The difference and connection between gateway and router (router)

From: http://www.kelenao8.cn/u/space.php?uid=3&do=blog&id=26 Gateway (gateways) refers to the communication between different networks of equipment and procedures, is an important component of network connectivity equipment, It not only has the function of routing, but also can transform between two different protocol sets, so that different networks are interconnected. For example, a NetWare LAN can access IBM's SNA network through a gateway so that the PC using the IPX protocol can communicate with the IBM host on the SNA network.   and the router (router) refers to such interface equipment and procedures. Gateways work with protocol translations between networks that use different network protocols. So a gateway is an access point that a network connects to another network. Personally, the router is also a gateway to the point of view of access points; Personally, this is also "default gateway" "not called" The reason for the default router.

Although routers are an example of gateways, gateways that do protocol translation are often implemented as software in the form of a router. So, gateways are often a feature of routers; Because of this, gateways and routers are now often interchangeable with two words, but also because of this, and the default gateway and default router "In this connection, gateways and routers two nouns have also become confusing.

In addition, many times, the device used as a gateway will also have the ability to install firewalls and proxy servers.

This refers to the term "default router" (router, which is quoted because it should actually be called the default gateway, the "default gateways"), and the concept of the "defaults route". The default route is a table entry in the Routing list. The next hop (next hop) specified by this table entry is the default router (the default gateway). "Default" here means that all packets that do not have a corresponding table entry in the routing table are sent to this gateway. Find the "corresponding" in the routing tables   A table entry is achieved by comparing the subnet mask of the IP address of the routing table entry with the subnet mask of the destination address. So, as long as the subnet mask for the default route is set to 0 (which is 0.0.0.0/0 in the routing table), the default route must be able to "correspond" to the destination address. A gateway is a network device that connects based on different communication protocols so that files can be transferred between these networks. In addition to transmitting information, the gateway translates this information into the accepted form of the protocol used by the receiving network. It has a close relationship with routers.