Shulou(Shulou.com)06/01 Report--

Network1.4

Network layer function and format:

Functions of the network layer:

-- defines a logical address based on ip protocol

-- connecting different media types

Choose the best path for data to pass through the network

IP address Planning:

The role of the IP address: to identify the network of a node

Composition of IP address: 32-bit binary (network part + host part)

Classification of IP addresses: IP addresses can be divided into five categories: Ameme, Breco, C, D, E, and each category has its own rules.

Class An address: 1Mui Mui Mui 126

Category B address: 128Muhami 191

Category C address: 192 Murray 223

Category D address: 224 Muay 239

Category E address: 240Murray 254

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Subnet mask:

Used to determine the network bit and host bit of IP

32 binary bits

-- the network portion of the corresponding IP address is represented by 1

-- the host portion of the corresponding IP address is indicated by 0

Class An address default subnet mask: 255.0.0.0

Class B address default subnet mask: 255.255.0.0

Default subnet mask for class C address: 255.255.255.0

Subnet planning: divide a large network into multiple smaller networks by lengthening the subnet mask

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Network layer protocols and equipment

Common network layer protocols:

ARP protocol:

-- IP address is resolved to MAC address

All hosts received ARP broadcasts of 10.1.1.1, but only 10.1.1.2 gave him single wave recovery and cached the MAC address of 10.1.1.1

ICMP protocol:

-- sent through IP datagrams to send error and control messages

-- ICMP defines many data types, such as:

-- the target is unreachable

-- TTL timeout

-- Information request

-- Information response

-- address request

-address reply

Application of ICMP protocol:

ICMP: check the connectivity of two-way channels

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