Communication Networks/IP Protocol and ICMP - Wikibooks, open books for an open world
But usually if the two peer neighbors can ping each other, we can consider the tcp is working well. So what is relationship between ping. Communication Networks/IP Protocol and ICMP 5 IPv4 and IPv6; 6 Internet Control Message Protocol (ICMP); 7 Classful Address File:IP oculo-facial-surgery.info TCP/IP, on the other hand, establishes a connection between two hosts so Of course, since ICMP uses IP, ICMP packet delivery is unreliable.
Understanding the ICMP Protocol (Part 2)
ICMP supports packets containing error, control, and informational messages. Some of ICMP's functions are to: Announce network errors, such as a host or entire portion of the network being unreachable, due to some type of failure.
When a router begins buffering too many packets, due to an inability to transmit them as fast as they are being received, it will generate ICMP Source Quench messages. Directed at the sender, these messages should cause the rate of packet transmission to be slowed.
Of course, generating too many Source Quench messages would cause even more network congestion, so they are used sparingly. ICMP supports an Echo function, which just sends a packet on a round--trip between two hosts. Ping, a common network management tool, is based on this feature. Ping will transmit a series of packets, measuring average round--trip times and computing loss percentages.
The official name of IPng is IPv6, where the v6 stands for version 6. The current version of IP is version 4, so it is sometimes referred to as IPv4. IPng is designed as an evolutionary upgrade to the Internet Protocol and will, in fact, coexist with the older IPv4 for some time.
Internet Protocol (IP)
IPng is designed to allow the Internet to grow steadily, both in terms of the number of hosts connected and the total amount of data traffic transmitted. The most significant and best known change is the expansion of the address space from 32 bit to bits but the format of IP packets has also been changed and the associated ICMP formats have also been revised.
The last eight words define the source address and the destination address, with four words allocated for each. The first four bits determine the version of the IP being used. Since IPv6 and IPv4 will be used in tandem as IPv4 is phased out, this format will help to easily distinguish packets from either version. The next four bits after the version number specifies the priority of the packet. IPv6 splits traffic into two categories: Congestion-controlled traffic may be delayed if the network is congested.
Non-congestion controlled traffic is typically associated with applications such as real-time audio and video, where it cannot be sensibly delayed and should be discarded instead.
About Internet Protocol (IP)
Those messages will indicate what happened to the packet that was sent. Well, it means that the destination computer does not actually have a service running on it. For example if the destination port number was 53, then that would mean that there is no DNS server running on that computer. This is how the source computer would find out that there is no such service.
Understanding the ICMP Protocol (Part 2)
The resulting ICMP error message would tell it as much. That is all well and good, but how does that ICMP error message tell the source computer exactly what packet it was that caused the ICMP error message to be generated? That is an excellent question. The way that ICMP works is that it will use IP to carry it around, and following the actual ICMP header will be the IP header, and first eight bytes of the transport protocol that actually caused the error to begin with.
A tad confusing, I realize, but please look at the packet above. I have underlined the portion, which shows the original packet that caused the ICMP error message to begin with. This way when the source computer receives this ICMP error message it will look at the IP header being carried, and the transport protocol as well.
Remember now, that within the first four bytes of the transport protocol, are the port numbers. Both source and destination are there.
This way the source computer is able to tell which process it was that needed to be made aware of the error i. Now we can also tell what exact type of ICMP error message this is by the type and code.
This is seen in the above bolded part of the packet. This is the standard ICMP header. So far so good, as this is exactly what the packets tells us in the ascii in the header part.
If you remember every core protocol has a checksum field. This is computed by the source computer, and then recalculated by the destination computer. It basically is used to make sure that the protocol header itself was not corrupted on the way to its destination. The only exception is UDP, which does not have to use the checksum value in its header.Relationship Marketing - What's this all about?