Method for acquiring, by SDN switch, exact flow entry, and SDN switch, controller, and system

Patent metadata

Field	Value
Publication number	US-9742656-B2
Application number	US-201615137963-A
Country	US
Kind code	B2
Filing date	Apr 25, 2016
Priority date	Oct 26, 2013
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

Embodiments of the present invention disclose a method for acquiring, by an SDN switch, an exact flow entry, applied to an SDN network, where the SDN network includes an SDN controller and multiple SDN switches, the SDN controller communicates with each SDN switch in an inband communication manner, and the method includes: first establishing, by a first SDN switch, a reliable connection to the SDN controller; then, sending a first control message based on a packet corresponding to a protocol for the reliable connection; adding path information of the first SDN switch to the control message; and subsequently, also adding, by each SDN switch that receives the first control message, path information of each SDN switch to the first control message, so that finally, the SDN controller knows an entire path, so as to deliver a flow table to the first SDN switch.

First claim

What is claimed is:

1. A method for acquiring, by a switch device in a software defined network SDN, an exact flow entry, applied to a second switch device in the SDN, wherein the second switch device is connected to a first switch device and an controller device in the SDN, to form an SDN network, the controller device communicates with each switch device in an inband communication manner, and the method comprises:
receiving a first control message sent by the first switch device and used for collecting path information, wherein the first control message carries path information of the first switch device, and the first control message is carried in a packet according to a protocol used by a reliable connection established between the first switch device and the controller device;
adding path information of the second switch device to the first control message, to obtain an updated first control message; and
forwarding, to the controller device, the updated first control message, to allow the controller device, after receiving a finally updated first control message comprising the updated first control message, to determine a routing path between the controller device and the first switch device according to path information added by each switch device to the finally updated first control message, and deliver an exact flow entry to the first switch device according to the routing path.

2. The method according to claim 1 , wherein the reliable connection established between the first switch device and the controller device comprises a TCP connection, wherein the packet comprises a TCP/IP packet, and wherein the TCP connection is established by forwarding, by the second switch device, a TCP/IP packet carrying information about three-way TCP handshake performed between the first switch device and the controller device.

3. The method according to claim 2 , wherein the second switch device stores an exact flow table, wherein the exact flow table comprises multiple exact flow entries, wherein each exact flow entry comprises multiple match fields and an instruction corresponding to the multiple match fields, and wherein the forwarding by the second switch device comprises:
receiving, by the second switch device, a first TCP/IP packet sent from the first switch device;
acquiring multiple pieces of feature information in the received first TCP/IP packet, wherein the feature information corresponds to match fields in an exact flow entry in the exact flow table in the second switch device; and
performing matching between the multiple pieces of feature information and the exact flow table in the second switch device, wherein if the matching fails and the received first TCP/IP packet carries a first type of TCP handshake message, wildcard-match matching is performed between one or more pieces of feature information in the multiple pieces of feature information and the exact flow table, wherein a forwarding route determined by using an instruction corresponding to one or more match fields used during the wildcard-match matching includes a route to the controller device, and wherein if the wildcard-match matching succeeds, the received first TCP/IP packet is processed according to an instruction in an exact flow entry successfully matched in the wildcard-match matching, so as to forward the first TCP/IP packet to the controller device, wherein the first type of TCP handshake message is a message of first TCP handshake or a message of third TCP handshake.

4. The method according to claim 3 , wherein the forwarding the TCP/IP packet by the second switch device further comprises:
receiving, by the second switch device, a third TCP/IP packet from the controller device, wherein the third TCP/IP packet carries a message of second handshake;
acquiring multiple pieces of feature information in the third TCP/IP packet, wherein the feature information corresponds to match fields in an exact flow entry in the exact flow table in the second switch device; and
performing matching between the multiple pieces of feature information of the third TCP/IP packet and the exact flow table in the second switch device, wherein if the matching of the multiple pieces of feature information of the third TCP/IP packet succeeds, the TCP/IP packet is forwarded according to an instruction in an exact flow entry successfully matched in the matching of the multiple pieces of feature information of the third TCP/IP packet, and wherein if the matching of the multiple pieces of feature information of the third TCP/IP packet fails and the third TCP/IP packet carries the message of second TCP handshake, the third TCP/IP packet is broadcasted.

5. The method according to claim 2 , wherein the second switch device stores an exact flow table, wherein the exact flow table comprises multiple exact flow entries, and wherein each exact flow entry comprises multiple match fields and an instruction corresponding to the multiple match fields, the method further comprising:
receiving, by the second switch device, a second TCP/IP packet sent from the first switch device and carrying the first control message, wherein the second TCP/IP packet comprises multiple pieces of feature information, wherein the feature information corresponds to match fields in an exact flow entry in the exact flow table in the second switch device; and
performing, by the second switch device, matching between the feature information in the second TCP/IP packet and the exact flow table, wherein if the matching fails and it is determined that the received second TCP/IP packet carries the first control message, wildcard-match matching is performed according to one or more pieces of feature information in the TCP/IP packet and the exact flow table, wherein a forwarding route determined by using an instruction corresponding to one or more match fields used during the wildcard-match matching is a route to the controller device, and wherein if the wildcard-match matching succeeds, the updated first control message is forwarded to the controller device according to an instruction in an exact flow entry successfully matched in the wildcard-match matching.

6. The method according to claim 5 , wherein, if the wildcard-match matching fails, an available output port of the second switch device is acquired wherein the path information corresponds to each available output port of the second switch device, and wherein the updated first control message is forwarded to the controller device from the available output port.

7. The method according to claim 3 , wherein the feature information comprises: destination MAC, a destination IP, and a destination port number, wherein the match fields used for wildcard-match matching include destination MAC, a destination IP, and a destination port number, and wherein the wildcard-match matching comprises:
performing matching between destination MAC, a destination IP, and a destination port number in the multiple pieces of feature information and destination MAC, a destination IP, and a destination port number in a flow entry, wherein if the matching of the destination MAC, the destination IP, and the destination port number in the multiple pieces of feature information succeeds, the received first TCP/IP packet is processed according to an instruction in an exact flow entry successfully matched in the matching.

8. The method according to claim 1 , wherein the SDN network is implemented based on an OpenFlow protocol, wherein the first control message comprises an OFPT_HELLO message defined in the OpenFlow protocol, wherein a body field of the OFPT_HELLO message is used for carrying the path information after being extended, and wherein the adding path information of the second switch device comprises:
adding the path informatio

Assignees

• Huawei Tech Co Ltd

Inventors

• Zheng Xiuli
• Wen Bailin
• Wang Rong

Classifications

• H04L45/26

  Route discovery packet · CPC title

• H04L45/42

  Centralised routing · CPC title

• H04L69/16

  Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP] · CPC title

• H04L45/64

  using an overlay routing layer · CPC title

• H04L45/02 Primary

  Topology update or discovery · CPC title