Automatic local LAPB device configuration method and apparatus
View Patent ↗A method and apparatus is disclosed for configuring a local LAPB device in accordance with a remote LAPB device using a received frame provided by the remote LAPB device.
1. A method of establishing operation of a local Link Access Protocol Balanced (LAPB) device operable as a data computing equipment device or a data terminal equipment device, the method comprising:
receiving an initiator frame for an asynchronous balanced mode of operation directed to said local LAPB device from a remote LAPB device;
determining, based upon information contained within said received initiator frame, whether said remote LAPB device is operating as a data computing equipment device or a data terminal equipment device;
if it is determined that said received frame information indicates that said remote LAPB device is operating as a data terminal equipment device, initiating operation of said local LAPB device as a data computing equipment device; and
if it is determined that said received frame information indicates that said remote LAPB device is operating as a data computing equipment device, initiating operation of said local LAPB device as a data terminal equipment device.
2. The method as claimed in claim 1 , further comprising monitoring to detect receipt of said initiator frame from said remote LAPB device and if no initiator frame is detected for a given first time period, providing an initiator frame to said remote LAPB device.
3. The method as claimed in claim 2 , wherein said monitoring to detect said initiator frame from said remote LAPB device is performed during a given period of time.
4. The method as claimed in claim 3 , further comprising providing said given period of time.
5. The method as claimed in claim 1 , wherein said initiator frame is an LAPB supervisory frame.
6. The method as claimed in claim 5 , wherein said LAPB supervisory frame is one of:
an LAPB SABM supervisory frame in basic mode frame format;
an LAPB SABME supervisory frame in extended mode frame format; and
an LAPB SM supervisory frame in super mode frame format.
7. The method as claimed in claim 1 , wherein said initiator frame is one of:
an LAPB DISC supervisory frame;
an LAPB DM supervisory frame; and
an LAPB FRMR frame.
8. An apparatus for establishing operation of a local Link Access Protocol Balanced (LAPB) device operable as a data computing equipment device or a data terminal equipment device, the apparatus comprising:
a communication port for receiving an initiator frame for an asynchronous balanced mode of operation originated from a remote LAPB device and directed to said local LAPB device;
a memory for storing data identifying at least one of a data computing equipment device and a data terminal equipment device;
a processing unit coupled to said communication port and said memory for determining whether information contained within said received initiator frame is indicative of said remote LAPB device operating as one of a data computing equipment device and a data terminal equipment device using said data stored in said memory and providing a configuration signal to said local LAPB device as a function thereof; and
said configuration signal for initiating operation of said local LAPB device as a data computing equipment device in the case where the received frame information is indicative of said remote LAPB device operating as a data terminal equipment device and further said configuration signal for initiating operation of said local LAPB device as a data terminal equipment device in the case where the received frame information is indicative of said remote LAPB device operating as a data computing equipment device.
9. The apparatus as claimed in claim 8 , wherein said communication port provides an initiator frame to said remote LAPB device in the case where no initiator frame is received from said remote LAPB device for a given period of time.
10. The apparatus as claimed in claim 9 , wherein said apparatus includes said local LAPB device.
11. The apparatus as claimed in claim 8 , wherein said apparatus includes said local LAPB device.
12. A method of establishing operation of a first Link Access Protocol Balanced (LAPB) device coupled to a second LAPB device in a network, said first LAPB device operable as a data terminal equipment device or a data computing equipment device, the method comprising:
receiving a first initiator frame for an asynchronous balanced mode of operation from the second LAPB device directed to the first LAPB device;
evaluating information contained within the received first initiator frame to determine if the second device is operating as a data terminal equipment device or a data computing equipment device;
if it is determined that the second LAPB device is operating as a data terminal equipment device, initiating operation of the first LAPB device as a data computing equipment device; and
if it is determined that the second LAPB device is operating as a data computing equipment device, initiating operation of the first LAPB device as a data terminal equipment device.
13. The method of claim 12 , further comprising:
determining whether the first initiator frame is received from the second LAPB device prior to expiration of a first predetermined time period; and
if the first initiator frame is not received prior to expiration of the first predetermined time period, sending a second initiator frame to the second LAPB device.
14. The method of claim 13 , further comprising:
determining whether a third initiator frame is received from the second device in response to the second initiator frame prior to expiration of a second predetermined time period; and
if the third initiator frame is not received prior to expiration of the second predetermined time period, setting a failure status condition.
15. The method of claim 13 , wherein each of the first and second initiator frames is an initiator frame for a first mode of LAPB operation.