In the process of using OpenStack, we encounter the creation of virtual machine routers, switches, etc.
1. What is their role in the end?
Why is 2.DHCP produced, and what is its role?
Switches: Generally used in the same network segment, working at the data link layer, for example we are in the same office, then the switch is used.
Routers are used in different network segments
In other words, an office Internet access, you can use the switch, as long as the plug-in Internet access to the Internet.
Router: It is for different offices to provide Internet services, different offices, using different network segments.
DHCP: To solve the problem of network configuration
What is a switch:
Working at the Data Link layer, the switch has a very high bandwidth of the back bus and the internal switching matrix. All the ports on the switch are hooked up on the back bus, and after the control circuit receives the packet, the processing port looks in the in-memory address table to determine which port the NIC (NIC) of the destination Mac (the hardware address of the network card) is hooked on, and the internal switch fabric quickly transmits the packet to the destination port. If the destination Mac does not exist, broadcast to all ports, and the receive Port responds, the switch will "learn" the new MAC address and add it to the internal MAC address table.
What is a router
For the different networks connected to each other, the router system constitutes the main thread of the Internet based on TCP/IP, and it can be said that routers form the skeleton of the Internet. Its processing speed is one of the main bottleneck of network communication, its reliability directly affects the quality of network interconnection. Therefore, in the campus network, regional network, and even the entire Internet research field, router technology has always been at the core position, its development process and direction, become a microcosm of the entire Internet research.
What is DHCP
In a network that uses the TCP/IP protocol, each computer must have at least one IP address in order to communicate with other computer connections. In order to facilitate the unified planning and management of IP addresses in the network, DHCP (Dynamic Host Configure Protocol, dynamically hosted Configuration Protocol) emerged. This kind of network service is advantageous to manage the client IP address effectively in the campus network, and does not need one to specify the IP address manually.
Developer must read OpenStack Network Foundation 2: Switches, routers, DHCP