Abstract:
A subscriber login server is used for managing a subscriber login session. The login server is associated with a DHCP server for configuring a premise equipment device and operator-managed device. A subscriber login client at the premise equipment device securely communicates login username and password identifiers to the subscriber login server without using PPP technology. The login server retrieves matching identifiers from a RADIUS server and authorizes service with messages to the DHCP server and the CMTS. 
     The login client can emulate a PPP login client so that a user&#39;s interface is similar to a PPPoE client. However, a layer-3 CMTS can be used instead of a layer-2 CMTS. In addition, subscriber authentication and accounting using RADIUS are preserved, positive network access control at the CMTS is maintained, and native IP traffic is routed or switched for maximum performance and QoS treatment.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims priority under 35 U.S.C. 120 to U.S. application Ser. No. 10/930,109 filed on Aug. 30, 2004. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to broadband communication, and more particularly to a method and system for logging in to a network using a layer 3 CMTS. 
       BACKGROUND 
       [0003]    Community antenna television (“CATV”) networks have been used for more then four decades to deliver television programming to a large number of subscribers. Increasingly, CATV networks are used by providers to provide data services to subscribers. For example, operator managed devices, such as cable modems, used in a broadband cable modem termination system (“CMTS”) are capable of transmitting and receiving Internet data using the Data Over Cable Service Interface Specification (“DOCSIS”) protocol. DOCSIS provides a standard that allows network devices made by different vendors to communication with one another. 
         [0004]    In addition to cable modem networks, where the modems are typically located at a customer&#39;s premises and a Cable Modem Termination System (“CMTS”) is located at an provider&#39;s/operator&#39;s head end location, Digital subscriber Line (“DSL”) technology is used by telephone companies to augment their ‘dial-up’ services to better compete with the cable companies broadband offerings. The telephone companies typically require that a user ‘log-in’ to the provider&#39;s network, either DSL or Dial-up, using Point-to-Point Protocol over Ethernet (“PPPoE”) technology. 
         [0005]    In the United States, this typically gives the data over cable providers a competitive differentiator, in that a cable modem broadband connection is typically ‘always on’ when the modem has been turned on and booted up. Thus, customers do not have to manually log on to the provider&#39;s network. 
         [0006]    However, outside of North America, many cable operators are part of a larger enterprise that provides Internet access via cable, DSL, and dial-up. Thus, operators typically manage the cable data service in the same way as the DSL and dial-up services. As such, access to the cable service is controlled via a PPPoE login client that is installed on each Customer Premise Equipment (“CPE”), such as a personal computer, for example. This is similar to the operator&#39;s DSL service configuration and thus is familiar to them. 
         [0007]    In such an architectural arrangement  2 , as shown in  FIG. 1 , the login client  4  communicates with a subscriber management server (“SMS”)  6  at the cable head end that authenticates the subscriber and logs session accounting records in a Remote Authentication Dial Up Server  10  (“RADIUS”), configures the IP settings of the client  4 , and terminates the PPPoE tunnel to allow the encapsulated IP packets to be routed to their destination. 
         [0008]    Turning now to  FIG. 2 , the configuration and subscriber login processes in a prior art system are illustrated to provide a comparison to the configuration and subscriber login pathways associated with system  18  as shown in  FIG. 3 , reference to which is discussed in detail below in the Detailed Description. In  FIG. 2 , when cable modem  16  boots up, it interacts with dynamic host configuration protocol (“DHCP”) server  14 . After network access has been provided to modem  16  and logged by DHCP server  14 , PPPoE client  4  establishes a session by sending login information, typically comprising a log in identifier and a password, to SMS  6 . SMS  6  interacts with RADIUS server  10  to record session statistics therein. These statistics are later used for billing and other purposes as discussed above. While this multi-path, distributed login scheme is functional, it is inefficient because different servers are used for configuring and logging in the CM  16  and CPE client  4 . In addition, the PPPoE client  4  encapsulates login data into Ethernet packets for communication with SMS  6 . Thus, CMTS  12  is a layer-2 switch because after modem  16  is registered at step A, the CPE client  4  is authenticated through SMS  6  at step B, after which the SMS records the session in the RADIUS server  10  at step C. As discussed above, this allows the SMS to authenticate the client  4 , so that a provider&#39;s operation can use a similar method for authenticating DSL, dial-up and cable subscribers. Thus, the same RADIUS server  10  can be used for all of a provider&#39;s customers. 
         [0009]    The advantage to this architecture is that the PPP and RADIUS components are in common with the DSL and dial-up architecture. Thus, efficiency of the operator&#39;s subscriber accounting and billing are more efficient. Also, some countries have laws that require operators to provide subscriber-access-records to law enforcement authorities; RADIUS accounting records may be used for this as well. 
         [0010]    The primary disadvantage to this architecture is that PPPoE encapsulates the IP packets between the client and the SMS in an Ethernet frame that must be forwarded via a Layer-2 switching CMTS  12 . This effectively limits the operator to using older generation Layer-2 switching CMTSs  12  instead of using next-generation Layer-3 routing IP CMTSs that are the current state of the art in terms of wire-speed Quality of Service (“QoS”), high capacity and high availability. Furthermore, there is a significant performance penalty for the encapsulation of IP in PPPoE as SMS  6  must be capable of high performance encapsulation and routing of the IP traffic in the PPPoE tunnels for each client. An additional issue is that PPPoE encapsulated IP headers cannot be inspected by the DOCSIS 1.1 service flow classifiers and hence any benefits of per application QoS (especially VoIP) are not available to PPPoE clients. 
         [0011]    As an alternative, if a Layer 2 Tunneling Protocol (“L2TP”) client is used for each subscriber (instead of a PPPoE client) to permit the use of PPP over a routing CMTS in the path, then the SMS performance is even further degraded. Another variation on this theme is for the routing CMTS  12  to perform a PPPoE-to-L2TP gateway function to allow the aggregation of the client PPP sessions into a single L2TP session to the SMS to reduce the performance impact on the SMS. However, this also imposes a significant performance penalty on the CMTS as the cost of the PPPoE encapsulation just moves from one device in the network to another. 
         [0012]    Another disadvantage is that the DOCSIS architecture uses the DHCP protocol to configure the cable modems and it is available to be used to configure the CPE as well. A DHCP server  14  that is typically integrated into a more functional subscriber management package provided by third party vendors can handle the management of both of these devices. But when PPPoE is used in a DOCSIS cable data system, cable modems  16  are configured via DHCP in one device and the CPEs  4  are configured via PPPoE in yet another device. This creates unnecessary management costs and complexity for the cable operator. 
         [0013]    Thus, there is a need in the art for a method and system that eliminates the need for PPPoE login in a cable modem data system. There is also a need in the art for a method and system that use layer-3 routing, rather than layer-2 switching. 
       SUMMARY 
       [0014]    An aspect unifies CPE and CM configuration via dynamic host configuration protocol (“DHCP”). Thus, subscriber authentication and accounting using RADIUS are preserved, positive network access control at the CMTS is maintained, and native IP traffic is routed or switched for maximum performance and QoS treatment. By taking the SMS device out of the IP traffic path, the need for PPPoE encapsulation and Layer-2 CMTSs is eliminated, a major bottleneck is removed and equipment costs are reduced. This aspect facilitates the same subscriber login and accounting semantics that are provided by the less efficient PPPoE architecture, but with better performance and fewer equipment costs. In addition, this solution will work for both routing and switching CMTSs and will make the transition to next generation routing CMTSs easier by not requiring a change to the CPE client configuration. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]      FIG. 1  illustrates a system for facilitating subscriber log-in using a PPPoE client over a cable modem data network. 
           [0016]      FIG. 2  illustrates the major steps in a system for facilitating subscriber log-in using a PPPoE client over a cable modem data network. 
           [0017]      FIG. 3  illustrates a system for using a DHCP server for providing secure client log-in via a layer-3 CMTS. 
           [0018]      FIG. 4  illustrates the major steps in a system for using a DHCP server associated with a subscriber login server for providing secure client log-in via a layer-3 CMTS. 
           [0019]      FIG. 5  illustrates a flow diagram of a process for using a DHCP server associated with a subscriber login server for providing secure client log-in via a layer-3 CMTS. 
       
    
    
     DETAILED DESCRIPTION 
       [0020]    As a preliminary matter, it will be readily understood by those persons skilled in the art that the present invention is susceptible of broad utility and application. Many methods, embodiments and adaptations of the present invention other than those herein described, as well as many variations, modifications, and equivalent arrangements, will be apparent from or reasonably suggested by the present invention and the following description thereof, without departing from the substance or scope of the present invention. 
         [0021]    Accordingly, while the present invention has been described herein in detail in relation to preferred embodiments, it is to be understood that this disclosure is only illustrative and exemplary of the present invention and is made merely for the purposes of providing a full and enabling disclosure of the invention. This disclosure is not intended nor is to be construed to limit the present invention or otherwise to exclude other embodiments, adaptations, variations, modifications and equivalent arrangements, the present invention being limited only by the claims appended hereto and the equivalents thereof. 
         [0022]    Turning now to the figures,  FIG. 3  illustrates a system  18  for facilitating a subscriber login client running on a subscriber&#39;s PC  4  securely communicating with a subscriber login server  22 . It will be appreciated that the login client  4  generally refers to an executable software program being run on a subscriber&#39;s (or customer&#39;s) premise equipment, typically a PC. Thus, for clarity, references herein to login client, PC, or CPE may be used interchangeably in conjunction with reference numeral  4 . 
         [0023]    To the subscriber, the interface of login client  4  appears like a PPPoE client. However, instead of contacting SMS  6  as shown in  FIG. 1 , client  4  securely contacts login server  22  using Secure Socket Layer (“SSL”) technology, e.g. HTTPS, and sends an encrypted userid and password to the login server. 
         [0024]    System  18  includes DHCP server  14 , as shown in  FIG. 1 . DHCP server  14  is complemented by login server  22  that manages the subscriber login session. Login server  22  communicates with RADIUS server  10  for subscriber authentication and accounting and with a DOCSIS CMTS  24  via simple network management protocol (“SNMP”) to control network access for CPE  4  and to obtain session traffic statistics. Login client  4  periodically “checks-in” with the login server  22  with a “hello” message to demonstrate client activity. Login server  22  preferably will automatically terminate a subscriber login session if client  4  does not check-in with the login server on a regular basis. RADIUS server  10  preferably provides subscriber authentication and accounting. 
         [0025]    Layer 3 DOCSIS CMTS  24  use the standard DOCSIS Subscriber Management filters  26  to positively control network access by CPE  4  as directed by login server  22  via SNMP. Also, session traffic statistics are available to login server  22  via DOCSIS SNMP MIBs. 
         [0026]    When the DHCP server  14  is complemented with client login server  22 , the steps differ from those discussed above in reference to  FIG. 2 .  FIG. 4  illustrates the main steps using a DHCP server associated with a subscriber login server for providing secure client log-in via a layer-3 CMTS. At step D, the modem  16  registers with the DHCP server  14  as in the prior art method, where DHCP server  14  assigns an IP address to the modem. In addition, at step D, the CPE also registers with the DHCP server  14  and receives its IP configuration as well. The login server  22  provides a login interface similar to the interface with which a CPE user  4  in  FIGS. 1 and 2  would interact in inputting login and password information for example. This preferably encrypted login and password information is transmitted at step E via secure sockets layer technology, as known in the art. 
         [0027]    Then, the login server  22  sends this information to the RADIUS server  10  and either receives back an authentication-allowed or authentication-disallowed at step F. If the former, login server  22  sends a session record to the radius server  10 . If the latter, the login server  22  sends an access declined message to the client  4 . If access is allowed, the login server sends a query message at step G to the DHCP server  14  containing the IP address of the client  4 . The DHCP server responds with a message containing the IP address of the CMTS  12  and the MAC address of modem  16  at step G. At step H, the login server  22  communicates messages with CMTS  12  via SNMP regarding session statistics, such as, for example, octet and packet counters for modem  16  service flows. A subscriber-specific session record is generated containing RADIUS session-id, start time, beginning octet and packet counters, as well as modem  16  MAC address, CPE  4  IP address, and CMTS  12  IP address, for example. Login server then sends an SNMP set message to CMTS  12  changing the DOCSIS Subscriber Management filter group associated with modem  16  from unauthorized to authorized. The login server  22  sends login confirmation to the client  4 , which displays a ‘login successful’ message and starts a timer for determining when to send the next periodic ‘hello’ message to the login server  22  stating to the login server that the client  4  is still present and the session is still active. 
         [0028]    Since the SMS server  6  and PPPoE tunnels are removed from the payload data path, CMTS  12  can be either a preferred layer-3 IP routing device or a layer-2 switching device that facilitates information flow between CPEs  4 - 4   n , modems and  16 - 16   n  and login server  22 . This eliminates the bottleneck that forms at SMS  6  in  FIGS. 1 and 4 , because traffic from each device does not have to be ‘squeezed’ through the same ‘opening’ at the SMS. Rather, the preferred layer-3 CMTS  12  facilitates a separate virtual pathway for each user-device  4  and/or  16 , such that traffic for each device can flow independently of traffic from the other devices. 
         [0029]    In addition, login server  22  communicates with the RADIUS server  10  separately from the traffic flows of payload data associated with user-devices  4  and  16 . Thus, RADIUS server  10  can still provide subscriber authentication and accounting. The login server  22  also communicates with the CMTS  12  via SNMP to control CPE access to network  28  and to obtain session traffic statistics. The login client  4  can periodically send a “hello” message to login server  22  to demonstrate that the client is still active. If the client  4  does not ‘check-in’ when expected, the login server  22  may automatically terminate the subscriber&#39;s login session. Since HTTPS, or similar secure protocol, messaging can be used for this ‘check-in’, payload traffic flow with network  28  is not interrupted. 
         [0030]    For purposes of illustration, a subscriber session scenario process  500  is illustrated in  FIG. 5 . Reference numerals from the previous figures apply and are used in the description of  FIG. 5 . In describing the start of the scenario, it is assumed that cable modem  16  has already been registered and configured via DHCP and that the CPE  4  has also been turned on and has been configured via DHCP with a public IP address, a DNS address, and a gateway address. DHCP server  14  learns the MAC address of the CM  16  hosting the CPE  4  via Option  82  and the IP address of CMTS  24  hosting the CM via the gateway address (giaddr). Furthermore, during cable modem registration, the initial IP filter groups (both upstream and downstream) for the CPE  4  attached to the CM  16  have been set to the unauthorized filter group that denies access to all IP addresses except the login server  22  and the DHCP server  14 . 
         [0031]    At step  504 , the subscriber starts the login client  4 , which displays a prompt for receiving the subscriber&#39;s userid and password. The client  4  securely contacts the login server  22  at step  504  using Secure Socket Layer (SSL) technology (e.g. HTTPS) and sends the encrypted userid and password to the login server  22  at  506 . The login server contacts the RADIUS server  10  at step  508  and sends an Access Request message corresponding to the subscriber. If an Access Accept response is received from the RADIUS server  10  at login server  22 , the login server sends an Accounting Start record to the RADIUS server. Otherwise, if an Access Reject response is received, the login server  22  sends a login failed message to the client  4 . 
         [0032]    At step  510 , the login server  22  sends a query containing the IP address associated with CPE  4  to DHCP server  14  and receives the management IP address for the CMTS  24  hosting the CPE and the MAC address associated with the cable modem  16  hosting the CPE. 
         [0033]    At step  512 , the login server  22  sends an SNMP ‘get’ message to CMTS  24  to obtain the current octet and packet counters for the service flows associated with the subscriber&#39;s CM  16 . A subscriber session database entry  30  is created for this session containing the RADIUS session-id, start time, and beginning octet and packet counters as well as the CM MAC, CPE IP, and CMTS IP addresses. 
         [0034]    At step  514 , login server  22  sends an SNMP ‘set’ message to CMTS  24  that changes the DOCSIS standard Subscriber Management filter group for the CM  16  hosting the CPE  4  from the CPE unauthorized filter group to the CPE authorized filter group. Note that the CPE unauthorized filter group allows the CPE  4  to only communicate with login server  22  and DHCP server  14 . However, it will be appreciated that if the client  4  is a browser, for example, the client would query a DNS server that would typically respond with the IP address for login server  22 , and the browser would then access the login server. The CPE authorized filter group allows unrestricted network access. However, the extent of ‘unrestrictedness’ may be determined by the cable operator. The login server  22  sends a login confirmation response to the login client/CPE  4  at step  516 . 
         [0035]    Step  518  summarizes multiple process steps that occur during a session that are typical for an internet browsing session with the exception of the periodic hello message sent by client  4  to the login server making it aware that the client session is still active. The login client  4  displays a login-successful message and starts a timer for the next periodic message to the login server  22 . A running session elapsed time display is also started. Traffic is passed by the CPE-authorized filter group  26  at the CMTS  24  and is counted in the service flow statistics for the CM  16 . If the subscriber attempts any access other than to the login server  22  before the login sequence is completed, this traffic will be silently discarded by the CMTS  24 . 
         [0036]    The login client  4  periodically sends a hello message to the login server  22 . If the client  4  does not check-in with a hello message on a regular basis, the server  22  automatically logs-out the subscriber. When the subscriber reactivates the login client  4  and logs out, the login client securely connects to the login server  22  and sends the logout message to the login server. 
         [0037]    At step  520 , login server  22  obtains a subscriber session record from a session database  30 , which maintains a log of each active session. Then at step  522  login server  22  sends an SNMP set message to the CMTS  24  that changes the DOCSIS standard Subscriber Management filter group  26  corresponding to the CM  16  hosting the CPE  4  from the CPE-authorized filter group to the CPE-unauthorized filter group. Access is now restricted to login server  22  only (or DNS server as discussed above). 
         [0038]    At step  524 , login server  22  sends an SNMP get message to the CMTS  24  to obtain the service flow counters for the CM  16 . Server  22  then computes the session elapsed time and the octets and packets-passed values and sends an Accounting End record to the RADIUS server  10  to be associated therein with the subscriber at step  526 . The Accounting End record includes the session-id, elapsed time of the session, and the number of input (upstream) and output (downstream) octets and packets transmitted during the session. 
         [0039]    At step  528 , login server  22  sends a logout confirmed message to the client  4 , including the final session elapsed time and the session octet and packet passed counts. The login client  4  displays the logout-successful message at step  530 , the message including the session elapsed time and the session octet and packet passed counts. It is noted that the session counts are preferably presented with respect to the subscriber&#39;s frame of reference, which is the directional inverse (upstream vs. downstream) of the RADIUS  10  accounting record. In other words, input to Radius server  10  is initiated by a subscriber, thus it is upstream, output from the RADIUS server is received by the subscriber, and thus is considered downstream. The process ends at step  532 . 
         [0040]    These and many other objects and advantages will be readily apparent to one skilled in the art from the foregoing specification when read in conjunction with the appended drawings. It is to be understood that the embodiments herein illustrated are examples only, and that the scope of the invention is to be defined solely by the claims when accorded a full range of equivalents.