Let the Fox Road entered Huashan in the middle of the year, then lazy eight years old, Yue did a group gave two people in the day, and the fox gave a story to the young teacher. She fell asleep. Later, Yue Unredun has received Laudno, Lu Da has some apprentices, and is busy with purging purple glow, there is no time to point to apprentice. So he did a HUB. From then on, Huashan sent e-commerce. Yue did not gave each apprentice online at the same time. This method quickly promoted in the Wuyue Sword. In order to interconnect between Wuyue Sword, the Lushan School left coldly developed router, so that the Wuyue Swords can interconnect. Let the foxhrie have given a story from the brother girl through the Internet. Soon, lazy Shan is sixteen years old and has become a slim little girl. Linghu Chong found that his gaze always stopped on the child's girl, every time with the Xiaoshi, I always hear my strong heartbeat, after a period of tea, I finally had one night, Linghu rushed on the Internet to send a feeling of love: You are a wind, I am a sand, you are a bee, I am a flower, you are a comb, I am a hair, you are a toothpaste, I am a toothbrush. The next day, Huashan School was opened, and the mood of Fox fell to the conference room, and found that the teacher's red face was hiding behind Master, and other brothers were secretly laughing at themselves, once, one The brother of the naughty brother is called the toothbrush, and quickly escaped. Asked Lu Da, I know that Laudno uses a tool called Netxray to take her online masterpiece. The fox failed to repent, so the closed door studied RFC, successfully developed Lanswitch. It can identify the device MAC address so that the data that makes the fox buning to the small teacher is only a person can receive. Let the foxhoke you can tell the story in the evening, and occasionally itch, you can do a few words. If you can't say it, you can't say it, then, the red face is imagined to see the expression after the young teacher. Lanswitch is a Layer 2 switching device that understands the Layer 2 network protocol address MAC address. The two-layer switch constantly collects the information in the operation to build its own address table, which is quite simple, mainly indicating which port is discovered on which port is discovered, so when the switch receives a data package, it The destination MAC address of the package will be checked, check the address table to determine which port is sent. Not like Hub, any hairper data will appear on all ports of HUB (regardless of whether you need it). In this way, Lanswitch also improves system security while increasing efficiency. The next year, Yue did not enroll a lot of disciples, Huashan sent a large growth, and the Lanswitch used also many times. However, the disciples were inexplicably mixed. At that time, Huashan sent a group of three. The four generations of disciples worship Miles Octagon, set up a field of field, often broadcasting eight hundred meters or more than one thousand meters; there is a question; one of the third generation disciples叫 **, every day in Huashan Pie, inner broadcast ** Dafa; more let the fox can't be affected, with the increase of Master's age, become more and more coming, every sentence must be repeated twenty times, Then broadcast online. Linghu Zhi and Xiaosi, Lu Da has some people to use a broadcast domain, but if you use a lanswitch, Master will definitely not agree, so he has modified the Software of Lanswitch, put the little teacher, Lu Da, etc. It is divided into a virtual network (VLAN), and others use additional VLANs, and the broadcast package is only transmitted within the VLAN, and the VLAN is connected to the router.
Yue Yue also suffered from Tianx Association, Li Hong to his harm, but in order to fight with left cold, the use of people, only tolerance, knowing this, is very happy, but still makes the fox privately modify the software, Filled him to think about the wall of the cliff, not to go down within a year. In the Huashan Palace, I re-use the VLAN to divide the subnet, divided into five subnets, Master and Teacher Niang, Xiaoshi and Lin Ping in a VLAN, ** disciples use a VLAN; the field disciples use a VLAN, other disciples A VLAN, but also a separate VLAN on the cliff. Linghu rushed to the cliff, it is not difficult, finally, the world is quiet, relying on the router of the left cool Zen, to make the fox fortune can tell the little teacher online, chat. The introduction of the LAN switches allows the network nodes to have alone, but for the second-layer broadcast packet, the Layer 2 switch is broadcast on each network node; at the same time, the MAC address that cannot be identified for the Layer 2 switch must also be Broadcast domain is broadcast. When multiple Layer 2 switch levels, all devices on the Layer 2 switching network receive broadcast messages. In a large two-layer broadcast area, a large number of broadcasts greatly reduce the efficiency of the second layer forwarding, in order to avoid the broadcast storm caused by broadcasts on large switches, it is necessary to further divide multiple virtual in a two-layer switching network. Net (VLAN). In a virtual network (VLAN), information issued by a workstation can only be sent to other sites having the same virtual network number (VLANID), and the other virtual network (VLAN) can not receive this information or broadcast frame. The virtual network (VLAN) can control the broadcast storm on the network and increase the security of the network. Communication between Different Virtual Network (VLANs) must be performed via a router. But happiness is always short, and it is always endless troubles. With the increase of the entire five-way sword, the speed of the router is getting slower. Linghu Chong finds that every time I tell the story, the answer of the young teacher is always in Shanshan, and there is very little words, always "hmm", "" or "I listen". Finally, one day, the router is no longer ping, so that the fox rushed three days without the news, facing the empty display, I couldn't help, on a snow, secretly down the mountain to find a young teacher, to the small teacher In front of the window, I found that the teacher is chatting online and the small forests. I didn't pay attention to myself, my heart sore, I went back to the cliff, a big disease. After the disease, I finally learned, I finally made a router. At this time, the Huashan School found that the Huashan Pist has already assigned an interface for each VLAN, and the interface is not enough, and two The exchange speed of the router is much lower than the speed of the second floor exchange through the router. After the Layer 2 switch divides the virtual subnet, there will be a problem: the forwarding between different virtual subnets need to be implemented by other routers. Different VLAN nodes between the Layer 2 switch need to be greatly wasted through the router device, while the high cost of the router makes it unable to meet the three-layer forwarding demand, three-layer exchange concept in the case of large quantities. Just in this case it was mentioned. This evening, letting Fox scorned the heart, borrowing alcohol, at this time, a black shadow appeared in front of him, it was a good old man, it was a wind clear.
Feng Qing listened to the doubts of Fox, said: The router interface is not enough, and the router can not be used inside the lanswitch; the switching speed is slow, because the router looks for network segment routing, and Lanswitch directly check the port, of course high speed. Why can't I find out the port according to IP addresses directly? Let Fox Chong listen, great admissions, but still do not understand, IP address is so much, and often change, how can I directly find the port? Feng Qingyang said: "You first sit down, let me ask you, how many disciples have Huashan send?" "" "" "Do you know where they live?" "I don't know." "Yue does not Group wants you to find someone who doesn't know where to live, how to find it? "" Tracing Huishan School phone number query system, find his address, then find him. "" If you come back, let you find this person, and How to find it? "" How to .... Tracing Huashan School phone number query system, find his address, then go to him. "" Don't you know the address of this person? "" Know, Master said, The address of Huashan School is so much, and often changes, don't know how to address. "" Yue Yue, this child, teaching the apprentices into wood! I ask you, what do you think should be? "" Go directly! "" Ok! You are still too benzene. After you know the address of a person, is it always remembered? "Some people remember. Other forgot." "Why for forgotten?" "Because I can't remember so many people, and I didn't find him for a while." "How is the address in the Huashan phone number query system?" "I shouted his name in the air, he heard Just come to me, tell me his address. "Feng Qingyang asked the problem with brain tendons, then the wind cleared:" Now you understand the truth of the port directly according to the IP address? When you understand this truth, you will naturally make a three-layer switch ", let the Fox Chong carefully recalled today, and finally understand the truth of the two-layer forwarding from the MAC address, three-layer forwarding can also be directly from IP The address corresponds to the port, the route of the IP address can be learned by ARP, and it also needs aging. Thus, the VLAN is forwarded in addition to the first package to get the host route through the ARP, and the other packets can find an outlet directly according to the IP address, and the forwarding speed is much higher than the speed of the router forward. When you look up, the wind is clear. One year later, the fox was so thinking about the cliff, successfully launched the Quidway S8016 routing switch. The intercommunication between VLANs is achieved, and interworking is achieved with the routers such as Lushan, Blackwood Cliff. The three-layer switch is to increase the three-layer switching function on the basis of the Layer 2 switch, but it is not a simple Layer 2 switch plus the router, two but uses different forwarding mechanisms. The forwarding of the router uses the longest matching method, realizing complex, usually using software to implement,. The routing of the three-layer switch is aimed for streaming. It uses Cache techniques, it is easy to use ASIC implementation, so it can greatly save costs and realize rapid forwarding.
