A router works by receiving data packets from devices on a local network and forwarding them towards their intended destinations. It operates at the network layer (Layer 3) of the OSI model, using IP addresses to determine where to send each packet. Routers maintain routing tables that contain information about the best paths to various networks, allowing them to make decisions about how to forward packets efficiently across interconnected networks.
Routers function by using a combination of hardware and software to manage data traffic within and between networks. They receive packets from connected devices, examine the destination IP address of each packet, and then determine the best path for forwarding based on their routing tables. This process ensures that data reaches its destination accurately and efficiently, even across complex networks with multiple interconnected routers.
To access the internet, a router typically connects to an internet service provider (ISP) via an external interface, such as an Ethernet port or a DSL modem. Once connected, the router uses protocols such as DHCP (Dynamic Host Configuration Protocol) to obtain an IP address from the ISP and establish a connection to the internet. It then manages data traffic between devices on the local network and external networks, forwarding packets to and from the internet based on the destination IP addresses in each packet.
Routers do not typically require a SIM card to function in traditional wired networking setups. SIM cards are commonly associated with mobile devices and wireless routers that use cellular networks for internet connectivity. In standard home or office networking environments, routers connect to the internet via Ethernet cables, DSL modems, or other wired connections provided by ISPs. However, some specialized routers designed for mobile broadband may incorporate SIM cards to access cellular networks for internet connectivity in areas where wired connections are unavailable or impractical.