Network basic Learning of Linux Operation and maintenance
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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