Resource reservation and admission control for IP network

• US 7,701,951 B2
• Filed: 03/06/2006
• Issued: 04/20/2010
• Est. Priority Date: 03/06/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Bommareddy, Satish, Parandekar, Harsh, Chapman, John T., Liu, Xiaomei
• Primary Examiner(s): Moe; Aung S
• Assistant Examiner(s): Louis; Vinncelas
• Application Number:
  US11/370,141
• Publication Number:
  US 20070206607A1
• Time in Patent Office: 1,506 Days
• Field of Search: 370/230, 370/392, 370/395.52, 370/395.53, 370/486, 370/220, 370/401, 370/467, 725/111, 725/109, 725/95, 725/117, 725/118
• US Class Current: 370/395.52
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 12/465 wherein a single frame includes a plurality of VLAN tags
• CPC Class Codes: H04L 45/68 Pseudowire emulation, e.g. IETF WG PWE3
• CPC Class Codes: H04L 47/70 Admission control; Resource allocation
• CPC Class Codes: H04L 47/724 at intermediate nodes, e.g. resource reservation protocol [RSVP]
• CPC Class Codes: H04L 47/728 for backup paths
• CPC Class Codes: H04L 47/825 Involving tunnels, e.g. MPLS

Abstract

A resource reservation and admission control scheme uses pseudowires to reserve bandwidth over a layer-2 and/or layer-3 network. The pseudowires are associated with ports on different network processing devices. During a resource reservation and admission control session, the physical links used by the pseudowire are selected and reserved to more effectively allocate network bandwidth. The negotiated pseudowire is then used to transport content for a communication session over the network. In one example application, the resource reservation and admission control scheme is used during a Downstream External PHY Interface (DEPI) session for pseudowires established between a Modular Cable Modem Termination System (M-CMTS) Core and an Edge Quadrature Amplitude Modulation Interface (EQAM) device. However, the reservation protocol can be used in any application that needs to reserve bandwidth over an Internet Protocol (IP) network.

Claims

1. A system, comprising:

a gateway operating between a packet switched cable network and an access network, the gateway comprising;

a processor to receive content for transporting using Data Over Cable System Interface Specification (DOCSIS) framing, over the packet switched cable network, and to an edge modulation device for remote modulation by the edge modulation device and downstream transmission from the edge modulation device;

the processor configured to identify a first packet switched bandwidth amount for communicating the content from the gateway, over the packet switched cable network, to the edge modulation device, the processor further configured to identify a second Quadrature Amplitude Modulation (QAM) bandwidth amount for communicating the content from the edge modulation device, over a Radio Frequency (RF) channel, to a cable modem;

the processor configured to filter available gateway ports according to the first packet switched bandwidth amount;

the processor configured to identify Virtual Local Area Network (VLAN) tags corresponding to the filtered available gateway ports; and

the processor configured to communicate the second QAM bandwidth amount and the VLAN tags over the packet switched cable network and to the edge modulation device;

wherein the edge modulation device of the system is configured to;

identify a subset of ports on the edge modulation device associated with the VLAN tags, each of the identified edge modulation device ports associated with a QAM channel;

filter the identified subset of ports by comparing the second QAM bandwidth amount to availability of the associated QAM channels;

select an edge modulation device port from the identified subset of ports according to said filtering; and

send back a message to the gateway identifying a tag that corresponds to the selected edge modulation device port;

wherein the gateway ports are associated with a VLAN and the processor sends a list of the VLAN tags to the edge modulation device and then receives back a selected one of the VLAN tags.

2. The system according to claim 1, wherein a pseudowire is established between endpoints, wherein the endpoints control reservation of resources for the pseudowire through distributing port selection.

3. The system according to claim 2, wherein the resource reservation is controlled by pseudowire endpoints and occurs according to a distributed selection process whereby a first pseudowire endpoint performs initial edge modulation device port filtering through filtering which of the gateway ports can be reserved and a second pseudowire endpoint performs subsequent edge modulation device port filtering based on an analysis of initial gateway port filtering information and bandwidth information transferred from the first pseudowire endpoint to the second pseudowire endpoint.

4. The system according to claim 1, including:

a first framer to negotiate a first VLAN tag for establishing a first pseudowire connection for carrying the content between the gateway and the edge modulation device over the packet switched cable network; and

a second framer to negotiate a second VLAN tag with the edge modulation device for establishing a second backup pseudowire connection for carrying the content between the gateway and the edge modulation device over the packet switched cable network if the first pseudowire connection fails.

12. The system of claim 1, wherein the edge modulation device is configured to:

filter the sent list of VLAN tags to identify only a subset of the VLAN tags from the list; and

send back a response to the gateway after receiving the list of VLAN tags from the gateway, wherein the response includes only the identified subset of VLAN tags, wherein the response does not include the VLAN tags from the list that were filtered by the edge modulation device.

13. The system of claim 12, wherein the gateway is configured to establish a logical connection to the edge modulation device based on which one of the VLAN tags was included in the response from the edge modulation device.

5. An M-CMTS core, comprising:

a processor to receive content to be Data Over Cable System Interface Specification (DOCSIS) framed and time-stamped by the M-CMTS core, sent over a packet switched portion of a cable network to an Edge Quadrature Amplitude Modulation (EQAM), processed by the EQAM including timestamp adjustment and modulation, and then sent over a subset of QAM channels extending from the EQAM to subscriber devices;

the processor configured to identify a bandwidth amount required for transferring the content in the DOCSIS frames over the packet switched portion of the cable network;

the processor configured to filter available local ports according to the bandwidth amount;

the processor configured to identify tunnel identifier tags corresponding to the filtered local ports, to transmit a list indicating the identified tunnel identifier tags;

the processor configured to communicate both the bandwidth amount and the list over the packet switched portion of the cable network and to the EQAM, the list of identified tunnel identifier tags to be used by the remote EQAM for identifying an initial subset of remote ports on the EQAM;

the processor configured to receive, over the packet switched portion of the cable network, a communication from the EQAM, the communication identifying a subsequently identified subset of remote ports on the EQAM, the subsequently identified subset obtained by the EQAM comparing the bandwidth amount to ports included in the initially identified subset; and

the processor configured to establish a pseudowire for transporting the content over the packet switched portion of the cable network, the pseudowire established between a filtered one of the local ports and one of the remote ports included in the subsequently identified subset, wherein the establishment of the psuedowire between the ports controls which of the QAM channels is used by the EQAM for forwarding the content to a cable modem.

6. The M-CMTS core according to claim 5, wherein the processor sends a connect speed requirement for the communication session to the EQAM and responsively receives back a selection of one of the tags from the list having an associated link with sufficient bandwidth for the required connect speed.

7. The M-CMTS core according to claim 6, wherein the processor sends the list of tags and the connect speed during initiation of a Downstream External PHY Interface (DEPI) session.

8. The M-CMTS core according to claim 5, wherein the processor generates a first list of tags for establishing a first pseudowire connection with the EQAM for conducting the communication session and generates a second list of tags for establishing a second pseudowire connection for conducting the communication session with the EQAM if the first pseudowire connection fails.

9. A method for reserving resources on a network, comprising:

negotiating with a Modular Cable Modem Termination System (M-CMTS) core using an Edge Quadrature Amplitude Modulation (EQAM) for reserving bandwidth for a communication session;

identifying a layer-2 identifier during the negotiation associated with a physical link that has bandwidth available for supporting the communication session;

receiving a list of Virtual Local Area Network (VLAN) tags that are associated with GE ports on the M-CMTS core that have available bandwidth for conducting the communication session;

selecting one of the VLAN tags from the list that also corresponds with a local GE port that has sufficient bandwidth for conducting the communication session, said selection identifying a VLAN tag that is associated with a QAM channel having sufficient bandwidth for conducting the communication session;

sending the selected VLAN tag back to the M-CMTS core;

establishing a virtual connection with the M-CMTS core using the selected VLAN tag, the virtual connection established over a GE network using the identified layer 2 identifier; and

conducting the communication session over the virtual connection.

10. The method according to claim 9, including:

receiving the VLAN tags during initiation of a Downstream External PHY Interface (DEPI) session;

selecting one of the VLAN tags and sending the selected VLAN tag back to the M-CMTS core;

using the selected VLAN tag to establish the virtual connection over the GE network between the M-CMTS core and the QAM channel; and

conducting the DEPI session over the virtual connection.

11. A system, comprising:

means for negotiating with a Modular Cable Modem Termination System (M-CMTS) core using an EQAM for reserving bandwidth for a communication session;

means for identifying a layer-2 identifier during the negotiation associated with a physical link that has bandwidth available for supporting the communication session;

means for receiving a list of Virtual Local Area Network (VLAN) tags that are associated with GE ports on the M-CMTS core that have available bandwidth for conducting the communication session;

means for selecting one of the VLAN tags from the list that also corresponds with a local GE port that has sufficient bandwidth for conducting the communication session, said selection means including means for identifying a VLAN tag that is associated with a Quadrature Amplitude Modulation (QAM) channel having sufficient bandwidth for conducting the communication session;

means for sending the selected VLAN tag back to the M-CMTS core;

means for establishing a virtual connection with the M-CMTS core using the selected VLAN tag, the virtual connection established over a GE network using the identified layer 2 identifier; and

means for conducting the communication session over the virtual connection.