Abstract:
A method and system are provided for controlling a volume of incoming traffic into a network having a plurality of ingress routers. The method includes monitoring respective loads of the plurality of ingress routers. The method further includes selecting a particular one of the plurality of ingress routers to receive future incoming traffic based on at least the respective loads of the plurality of ingress routers. The method also includes creating a mapping between an internal source IP address and a client IP address. The internal source IP address relates to the particular one of the plurality of routers. The client IP address is for a client device accessing the Internet through the network. The method additionally includes rewriting a destination IP address of the incoming traffic based on the mapping. At least the monitoring, selecting, and creating steps are performed by a controller.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    The present invention relates generally to networks and, in particular, to controlling incoming traffic into a network. 
         [0003]    2. Description of the Related Art 
         [0004]    Networks are increasingly connected to multiple providers for reliability purposes, and one of the network operators&#39; main objectives is to control (e.g., load balance) the incoming traffic across the ingress border routers to lower transit costs, avoid network congestion, offer better performances, and withstand traffic surges (e.g., flash crowds). 
         [0005]    However, the tools network operators currently have at their disposal are very rudimentary. Existing methods for controlling incoming traffic are manual, error prone, vulnerable to instabilities, and provide unpredictable outcomes. 
         [0006]    The current protocols allow operators to control the outgoing traffic but a systematic solution for controlling incoming traffic is urgently lacking. 
       SUMMARY 
       [0007]    According to an aspect of the present principles, there is provided a method for controlling a volume of incoming traffic into a network having a plurality of ingress routers. The method includes monitoring respective loads of the plurality of ingress routers. The method further includes selecting a particular one of the plurality of ingress routers to receive future incoming traffic based on at least the respective loads of the plurality of ingress routers. The method also includes creating a mapping between an internal source IP address and a client IP address. The internal source IP address relates to the particular one of the plurality of routers. The client IP address is for a client device accessing the Internet through the network. The method additionally includes rewriting a destination IP address of the incoming traffic based on the mapping. At least the monitoring, selecting, and creating steps are performed by a controller. 
         [0008]    According to another aspect of the present principles, there is provided a computer readable storage medium including a computer readable program for controlling a volume of incoming traffic into a network having a plurality of ingress routers. The computer readable program when executed on a computer causes the computer to perform the following steps. Respective loads of the plurality of ingress routers are monitored. A particular one of the plurality of ingress routers is selected to receive future incoming traffic based on at least the respective loads of the plurality of ingress routers. A mapping is created between an internal source IP address and a client IP address. The internal source IP address relates to the particular one of the plurality of routers. The client IP address is for a client device accessing the Internet through the network. A destination IP address of the incoming traffic is rewritten based on the mapping. At least the monitoring, selecting, and creating steps are performed by a controller. 
         [0009]    According to yet another aspect of the present principles, there is provided a system for controlling a volume of incoming traffic into a network. The system includes a plurality of ingress routers for the network. The system further includes a controller for monitoring respective loads of the plurality of ingress routers, selecting a particular one of the plurality of ingress routers to receive future incoming traffic based on at least the respective loads of the plurality of ingress routers, and creating a mapping between an internal source IP address and a client IP address. The internal source IP address relates to the particular one of the plurality of routers. The client IP address is for a client device accessing the Internet through the network. The particular one of the plurality of ingress routers rewrites a destination IP address of the incoming traffic based on the mapping. 
         [0010]    These and other features and advantages will become apparent from the following detailed description of illustrative embodiments thereof, which is to be read in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0011]    The disclosure will provide details in the following description of preferred embodiments with reference to the following figures wherein: 
           [0012]      FIG. 1  shows an exemplary environment  100  to which the present principles can be applied, in accordance with an embodiment of the present principles; 
           [0013]      FIG. 2  shows an exemplary method  200  for controlling incoming traffic for a network, in accordance with an embodiment of the present principles; and 
           [0014]      FIGS. 3 and 4  show another exemplary method  300  for controlling incoming traffic for a network, in accordance with an embodiment of the present principles. 
       
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
       [0015]    The present principles are directed to controlling incoming traffic into a network. 
         [0016]    In an embodiment, network entities at the perimeter of a network rewrite the source Internet Protocol (IP) address of outgoing traffic such that the replies can enter the network through the desired border routers. 
         [0017]    In an embodiment, the network entities can predict the volume of incoming traffic of a given flow (e.g., based on historical data, external information, and/or so forth) and use this information to rewrite the source IP address. As an example, a HTTP reply from a news website can be on the order of 100 KB. In contrast, a HTTP request to download a particular software program can be in the range of several MB of incoming traffic. As such, based on the destination IP address (i.e., server IP address) of a request, the network entities can determine the most appropriate ingress routers where the reply should enter the network (e.g., to achieve load balancing). 
         [0018]    Thus, in an embodiment, source IP addresses for reply packets are rewritten to enter a desired ingress router. In an embodiment, the present principles can be implemented using a software defined network. In an embodiment, a controller has a global view of the network, including the load of each ingress border router. The controller can access counters at ingress routers and select source IP address accordingly. The controller can create “rewrite rules”. For example, source IP addresses can be allocated taking into account destination IP address (e.g., a small file size (e.g., a website) versus a large file size (e.g., an iso image)). For TCP connections, the address rewriting happens consistently for each flow (or even for each destination address). 
         [0019]    Hence, when a new flow (e.g., HTTP request) is initiated by a client in the network, the controller can determine the rewriting rules for the source IP address. For example, if the network has two border routers X and Y advertising 10.1/16 and 10.2/16 to their providers respectively, and the router X is overloaded, then the controller should create a state to rewrite the source IP address of the new flow to be in the 10.2/16 range (e.g., 10.2.1.1). This will ensure that the reply to this flow will be entering the network through router Y. In an embodiment, the controller can create the rules so that at the perimeter, the appropriate IP fields are updated and the reply can reach the client. 
         [0020]      FIG. 1  shows an exemplary environment  100  to which the present principles can be applied, in accordance with an embodiment of the present principles. The environment  100  includes a network  110 , border routers  141  and  142  corresponding to an Internet Service Provider ISP1 network  140 , border routers  151  and  152  corresponding to an Internet Service Provider ISP2 network  150 , and a server  161  accessible through the Internet  160 . The network  110  includes border routers  111 ,  112 , and  113 , a network controller (e.g., processor)  120 , and a switch  130 . The network controller  120  includes a memory  121 . A client  170  accesses the server  161  though the Internet  160  and network  140  and/or network  150 . 
         [0021]    It is to be appreciated that while the network controller  120  is shown as a standalone element in network  110 , in other embodiments, the network controller  120  can be incorporated into one or more other elements of network  110 . For example, the network controller  120  can be incorporated into the switch  130  and/or one or more of the border routers  111 ,  112 , and  113 . These and other variations of environment  100  are readily contemplated by one of ordinary skill in the art given the teachings of the present principles provided herein, while maintaining the spirit of the present principles. 
         [0022]      FIG. 2  shows an exemplary method  200  for controlling incoming traffic for a network, in accordance with an embodiment of the present principles. 
         [0023]    At step  205 , receive a newly originated connection request to the server  161  by the network controller  120 . 
         [0024]    At step  210 , check destination IP address and determine average transfer size from this server  161 . 
         [0025]    At step  215 , inspect boarder router&#39;s load and select appropriate ingress point(s) to satisfy desired policy. 
         [0026]    At step  220 , create mapping rules to ensure traffic flow will enter the network  110  through the selected ingress point(s). 
         [0027]    At step  225 , install the mapping at the ingress point(s) so that packets can be routed between the client  170  and the server  161 . 
         [0028]    For the sake of clarity and illustration, a detailed example of an implementation of method  200  is described hereinafter with respect to method  300 . Method  300  is shown and described with respect to  FIGS. 3 and 4 . 
         [0029]      FIGS. 3 and 4  show another exemplary method  300  for controlling incoming traffic for a network, in accordance with an embodiment of the present principles. 
         [0030]    At step  305 , the network controller  120  continuously monitors the respective loads of the border routers  111 ,  112 , and  113 . 
         [0031]    At step  310 , client  170  (IP address: 192.168.1.1) sends a connection request to server  161  (IP address: 2.2.2.2). 
         [0032]    At step  315 , in the absence of an entry for the above flow in the switch  130 , the switch  130  forwards the client&#39;s request to the network controller  120 . 
         [0033]    At step  320 , the network controller  120  optionally estimates the transfer size (e.g., based on previous requests to the server IP address 2.2.2.2). 
         [0034]    At step  325 , the network controller  120  selects the appropriate ingress border router (from among routers  111 ,  112 , and  113 ) to satisfy a desired policy (e.g., promulgated by a network administrator). The selection can be based on, e.g., the respective loads of the ingress routers and/or the transfer size. Of course, the selection can be further based on other considerations readily determined by one of ordinary skill in the art, given the teachings of the present principles provided herein. For illustration purposes, we assume router  111  is the selected router. The router  111  advertises the prefix 9.2.1.0/24 to ISP1 network  140 . 
         [0035]    At step  330 , the network controller  120  creates a mapping from the client IP address to an IP address in its subnet: e.g., 192.168.1.1←→9.2.1.65, and installs this mapping in the selected router  111 . 
         [0036]    At step  335 , the client request is forwarded from the switch  130  to the selected router  111 . 
         [0037]    At step  340 , based on the mapping created in step  330 , the selected router  111  overwrites the source IP address of the client request from 192.168.1.1 to 9.2.1.65, and then forwards client request to the server  161 . 
         [0038]    At step  345 , upon receiving the client request, the server  161  (IP address 2.2.2.2) replies to the client  170  (IP address: 9.2.1.65). 
         [0039]    At step  350 , since the client address (9.2.1.65) belongs to the subnet advertised by selected router  111 , the reply enters the network  110  through the selected router  111 . 
         [0040]    At step  355 , the selected router  111  overwrites the destination IP address of the reply from 9.2.1.65 to 192.168.1.1. 
         [0041]    At step  360 , the selected router  111  forwards the packet to the client  170 . 
         [0042]    At step  365 , subsequent packets between the client  170  and server  161  can be exchanged: The client  170  still writes its source IP address as 192.168.1.1. The selected router  111  overwrites it (i.e., source IP address 192.168.1.1) to 9.2.1.65 forcing the return packets to come to the selected router  111 . For return packets coming from 2.2.2.2 to 9.2.1.65, the selected router  111  overwrites the destination IP address from 9.2.1.65 to 192.168.1.1 and forwards them to the client  170 . 
         [0043]    The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
         [0044]    The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
         [0045]    Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
         [0046]    Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
         [0047]    Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
         [0048]    These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
         [0049]    The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
         [0050]    The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
         [0051]    Reference in the specification to “one embodiment” or “an embodiment” of the present principles, as well as other variations thereof, means that a particular feature, structure, characteristic, and so forth described in connection with the embodiment is included in at least one embodiment of the present principles. Thus, the appearances of the phrase “in one embodiment” or “in an embodiment”, as well any other variations, appearing in various places throughout the specification are not necessarily all referring to the same embodiment. 
         [0052]    It is to be appreciated that the use of any of the following “/”, “and/or”, and “at least one of”, for example, in the cases of “A/B”, “A and/or B” and “at least one of A and B”, is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of both options (A and B). As a further example, in the cases of “A, B, and/or C” and “at least one of A, B, and C”, such phrasing is intended to encompass the selection of the first listed option (A) only, or the selection of the second listed option (B) only, or the selection of the third listed option (C) only, or the selection of the first and the second listed options (A and B) only, or the selection of the first and third listed options (A and C) only, or the selection of the second and third listed options (B and C) only, or the selection of all three options (A and B and C). This may be extended, as readily apparent by one of ordinary skill in this and related arts, for as many items listed. 
         [0053]    Having described preferred embodiments of a system and method (which are intended to be illustrative and not limiting), it is noted that modifications and variations can be made by persons skilled in the art in light of the above teachings. It is therefore to be understood that changes may be made in the particular embodiments disclosed which are within the scope of the invention as outlined by the appended claims. Having thus described aspects of the invention, with the details and particularity required by the patent laws, what is claimed and desired protected by Letters Patent is set forth in the appended claims.