subnetting and supernetting

, the network number is not many. Previously learned IP address can provide Class A network 126, Class B network about 1600, C class network about 2 million, so with the rapid development of the Internet, access to the Internet more and more sites, resulting in fewer IP address resources, In order to make better use of the existing IP address resources and reduce waste, the IP address can be further divided into smaller networks, that is, sub-network division. In order to create subnets, the hos

. However, you can also divide the data in the middle of the byte. For more information, see related TCP/IP books. Subnet allows us to have a new network of scale, including a small network used for point-to-point connection (for example, a mask of 255.255.255.252, a 30-bit network address, and a two-bit host address: subnet of two hosts), or medium-sized network (such as mask 255.255.240.0, 20-bit network address, 12-bit host address: Subnet of 4094 hosts ). Note that DNS is designed to only al

to obtain 15 available subnets ). You can see that when the number of hosts in each subnet is small, you can use this method to save IP resources and obtain more subnets. In actual use, for example, if you assign an IP address to the devices at both ends of a point-to-point connection, if you assign an IP address strictly according to the classification of subnets, then you can only assign a class C subnet to it. A Class C network contains 254 (that is, the 8th power of 2-2) Available addresses

Class C network contains 254 (that is, the 8th power of 2-2) Available addresses, and you only use 2, 252 available addresses are wasted. In this case, if the/30 mask is used, a subnet only contains 2 (that is, 2 to the power of 2-2) Valid addresses, so that other subnet addresses can be used. Supernetting is a concept similar to subnet (or a relative concept). IP addresses are divided into independent network addresses and host addresses based on th

About 192.168.0.0/24 and CIDR, this is actually a CIDR block, or a Subnet, in the form of Classless and Subnet Address Extensions and Supernetting. We know that to determine a subnet, we need to know the host address and subnet mask, but in the form of CIDR, we can simply get two values. For example, "192.168.0.0/24" indicates that the IP address of this network segment starts from 192.168.0.1 and ends at 192.168.0.254 (192.168.0.0 and 192.168.0.255 h

UNIX routed routing daemon usually uses the RIP Protocol of version 1, which is designed before the appearance of the subnet mask. The preceding section only describes three subnet masks: 255.0.0.0, 255.255.0.0, and 255.255.255.0. They are byte-aligned subnet masks. However, you can also divide the data in the middle of the byte. For more information, see related TCP/IP books. Subnet allows us to have a new network of scale, including a small network used for point-to-point connection, such as

In fact, this form is represented by a CIDR (classless and subnet address extensions and supernetting), or a subnet. We know that to determine a subnet, we need to know the host address and subnet mask, but in the form of CIDR, we can simply get two values. For example, 192.168.0.0/24 indicates that the IP address of this network segment starts from 192.168.0.1 and ends at 192.168.0.254 (192.168.0.0 and 192.168.0.255 have special meanings and cannot b

0 , a long line of digits, and a bit representing the network portion of the front-to-back continuous 1 . The default subnet mask, not all networks require subnets:The default subnet mask for class A IP addresses is 255.0.0.0;The class B IP address is 255.255.0.0;the class C is 255.255.255.0. The subnet mask uses the same addressing format as the IP address, the portion of the subnet mask of 1 corresponds to the network (and subnet) portion, and the subnet mask of 0 corresponds to the host por

must be started to block the port that generated the loop. The router's routing protocol does not have this problem, there can be multiple paths between routers to balance the load, improve reliability.2. Load concentration: There can only be one path between switches, so that information is concentrated on one communication link and cannot be dynamically allocated to balance the load. While the router routing protocol algorithm can avoid this, the OSPF routing protocol algorithm can not only p

algorithm must be started to block the port that generated the loop. The router's routing protocol does not have this problem, there can be multiple paths between routers to balance the load, improve reliability.2. Load concentration: There can only be one path between switches, so that information is concentrated on one communication link and cannot be dynamically allocated to balance the load. While the router routing protocol algorithm can avoid this, the OSPF routing protocol algorithm can

I. OSI seven-layer modelSecond, the TCP/IP modelThree-time handshake principleThird, the default port for common servicesIv. IP Address, subnetting basicsCommunication principle: The interaction of general data is generated in the application layer (TCP/IP model), the application layer can be seen as a porter, the different layers of the protocol defines the work of different porters, until finally, the transfer of data to another host application.I.

the internet, and the host number identifies a host on the subnet. When an Internet address is decomposed into two domains, it has an important advantage: when IP packets reach another network from one network on the Internet, the selection path can be based on the network rather than the host. This advantage is particularly noticeable in large networks because the routing table stores only network information rather than host information, which can greatly simplify the routing table 　　Sub-Net

into a hardware address, This hardware address is placed at the header of the Mac frame of the link layer, and then the next hop router is found based on this hardware address. Dividing the subnet only divides the host number of the IP address, not the original network number of the IP address. The same IP address and different subnet masks can be used to derive the same network location. However, different mask effects are not the same. No classification addressing CIDR (constituting a network

unique in a network. Each network device uses an IP address as the unique identifier.4 IP Address Classification:IP address addressing has undergone three historical stages:1 Classified IP addresses: the corresponding standard protocol was adopted in 19812 subnetting: This is an improvement to the most basic address method for IP addresses, which was passed in RFC 950 in 19853 Composition of the Net: presented in 1993.IP address = network number + ho

[Translation] IP subnet division Original article title: IP subnetting made easy Address: http://articles.techrepublic.com.com/5100-10878_11-6089187.html IP network engineers need to have a solid understanding of how IP subnet division works. however, this topic is often ignored by instructors and the students are very confused and nervous about it. george ou developed a simple, graphical method to explain IP subnet division in a simple and easy-to-u

The following is from the author of the "network administrator must read-Super network Management Experience" (2nd edition) The first thing to understand here is what it means to make a molecular network, which is one of the things that many readers don't understand. As we all know, the use of subnetting subnet in the subnet division not only can not increase the new available IP address, but also loss of a part of the IP address. To illustrate this

addresses in an organization , you can also pull out part of it to be used as a subnet network number, which is called a subnet partition based on a classified IP address. So an organization can carry multiple sub bodies of the same size, attention is the same size! But this is only the first step in fission ... 1.1.1. Question: Why do subnets have to be the same size? Subnet partition scale must be the same as the implication is that the subnet mask must be consistent, this becomes a class o

.xx.xx.xxC: The beginning is 100 i.e. 192.xx.xx.xx-223.xx.xx.xx127.XX.XX.XX is used to make the loop network inside the operating system.In the same network segment, a class can be used. Generally a network segment not more than 30 hosts on it, network performance is better.5. Using netmask (subnet mask) to achieve subnetting, define the most important parameters of the network segmentFor netmask, since net_id is immutable, it is simple to understand

network number is set to 1, and the location of the corresponding host number is set to 0. That is, the network address can be computed by the IP address and subnet mask.Another important function of the subnet mask is subnetting ..... Don't dwell on it.IP Address TranslationThe syntax for the inet_addr () function is as follows:#include This function uses string as the input parameter and converts the dot decimal IP address into a 32-bit binary nota

Original article title: IP subnetting made easy Address: http://articles.techrepublic.com.com/5100-10878_11-6089187.html IP network engineers need to have a solid understanding of how IP subnet division works. however, this topic is often ignored by instructors and the students are very confused and nervous about it. george ou developed a simple, graphical method to explain IP subnet division in a simple and easy-to-understand manner. IP subnet divi