IP address-Computer network

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1. MAC address and IP address are global (global distribution), but IP addresses are layered and routable.

The IP address is distributed progressively by ICANN and China is cnnic.

Each interface of a host or router can be configured with one or more IP addresses.

2. IP Address Structure

　

The IP addresses are divided into network numbers and host identifier.

Network number: The network on which the host that identifies the IP address is located, and the host number is used to determine which host is part of the network.

3. There are class nets

The traditional IP address is divided into 5 categories.

　　

The 5 columns correspond to the number of bits for the class network, the address network number and the host number, the first dotted decimal range, the address range, the default subnet mask for each class, and the resolution bit for the address header.

　　

4. IPv4 address exhaustion Status: TheInternet in the convenience of hundreds of millions of users at the same time, they face a fatal problem, the building of this omnipotent Internet base IPV4 protocol can no longer provide a new network address.

5. Sub-Network partitioning issues:

　　

6. VLSM: English full name Variable-length Subnet mask, changing the eldest son Netmask, allowing a class network to be divided into a number of different sizes of subnets.

　　

7. CIDR: Classless Inter-domian Routing, non-class inter-domain routing protocol

　　

8. Private IP Address

The private IP address does not need to be assigned by the IANA these agencies, and anyone can use the IP address.

(1). 10.0.0.0~10.255.255.255

(2). 172.16.0.0~172.31.255.255

(3). 192.168.0.0~192.168.255.255

　　Private addresses can only be used for internal networks. Routers on the backbone will filter out IP datagrams with the destination address as the private address . IP datagrams leaving the internal network must use the IANA-assigned global address as the destination address, which involves the next content Nat.

9. NAT: network address translation

Network address Translation Maps an internal address to an external address, for example, mapping the private address of a xiaonei to an external global address.

　　

　　

IP address-Computer network