TWI400908B - Cable modem and method for connecting a computer to the internet thereof - Google Patents

Description

Cable data machine and method for connecting computer to network

The present invention relates to a data machine, and more particularly to a cable modem and a method of connecting a computer to a network using the same.

Network communication is inseparable from the transmission control protocol/Internet protocol (TCP/IP) protocol. In a TCP/IP network, each computer wants to communicate with other devices on the network. All necessary network configuration must be performed. Some main parameters such as IP address, subnet mask, default gateway, and network name system (DNS) server are essential. Usually, when an IP address is assigned to a computer, it can no longer be used by other computers during the lease period. For example, if computer A applies for IP address D1, even if computer A is turned off and its IP address D1 is idle during its lease term T1, it cannot be used by other computers. Other computers can only apply for IP addresses that are not leased, and the IP address is a limited resource. The more computers that apply for access to the network, the fewer IP addresses that can be assigned.

In addition, cable modems are widely used for bidirectional transmission of data packets between the client and the network server, such as cable modem forwarding. Brain A applies for the IP address D1 packet to the network server, and receives the IP address D1 returned by the network server, thereby realizing communication between the computer A and other devices in the network. At present, when the computer A and a cable modem are connected, other computers cannot send packets to the network server even if they are connected to the cable modem, because other computer MAC addresses are known with the cable modem. Computer A has a different MAC address, so the packets it sends will be discarded by the cable modem.

In view of the above, it is necessary to provide a cable modem and a method for connecting the computer to the network, in the lease term of the IP address of a computer connected to the cable modem, when the computer is turned off, the cable The modem can allow other computers to connect to the network using the IP address.

A cable modem is connected to a plurality of computers via an Ethernet network. When the cable modem receives a data packet, it determines whether the source MAC address in the data packet is the MAC address of the known computer. If the source MAC address in the packet is the MAC address of its known computer, the cable modem transmits the packet to the network for processing. If the source MAC address in the packet is not the MAC address of its known computer, the cable modem sends an ARP request to its known computer to confirm that the computer is powered off. If the known computer is in the off state, the cable modem replaces the source MAC address in the data packet with the MAC address of the known computer and transmits it to the network for processing.

A method for connecting a computer to a network using a cable modem, comprising the steps of: (a) receiving a data packet; and (b) checking a source MAC in the data packet. Whether the address is the same as the MAC address of a known client computer. If they are the same, step (c) is performed. If not, step (d) is performed; (c) the packet is transmitted to the network via the Internet. The server is processed by the server; (d) sending an ARP request packet to the known client computer; (e) determining whether the ARP response packet returned by the known client computer is received, if an ARP response is received. In the data package, step (f) is performed. If the ARP response data package is not received, step (g) is performed; (f) determining that the known client computer is powered on, discarding the data package; (g) After the known client computer is determined to be in a shutdown state, the source MAC address in the data packet is replaced with the MAC address of the known client computer, and then the process proceeds to step (c).

Compared with the prior art, the cable modem provided by the present invention and the method for connecting the computer to the network can allow other computers to use when the computer is in the shutdown state within the lease term of the IP address of one computer. The IP address is connected to the network, saving IP address resources.

10, 20‧‧‧ computer

30‧‧‧Ethernet

40‧‧‧cable modem

50‧‧‧Internet

60‧‧‧Web server

S201‧‧‧ Receive a package

S203‧‧ Is the source MAC address in the packet the same as the MAC address of the known PC?

S205‧‧‧Send ARP packets to known PCs

S207‧‧‧ Received an ARP response packet from a known PC backhaul?

S209‧‧‧Abandon the package

S211‧‧‧ Is this data package a DHCP packet?

S213‧‧Replace the chaddr address in the packet with the MAC address of the known PC

S215‧‧Replace the source MAC address in the packet with the MAC address of the known PC

S217‧‧‧Transfer the package to the web server

1 is an application environment diagram of a preferred embodiment of a cable data machine of the present invention.

2 is a flow chart of a preferred embodiment of a method for connecting a computer to a network using a cable modem.

1 is an application environment diagram of a preferred embodiment of the cable data machine of the present invention. The client computer, such as the computers 10, 20 shown in FIG. 1, is communicatively coupled to a cable modem 40 via an Ethernet 30. Cable modem 40 through the Internet (Internet) 50 and network server 60 communications. In the present embodiment, the computer 10 is a client computer that has obtained the IP address assigned by the network server 60, and the cable modem 40 knows the media access control (MAC) address of the computer 10.

During the lease term of the IP address, each time the computer 10 is turned on, the computer 10 sends a request packet to the cable modem 40, requesting the cable modem 40 to forward the request packet to the network server 60, requesting to continue using the lease. The IP address is used for network connection.

In this embodiment, the working principle of the cable modem 40 is as follows: the cable modem 40 receives the request packet sent by the client, and checks the source MAC address in the request packet as the MAC address of the known computer 10. If the source MAC address in the request packet is the MAC address of the known computer 10, it is determined that the client is the computer 10 that has obtained the IP address assigned by the network server 60, and transmits the request packet to The network server 60 processes. Generally speaking, the data packet transmitted in the network includes at least a source address and a destination address, wherein the source address is a sender address, such as a source MAC address, and the destination address is a receiver address, such as a destination. MAC address.

If the cable modem 40 checks that the source MAC address in the request packet is different from the MAC address of the known computer 10, then sends an address resolution protocol (ARP) packet to the computer 10, and Wait for the ARP response packet from the computer 10 to return. If the ARP response packet returned by the computer 10 is received, the computer 10 is turned on, and the cable modem 40 discards the received request packet. If you have not received the computer 10 return The ARP response packet indicates that the computer 10 is in the shutdown state, and the cable modem 40 modifies the source MAC address in the request packet to the MAC address of the known computer 10, and sends the request packet to the network. The server 60 processes. After confirming that the source MAC address in the data packet is a known MAC address, the network server 60 treats the data packet as a data packet sent by the computer 10. Thus, when the computer 10 is in the off state, the cable modem 40 can cause other clients, such as the computer 20, to connect to the Internet 50 by borrowing an IP address that is not used by the computer 10.

2 is a flow chart of a preferred embodiment of a method for connecting a computer to a network using a cable modem.

In step S201, the cable modem 40 receives a data packet.

In step S203, the cable modem 40 checks whether the source MAC address in the packet is the same as the MAC address of the computer 10 known to the cable modem 40. For example, in the present embodiment, the MAC address of the computer 10 is "00D059AB0301". If the source MAC address in the data packet is the same as the MAC address of the computer 10, for example, the source MAC address in the data packet is "00D059AB0301", the flow directly proceeds to step S217, and the cable modem 40 transmits the data packet. Internet 50 is transmitted to network server 60. Otherwise, if the source MAC address in the data packet is different from the MAC address of the known computer 10, for example, the source MAC address in the data packet is "00D059AA4240", the flow advances to step S205.

In step S205, the cable modem 40 sends an ARP packet to the known computer 10 and waits for the ARP response packet returned by the computer 10.

In step S207, the cable modem 40 determines whether the ARP received by the computer 10 is received. Answer the information package. If the ARP response data packet sent back by the computer 10 is received, it indicates that the computer 10 is in the power-on state, the flow proceeds to step S209, and the cable data machine 40 discards the data package. If the ARP response packet returned by the computer 10 is not received, it indicates that the computer 10 is in the shutdown state, and the flow proceeds to step S211.

In step S211, the cable modem 40 checks whether the data packet is a dynamic host configuration protocol (DHCP) packet. Unlike other types of data packets (such as APR data packets), the sender's MAC address is only recorded in one field. In the DHCP data packet, the client identifier field and the client's Ethernet address (client) The ethernet address, chaddr) field records the sender's MAC address. If the packet is a DHCP packet, the flow advances to step S213. If the packet is not a DHCP packet, the flow advances to step S215.

In step S213, the cable modem 40 replaces the MAC address recorded in the chaddr field in the data packet with the known MAC address, for example, "00D059AB0301". Thereafter, the flow proceeds to step S215.

In step S215, the cable modem 40 replaces the source MAC address in the data packet with the known MAC address, for example, "00D059AB0301". Thereafter, the flow proceeds to step S217.

The above is only the preferred embodiment of the present invention, and has been used in a wide range of applications. Any other equivalent changes or modifications which are not departing from the spirit of the present invention should be included in the following claims. Inside.

S201‧‧‧ Receive a package

S203‧‧ Is the source MAC address in the packet the same as the MAC address of the known PC?

S205‧‧‧Send ARP packets to known PCs

S207‧‧‧ Received an ARP response packet from a known PC backhaul?

S209‧‧‧Abandon the package

S211‧‧‧ Is this data package a DHCP packet?

S213‧‧Replace the chaddr address in the packet with the MAC address of the known PC

S215‧‧Replace the source MAC address in the packet with the MAC address of the known PC

S217‧‧‧Transfer the package to the web server

Claims (4)

A cable data machine, which is connected to a plurality of client computers via an Ethernet network and communicates with a network server via the Internet. After the cable modem is powered on, the following steps are performed: (a) receiving a data (b) Check whether the source media access control address in the data packet is the same as the media access control address of a known client computer. If they are the same, perform step (g). If not, perform the steps. (c); (c) transmitting an address resolution protocol packet to the known client computer; (d) determining whether the address resolution protocol response packet returned by the known client computer is received, if Receiving the address resolution agreement response data packet, performing step (e), if the address resolution agreement response data packet is not received, performing step (f); (e) determining that the known client computer is powered on, discarding (f) determining that the known client computer is in a shutdown state, replacing the source media access control address in the data packet with a media access control address of a known client computer; and (g ) through the internet Road transmitting the data packet to the web server process. The cable data machine of claim 1, wherein the step (f) further comprises: If the data packet is a dynamic host configuration protocol data package, the client Ethernet address in the dynamic host configuration protocol data package is replaced with the media access control address of the known user computer. A method for connecting a client computer to a network using a cable modem, the method comprising: (a) receiving a data packet; and (b) checking whether the source media access control address in the data packet is associated with a known client computer The media access control addresses are the same. If they are the same, step (g) is performed. If not, step (c) is performed; (c) an address resolution protocol packet is sent to the known client computer; d) determining whether the address resolution protocol response data packet returned by the known client computer is received, and if the address resolution agreement response data packet is received, performing step (e), if the address resolution agreement response data is not received If the packet is executed, step (f) is performed; (e) determining that the known client computer is powered on, discarding the data package; (f) determining that the known client computer is in a shutdown state, and the data package is The source media access control address is replaced with a media access control address of a known client computer; and (g) the packet is transmitted over the Internet to a web server for processing. The method of claim 3, wherein the step (f) further comprises: if the data packet is a dynamic host configuration protocol data package, the client side Ethernet address in the dynamic host configuration agreement data package Replace with a known client computer Media access control address.