Network engineers must know the 10 technical points of IPv6. It is recommended to collect them!

In the past 10 Mid year ,IPV6 Its global penetration rate is less than that of all Internet traffic 1% To the present 36% above ,IPV6 The relevance to the network engineer profession is now higher than ever , Today's article hopes that every network engineer will have a look , This article mainly introduces ipv6 Of 10 Technical points .

1. IPV6 The penetration rate exceeds 25%

Let's take a look Google Made of IPV6 Popular map ：

It is obvious from the picture that ipv6 The penetration rate of is rising so fast , Until now, , Has almost surpassed 36% 了 .

I believe that it will slowly occupy a market in the near future , Even beyond ipv4.

2. Huge address space

establish IPV6 The main motivation for is the need for a larger address space .

One IPV4 The address contains 32 Bit data , Can provide 2 Of 32 Power Maximum address space of addresses , About equal to 40 Billion An address .

IPv6 Can provide up to 2 Of 128 Power An address , This is far greater than the number of stars in the universe , This order of magnitude is enough for humans to use for quite some time .

3. IPV6 Medium NAT

NAT The purpose of protocol network address translation is to convert private addresses IPV4 Address aggregation to a public address to minimize IPV4 Waste of address .

However , about IPV6, There is no danger of running out of addresses , therefore NAT It is no longer standard practice . Theoretically, it can still be configured, but it is not recommended .

Some people think that NAT Provide security benefits , But the reality is that this is not the purpose of the agreement , And it's better than passing NAT Better ways to protect the network .

4. DHCPV6 and SLAAC

IPV Of 4DHCP Will be in IPV6 Disappear in , Two options will replace ：

• DHCPV6
• SLAAC

It is not yet clear which will take the lead .

SLAAC, Stateless address auto configuration , stay SLAAC in , The host listens for router advertisements (RA) Message to configure its IPV6 Address , The host will use RA Assign yourself a unique address in combination with other data , The agreement is No state Of , Because there is no device tracking configured address list on the network .

SLAAC, This agreement is somewhat similar to DHCP The state of being IPV4 edition , Interestingly ,SLAAC You can also use DHCPv6 Get data for self allocation of stateless addresses , therefore , According to the required design ,DHCPv6 Protocols can be used for stateful or stateless settings .

5. Hexadecimal symbols

write in IPV4 The standard way to address is to split the value into 4 Eight octets , And write each octet in decimal notation .

This method is suitable for IPV6 It is not concise enough , therefore ,IPV6 Use Hexadecimal notation , Every “ Hexadecimal ” use The colon Separate , Hex is 16 A wide , Twice the size of octets , Here is IPV6 Examples of addresses .

2001:0db8:0a0b:12f0:0000:0000:0000:0001

6. IPV6 Compressed format

RFC 5952 It is recommended to use a shorthand format to write IPV6 Address , This makes the address more readable to humans , The rules of notation are simple .

Omit leading zeros in each hex .

Double colons are used to completely omit subsequent hexadecimal values that are zero .

for example , We can use the following abbreviation to write our previous IPV6 Address .

2001:db8:a0b:12f0::1

7. Loopback address

IPV4 The most common loopback address in is 127.0.0.1

about IPV6, The most common loopback addresses are as follows :

0000:0000:0000:0000:0000:0000:0000:0001

We can use our shorthand symbols to write this address very succinctly , As shown below , It's even better than IPV4 The address should be simple ！

::1

8. IPV6 The Internet in

stay IPV4 in , The size of the network portion of the address will vary , Subnet mask Will describe IP The number of bits in the address representing the network part .

stay IPV6 in , The network part of the address is almost always 64 position , This part can be further divided into two parts , front 48 On behalf of Global unicast address , after 16 On behalf of subnet ID.

9. AAAA DNS Record

Any managed IPV4 DNS Server people will be very familiar with the host name resolution “A” Record .

stay IPV6 In the world ,DNS Still relevant , But use “AAAA” Record instead of “A” Record . These records are also known as Quad A Record .

10. IPV6/IPV4 Compatibility

IPV6 Essentially with IPV4 Are not compatible .

therefore , As the world turns IPV6, Technologies have been developed to create compatibility for long-term migrations , Two such technologies are “Lightweight 4over6” and “NAT64”, I'll take you through these two technologies later .