MMC card is also a flash memory card, and its interface specification is compatible with SD card.
To explain the concept of router, we should first introduce what is routing. The so-called "routing" refers to the behavior and action of transmitting data from one place to another, and the Router is the machine that performs this behavior and action, and the English name is router. It is a network layer device that uses one or more measurement factors to determine the best path that network communication can take. Routers forward packets from one network to another based on network layer information. Occasionally called gateway (although this definition of gateway is out of date now).
The main functions of the router:
First, network interconnection, routers support various LAN and WAN interfaces, which are mainly used for interconnection of LAN and WAN to realize communication between different networks;
The second is data processing, including packet filtering, packet forwarding, priority, multiplexing, encryption, compression and firewall functions;
Thirdly, network management. The functions provided by routers include configuration management, performance management, fault-tolerant management and flow control.