The network layer has four protocols: ARP protocol, IP protocol, ICMP protocol, and IGMP protocol. The ARP protocol provides services for the IP protocol, the IP protocol provides services for the ICMP protocol, and the ICMP protocol provides services for the IGMP protocol.
The operating environment of this article: Windows 7 system, Dell G3 computer.
What are the network layer protocols?
Network layer protocol, the third layer of the OSI reference model. It controls the work of the communication subnet, provides means to establish, maintain and release connections, and ensures transparent data transmission between transport layer entities.
Network layer protocols include:ARP protocol, IP protocol, ICMP protocol, and IGMP protocol.
ARP protocol:
Address Resolution Protocol, or ARP (Address Resolution Protocol), is a TCP/IP protocol that obtains a physical address based on an IP address.
When the host sends information, it broadcasts the ARP request containing the target IP address to all hosts on the local area network, and receives the return message to determine the physical address of the target; after receiving the return message, the IP address and The physical address is stored in the local ARP cache and retained for a certain period of time. The ARP cache is directly queried on the next request to save resources.
The address resolution protocol is based on mutual trust between hosts in the network. Hosts on the local area network can send ARP response messages independently, and other hosts will not detect the message when they receive the response message. The authenticity will be recorded in the local ARP cache; thus the attacker can send a fake ARP reply message to a certain host, so that the information sent cannot reach the expected host or reaches the wrong host, which constitutes An ARP spoof.
The ARP command can be used to query the correspondence between IP addresses and MAC addresses in the local ARP cache, add or delete static correspondence, etc. Relevant protocols include RARP and proxy ARP. NDP is used to replace Address Resolution Protocol in IPv6.
IP Protocol:
IP is the abbreviation of Internet Protocol and is the network layer protocol in the TCP/IP system. The purpose of designing IP is to improve the scalability of the network: first, to solve Internet problems and realize the interconnection of large-scale and heterogeneous networks; second, to separate the coupling relationship between top-level network applications and underlying network technologies to facilitate the two. Develop independently. According to the end-to-end design principle, IP only provides a connectionless, unreliable, best-effort packet transmission service to the host.
ICMP protocol:
ICMP (Internet Control Message Protocol) Internet Control Message Protocol. It is a subprotocol of the TCP/IP protocol suite and is used to transmit control messages between IP hosts and routers. Control messages refer to messages about the network itself, such as network connectivity, whether the host is reachable, and whether routes are available. Although these control messages do not transmit user data, they play an important role in the transmission of user data.
ICMP uses the base support of IP as if it were a higher level protocol, however, ICMP is actually an integral part of IP and must be implemented by every IP module.
IGMP protocol:
Internet Group Management Protocol (IGMP, Internet Group Management Protocol) is a multicast protocol in the Internet protocol family.
A sub-protocol of the TCP/IP protocol suite, used by IP hosts to report their group membership to any directly adjacent router. Allows Internet hosts to participate in multicast, and is the protocol used by IP hosts to report multicast group membership to neighboring multicast routers. Multicast routers are multicast-enabled routers that send IGMP queries to the local network. The host responds to the query by sending an IGMP report. Multicast routers are responsible for forwarding multicast packets to all multicast members in the network.
Internet Group Management Protocol (IGMP) is a protocol corresponding to the network layer in the Open Source Systems Interconnection (OSI) seven-layer framework model. The Internet Group Management Protocol (IGMP) is described in detail in the standard document (RFC) 2236. prepared by the Internet Engineering Task Force (IETF).
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