FIELD OF THE INVENTION
This application relates to the SDN (Software Defined Network) technology and in particular, to a forwarding method and network apparatus based on flow.

BACKGROUND
The SDNC (Software Defined Network Controller) is a new concept in the networking industry. Existing individual protocol functions (such as topology discovery, traffic engineering, best path and route selection etc.) in each of the network elements will be removed, and these functions will be maintained in a SDNC, which is a centrally entity independent of hardware.

Figure 1 is a topology showing SDNC in the prior art. As shown in Figure 1, the SDNC will control the open-flow enabled switch. The switches communicate with the SDNC and the SDNC manages the switches via the Open Flow protocol.

A switch may consist of one or more flow tables and a group table. Using the Open Flow protocol, the SDNC can add, update and delete flow entries in flow tables both reactively and proactively.

However, the applicant found that: currently the IP packet forwarding decision will based on the topology found by IGP (Interior Gateway Protocol), where SPF (Shortest Path First) is running. But the current IGP calculated SPF will make non-best route path as underutilized, so there is a need to bring the TE (Traffic Engineering) concepts for IP network.

SUMMARY

Embodiments of the present invention pertain to a forwarding method and network apparatus based on flow. The objects of the invention are to introduce flow based routing in IP network, and setup the TE kind of explicit path in SDN.

According to a first aspect of the embodiments of the present invention, a forwarding method based on flow is provided, applied in a SDN (Software Defined Network), the method comprising: receiving, by an ingress node, routing information from a SDNC;
receiving, by the ingress node, a first packet, wherein the first packet comprising prefix information of an IP address;

acquiring, by the ingress node, a flow identifier according to the prefix information and the routing information, wherein the routing information comprising a relationship among the flow identifier, the prefix information of the IP address and a next-hop IP address;

obtaining, by the ingress node, a second packet by adding the flow identifier into the first packet; sending, by the ingress node, the second packet to a device which owns the next-hop IP address.

According to another aspect of the embodiments of the present invention, wherein the type of relationship is active or backup.

According to a second aspect of the embodiments of the present invention, a forwarding method based on flow is provided, applied in a SDN, the method comprising:

receiving, by an egress node, routing information from a SDNC, wherein the routing information comprising a relationship between a flow identifier and prefix information of an IP address;

receiving, by the egress node, a second packet, wherein the second packet comprising the flow identifier and the prefix information;

removing, by the egress node, the flow identifier from the second packet, so as to generate a first packet;
sending, by the egress node, the first packet to a device.

According to a third aspect of the embodiments of the present invention, a forwarding method based on flow is provided, applied in a SDN, the method comprising:

generating, by a SDNC, first routing information for an ingress node, wherein the first routing information comprising a relationship among a flow identifier, prefix information of an IP address and a next-hop IP address;

generating, by the SDNC, second routing information for an egress node which is on an identical path with the ingress node, wherein the second routing information comprising a relationship between a flow identifier and prefix information of an IP address;
sending, by the SDNC, the first routing information to the ingress node and the second routing information to the egress node.

According to another aspect of the embodiments of the present invention, wherein the method further comprising:
receiving, by the SDNC, a path trigger request;
calculating, by the SDNC, the path with required constraint;
updating, by the SDNC, the relationship based on the result of calculation.

According to another aspect of the embodiments of the present invention, wherein the SDNC provides the first routing information and the second routing information by multicast mechanism.

According to a fourth aspect of the embodiments of the present invention, an ingress node is provided, the ingress node comprising:
a first receiving unit, configured to receive routing information from a SDNC;
a second receiving unit, configured to receive a first packet, wherein the first packet comprising prefix information of an IP address;

an acquiring unit, configured to acquire a flow identifier according to the prefix information and the routing information, wherein the routing information comprising a relationship among the flow identifier, the prefix information of the IP address and a next-hop IP address;
an obtaining unit, configured to obtain a second packet by adding the flow identifier into the first packet;
a first sending unit, configured to send the second packet to a device which owns the next-hop IP address.

According to a fifth aspect of the embodiments of the present invention, an egress node is provided, the egress node comprising:

a third receiving unit, configured to receive routing information from a SDNC, wherein the routing information comprising a relationship between a flow identifier and prefix information of an IP address;
a fourth receiving unit, configured to receive a second packet, wherein the second packet comprising the flow identifier and the prefix information;

a removing unit, configured to remove the flow identifier from the second packet, so as to generate a first packet;

a second sending unit, configured to send the first packet to a device.

According to a sixth aspect of the embodiments of the present invention, a SDNC is provided, the SDNC comprising:

a first generating unit, configured to generate first routing information for an ingress node, wherein the first routing information comprising a relationship among a flow identifier, prefix information of an IP address and a next-hop IP address;

a second generating unit, configured to generate second routing information for an egress node which is on an identical path with the ingress node, wherein the second routing information comprising a relationship between a flow identifier and prefix information of an IP address;

a third sending unit, configured to send the first routing information to the ingress node and the second routing information to the egress node.

According to another aspect of the embodiments of the present invention, wherein the SDNC further comprising:

a fifth receiving unit, configured to receive a path trigger request;
a calculating unit, configured to calculate the path with required constraint;
an updating unit, configured to update the relationship based on the result of calculation.

The advantages of the present invention exist in that: relationship between flow and path is established by SDNC; so that flow based routing is introduced in IP network, and the TE kind of explicit path is set in SDN.

These and further aspects and features of the present invention will be apparent with reference to the following description and attached drawings. In the description and drawings, particular embodiments of the invention have been disclosed in detail as being indicative of some of the ways in which the principles of the invention may be employed, but it is understood that the invention is not limited correspondingly in scope. Rather, the invention includes all changes, modifications and equivalents coming within the spirit and terms of the appended claims.

Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

It should be emphasized that the term "comprises/comprising" when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

Many aspects of the invention can be better understood with reference to the following drawings. The components in the drawings are not necessarily to scale, emphasis instead being placed upon clearly illustrating the principles of the present invention. To facilitate illustrating and describing some parts of the invention, corresponding portions of the drawings may be exaggerated in size, e.g., made larger in relation to other parts than in an exemplary device actually made according to the invention. Elements and features depicted in one drawing or embodiment of the invention may be combined with elements and features depicted in one or more additional drawings or embodiments. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the several views and may be used to designate like or similar parts in more than one embodiment.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING

The drawings are included to provide further understanding of the present invention, which constitute a part of the specification and illustrate the preferred embodiments of the present invention, and are used for setting forth the principles of the present invention together with the description. The same element is represented with the same reference number throughout the drawings.

In the drawings:
Figure 1 is a topology showing SDNC in the prior art;
Figure 2 is a flowchart of the forwarding method based on flow in accordance with an embodiment of the present invention;
Figure 3 is a flowchart of the forwarding method based on flow in accordance with an embodiment of the present invention;
Figure 4 is an example of SDNC in accordance with an embodiment of the present invention;
Figure 5 is an example of the relationship in accordance with an embodiment of the present invention;
Figure 6 is an example of active and backup Path-Flow table in accordance with an embodiment of the present invention;
Figure 7 is a flowchart of updating in accordance with an embodiment of the present invention;
Figure 8 is an example of the process of updating in accordance with an embodiment of the present invention;
Figure 9 is an example of the multicast mechanism in accordance with an embodiment of the present invention;
Figure 10 is a flowchart of the forwarding method based on flow in accordance with an embodiment of the present invention;
Figure 11 is a flowchart of the forwarding method based on flow in accordance with an embodiment of the present invention;
Figure 12 is a schematic diagram of the network apparatus in accordance with an embodiment of the present invention;
Figure 13 is another schematic diagram of the network apparatus in accordance with an embodiment of the present invention;
Figure 14 is a schematic diagram of the network apparatus in accordance with an embodiment of the present invention;

Figure 15 is a schematic diagram of the network apparatus in accordance with an embodiment of the present invention;
Figure 16 is a schematic block diagram showing the systematic structure of the network apparatus of the embodiments of the present invention.

DETAILED DESCRIPTION
The many features and advantages of the embodiments are apparent from the detailed specification and, thus, it is intended by the appended claims to cover all such features and advantages of the embodiments that fall within the true spirit and scope thereof. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the inventive embodiments to the exact construction and operation illustrated and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope thereof.

The preferred embodiments of the present invention are described as follows in reference to the drawings.

Embodiment 1
This embodiment of the present invention provides a forwarding method based on flow, applied in a SDNC side of a Software Defined Network.
Figure 2 is a flowchart of the forwarding method based on flow in accordance with an embodiment of the present invention. As shown in Figure 2, the method includes:
Step 201, a SDNC generates first routing information for an ingress node, wherein the first routing information comprising a relationship among a flow identifier, prefix information of an IP address and a next-hop IP address;
Step 202, the SDNC generates second routing information for an egress node which is on an identical path with the ingress node, wherein the second routing information comprising a relationship between a flow identifier and prefix information of an IP address;
Step 203, the SDNC sends the first routing information to the ingress node and the second routing information to the egress node.

In this embodiment, one or more edge nodes (such as ingress nodes and egress nodes) are in the scope of the SDNC administration. As for the other detail description of the ingress node and egress node, please refer to the prior art.

In this embodiment, the flow may have an identifier. As for the other detail description of the flow, please refer to the prior art. For example, the flow identifier can be carried in "option field" in IPv4, or can be carried in "flow-label" in case of IPv6.

In this embodiment, the SDNC may use table to store the established relationship. The SDNC may store an identifier of the flow and the path information in a table, which is named as Path-Flow table.

It can be seen from the above embodiment that: relationship between flow and path is established by SDNC; so that flow based routing is introduced in IP network, and the TE kind of explicit path is set in SDN.

Furthermore, IGP method of SPF based forwarding can be avoided and links are utilized effectively; all the links in the SDNC domain will be utilized effectively even for IP traffic; and bring the traffic engineering concepts to IP network.

Embodiment 2

This embodiment of the present invention provides a forwarding method based on flow, applied in a SDNC side. This embodiment is based on the embodiment 1 and the same content will not be described.

Figure 3 is a flowchart of the forwarding method based on flow in accordance with an embodiment of the present invention, as shown in Figure 3, the method includes:

Step 301, a SDNC establishes relationship between flow and path;

In this embodiment, the SDNC may generate first routing information for an ingress node, wherein the first routing information comprising a relationship among a flow identifier, prefix information of an IP address and a next-hop IP address;

Furthermore, the SDNC may generate second routing information for an egress node which is on an identical path with the ingress node, wherein the second routing information comprising a relationship between a flow identifier and prefix information of an IP address.

Step 302, the SDNC stores the identifier of the flow and the path information in table.

In this embodiment, the path information may include prefix information of an IP address and a next-hop IP address; or the path information may include prefix information of an IP address.

Such that the table may include the first routing information comprising a relationship among a flow identifier, prefix information of an IP address and a next-hop IP address; or the table may include the second routing information comprising a relationship between a flow identifier and prefix information of an IP address.

Step 303, the SDNC provides information of the relationship to one or more nodes, so that the one or more nodes forward packet according to the relationship.

In this embodiment, by using table(s), the SDNC may send the first routing information to the ingress node and the second routing information to the egress node.

In this embodiment, the SDNC may run CSPF (Constrained Shortest Path First) algorithm on IGP LSDB (Link State Database) to acquire Path information. And the SDNC may establish the relationship between flow and path.

For example, the path information (such as Path) may include SA (source Address)
and DA (Destination Address), and the flow may have an identifier (such as Flow-id). The
relationship between "Flow-id" and "Path" may be established, and the relationship is with
"Key = Flow-id + SA + DA +

Figure 4 is an example of SDNC in accordance with an embodiment of the present invention. As shown in Figure 4, there is a Path-Flow table in the SDNC, the relationship between flow and path is in the Path-Flow table. And the relationship may be downloaded from the SDNC. As shown in Figure 4, there is a "Flow-id" between SA and DA.

Figure 5 is an example of the relationship in accordance with an embodiment of the present invention. As shown in Figure 5, the flow "F1" may correspond to the path "A- 1 -F ", the flow "F2" may correspond to the path "A- 1 -5 -F", the flow "F3" may correspond to the path "B -2 -4 -D".

In an implement way, the node may be an ingress node, and the method may further include: the SDNC provides prefix information of IP address to the node, so that the node gets a flow identifier according to the relationship and the prefix information, carries the flow identifier in a packet and forwards the packet.

In this implement way, the ingress node may require both "Path-Flow table" and "Prefix table". Each prefix in the Prefix table will have direct relationship with the Path-Flow table with Flow-id as key.

And when the ingress node receives a packet, the ingress node may add the flow identifier in the packet, and forward the packet according to the information of the "Path-Flow table" and "Prefix table".

In another implement way, the node may be an egress node, and the egress node may require "Path-Flow table" only. When the egress node receives a packet, the ingress node may remove the flow identifier from the packet and forward the packet.

In this embodiment, the type of relationship may be active or backup. There will separate active and backup Path-Flow table where each prefix will be pointed.

Figure 6 is an example of active and backup Path-Flow table in accordance with an embodiment of the present invention. As shown in Figure 6, there are an active Path-Flow table and a backup Path-Flow table.

Where, in the active Path-Flow table, the flow "Fl" may correspond to the path "A-1 - F ", the flow "F2" may correspond to the path "A - 1 -5 -F", the flow "F3" may correspond to the path "B -2 -4 -D". In the backup table, the flow "F1'" may correspond to the path "A-2-5-F".

In this embodiment, the SDNC may update the relationship between flow and path. Figure 7 is a flowchart of updating in accordance with an embodiment of the present invention, as shown in Figure 7, the method includes:
Step 701, the SDNC receives a path trigger request;
Step 702, the SDNC calculates the path with required constraint;
Step 703, the SDNC updates the relationship based on the result of calculation.

Figure 8 is an example of the process of updating in accordance with an embodiment of the present invention. As shown in Figure 8, the SDNC may receive a path trigger request, and the SDNC may run path calculation algorithm (such as CSPF etc.) with required constraint on LSDB or TEDB.

Then the SDNC will calculate the path and update the relationship to the Path-Flow table, and the Path-Flow table will be downloaded to one or more nodes. Then the SDNC may update the LSDB or TEDB directly based on bandwidth (such as resource utilized for the path). Furthermore, there is not IGP flooding of TE attributes since the SDNC is available centrally.

In this embodiment, two options may be available to download the relationship or prefix information. One is unicast mechanism, and the SDNC will selectively download the requirement information to the node. The other is multicast mechanism, and one of nodes may be a "virtual node".

Figure 9 is an example of the multicast mechanism in accordance with an embodiment of the present invention. As shown in Figure 9, one of the nodes will be 'Virtual Node', the virtual node will receive all the multicast join request from open-flow enabled node. There are some groups (such as Group-X, Group-Y), for example, Group 1 = Fl,Group2 = F2.

For example, all the open-flow edge nodes will send multicast join request (Group-X) to get the virtual node; all the open-flow inner nodes will send multicast join request (Group-Y) to get the virtual node.

As shown in Figure 9, the SDNC as multicast source will send single Group-X information (such as Path-Flow table and Prefix table of Flow-X) to the virtual node. The SDNC as multicast source will send single Group-Y information (such as Path-Flow table of Flow-Y) to the virtual node. Furthermore, the virtual node will send Path-Flow table and Prefix table to all edge node, and only send Path-Flow table to inner nodes based on the multicast join request.

In this embodiment, multicast mechanism of SDNC downloading to Path-Flow table to nodes will reduce overall management traffic in the infrastructure. Furthermore, building the service concept is very easy even for pure IP traffic without any complex technology by mapping service to flow identifier.

It can be seen from the above embodiment that: relationship between flow and path is established by SDNC; so that flow based routing is introduced in IP network, and the TE kind of explicit path is set in SDN.

Furthermore, IGP method of SPF based forwarding can be avoided and links are utilized effectively; all the links in the SDNC domain will be utilized effectively even for IP traffic; and bring the traffic engineering concepts to IP network.

Embodiment 3
This embodiment of the present invention provides a forwarding method based on flow, applied in an ingress node side of a SDN. This embodiment corresponds to the method of the above embodiment 1 or 2, and the same content will not be described.

Figure 10 is a flowchart of the forwarding method based on flow in accordance with an embodiment of the present invention, as shown in Figure 10, the method includes:
Step 1001, an ingress node receives routing information frpm a SDNC;
Step 1002, the ingress node receives a first packet, wherein the first packet comprising prefix information of an IP address;
Step 1003, the ingress node acquires a flow identifier according to the prefix information and the routing information, wherein the routing information comprising a relationship among the flow identifier, the prefix information of the IP address and a next-hop IP address;
Step 1004, the ingress node obtains a second packet by adding the flow identifier into the first packet;
Step 1005, the ingress node sends the second packet to a device which owns the next-hop IP address.

It can be seen from the above embodiment that: relationship between flow and path is established by SDNC; so that flow based routing is introduced in IP network, and the TE kind of explicit path is set in SDN.

Furthermore, IGP method of SPF based forwarding can be avoided and links are utilized effectively; all the links in the SDNC domain will be utilized effectively even for IP traffic; and bring the traffic engineering concepts to IP network.

Embodiment 4

This embodiment of the present invention provides a forwarding method based on flow, applied in an egress node side of a SDN. This embodiment corresponds to the method of the above embodiment 1 or 2, and the same content will not be described.

Figure 11 is a flowchart of the forwarding method based on flow in accordance with an embodiment of the present invention, as shown in Figure 11, the method includes:

Step 1101, an egress node receives routing information from a SDNC, wherein the routing information comprising a relationship between a flow identifier and prefix information of an IP address;

Step 1102, the egress node receives a second packet, wherein the second packet comprising the flow identifier and the prefix information;

Step 1103, the egress node removes the flow identifier from the second packet, so as to generate a first packet;

Step 1104, the egress node sends the first packet to a device.

It can be seen from the above embodiment that: relationship between flow and path is established by SDNC; so that flow based routing is introduced in IP network, and the TE kind of explicit path is set in SDN.

Furthermore, IGP method of SPF based forwarding can be avoided and links are utilized effectively; all the links in the SDNC domain will be utilized effectively even for IP traffic; and bring the traffic engineering concepts to IP network.

Embodiment 5

This embodiment of the present invention further provides a SDNC. This embodiment corresponds to the method of the above embodiment 1 or 2, and the same content will not be described.

Figure 12 is a schematic diagram of the SDNC in accordance with an embodiment of the present invention. As shown in Figure 12, the SDNC 1200 includes: a first generating unit 1201, a second generating unit 1202 and a third sending unit 1203.

In this embodiment, the function of provision tunnel may be integrated in the SDNC; other parts of the SDNC can refer to the existing technology and not be described in the present application. However, it is not limited thereto, and particular implement way may be determined as actually required.

Where, the first generating unit 1201 is configured to generate first routing information for an ingress node, wherein the first routing information comprising a relationship among a flow identifier, prefix information of an IP address and a next-hop IP address;

the second generating unit 1202 is configured to generate second routing information for an egress node which is on an identical path with the ingress node, wherein the second routing information comprising a relationship between a flow identifier and prefix information of an IP address;

the third sending unit 1203 is configured to send the first routing information to the ingress node and the second routing information to the egress node.

Figure 13 is another schematic diagram of the SDNC in accordance with an embodiment of the present invention. As shown in Figure 13, the SDNC 1300 includes: a first generating unit 1201, a second generating unit 1202 and a third sending unit 1203. As described in above.

As shown in Figure 13, the network apparatus may further include: a fifth receiving unit 1304, a calculating unit 1305 and an updating unit 1306.

Where, the fifth receiving unit 1304 is configured to receive a path trigger request; the calculating unit 1305 is configured to calculate the path with required constraint; the updating unit 1306 is configured to update the relationship based on the result of calculation.

In implement, the third sending 1203 may provide the relationship and the prefix information by multicast mechanism. The type of relationship may be active or backup.

It can be seen from the above embodiment that: relationship between flow and path is established by SDNC; so that flow based routing is introduced in IP network, and the TE kind of explicit path is set in SDN.

Furthermore, IGP method of SPF based forwarding can be avoided and links are utilized effectively; all the links in the SDNC domain will be utilized effectively even for IP traffic; and bring the traffic engineering concepts to IP network.

Embodiment 6

This embodiment of the present invention further provides an ingress node. This embodiment corresponds to the method of the above embodiment 3, and the same content will not be described.

Figure 14 is a schematic diagram of the ingress node in accordance with an embodiment of the present invention. As shown in Figure 14, the ingress node 1400 includes: a first receiving unit 1401, a second receiving unit 1402, an acquiring unit 1403, an obtaining unit 1404 and a first sending unit 1405.

In this embodiment, the function of provision tunnel may be integrated in the ingress node; other parts of the ingress node can refer to the existing technology and not be described in the present application. However, it is not limited thereto, and particular implement way may be determined as actually required.

Where, the first receiving unit 1401 is configured to receive routing information from a SDNC; the second receiving unit 1402 is configured to receive a first packet, wherein the first packet comprising prefix information of an IP address; the acquiring unit 1403 is configured to acquire a flow identifier according to the prefix information and the routing information, wherein the routing information comprising a relationship among the flow identifier, the prefix information of the IP address and a next-hop IP address; the obtaining unit 1404 is configured to obtain a second packet by adding the flow identifier into the first packet; the first sending unit 1405 is configured to send the second packet to a device which owns the next-hop IP address.

It can be seen from the above embodiment that: relationship between flow and path is established by SDNC; so that flow based routing is introduced in IP network, and the TE kind of explicit path is set in SDN.

Furthermore, IGP method of SPF based forwarding can be avoided and links are utilized effectively; all the links in the SDNC domain will be utilized effectively even for IP traffic; and bring the traffic engineering concepts to IP network.

Embodiment 7

This embodiment of the present invention further provides an egress node. This embodiment corresponds to the method of the above embodiment 4, and the same content will not be described.

Figure 15 is a schematic diagram of the egress node in accordance with an embodiment of the present invention. As shown in Figure 15, the egress node 1500 includes: a third receiving unit 1501, a fourth receiving unit 1502, a removing unit 1503 and a second sending unit 1504.

In this embodiment, the function of provision tunnel may be integrated in the egress node; other parts of the egress node can refer to the existing technology and not be described in the present application. However, it is not limited thereto, and particular implement way may be determined as actually required.

Where, the third receiving unit 1501 is configured to receive routing information from a SDNC, wherein the routing information comprising a relationship between a flow identifier and prefix information of an IP address; the fourth receiving unit 1502 is configured to receive a second packet, wherein the second packet comprising the flow identifier and the prefix information; the removing unit 1503 is configured to remove the flow identifier from the second packet, so as to generate a first packet; the second sending unit 1504 is configured to send the first packet to a device.

It can be seen from the above embodiment that: relationship between flow and path is established by SDNC; so that flow based routing is introduced in IP network, and the TE kind of explicit path is set in SDN.

Furthermore, IGP method of SPF based forwarding can be avoided and links are utilized effectively; all the links in the SDNC domain will be utilized effectively even for IP traffic; and bring the traffic engineering concepts to IP network.

It should be understood that each of the parts of the present invention may be implemented by hardware, software, firmware, or a combination thereof. In the above embodiments, multiple steps or methods may be realized by software or firmware that is stored in the memory and executed by an appropriate instruction executing system. For example, if it is realized by hardware, it may be realized by any one of the following technologies known in the art or a combination thereof as in another embodiment: a discrete logic circuit having a logic gate circuit for realizing logic functions of data signals, application-specific integrated circuit having an appropriate combined logic gate circuit, a programmable gate array (PGA), and a field programmable gate array (FPGA), etc.

Figure 16 is a schematic block diagram showing the systematic structure of the network apparatus of the embodiments of the present invention. Such a figure is just exemplary and other types of structures may also be used for supplementing or replacing this structure, so as to implement the function of telecommunications or other functions.

As shown in Figure 16, the network apparatus 1600 may include a CPU 1601, a communication interface 1602, an input device 1603, a memory 1604 and an output device 1605.

Where, the CPU 1601 (also referred to as a controller or an operational control, which may include a microprocessor or other processing devices and/or logic devices) receives input and controls each part and operation of the network apparatus. The input device 1603 provides input to the CPU 1601. The input device 1603 may be for example a key or touch input device. The output device 1605 receives the data from the CPU 1601 and sends it to other apparatus.

The memory 1604 is coupled to the CPU 1601. The memory 1604 may be a solid memory, such as a read-only memory (ROM), a random access memory (RAM), and a SIM card, etc., and may also be such a memory that stores information even when the power is interrupted, may be optionally erased and provided with more data. Examples of such a memory are sometimes referred to as an EPROM, etc. The memory 1604 may also be certain other types of devices.

The communication interface 1602 may be a transmitter/receiver which transmitting and receiving signals via an antenna. The communication interface 1602 (transmitter/receiver) is coupled to the CPU 1601 to provide input signals and receive output signals, this being similar to the case in a conventional communication center.

The description or blocks in the flowcharts or of any process or method in other manners may be understood as being indicative of comprising one or more modules, segments or parts for realizing the codes of executable instructions of the steps in specific logic functions or processes, and that the scope of the preferred embodiments of the present invention comprise other implementations, wherein the functions may be executed in manners different from those shown or discussed, including executing the functions according to the related functions in a substantially simultaneous manner or in a reverse order, which should be understood by those skilled in the art to which the present invention pertains.

The logic and/or steps shown in the flowcharts or described in other manners here may be, for example, understood as a sequencing list of executable instructions for realizing logic functions, which may be implemented in any computer readable medium, for use by an instruction executing system, device or apparatus (such as a system including a computer, a system including a processor, or other systems capable of extracting instructions from an instruction executing system, device or apparatus and executing the instructions), or for use in combination with the instruction executing system, device or apparatus.

The above literal description and drawings show various features of the present invention. It should be understood that those skilled in the art may prepare appropriate computer codes to carry out each of the steps and processes as described above and shown in the drawings. It should be also understood that all the terminals, computers, servers, and networks may be any type, and the computer codes may be prepared according to the disclosure to carry out the present invention by using the apparatus.

Particular embodiments of the present invention have been disclosed herein. Those skilled in the art will readily recognize that the present invention is applicable in other environments. In practice, there exist many embodiments and implementations. The appended claims are by no means intended to limit the scope of the present invention to the above particular embodiments. Furthermore, any reference to "a device to..." is an explanation of device plus function for describing elements and claims, and it is not desired that any element using no reference to "a device to..." is understood as an element of device plus function, even though the wording of "device" is included in that claim.

Although a particular preferred embodiment or embodiments have been shown and the present invention has been described, it is obvious that equivalent modifications and variants are conceivable to those skilled in the art in reading and understanding the description and drawings. Especially for various functions executed by the above elements (portions, assemblies, apparatus, and compositions, etc.), except otherwise specified, it is desirable that the terms (including the reference to "device") describing these elements correspond to any element executing particular functions of these elements (i.e. functional equivalents), even though the element is different from that executing the function of an exemplary embodiment or embodiments illustrated in the present invention with respect to structure. Furthermore, although the a particular feature of the present invention is described with respect to only one or more of the illustrated embodiments, such a feature may be combined with one or more other features of other embodiments as desired and in consideration of advantageous aspects of any given or particular application.

WE CLAIM

1. A forwarding method based on flow, applied in a SDN (Software Defined Network), the method comprising:
receiving, by an ingress node, routing information from a SDNC (Software Defined Network Controller);
receiving, by the ingress node, a first packet, wherein the first packet comprising prefix information of an IP address;
acquiring, by the ingress node, a flow identifier according to the prefix information and the routing information, wherein the routing information comprising a relationship among the flow identifier, the prefix information of the IP address and a next-hop IP address;
obtaining, by the ingress node, a second packet by adding the flow identifier into the first packet;
sending, by the ingress node, the second packet to a device which owns the next-hop IP address.

2. The method as claimed in claim 1, wherein the type of relationship is active or backup.

3. A forwarding method based on flow, applied in a SDN, the method comprising:
receiving, by an egress node, routing information from a SDNC, wherein the routing
information comprising a relationship between a flow identifier and prefix information of an IP address;
receiving, by the egress node, a second packet, wherein the second packet comprising the flow identifier and the prefix information;
removing, by the egress node, the flow identifier from the second packet, so as to generate a first packet;
sending, by the egress node, the first packet to a device.

4. A forwarding method based on flow, applied in a SDN, the method comprising:
generating, by a SDNC, first routing information for an ingress node, wherein the first routing information comprising a relationship among a flow identifier, prefix information of an IP address and a next-hop IP address;

generating, by the SDNC, second routing information for an egress node which is on an identical path with the ingress node, wherein the second routing information comprising a relationship between a flow identifier and prefix information of an IP address;
sending, by the SDNC, the first routing information to the ingress node and the second routing information to the egress node.

5. The method as claimed in claim 4, wherein the method further comprising:
receiving, by the SDNC, a path trigger request;
calculating, by the SDNC, the path with required constraint;
updating, by the SDNC, the relationship based on the result of calculation.

6. The method as claimed in claim 4, wherein the SDNC provides the first routing information and the second routing information by multicast mechanism.

7. An ingress node, the ingress node comprising:

a first receiving unit, configured to receive routing information from a SDNC;

a second receiving unit, configured to receive a first packet, wherein the first packet comprising prefix information of an IP address;

an acquiring unit, configured to acquire a flow identifier according to the prefix information and the routing information, wherein the routing information comprising a relationship among the flow identifier, the prefix information of the IP address and a next-hop IP address;

an obtaining unit, configured to obtain a second packet by adding the flow identifier into the first packet;

a first sending unit, configured to send the second packet to a device which owns the next-hop IP address.

8. An egress node, the egress node comprising:

a third receiving unit, configured to receive routing information from a SDNC, wherein the routing information comprising a relationship between a flow identifier and prefix information of an IP address;

a fourth receiving unit, configured to receive a second packet, wherein the second packet comprising the flow identifier and the prefix information;

a removing unit, configured to remove the flow identifier from the second packet, so as to generate a first packet;

a second sending unit, configured to send the first packet to a device.

9. A SDNC, the SDNC comprising:
a first generating unit, configured to generate first routing information for an ingress node, wherein the first routing information comprising a relationship among a flow identifier, prefix information of an IP address and a next-hop IP address;

a second generating unit, configured to generate second routing information for an egress node which is on an identical path with the ingress node, wherein the second routing information comprising a relationship between a flow identifier and prefix information of an IP address;

a third sending unit, configured to send the first routing information to the ingress node and the second routing information to the egress node.

10. The SDNC as claimed in claim 9, wherein the SDNC further comprising:
a fifth receiving unit, configured to receive a path trigger request;
a calculating unit, configured to calculate the path with required constraint; an updating unit, configured to update the relationship based on the result of calculation.