Apparatus and methods for use therein for an ISDN LAN modem that provides enhanced network activity

• US 6,029,203 A
• Filed: 09/26/1997
• Issued: 02/22/2000
• Est. Priority Date: 09/26/1997
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Zhang, Siuling C., Douglas, C. Paul, Bhatia, Rajiv
• Primary Examiner(s): Maung, Zarni
• Assistant Examiner(s): Cardone, Jason D.
• Application Number:
  US08/938,369
• Time in Patent Office: 879 Days
• Field of Search: 709/229, 709/216, 709/217, 709/218, 709/219, 709/228, 709/236, 709/105, 709/244, 709/248, 370/431, 370/437, 370/445, 370/465, 707/10, 371/25.1, 371/26, 324/73
• US Class Current: 709/244
• CPC Class Codes: H04L 45/00 Routing or path finding of packets in data switching networks routing or path finding in wireless networks H04W40/00
• CPC Class Codes: H04L 45/243 using M+N parallel active paths
• CPC Class Codes: H04L 45/34 Source routing
• CPC Class Codes: H04M 11/068 using time division multiplex techniques; integrated services digital networks H04Q11/0428
• CPC Class Codes: H04Q 11/0457 Connection protocols
• CPC Class Codes: H04Q 11/0471 Terminal access circuits

Abstract

Apparatus, and accompanying methods for use therein, for an ISDN LAN modem that is suited for small user environments and which contains an internal ISDN router having a self-contained network hub for inter-connecting multiple network devices, such as workstations, to each other through a local area network (LAN) and for permitting each of those devices to each gain access through the router to any one of a number of different remote networks. Through use of a multi-tiered routing hierarchy including both destination- and source-based routing, the LAN modem accommodates several modalities of network communication not heretofore possible in a conventional router. Specifically, several different workstations can simultaneously communicate through the LAN modem with a common remote network and share a single user account at a corresponding network service provider. Also, the LAN modem can simultaneously route packet traffic between multiple workstations on the LAN and different remote networks through different ISDN connections simultaneously existing between the LAN modem and corresponding network service providers.

Claims

1. Apparatus for a network communication device which is connectable to both a public switched telephone network (PSTN) and a local area network (LAN) for simultaneously providing separate first and second communication channels over a common communication path between the PSTN to the device such that each of first and second host devices connected to the LAN can simultaneously communicate, through the communication device over the common communication path and via the first and second channels, with a different corresponding network service provider accessible through the PSTN, the apparatus comprising:

a processor;

a memory, connected to the processor, for storing executable instructions therein;

communication circuitry, connected to and controlled by the processor, for establishing, over the common communication path, coincident first and second network connections between the communication device and the PSTN, and, via the LAN, the first and second host devices, respectively, wherein each of the connections is established over a different corresponding one of the first and second channels; and

a source-based routing table (SBRT), stored within the memory, which specifies, for each of the first and second host devices, a different corresponding network service provider, which is then being accessed by said each host device, and which specific one of the first and second channels is to be used to carry packets, via the communication device and the PSTN, between said different corresponding network service provider and said each host device;

wherein, in response to the executable instructions, the processor routes each one of a plurality of packets appearing on the LAN and originating from either the first or second host device via the specific one of the first and second channels as specified in the SBRT, given the source of said each packet, to the corresponding first or second network service provider that is to receive said each packet such that the communication device can simultaneously provide two separate packet connections, over the common communication path and via the PSTN, between the first and second host devices and corresponding different ones of the first and second network service providers.

2. The apparatus in claim 1 wherein the processor, through execution of the instructions:

in response to an outgoing packet generated by either one of the first and second host devices and destined to a corresponding different one of the network service providers, determines whether a corresponding one of the network connections has been established between the communication device, through the PSTN, to the corresponding one of the network service providers; and

if an entry in the SBRT indicates that the corresponding one network connection has not yet been established;

establishes the corresponding one network connection to the PSTN over an available one of the channels;

updates the entry in the SBRT to reflect the one channel then being used for the corresponding one network connection between said one of the first and second host devices and the corresponding one of the network service providers; and

routes the outgoing packet, via the one channel, over the corresponding one network connection to the corresponding one of the network service providers;

or

if the entry in the SBRT indicates that the corresponding one network connection is already established, routes the outgoing packet over the channel specified in the entry via said corresponding one network connection to the corresponding one network service provider.

3. The apparatus in claim 2 wherein the first and second network service providers each provides access to either a private network or public network, wherein the public network is an Internet.

4. The apparatus in claim 3 wherein the SBRT comprises a separate entry for each of the first and second host devices that specifies, for said each host device, the permitted network service providers, and, for each such permitted network service provider, a corresponding ISDN directory numbers and network parameters.

5. The apparatus in claim 4 wherein the network parameters comprise a domain name, subnet mask, user account and password.

6. The apparatus in claim 4 wherein the private network provides access to the Internet.

7. The apparatus in claim 3 wherein each of the first and second communication channels is a separate ISDN B-channel.

8. The apparatus in claim 3 wherein the processor, in response to the stored instructions and an incoming packet appearing on the LAN and originating with either the first or second host device:

translates private source address information contained in the incoming packet into public source address information for use by the network communication device, wherein the private source address information, for the incoming packet, specifies a private source address of a corresponding one of the first and second host devices and an identifier of an associated application session executing at the corresponding one host device which generated the incoming packet;

substitutes the public source address information into the incoming packet for the private source address information contained therein so as to form an outbound packet, wherein the public source address information contains a predefined public address, associated with the network communication device, as a source address; and

transmits the outbound packet, via the communication circuitry and the corresponding first or second communication channel, to the corresponding first or second network service provider.

9. The apparatus in claim 8 wherein the public and private source addresses of the first and second host devices and the public address of the network communication device each comprise a corresponding Internet protocol (IP) address.

10. The apparatus in claim 9 wherein the public and private source address informations each comprise an associated IP address, an associated protocol number and an associated port number.

11. The apparatus in claim 10 wherein the SBRT comprises a separate entry for each of the first and second host devices that specifies, for said each host device, the permitted network service providers, and, for each such permitted network service provider, a corresponding ISDN directory numbers and network parameters.

12. The apparatus in claim 11 wherein the network parameters comprise a domain name, subnet mask, user account and password.

13. The apparatus in claim 10 wherein each of the first and second communication channels is a separate ISDN B-channel.

14. The apparatus in claim 3 wherein the processor, in response to the stored instructions and an incoming packet from the network service provider and appearing on either the first or second communication channels:

translates public destination address information contained in the incoming packet into private destination address information associated with a corresponding one of the first and second host devices, wherein the public destination address information contains a public address associated with the network communication device as a destination address;

substitutes the private destination address information into the incoming packet for the public destination address information contained therein so as to form an inbound packet, wherein the private destination address information for the packet specifies a private destination address of the corresponding one host device and an identifier of an associated application session executing thereat which is to receive the incoming packet; and

transmits the inbound packet over the LAN to the corresponding one host device.

15. The apparatus in claim 14 wherein the public and private destination addresses of the first and second host devices and the public address of the network communication device each comprise a corresponding Internet protocol (IP) address.

16. The apparatus in claim 15 wherein the public and private destination address informations each comprise an associated IP address, an associated protocol number and an associated port number.

17. The apparatus in claim 16 wherein the SBRT comprises a separate entry for each of the first and second host devices that specifies, for said each host device, the permitted network service providers, and, for each such permitted network service provider, a corresponding ISDN directory numbers and network parameters.

18. The apparatus in claim 17 wherein the network parameters comprise a domain name, subnet mask, user account and password.

19. The apparatus in claim 16 wherein each of the first and second communication channels is a separate ISDN B-channel.

20. The apparatus in claim 3 wherein the processor, in response to the stored instructions and a packet appearing on the LAN and emanating from either the first or second host device:

selects, in response to an identification, contained in the packet, of one of either the first or second host device as a source of the packet and a predefined hierarchically related routing criteria, associated with the one host device, from a pre-defined plurality of network service providers through which the one host device is permitted to access, the first or second network service provider, respectively, as the particular one network service provider for the corresponding one host device to which the packet is to be routed, the plurality of network service providers specifying the first and second network service providers; and

routes the packet, via the first or second communication channel as specified in the SBRT, to the particular one network service provider.

21. The apparatus in claim 20 wherein the processor, in response to the executable instructions, determines, from a source address contained in the packet, at least one of the plurality of network service providers through which the one host device is permitted to access so as to define a set of permitted network service providers.

22. The apparatus in claim 21 wherein the hierarchically related routing criteria specifies a hierarchy of different types of network service providers through which the one host device can attempt to establish network access.

23. The apparatus in claim 22 wherein the hierarchically related routing criteria selects the particular one network service provider as:

(a) first, any one of the set of permitted network service providers then having a domain name that matches a domain name contained in the packet, (b) second, if no such domain name match is found, any one of the set of permitted network service providers that is an Internet service provider (ISP), and (c) third, if none of the network service providers is an Internet service provider, then any one of the set of permitted network service providers that is a network service provider for a private network (PN) that provides Internet access.

24. The apparatus, in claim 23 further comprising a list, stored in the memory, of different network service providers, wherein the network service provider list contains a separate entry for each different network service provider to which the one host device is permitted to access.

25. The apparatus, in claim 24 wherein the processor, in response to the executable instructions:

determines, through accessing an entry in the SBRT, whether a connection then exists to the particular one network service provider; and

if the connection does not then exist and prior to routing the packet to the particular one network service provider, establishes the connection, based on predefined network parameters specified in the network provider list, to the particular one network service provider.

26. The apparatus in claim 25 wherein the network parameters further comprise:

an indication as to whether the particular one network service provider is an ISP or a PN; and

if the particular one network service provider is a PN;

an indication as to whether the Internet is accessible through the PN; and

predefined network identification for the PN.

27. The apparatus in claim 20 wherein the SBRT comprises a separate entry for each of the first and second host devices that specifies, for said each host device, the permitted network service providers, and, for each such permitted network service provider, a corresponding ISDN directory numbers and network parameters.

28. The apparatus in claim 27 wherein the network parameters comprise a domain name, subnet mask, user account and password.

29. The apparatus in claim 20 wherein each of the first and second communication channels is a separate ISDN B-channel.

30. A method, for use in a network communication device which is connectable to both a public switched telephone network (PSTN) and a local area network (LAN), for simultaneously providing separate first and second communication channels over a common communication path between the PSTN to the device such that each of first and second host devices connected to the LAN can simultaneously communicate, through the communication device over the common communication path and via the first and second channels, with a different corresponding network service provider accessible through the PSTN, wherein the communication device comprises:

a processor;

a memory, connected to the processor, for storing executable instructions therein;

communication circuitry, connected to and controlled by the processor, for establishing, over the common communication path, coincident first and second network connections between the communication device and the PSTN, and, via the LAN, the first and second host devices, respectively, wherein each of the connections is established over a different corresponding one of the first and second channels; and

a source-based routing table (SBRT), stored within the memory, which specifies, for each of the first and second host devices, a different corresponding network service provider, which is then being accessed by said each host device, and which specific one of the first and second channels is to be used to carry packets, via the communication device and the PSTN, between said different corresponding network service provider and said each host device;

wherein the method comprises the step, implemented through the executable instructions, of;

routing each one of a plurality of packets appearing on the LAN and originating from either the first or second host device via the specific one of the first and second channels as specified in the SBRT, given the source of said each packet, to the corresponding first or second network service provider that is to receive said each packet such that the communication device can simultaneously provide two separate packet connections, over the common communication path and via the PSTN, between the first and second host devices and corresponding different ones of the first and second network service providers.

31. The method in claim 30 further comprising the steps of:

in response to an outgoing packet generated by either one of the first and second host devices and destined to a corresponding different one of the network service providers, determining whether a corresponding one of the network connections has been established between the communication device, through the PSTN, to the corresponding one of the network service providers; and

if an entry in the SBRT indicates that the corresponding one network connection has not yet been established;

establishing the corresponding one network connection to the PSTN over an available one of the channels;

updating the entry in the SBRT to reflect the one channel then being used for the corresponding one network connection between said one of the first and second host devices and the corresponding one of the network service providers; and

routing the outgoing packet, via the one channel, over the corresponding one network connection to the corresponding one of the network service providers;

or

if the entry in the SBRT indicates that the corresponding one network connection is already established, routing the outgoing packet over the channel specified in the entry via said corresponding one network connection to the corresponding one network service provider.

32. The method in claim 31 wherein the first and second network service providers each provides access to either a private network or public network, wherein the public network is an Internet.

33. The method in claim 32 wherein the SBRT comprises a separate entry for each of the first and second host devices that specifies, for said each host device, the permitted network service providers, and, for each such permitted network service provider, a corresponding ISDN directory numbers and network parameters.

34. The method in claim 32 further comprising the steps of, in response to an incoming packet appearing on the LAN and originating with either the first or second host device:

translating private source address information contained in the incoming packet into public source address information for use by the network communication device, wherein the private source address information, for the incoming packet, specifies a private source address of a corresponding one of the first and second host devices and an identifier of an associated application session executing at the corresponding one host device which generated the incoming packet;

substituting the public source address information into the incoming packet for the private source address information contained therein so as to form an outbound packet, wherein the public source address information contains a predefined public address, associated with the network communication device, as a source address; and

transmitting the outbound packet, via the communication circuitry and the corresponding first or second communication channel, to the corresponding first or second network service provider.

35. The method in claim 34 wherein the public and private source addresses of the first and second host devices and the public address of the network communication device each comprise a corresponding Internet protocol (IP) address.

36. The method in claim 35 wherein the public and private source address informations each comprise an associated IP address, an associated protocol number and an associated port number.

37. The method in claim 32 further comprising the steps of, in response to an incoming packet from the network service provider and appearing on either the first or second communication channels:

translating public destination address information contained in the incoming packet into private destination address information associated with a corresponding one of the first and second host devices, wherein the public destination address information contains a public address associated with the network communication device as a destination address;

substituting the private destination address information into the incoming packet for the public destination address information contained therein so as to form an inbound packet, wherein the private destination address information for the packet specifies a private destination address of the corresponding one host device and an identifier of an associated application session executing thereat which is to receive the incoming packet; and

transmitting the inbound packet over the LAN to the corresponding one host device.

38. The method in claim 37 wherein the public and private destination addresses of the first and second host devices and the public address of the network communication device each comprise a corresponding Internet protocol (IP) address.

39. The method in claim 38 wherein the public and private destination address informations each comprise an associated IP address, an associated protocol number and an associated port number.

40. The method in claim 32 further comprising the steps of, in response to a packet appearing on the LAN and emanating from either the first or second host device:

selecting, in response to an identification, contained in the packet, of one of either the first or second host device as a source of the packet and a predefined hierarchically related routing criteria, associated with the one host device, from a pre-defined plurality of network service providers through which the one host device is permitted to access, the first or second network service provider, respectively, as the particular one network service provider for the corresponding one host device to which the packet is to be routed, the plurality of network service providers specifying the first and second network service providers; and

routing the packet, via the first or second communication channel as specified in the SBRT, to the particular one network service provider.

41. The method in claim 40 further comprising the step of determining, from a source address contained in the packet, at least one of the plurality of network service providers through which the one host device is permitted to access so as to define a set of permitted network service providers.

42. The method in claim 41 wherein the hierarchically related routing criteria specifies a hierarchy of different types of network service providers through which the one host device can attempt to establish network access.

43. The method in claim 42 wherein the hierarchically related routing criteria selects the particular one network service provider as:

(a) first, any one of the set of permitted network service providers then having a domain name that matches a domain name contained in the packet, (b) second, if no such domain name match is found, any one of the set of permitted network service providers that is an Internet service provider (ISP), and (c) third, if none of the network service providers is an Internet service provider, then any one of the set of permitted network service providers that is a network service provider for a private network (PN) that provides Internet access.

44. The method, in claim 43 further comprising the steps of:

determining, through accessing an entry in the SBRT, whether a connection then exists to the particular one network service provider; and

if the connection does not then exist and prior to routing the packet to the particular one network service provider, establishing the connection to the particular one network service provider.