Dynamic control channel establishment for software-defined networks having centralized control

Patent metadata

Field	Value
Publication number	US-9100285-B1
Application number	US-201514672058-A
Country	US
Kind code	B1
Filing date	Mar 27, 2015
Priority date	Dec 18, 2012
Publication date	Aug 4, 2015
Grant date	Aug 4, 2015

Abstract

Dynamic control channel establishment for an access network is described in which a centralized controller provides seamless end-to-end service from a core-facing edge of a network to access nodes. For example, a method includes receiving, by the centralized controller, a discover message originating from a network node, which includes an intermediate node list that specifies a plurality of network nodes the discover message traversed from the network node to an edge node, determining, based on the plurality of nodes specified by the discover message, a path from the edge node to the network node, allocating each of a plurality of Multi-protocol Label Switching (MPLS) labels to a respective outgoing interface of each of the plurality of network nodes, and outputting one or more control messages for configuring the network node, wherein the control messages are encapsulated within a label stack comprising the allocated plurality of labels.

First claim

The invention claimed is:

1. A method comprising:
sending, by a network node, a plurality of hello messages to neighboring network nodes within a network, wherein each of the plurality of hello messages is sent on a different respective network link coupled to the network node and includes an indicator specifying a respective distance as a number of network hops from the network node to a centralized controller that manages the network;
receiving, by the network node, a plurality of hello reply messages from respective neighboring network nodes within the network in response to the plurality of hello messages, wherein each of the plurality of hello reply messages is received on a different respective network link coupled to the network node and includes a respective indicator specifying a respective distance as a number of network hops from the respective neighboring network node sending the hello reply messages to a centralized controller that manages the network;
determining, by the network node and based at least in part on the respective distance specified by one or more of the plurality of hello reply messages received from the neighboring network nodes, an active one of the network links coupled to the network node to one of the neighboring network nodes having a shortest distance to the centralized controller;
forwarding, by the network node, a discover message on the active link to the neighboring network node having the shortest distance to the centralized controller, wherein the discover message includes a neighbor node list specifying a set of neighboring network nodes from which hello reply packets were received and an intermediate node list that will specify a set of network nodes the discover message will traverse; and
after receiving a discover reply message sent by the centralized controller in response to the centralized controller receiving the discover message, sending, by the network node, a control message to the centralized controller encapsulated with a Multi-protocol Label Switching (MPLS) label that indicates the control message is to be automatically forwarded by a receiving one of the network nodes along a shortest path toward the centralized controller.

2. The method of claim 1 , further comprising:
receiving, by the network node, a second discover message from a neighboring one of the network nodes;
checking, by the network node, whether an intermediate node list specified by the second discover message includes the network node;
in response to determining that the intermediate node list includes the network node, discarding the second discover message; and
in response to determining that the intermediate node list does not include the network node:
updating, by the network node, the intermediate node list to include the network node and an ingress port and egress port of the network node; and
forwarding, by the network node, an updated second discover message on the active link to the neighboring network node having the shortest distance to the centralized controller.

3. The method of claim 2 , wherein the intermediate node list identifies a Media Access Control (MAC) address of each of the plurality of network nodes, and corresponding ingress and egress port pairs through which the discover message traversed from the network node to an edge node, inclusive of the network node and the edge node.

4. The method of claim 1 , further comprising:
by the network node, periodically broadcasting a hello message as a link-local broadcast message on all ports of the network node;
by the network node, receiving respective hello reply messages from the neighboring network nodes in response to the broadcast hello messages;
in response to receiving the respective hello reply messages:
setting as active a link on which the respective hello reply messages are received from the neighboring network nodes; and
updating a table of shortest distances to the centralized controller based on at least one member selected from a group consisting of (1) the number of network hops specified by the hello messages and (2) the number of network hops specified by the respective hello reply messages; and

by the network node, adding the neighboring network nodes from which hello reply messages are received to the neighbor node list.

5. The method of claim 1 , wherein the discover message comprises a first discover message that specifies a first generation number, the method further comprising:
sending, by the network device, a keepalive message to the centralized controller; and
in response to receiving no keepalive reply message from the centralized controller within a time period after sending the keepalive message, forwarding a second discover message on the active link, wherein the second discover message specifies a second generation number having a value greater than a value of the first generation number.

6. The method of claim 1 , further comprising:
receiving, by the network node, a control message sent by the centralized controller and destined for a neighboring network node, wherein the control message is encapsulated within a label stack comprising a plurality of MPLS labels allocated by the centralized controller;
by the network node, removing an outer label of the label stack; and
forwarding the control message with a modified label stack to a next hop selected based on the outer label.

7. The method of claim 1 , wherein sending the control message to the centralized controller comprises sending an endpoint indication message that indicates an endpoint status change, wherein the endpoint indication message specifies a type of an endpoint, an address of the endpoint, and a status of the endpoint indicating whether the endpoint is up or down.

8. The method of claim 7 , wherein sending the control message to the centralized controller comprises sending a direct switch response message to acknowledge receipt of a direct switch request message from the centralized controller for mapping traffic from the endpoint to a pseudo wire.

9. The method of claim 1 , wherein sending the control message to the centralized controller comprises sending a pseudo wire response message to acknowledge receipt of a pseudo wire request message from the centralized controller for creating a pseudo wire on the network node.

10. A network node comprising:
one or more processors;
one or more physical interfaces configured to send a plurality of hello messages to neighboring network nodes within a network, wherein each of the plurality of hello messages is sent on a different respective network link coupled to the network node and includes an indicator specifying a respective distance as a number of network hops from the network node to a centralized controller that manages the network,
wherein the one or more physical interfaces receive a plurality of hello reply messages from respective neighboring network nodes within the network in response to the plurality of hello messages, wherein each of the plurality of hello reply messages is received on a different respective network link coupled to the network node and includes a respective indicator specifying a respective distance as a number of network hops from the respective neighboring network node sending the hello reply messages to a centralized controller that manages the network; and
a protocol module executing on the one or more processors, wherein the protocol module is configured to determine, based at least in part on the respective distance specified by one or more of the plurality of hello reply messages received from the neighboring network nodes, an active one of the network links coupled to the network node to one of the neighboring network nodes ha

Assignees

• Juniper Networks Inc

Inventors

• Choudhury Abhijit K
• Murphy James M
• Sindhu Pradeep
• Boddu Jayabharat

Classifications

• H04L45/02

  Topology update or discovery · CPC title

• H04L41/12

  Discovery or management of network topologies · CPC title

• H04L41/40

  using virtualisation of network functions or resources, e.g. SDN or NFV entities · CPC title

• H04L45/68

  Pseudowire emulation, e.g. IETF WG PWE3 · CPC title

• H04L45/026 Primary

  Details of "hello" or keep-alive messages · CPC title