv4 is the bearer and IPv6 is the passenger)
   2. Dual stack technology
   3. Translation technology (to make pure IPv6 nodes communicate with pure IPv4 nodes)

 

Three dynamic tunnel technologies

1) 6to4 technology, the prefix is ​​0x2002 to indicate the 6to4 address

2002+32-bit IP4 address+16-bit subnet bit+64-bit interface identifier (MAC address is split into 24-bit+24-bit, plus FFFE in the middle)

2) 6over4 technology

    3) ISATAP tunnel (dual stack technology)

 

SIIT protocol translation technology

1. IPv4 mapped address (convert IPv4 to IPv6),

   

1.  

 

NAT-PT (Stateful Translation Technology) is a communication between pure IPv6 nodes and IPv4 nodes. Basically one-way

1. Static
2. dynamic
3. NAPT-PT is one-way, enabling a group of IPv6 addresses to share the same IPv4 address

Two-way NAPT-PT

 

Dual stack technology

1. TO

Insert three special expansion modules into the IPv4 protocol stack

1. converter
2. Extended domain name resolver
3. Address mapper

1. BEER