default route,i think...it should be by default...
(中)什麼樣的路線讓路由器轉發數據包,即使它的路由表中沒有具體的路線到目的地網絡? "
This is CCNA discovery 1 -Chapter 3-English exam No 18 . Default route is correct answer.
The router should have a "default route", which basically says "everything else should be sent to..." (for example, to the ISP).
A dedicated route
Network Layer
The details vary enormously from protocol to protocol, but the basics are the same for all of them. A stream of data is split into packets, the packet has a header which contains (amongst other things) the destination for the packet. The network uses the destination address to deliver the network to the correct destination.
It uses the MAC address, Media Access Control. Every packet sent from a computer contains its MAC address. The router stores this in its routing table. When it receives a packet with a destiation address of that MAC address, then it forwards it to that computer. This is called NAT, Network Address Translation. It uses the Destination IP address
In computer networking, a packet is a segment of data that is sent over a network from one device, including a computer, to another device. It contains the size, data, type, source. and destination that helps it get to the right destination.
IT uses the destination MAC address to selectively forward a frame
Generally speaking, routers will unicast-forward incoming packets which have a network broadcast address as destination, unless they are directly connected to that network/subnet and therefore know that the destination address is a broadcast address
destination network address
A unicast message is a message directed to a specific device on a network (just one specific device). It would have a destination IP address that corresponds to that device.
In a packet-switched data network, what is used to reassemble the packets in the correct order at the destination device?
First, routing is the process a router performs when making forwarding decisions for each packet arriving at the gateway interface. To forward a packet to a destination network, the router requires a route to that network. If a route to a destination network does not exist on the router, the packet will be forwarded to the default gateway. Now, the destination network can be a number of routers or hops away from the default gateway. If the router has an entry for the network in its routing table, it would only indicate the next-hop router to which the packet is to be forwarded to and not the exact route to the final router. To sum it up, the routing process uses a routing table to map the destination address to the next hop and then forwards the packet to the next-hop address.
First, routing is the process a router performs when making forwarding decisions for each packet arriving at the gateway interface. To forward a packet to a destination network, the router requires a route to that network. If a route to a destination network does not exist on the router, the packet will be forwarded to the default gateway. Now, the destination network can be a number of routers or hops away from the default gateway. If the router has an entry for the network in its routing table, it would only indicate the next-hop router to which the packet is to be forwarded to and not the exact route to the final router. To sum it up, the routing process uses a routing table to map the destination address to the next hop and then forwards the packet to the next-hop address.
In a datagram network, the destination addresses are unique. They cannot be duplicated in the routing table.