Previously, you could use VLAN in a switch to break down a large LAN into several small LAN, and then use DHCP to help each LAN have its own IP address, each of which belongs to its own IP address. Then let's talk about the remaining things.
What will the switch do?First, not every vswitch can be used.
L3 SwitchThis function is available. This
Layer 3The concept refers to the Layer 3 of OSI: network layer. It is more practical: Generally, it is a series starting with Cisco Catalyst 3. Different from L2 switches, they have an additional routing template, which is much larger. The routing means:
Choose a name. It is like saying that if you want to take the subway to the Guangzhou Railway Station, you can "first take line 4, then turn line 8, and then take line 2 ", alternatively, you can "take line 4 first and then switch to line 5". Of course, if you have a leisurely experience, you can also take the subway around Guangzhou and then go to the railway station. However, data transmission is usually 100,000 in a rush. Of course, the sooner the better. Therefore, the more specific features of the routing module are as follows:
Select all possible routes and find the shortest path.. However, to connect a vswitch to a network, you only need to check the CIDR block of its destination IP address.
IP PortAnd then throw it there. It uses
Longest Matching Principle, Not like the MAC address. Each address must be matched one by one before forwarding. The more network bits match, the better. It uses its own TCAM table instead of the two-layer MAC table. The current switch generally uses CEF technology, which is a proprietary Cisco technology. However, the technology of other vendors is similar to its principle. The core of CEF is hardware and software isolation. MSFC is responsible for protocol negotiation and path calculation, which is equivalent to brain. The other layer is PFC, which is specifically used to forward data. From the "brain", it receives the strategy, and then this strong worker will start to work hard. After so long, it is only limited to the size of the internal LAN of a company or a building dormitory. It's time to scale up ......
This article from the "small days, slowly" blog, please be sure to keep this source http://yangxiaoxiao.blog.51cto.com/6916159/1271486
