Techniques for Migrating a Point to Point Protocol to a Protocol for an Access Network

• US 20090154466A1
• Filed: 12/16/2008
• Published: 06/18/2009
• Est. Priority Date: 11/29/2004
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Mammoliti, Vincent John, Townsley, William Mark, Jones, Huw
• Granted Patent: US 8,086,749 B2
• Time in Patent Office: Days
• US Class Current: 370/395.100
• CPC Class Codes: H04L 69/03 Protocol definition or specification protocol conformance testing H04L1/244
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/168 specially adapted for link layer protocols, e.g. asynchronous transfer mode [ATM], synchronous optical network [SONET] or point-to-point protocol [PPP]
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC

Abstract

Techniques for managing a persistent session associated with a particular Media Access Control (MAC) include determining at a broadband remote access server whether an elapsed time since a data packet is received with the particular MAC address exceeds a threshold time. If so, then point-to-point protocol (PPP) control data is sent in a data link protocol payload that is encapsulated in a data packet with an Ethernet destination field that indicates the particular MAC address. The PPP control data indicates a request for an echo. It is determined whether a data packet with the particular MAC address in an Ethernet source field is received within a particular time interval. If not, then a session associated with the particular MAC address is terminated. These techniques allow PPP control plane functionality while utilizing IP over Ethernet for the data plane.

Claims

1. A method for managing, at a broadband remote access server, a persistent session associated with a particular Media Access Control (MAC) address:

determining whether an elapsed time since a data packet is received with the particular MAC address exceeds a threshold time; and

if it is determined that the elapsed time exceeds the threshold time, then performing the steps of;

sending point-to-point protocol (PPP) control data in a data link protocol payload that is encapsulated in a data packet with an Ethernet destination field that indicates the particular MAC address, wherein the PPP control data indicates a request for an echo;

determining whether a data packet with the particular MAC address in an Ethernet source field is received within a particular time interval; and

if it is determined that the data packet with the particular MAC address in an Ethernet source field is not received within the particular time interval, then terminating a session associated with the particular MAC address.

2. The method as recited in claim 1, wherein the data link protocol is Ethernet.

7. The method as recited in claim 1, further comprising:

receiving the data packet that uses an inbound protocol that is different from point to point protocol (PPP) and from PPP over Ethernet (PPPoE) and from PPP over Asynchronous Transfer Mode (ATM) protocol (PPPoA); and

determining whether an inbound protocol type field in the data packet includes data that indicates PPP control data.

3. An apparatus for managing, at a broadband remote access server, a persistent session associated with a particular Media Access Control (MAC) address, comprising:

a network interface that is coupled to a network for communicating one or more packet flows therewith;

one or more processors; and

one or more stored sequences of instructions which, when executed by the one or more processors, causes the one or more processors to carry out the steps of;

determining whether an elapsed time since a data packet is received with the particular MAC address exceeds a threshold time; and

if it is determined that the elapsed time exceeds the threshold time, then performing the steps of;

sending point-to-point protocol (PPP) control data in a data link protocol payload that is encapsulated in a data packet with an Ethernet destination field that indicates the particular MAC address, wherein the PPP control data indicates a request for an echo;

determining whether a data packet with the particular MAC address in an Ethernet source field is received within a particular time interval; and

if it is determined that the data packet with the particular MAC address in an Ethernet source field is not received within the particular time interval, then terminating a session associated with the particular MAC address.

4. The apparatus as recited in claim 3, wherein the data link protocol is Ethernet.

5. A computer-readable volatile or non-volatile medium carrying one or more sequences of instructions for managing, at a broadband remote access server, a persistent session associated with a particular Media Access Control (MAC) address, wherein execution of the one or more sequences of instructions by one or more processors causes the one or more processors to perform the steps of:

determining whether an elapsed time since a data packet is received with the particular MAC address exceeds a threshold time; and

if it is determined that the elapsed time exceeds the threshold time, then performing the steps of;

sending point-to-point protocol (PPP) control data in a data link protocol payload that is encapsulated in a data packet with an Ethernet destination field that indicates the particular MAC address, wherein the PPP control data indicates a request for an echo;

determining whether a data packet with the particular MAC address in an Ethernet source field is received within a particular time interval; and

if it is determined that the data packet with the particular MAC address in an Ethernet source field is not received within the particular time interval, then terminating a session associated with the particular MAC address.

6. The computer-readable medium as recited in claim 5, wherein the data link protocol is Ethernet.