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This article mainly introduces which protocols are used in conjunction with the IP protocol. It is very detailed and has a certain reference value. Friends who are interested must read it!

The four protocols used with IP are: 1. Address Resolution Protocol (ARP;2), inverse address Resolution Protocol (RARP;3), Internet Control message Protocol (ICMP;4), Internet Group Management Protocol (IGMP).

The four protocols used in conjunction with the IP protocol are:

Address Resolution Protocol ARP

Description:

Each host of ARP has an ARP cache (ARP cache), which contains a mapping table of IP addresses to hardware addresses of hosts and routers on the local area network.

Function:

Learn the physical address from the IP address

Steps:

Note:

Other hosts on the network do not respond to ARP queries, and only when the receiving host receives the frame does it respond to the sending host.

ARP is to solve the mapping problem between IP address and hardware address of host or router on the same local area network. If the host you are looking for and the source host are not on the same local area network, you should find the hardware address of a router located on this local area network through ARP, and then send the packet to this router and ask the router to forward the packet to the next network. The next network will do the rest of the work.

The resolution from IP address to hardware address is carried out automatically, and the host user does not know about this address resolution process.

If a host or router wants to communicate with another host or router with a known IP address on this network, the ARP protocol will automatically resolve the IP address to the hardware address required by the link layer.

Four typical situations:

The sender is the host and sends the IP Datagram to another host on this network. Then use ARP to find the hardware address of the destination host.

The sender is the host that wants the IP Datagram to be sent to another network. At this point, ARP finds the hardware address of a router on this network. The rest of the work is done by this router

The sender is the router that forwards the IP Datagram to a host on this network. Then use ARP to find the hardware address of the destination host.

The sender is the router that forwards the IP Datagram to a host on another network. At this time, use ARP to find the hardware address of a router on this network. The rest of the work is done by this router

Header format:

Description:

The hardware type field indicates the type of hardware address. A value of 1 indicates an Ethernet address

The protocol type field indicates the type of protocol address to be mapped. Its value of 0x0800 indicates the IP address.

Hardware address length and protocol address length indicate the length of hardware address and protocol address respectively, in bytes. For ARP requests or replies to IP addresses on Ethernet, their values are 6 and 4, respectively

The action field indicates four types of operations: ARP request (value 1), ARP reply (value 2), RARP request (value 3), and RARP reply (value 4)

The next four fields are the hardware address of the sender (in this case, the Ethernet address), the protocol address of the sender (IP address), the hardware address of the destination, and the protocol address of the destination.

2. Inverse address Resolution Protocol RARP

Definition:

Inverse address Resolution Protocol RARP enables hosts that only know their hardware addresses to know their IP addresses

Purpose:

This kind of host is often a diskless workstation. Therefore, the RARP protocol is rarely used at present.

RARP and RAP:

Internet Control message Protocol (ICMP)

Objective:

To improve the chances of successful delivery of IP datagrams

Note:

Allow hosts and routers to report errors and provide reports on anomalies

ICMP is not a high-level protocol, but an IP layer protocol.

The ICMP message, as the data of the IP layer Datagram, together with the header of the Datagram, forms the IP Datagram and sends it out.

The first four bytes of the ICMP message are in a uniform format, with three fields: type, code, check and. The content of the next four bytes is related to the type of ICMP

Species:

ICMP error report message:

The end point is unreachable.

Source point suppression (Source quench)

The time exceeds

Parameter problem

Change routing (redirect) (Redirect)

ICMP inquiry message:

Send back requests and reply messages

Timestamp request and reply message

Message format:

4. Internet Group Management Protocol IGMP

Message format:

Function:

It is the protocol responsible for the management of IP multicast members in the TCP/IP protocol family, which is used to establish and maintain multicast group membership between IP hosts and their directly adjacent multicast routers.

Features:

When a host joins a new group, it sends an IGMP message to the group address to announce its membership, from which multicast routers and switches can learn the membership of the group. Using the information obtained from IGMP, routers and switches maintain a list of multicast group members on each interface

Two stages:

Join: when a host joins a new multicast group, it sends an IGMP message to the multicast address of the multicast group, declaring that it wants to be a member of the group. After receiving the IGMP message, the local multicast router forwards the group membership to other multicast routers on the Internet

Ask: periodically inquire the hosts on the local LAN to know if they continue to be members of the group

Note:

Because group membership is dynamic, the local multicast router considers the group to be active as long as it has a host response to the group

However, if a group still does not have a host response after several inquiries, the group membership will no longer be forwarded to other multicast routers

Packet:

IGMP uses IP Datagram to deliver its message (that is, IGMP message plus IP header to form IP Datagram), but it also provides services to IP

Specific measures:

All communication between the host and the multicast router uses IP Multicast

When probing group membership, multicast routers only need to send a query message requesting information to all groups, but not to each group. The default query rate is sent every 125 seconds

When several multicast routers are connected to the same network, they can quickly and effectively select one of them to inquire about the membership of the host.

There is a value N in the IGMP query message, which indicates a maximum response time (the default is 10 seconds). When a query is received, the host randomly selects the delay to send the response between 0 and N. The response corresponding to the minimum delay is sent first.

Every host in the same group listens to the response. As long as other hosts in this group send the response first, they can stop sending the response.

The above is all the contents of the article "what are the protocols used with the IP Agreement?" Thank you for reading! Hope to share the content to help you, more related knowledge, welcome to follow the industry information channel!

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