Abstract:
Disclosed are communication methods in a divided vehicle network. An operation method of a first end node includes: generating a frame; and transmitting the frame to a switch connected to the first end node. A source internet protocol (IP) address of the frame is set to an IP address of the first end node, a destination IP address of the frame is set to an IP address of a second end node belonging to a second domain in the vehicle network, a source medium access control (MAC) address of the frame is set to a MAC address of the first end node, and a destination MAC address of the frame is set to a MAC address of a gateway supporting inter-domain communications.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims the benefit of and priority to Korean Patent Application No. 10-2016-0023719, filed on Feb. 26, 2016 in the Korean Intellectual Property Office (KIPO), the entirety of which is incorporated by reference as if fully set forth herein. 
       BACKGROUND 
       [0002]    1. Technical Field 
         [0003]    The present disclosure relates generally to communication methods, and more specifically, to communication methods in which a virtual medium access control (MAC) address is used in a divided vehicle network. 
         [0004]    2. Description of the Related Art 
         [0005]    The number and variety of electronic devices installed within a vehicle have been increasing significantly along with the recent digitalization of vehicle parts. Electronic devices may currently be used throughout the vehicle, such as in a power train control system (e.g., an engine control system, an automatic transmission control system, or the like), a body control system (e.g., a body electronic equipment control system, a convenience apparatus control system, a lamp control system, or the like), a chassis control system (e.g., a steering apparatus control system, a brake control system, a suspension control system, or the like), a vehicle network (e.g., a controller area network (CAN), a FlexRay-based network, a media oriented system transport (MOST)-based network, or the like), a multimedia system (e.g., a navigation apparatus system, a telematics system, an infotainment system, or the like), and so forth. 
         [0006]    The electronic devices comprising each of these systems are connected via the vehicle network, which supports functions of the electronic devices. For instance, the CAN may support a transmission rate of up to 1 Mbps and may support automatic retransmission of colliding messages, error detection based on a cycle redundancy interface (CRC), or the like. The FlexRay-based network may support a transmission rate of up to 10 Mbps and may support simultaneous transmission of data through two channels, synchronous data transmission, or the like. The MOST-based network is a communication network for high-quality multimedia, which may support a transmission rate of up to 150 Mbps. 
         [0007]    Meanwhile, the telematics system, the infotainment system, as well as enhanced safety systems of a vehicle, require higher transmission rates and system expandability. However, the CAN, FlexRay-based network, and the like may not sufficiently support such requirements. The MOST-based network, in particular, may support a higher transmission rate than the CAN and the FlexRay-based network. However, applying the MOST-based network to vehicle networks can be costly. 
         [0008]    Due to these limitations, an Ethernet-based network is often utilized as a vehicle network. The Ethernet-based network may support bi-directional communication through one pair of windings and may support a transmission rate of up to 10 Gbps. 
         [0009]    In addition, the amount of data traffic may increase due to the increasing number of electronic devices comprising a vehicle network, and accordingly the load of the vehicle network may also increase. In order to distribute the load of the vehicle network, a virtual local area network (VLAN) technique may be used for the vehicle network. The vehicle network to which the VLAN related technique is applied may be divided into at least one domain. For example, a switch constituting the vehicle network may be connected to an end node belonging to a first domain, and an end node and a router (or, a gateway, etc.) belonging to a second domain. Communications between end nodes belonging to different domains may be supported through switches and routers. For this, the switch is required to support layer-3 related functions, and the router is required to have network interface cards (NICs) for respective domains. 
         [0010]    Since switches supporting layer-3 functions and routers including a plurality of NICs are necessary for communications between end nodes belonging to different domains in the vehicle network to which the VLAN technique is applied, the communications between end nodes belonging to different domains may cause implementation difficulty due to higher cost and complexity. 
       SUMMARY 
       [0011]    The present disclosure provides a method for dividing a vehicle network. The present disclosure also provides a communication method in a divided vehicle network. 
         [0012]    In accordance with embodiments of the present disclosure, an operation method of a first end node belonging to a first domain in a vehicle network includes: generating a frame; and transmitting the frame to a switch connected to the first end node. A source internet protocol (IP) address of the frame is set to an IP address of the first end node, a destination IP address of the frame is set to an IP address of a second end node belonging to a second domain in the vehicle network, a source medium access control (MAC) address of the frame is set to a MAC address of the first end node, and a destination MAC address of the frame is set to a MAC address of a gateway supporting inter-domain communications. 
         [0013]    The switch may support layer-2 functions, and configure domains for respective ports of the switch. 
         [0014]    The gateway may have MAC addresses for the first and second domains, and a MAC address of the gateway set as the destination MAC address of the frame may be a MAC address configured for the first domain. 
         [0015]    The gateway may have a plurality of MAC addresses, one of the plurality of MAC addresses may be a physical MAC address, and the remainder of the plurality of MAC addresses may be virtual MAC addresses. 
         [0016]    Further, in accordance with embodiments of the present disclosure, an operation method of a switch in a vehicle network includes: receiving a frame from a first end node belonging to a first domain in the vehicle network; identifying a communication node indicated by a destination medium access control (MAC) address of the frame; and transmitting the frame to a gateway supporting inter-domain communications when the identified communication node is the gateway. 
         [0017]    A source internet protocol (IP) address of the frame may be set to an IP address of the first end node, and a destination IP address of the frame may be set to an IP address of a second end node belonging to a second domain in the vehicle network. 
         [0018]    The destination MAC address of the frame may be a MAC address configured for the first domain. 
         [0019]    The switch supports layer-2 functions, and configures domains for respective ports of the switch. 
         [0020]    The frame may be received from the first end node through a first port configured for the first domain. 
         [0021]    The operation method may further include: receiving the frame from the gateway; identifying a communication node indicated by a changed destination MAC address of the frame received from the gateway; and transmitting the frame to a second end node belonging to a second domain in the vehicle network when the identified communication node is the second end node. 
         [0022]    A source MAC address of the frame received from the gateway may be a MAC address configured for the second domain. 
         [0023]    The frame may be received from the second end node through a second port configured for the second domain. 
         [0024]    Further, in accordance with embodiments of the present disclosure, an operation method of a gateway in a vehicle network includes: receiving a frame from a switch; changing a destination medium access control (MAC) address of the frame to a MAC address of an end node indicated by a destination internet protocol (IP) address of the frame, when the frame is used for communication between end nodes belonging to different domains; and transmitting the frame having the changed destination MAC address to the switch. 
         [0025]    The destination MAC address of the frame received from the switch may be a MAC address configured for a domain to which an end node indicated by a source IP address or a source MAC address of the frame belongs. 
         [0026]    The frame may be used for communication between end nodes belonging to different domains, when a domain to which an end node indicated by a source IP address or a source MAC address of the frame belongs is different from a domain to which an end node indicated by the destination IP address of the frame belongs. 
         [0027]    The frame may be used for communication between end nodes belonging to different domains, when a domain corresponding to a MAC address of the gateway which is configured as the destination MAC address of the frame is different from a domain to which an end node indicated by the destination IP address of the frame belongs. 
         [0028]    A source MAC address of the frame may be changed to a MAC address configured for a domain to which an end node indicated by the destination IP address of the frame belongs. 
         [0029]    The gateway supports inter-domain communications and has MAC addresses configured for one or more domains. 
         [0030]    The gateway may have a plurality of MAC addresses, one of the plurality of MAC addresses may be a physical MAC address, and the remainder of the plurality of MAC addresses may be virtual MAC addresses. 
         [0031]    The gateway may include a single network interface card (NIC). 
         [0032]    According to the present disclosure, a vehicle network can be divided into a plurality of domains (or, VLANs) so that load of the vehicle network can be reduced. Accordingly, bandwidth of the vehicle network can be increased, and restriction on installation positions of communication nodes can be reduced, and thus it can become possible to design the vehicle network with flexibility. Also, switches supporting only layer-2 functions and gateways having a single NIC can be used, whereby a desired vehicle network can be constructed with relatively lower cost. 
         [0033]    Further, security of the vehicle network can be enhanced by separating the vehicle network from external networks. Especially, in a case that diagnostics based on diagnostic over IP (DoIP) are being performed, security between end nodes belonging to the vehicle network and a diagnostic apparatus locating in the external network can be remarkably enhanced. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0034]    Forms of the present disclosure will become more apparent by describing in detail forms of the present disclosure with reference to the accompanying drawings, in which: 
           [0035]      FIG. 1  is a diagram showing a vehicle network topology according to embodiments of the present disclosure; 
           [0036]      FIG. 2  is a diagram showing a communication node constituting a vehicle network according to embodiments of the present disclosure; 
           [0037]      FIG. 3  is a block diagram illustrating an example of a CAN-based vehicle network topology; 
           [0038]      FIG. 4  is a block diagram illustrating a first exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied; 
           [0039]      FIG. 5  is a sequence chart illustrating a first exemplary embodiment of a communication method in a vehicle network according to the present disclosure; 
           [0040]      FIG. 6  is a block diagram illustrating a second exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied; 
           [0041]      FIG. 7  is a sequence chart illustrating a second exemplary embodiment of a communication method in a vehicle network according to the present disclosure; 
           [0042]      FIG. 8  is a block diagram illustrating a third exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied; 
           [0043]      FIG. 9  is a sequence chart illustrating a third exemplary embodiment of a communication method in a vehicle network according to the present disclosure; 
           [0044]      FIG. 10  is a block diagram illustrating a fourth exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied; and 
           [0045]      FIG. 11  is a block diagram illustrating a fifth exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied. 
       
    
    
       [0046]    It should be understood that the above-referenced drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the disclosure. The specific design features of the present disclosure, including, for example, specific dimensions, orientations, locations, and shapes, will be determined in part by the particular intended application and use environment. 
       DETAILED DESCRIPTION OF THE EMBODIMENTS 
       [0047]    Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present disclosure. Further, throughout the specification, like reference numerals refer to like elements. 
         [0048]    The terminology used herein is for the purpose of describing particular forms only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
         [0049]    It is understood that the term “vehicle” or “vehicular” or other similar term as used herein is inclusive of motor vehicles in general such as passenger automobiles including sports utility vehicles (SUV), buses, trucks, various commercial vehicles, watercraft including a variety of boats and ships, aircraft, and the like, and includes hybrid vehicles, electric vehicles, combustion, plug-in hybrid electric vehicles, hydrogen-powered vehicles and other alternative fuel vehicles (e.g., fuels derived from resources other than petroleum). 
         [0050]    Although embodiments are described herein as using a plurality of units to perform the exemplary process, it is understood that the exemplary processes may also be performed by one or plurality of modules. Additionally, it is understood that the term controller/controller unit/control unit refers to a hardware device that includes a memory and a processor. The memory is configured to store the modules, and the processor is specifically configured to execute said modules to perform one or more processes which are described further below. Moreover, it is understood that the units or modules described herein may embody a controller/control unit for controlling operation of the unit or module. 
         [0051]    Further, control logic of the present disclosure may be embodied as non-transitory computer readable media on a computer readable medium containing executable program instructions executed by a processor, controller/control unit or the like. Examples of the computer readable mediums include, but are not limited to, ROM, RAM, compact disc (CD)-ROMs, magnetic tapes, floppy disks, flash drives, smart cards and optical data storage devices. The computer readable recording medium can also be distributed in network coupled computer systems so that the computer readable media is stored and executed in a distributed fashion, e.g., by a telematics server or a Controller Area Network (CAN). 
         [0052]    Since the present disclosure may be variously modified and have several forms, specific embodiments will be shown in the accompanying drawings and be described in detail in the detailed description. It should be understood, however, that it is not intended to limit the present disclosure to the specific embodiments but, on the contrary, the present disclosure is to cover all modifications and alternatives falling within the spirit and scope of the present disclosure. 
         [0053]    Relational terms such as first, second, and the like may be used for describing various elements, but the elements should not be limited by the terms. These terms are only used to distinguish one element from another. For example, a first component may be named a second component without being departed from the scope of the present disclosure and the second component may also be similarly named the first component. The term “and/or” means any one or a combination of a plurality of related and described items. 
         [0054]    When it is mentioned that a certain component is “coupled with” or “connected with” another component, it should be understood that the certain component is directly “coupled with” or “connected with” to the other component or a further component may be located therebetween. In contrast, when it is mentioned that a certain component is “directly coupled with” or “directly connected with” another component, it will be understood that a further component is not located therebetween. 
         [0055]    Unless specifically stated or obvious from context, as used herein, the term “about” is understood as within a range of normal tolerance in the art, for example within 2 standard deviations of the mean. “About” can be understood as within 10%, 9%, 8%, 7%, 6%, 5%, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or 0.01% of the stated value. Unless otherwise clear from the context, all numerical values provided herein are modified by the term “about.” 
         [0056]    Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. Terms such as terms that are generally used and have been in dictionaries should be construed as having meanings matched with contextual meanings in the art. In this description, unless defined clearly, terms are not ideally, excessively construed as formal meanings. 
         [0057]    Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In describing the disclosure, to facilitate the entire understanding of the disclosure, like numbers refer to like elements throughout the description of the figures and the repetitive description thereof will be omitted. 
         [0058]      FIG. 1  is a diagram showing a vehicle network topology according to embodiments of the present disclosure. 
         [0059]    As shown in  FIG. 1 , a communication node included in the vehicle network may be a gateway, a switch (or bridge), or an end node. The gateway  100  may be connected with at least one switch  110 ,  110 - 1 ,  110 - 2 ,  120 , and  130  and may be configured to connect different networks. For example, the gateway  100  may support connection between a switch which supports a controller area network (CAN) (e.g., FlexRay, media oriented system transport (MOST), or local interconnect network (LIN)) protocol and a switch which supports an Ethernet protocol. Each of the switches  110 ,  110 - 1 ,  110 - 2 ,  120 , and  130  may be connected to at least one of end nodes  111 ,  112 ,  113 ,  121 ,  122 ,  123 ,  131 ,  132 , and  133 . Each of the switches  110 ,  110 - 1 ,  110 - 2 ,  120 , and  130  may interconnect the end nodes  111 ,  112 ,  113 ,  121 ,  122 ,  123 ,  131 ,  132 , and  133 , and control at least one of end nodes  111 ,  112 ,  113 ,  121 ,  122 ,  123 ,  131 ,  132 , and  133  connected to the switch. 
         [0060]    The end nodes  111 ,  112 ,  113 ,  121 ,  122 ,  123 ,  131 ,  132 , and  133  may include an electronic control unit (ECU) configured to control various types of devices mounted within a vehicle. For example, the end nodes  111 ,  112 ,  113 ,  121 ,  122 ,  123 ,  131 ,  132 , and  133  may include the ECU included in an infotainment device (e.g., a display device, a navigation device, and an around view monitoring device). 
         [0061]    The communication nodes (e.g., a gateway, a switch, an end node, or the like) included in the vehicle network may be connected in a star topology, a bus topology, a ring topology, a tree topology, a mesh topology, or the like. In addition, the communication nodes of the vehicle network may support the CAN protocol, the FlexRay protocol, the MOST protocol, the LIN protocol, or the Ethernet protocol. Forms of the present disclosure may be applied to the foregoing network topologies. The network topology to which embodiments of the present disclosure may be applied is not limited thereto and may be configured in various ways. 
         [0062]      FIG. 2  is a diagram showing a communication node constituting a vehicle network according to embodiments of the present disclosure. Notably, the various methods discussed herein below may be executed by a controller having a processor and a memory. 
         [0063]    As shown in  FIG. 2 , a communication node  200  of a network may include a PHY layer unit  210  and a controller unit  220 . In addition, the communication node  200  may further include a regulator (not shown) for supplying power. In particular, the controller unit  220  may be implemented to include a medium access control (MAC) layer. A PHY layer unit  210  may be configured to receive or transmit signals from or to another communication node. The controller unit  220  may be configured to control the PHY layer unit  210  and perform various functions (e.g., an infotainment function, or the like.). The PHY layer unit  210  and the controller unit  220  may be implemented as one system on chip (SoC), or alternatively may be implemented as separate chips. 
         [0064]    Further, the PHY layer unit  210  and the controller unit  220  may be connected via a media independent interface (MII)  230 . The MII  230  may include an interface defined in the IEEE 802.3 and may include a data interface and a management interface between the PHY layer unit  210  and the controller unit  220 . One of a reduced MII (RMII), a gigabit MII (GMII), a reduced GMII (RGMII), a serial GMII (SGMII), a 10 GMII (XGMII) may be used instead of the MII  230 . A data interface may include a transmission channel and a reception channel, each of which may have an independent clock, data, and a control signal. The management interface may include a two-signal interface, one signal for the clock and one signal for the data. 
         [0065]    Particularly, the PHY layer unit  210  may include a PHY layer interface unit  211 , a PHY layer processor  212 , and a PHY layer memory  213 . The configuration of the PHY layer unit  210  is not limited thereto, and the PHY layer unit  210  may be configured in various ways. The PHY layer interface unit  211  may be configured to transmit a signal received from the controller unit  220  to the PHY layer processor  212  and transmit a signal received from the PHY layer processor  212  to the controller unit  220 . The PHY layer processor  212  may be configured to execute operations of the PHY layer interface unit  211  and the PHY layer memory  213 . The PHY layer processor  212  may be configured to modulate a signal to be transmitted or demodulate a received signal. The PHY layer processor  212  may be configured to control the PHY layer memory  213  to input or output a signal. The PHY layer memory  213  may be configured to store the received signal and output the stored signal based on a request from the PHY layer processor  212 . 
         [0066]    The controller unit  220  may be configured to monitor and control the PHY layer unit  210  using the MII  230 . The controller unit  220  may include a controller interface unit  221 , a controller processor  222 , a main memory  223 , and a sub memory  224 . The configuration of the controller unit  220  is not limited thereto, and the controller unit  220  may be configured in various ways. The controller interface unit  221  may be configured to receive a signal from the PHY layer unit  210  (e.g., the PHY layer interface unit  211 ) or an upper layer (not shown), transmit the received signal to the controller processor  222 , and transmit the signal received from the controller processor  222  to the PHY layer unit  210  or upper layer. The controller processor  222  may further include an independent memory control logic or an integrated memory control logic for controlling the controller interface unit  221 , the main memory  223 , and the sub memory  224 . The memory control logic may be implemented to be included in the main memory  223  and the sub memory  224  or may be implemented to be included in the controller processor  222 . 
         [0067]    Further, each of the main memory  223  and the sub memory  224  may be configured to store a signal processed by the controller processor  222  and may be configured to output the stored signal based on a request from the controller processor  222 . The main memory  223  may be a volatile memory (e.g., a random access memory (RAM)) configured to temporarily store data required for the operation of the controller processor  222 . The sub memory  224  may be a non-volatile memory in which an operating system code (e.g., a kernel and a device driver) and an application program code for performing a function of the controller unit  220  may be stored. A flash memory having a high processing speed, a hard disc drive (HDD), or a compact disc-read only memory (CD-ROM) for large capacity data storage may be used as the non-volatile memory. Typically, the controller processor  222  may include a logic circuit having at least one processing core. A core of an Advanced RISC Machines (ARM) family or a core of an Atom family may be used as the controller processor  222 . 
         [0068]    A method performed by a communication node and a corresponding counterpart communication node in a vehicle network will be described below. Although the method (e.g., signal transmission or reception) performed by a first communication node will be described below, the method is applicable to a second communication node that corresponds to the first communication node. In other words, when an operation of the first communication node is described, the second communication node corresponding thereto may be configured to perform an operation that corresponds to the operation of the first communication node. Additionally, when an operation of the second communication node is described, the first communication node may be configured to perform an operation that corresponds to an operation of a switch. 
         [0069]    Due to the increasing number of end nodes in a CAN-based vehicle network, load of the vehicle network can be increased. In order to distribute the increased network load, a plurality of domains for respective functions of a vehicle may be configured. 
         [0070]      FIG. 3  is a block diagram illustrating an example of a CAN-based vehicle network topology. 
         [0071]    As shown in  FIG. 3 , the CAN-based vehicle network may be divided into a body control domain  310 , a chassis control domain  320 , and a multimedia domain  330 . End nodes ADM, DDM, PTM, HSM, ARS, APSM, FSJB, RSJB, SCM, PSM, MFSW, SWRC (HAPTIC), ILM, HUD, and SMK, belonging to the body control domain  310 , may perform body electronic equipment control functions, convenience equipment control functions, lamp control functions and so on. The end nodes belonging to the body control domain  310  may be connected through a bus, and support transmission speed up to 100 Kbps. 
         [0072]    End nodes EHPS, EMS, TCU, ECS, ESC, SCC, AAF, BSD, HUD, SMK, AVM/PGS, CLU, CUbiS/CUbiS-T/TMU, DATC, AFLS, SAS, ACU, LDWS, PSB_LH, PSB_RH, and SBW, belonging to the chassis control domain  320 , may perform steering system control functions, break control functions, suspension control functions and so on. The end nodes belonging to the chassis control domain  320  may also be connected through a bus, and support transmission speed up to 500 Kbps. 
         [0073]    End nodes AVM/PGS, CLU, CUbiS/CUbiS-T/TMU, CLOCK, RSE2 (DIS), HU (DIS), MON, RRC, AMP, CCP (DIS), RSE1 (DIS), and EDT, belonging to the multimedia domain  330 , may perform navigation functions, telematics functions, infotainment functions and so on. The end nodes belonging to the multimedia domain  330  may also be connected through a bus, and support transmission speed up to 100 Kbps. 
         [0074]    Meanwhile, end nodes (e.g., HUD and SMK) belonging to both of the body control domain  310  and the chassis control domain  320 , and end nodes (e.g., AVM/PGS, CLU, and CUbiS/CUbiS-T/TMU) belonging to both of the chassis control domain  320  and the multimedia domain  330  may exist. The domains  310 ,  320 , and  330  may be connected to a gateway  340 , and communications between end nodes belonging to different domains may be performed through the gateway  340 . For example, when a first end node belonging to the body control domain  310  wants to transmit a frame to a second end node belonging to the chassis control domain  320 , the first end node may transmit to the gateway  340  a frame indicating the second end node as its destination. The gateway  340  may receive the frame from the first end node, identify that the destination of the received frame is the second end node, and transmit the received frame to the second end node. 
         [0075]    Meanwhile, virtual local area network (VLAN) technologies may be applied to a vehicle network. The VLAN technologies may be classified into MAC address based VLAN technologies, port based VLAN technologies, etc. In case that the MAC address based VLAN technology is applied to the vehicle network, the vehicle network may be dynamically divided into a least one domain. Here, a domain may correspond to a VLAN. In the vehicle network to which the MAC address based VLAN technology is applied, a separate server (e.g., a VLAN management policy server (VMPS), etc.) for storing and managing MAC addresses of communication nodes belonging to domains becomes necessary, and communications between nodes may be performed in a rather complicated manner. In case that the port based VLAN technology is applied to the vehicle network, the vehicle network may be statically divided into at least one domain. 
         [0076]      FIG. 4  is a block diagram illustrating a first exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied. 
         [0077]    As shown in  FIG. 4 , in the vehicle network, domains may be assigned to respective ports of the switches  410  and  420 . For example, end nodes  411  and  412  connected to ports P 11  and P 12  of the switch  410 , and end nodes  421  and  422  connected to ports P 21  and P 22  of the switch  420  may belong to a first domain  401 . End nodes  413  and  414  connected to ports P 13  and P 14  of the switch  410 , and end nodes  423 ,  424 , and  425  connected to ports P 23 , P 24 , and P 25  of the switch  420  may belong to a second domain  402 . End nodes  415  and  416  connected to ports P 15  and P 16  of the switch  410 , and an end node  426  connected to a port P 26  of the switch  420  may belong to a third domain  403 . 
         [0078]    Table 1 below shows mapping relations among domains, ports, and MAC addresses. Here, the MAC addresses may be MAC addresses of communication nodes connected to the corresponding ports. Communication nodes constituting the vehicle network may have the mapping table in advance. 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                 Domain 
                 Port 
                 MAC address 
               
               
                   
                   
               
             
             
               
                   
                 First 
                 P11 
                 M11 
               
               
                   
                 Domain 
                 P12 
                 M12 
               
               
                   
                   
                 P21 
                 M21 
               
               
                   
                   
                 P22 
                 M22 
               
               
                   
                 Second 
                 P13 
                 M13 
               
               
                   
                 Domain 
                 P14 
                 M14 
               
               
                   
                   
                 P23 
                 M23 
               
               
                   
                   
                 P24 
                 M24 
               
               
                   
                   
                 P25 
                 M25 
               
               
                   
                 Third 
                 P15 
                 M15 
               
               
                   
                 Domain 
                 P16 
                 M16 
               
               
                   
                   
                 P26 
                 M26 
               
               
                   
                   
               
             
          
         
       
     
         [0079]    The switch  410  and the switch  420  may be connected through a trunk link, and communications between end nodes which are connected to different switches and belong to different domains may be performed through the trunk link. Communications between end nodes belonging to the same domain may be performed as follows. 
         [0080]      FIG. 5  is a sequence chart illustrating a first exemplary embodiment of a communication method in a vehicle network according to the present disclosure. 
         [0081]    As shown in  FIG. 5 , the switch  410  and end nodes  411  and  412  may be corresponding nodes illustrated in  FIG. 4 , and constitute the vehicle network illustrated in  FIG. 4 . The end nodes  411  and  412  may belong to the first domain  401 . The end node  411  may be connected to the switch  410  via the port P 11 , and the end node  412  may be connected to the switch  410  via the port P 12 . As shown in the table 1, the MAC address of the end node  411  may be M 11 , and the MAC address of the end node  412  may be M 12 . 
         [0082]    The end node  411  may generate a frame to be transmitted to the end node  412  (S 500 ). The frame may comprise address information and a payload. A destination MAC address of the frame may be configured to be M 12  which is the MAC address of the end node  412 , and a source MAC address of the frame may be configured to be M 11  of the MAC address of the end node  411 . The end node  411  may transmit the frame to the switch  410  via the port P 11  (S 510 ). The switch  410  may receive the frame from the end node  411 . Since the frame is received through the port P 11 , the switch  410  may identify that the frame has been transmitted from the end node  411  connected to the port P 11 . Additionally or alternatively, by identifying that source MAC address of the received frame, the switch  410  may identify that the frame has been transmitted from the end node  411 . 
         [0083]    Also, the switch  410  may identify the destination MAC address of the received frame (S 520 ). Since the destination MAC address of the frame is configured as M 12  which is the MAC address of the end node  412 , the switch  410  may identify that the destination of the frame is the end node  412 . The switch  410  may transmit the frame to the end node  412  through the port P 12  (S 530 ). The end node  412  may receive the frame from the switch  410 , and identify that the destination of the frame is the end node  412  by checking the destination MAC address of the received frame. Therefore, the end node  412  may decode the payload included in the frame (S 540 ). 
         [0084]    Referring once again to  FIG. 4 , in a case that the switches  410  and  420  support only layer-2 functions (i.e., when the switches  410  and  420  do not support layer-3 functions), since the switches  410  and  420  cannot identify IP addresses of the frame, communications between end nodes belonging to different domains may not be supported. However, if the switches  410  and  420  support layer-3 functions and are connected to a router (e.g., a router having network interface cards (NICs) for respective domains, communications between end nodes belonging to different domains may be supported. 
         [0085]      FIG. 6  is a block diagram illustrating a second exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied, and  FIG. 7  is a sequence chart illustrating a second exemplary embodiment of a communication method in a vehicle network according to the present disclosure. 
         [0086]    As shown in  FIGS. 6 and 7 , a switch  600  may support layer-3 functions. Also, domains  601  and  602  are assigned to respective ports of the switch  600 . For example, end nodes  610  and  620  connected to ports P 1  and P 2  of the switch  600  may belong to a first domain  601 , and end nodes  630  and  640  connected to ports P 3  and P 4  of the switch  600  may belong to a second domain  602 . A port P 5  of the switch  600  may be configured for the first domain  601 , and the port P 6  of the switch  600  may be configured for the second domain  602 . That is, the port P 5  of the switch  600  may be used for supporting communications with the end nodes  610  and  620  belonging to the first domain  601 , and the port P 6  of the switch  600  may be used for supporting communications with the end nodes  630  and  640  belonging to the second domain  602 . 
         [0087]    The switch  600  may be connected to a router  650  through the ports P 5  and P 6 . The router  650  may comprise NICs for respective domains  601  and  602 . For example, the router  650  may comprise a first NIC for the first domain  601  and a second NIC for the second domain  602 . Thus, the router  650  may have IP addresses and MAC addresses for respective domains  601  and  602 . Table 2 below shows mapping relations among domains, ports, MAC addresses, and IP addresses. Here, the MAC address may be a MAC address of a communication node connected to the corresponding port, and the IP address may be an IP address of a communication node connected to the corresponding port. Communication nodes constituting the vehicle network may have the mapping table in advance. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                   
                 TABLE 2 
               
               
                   
                   
               
               
                   
                 Domain 
                 Port 
                 MAC address 
                 IP address 
               
               
                   
                   
               
             
             
               
                   
                 First 
                 P1 
                 M1 
                 192.168.0.2 
               
               
                   
                 Domain 
                 P2 
                 M2 
                 192.168.0.3 
               
               
                   
                   
                 P5 
                 M5 
                 192.168.0.1 
               
               
                   
                 Second 
                 P3 
                 M3 
                 192.168.1.2 
               
               
                   
                 Domain 
                 P4 
                 M4 
                 192.168.1.3 
               
               
                   
                   
                 P6 
                 M6 
                 192.168.1.1 
               
               
                   
                   
               
             
          
         
       
     
         [0088]    The end node  610  may generate a frame to be transmitted to the end node  630  (S 700 ). The frame may comprise address information and a payload. A destination IP address of the frame may be configured to be 192.168.1.2 which is the IP address of the end node  630 , and a source IP address of the frame may be configured to be 192.168.0.2 which is the IP address of the end node  610 . Also, a destination MAC address of the frame may be configured to be M 3  which is the MAC address of the end node  630  or M 5  which is the MAC address for the first domain  601  among MAC addresses of the router  650 , and a source MAC address of the frame may be configured to be M 1  which is the MAC address of the end node  610 . The end node  610  may transmit the frame to the switch  600  through the port P 1  (S 710 ). The switch  600  may receive the frame from the end node  610 . Since the frame is received through the port P 1 , the switch  600  may identify that the frame has been transmitted from the end node  610  connected to the port P 1 . Additionally or alternatively, the switch  600  may identify that the frame has been transmitted from the end node  610  by checking the source MAC (or IP) address of the frame. 
         [0089]    Also, the switch  600  may identify the destination IP address of the received frame (S 720 ). Since the destination IP address of the frame is configured as 192.168.1.2 which is the IP address of the end node  630 , the switch  600  may identify that the destination of the frame is the end node  630  belonging to the second domain  602 . Since the frame is for communication between the end nodes  610  and  630  belonging to different domains, the switch  600  may transmit the frame to the router  650  via the port P 5  (S 730 ). 
         [0090]    The router  650  may receive the frame from the switch  600 . The router  650  may identify that the destination IP address of the received frame is 192.168.1.2 which is the IP address of the end node  630 , and accordingly identify that the destination of the frame is the end node  630  belonging to the second domain  602  (S 740 ). Here, in a case that the destination MAC address of the frame is configured as M 5  which is the MAC address for the first domain  601  among MAC addresses of the router  650 , the router  650  may change the destination MAC address of the frame from M 5  to M 3  which is the MAC address of the end node  630 , and change the source MAC address of the frame to M 6  which is the MAC address for the second domain  602  among MAC addresses of the router  650 . The router  650  may transmit the frame to the switch  600  through the port P 6  configured for the second domain  602  (S 750 ). 
         [0091]    The switch  600  may receive the frame from the router  650 , and identify that the destination of the frame is the end node  630  by checking the destination IP (or, MAC) address of the received frame (S 760 ). The switch  600  may transmit the frame to the end node  630  through the port P 3  (S 770 ). The end node  630  may receive the frame from the switch  600 , and identify that the destination of the frame is the end node  630  by checking the destination IP (or, MAC) address of the received frame. Accordingly, the end node  630  may decode the payload included in the received frame (S 780 ). 
         [0092]    As described above, in order to support communications between end nodes belonging to different domains, switches supporting layer-3 functions and a router comprising a plurality of NICs (i.e., NICs for respective domains) are demanded. In a vehicle network, the switches support layer-3 functions and the router comprising a plurality of NICs may become a reason of increasing cost of a vehicle, and thus it is not easy to divide a vehicle network into a plurality of domains. Hereinafter, a vehicle network, which is divided into a plurality of domains by using switches supporting only layer-2 functions and a communication (e.g., gateway) having a single NIC, will be described. 
         [0093]      FIG. 8  is a block diagram illustrating a third exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied. 
         [0094]    As shown in  FIG. 8 , a switch  800  may support layer-2 functions. Domains  801 ,  802 , and  803  may be assigned to respective ports of the switch  800 . For example, end nodes  810  and  820  connected to ports P 1  and P 2  of the switch  800  may belong to a first domain  801 , end nodes  830  and  840  connected to ports P 3  and P 4  of the switch  800  may belong to a second domain  802 , and end nodes  850 ,  860 , and  870  connected to ports P 5 , P 6 , and P 7  may belong to a third domain  803 . 
         [0095]    A gateway  880  may be connected to a port P 8  of the switch  800 . A link between the switch  800  and the gateway  880  may be different from the trunk link explained with reference to  FIG. 4 . The port P 8  of the switch  800  may be used commonly by the domains  801 ,  802 , and  803 . For example, in a case that the port P 8  is used for the first domain  801 , frames generated by the end nodes  810  and  820  belonging to the first domain  801  may be transmitted through the port P 8  of the switch  800 . In a case that the port P 8  is used for the second domain  802 , frames generated by the end nodes  830  and  840  belonging to the second domain  802  may be transmitted through the port P 8  of the switch  800 . In a case that the port P 8  is used for the third domain  803 , frames generated by the end nodes  850 ,  860 , and  870  belonging to the third domain  803  may be transmitted through the port P 8  of the switch  800 . 
         [0096]    The gateway  880  may comprise a single NIC, and accordingly configure a single physical MAC address. Also, the gateway  880  may configure MAC addresses for respective domains. In the case that the gateway  880  supports three domains  801 ,  802 , and  803 , the gateway  880  may further configure two virtual MAC addresses. The gateway  880  may use the physical MAC address for the first domain  801 , the first virtual MAC address for the second domain  802 , and the second virtual MAC address for the third domain  803 . 
         [0097]    Table 3 below shows mapping relations among domains, ports, and MAC addresses. Here, the MAC addresses may be MAC addresses of communication nodes connected to the corresponding ports. Communication nodes constituting the vehicle network may have the mapping table in advance. 
         [0000]    
       
         
               
               
               
               
               
             
           
               
                   
                 TABLE 3 
               
               
                   
                   
               
               
                   
                 Domain 
                 Port 
                 MAC address 
                 IP address 
               
               
                   
                   
               
             
             
               
                   
                 First 
                 P1 
                 M1 
                 192.168.0.11 
               
               
                   
                 Domain 
                 P2 
                 M2 
                 192.168.0.12 
               
               
                   
                   
                 P8 
                 M8 
                 192.168.3.10 
               
               
                   
                 Second 
                 P3 
                 M3 
                 192.168.1.11 
               
               
                   
                 Domain 
                 P4 
                 M4 
                 192.168.1.12 
               
               
                   
                   
                 P8 
                 M9 
                 192.168.3.10 
               
               
                   
                 Third 
                 P5 
                 M5 
                 192.168.2.11 
               
               
                   
                 Domain 
                 P6 
                 M6 
                 192.168.2.12 
               
               
                   
                   
                 P7 
                 M7 
                 192.168.2.13 
               
               
                   
                   
                 P8 
                 M10 
                 192.168.3.10 
               
               
                   
                   
               
             
          
         
       
     
         [0098]    According to Table 3, the gateway  880  may have MAC addresses for respective domains  801 ,  802 , and  803 . Also, the gateway  880  may use a single IP address regardless of the domains  801 ,  802 , and  803 . Alternatively, the gateway  880  may use different IP addresses for respective domains  801 ,  802 , and  803 . 
         [0099]    Hereinafter, methods for communications between communication nodes in a vehicle network divided into a plurality of domains will be described. 
         [0100]      FIG. 9  is a sequence chart illustrating a third exemplary embodiment of a communication method in a vehicle network according to the present disclosure. 
         [0101]    As shown in  FIG. 9 , the switch  800 , the end nodes  810  and  860 , and the gateway may be the corresponding ones illustrated in  FIG. 8 , and constitute the vehicle network explained with reference to  FIG. 8 . 
         [0102]    The end node  810  belonging to the first domain  801  may generate a frame to be transmitted to the end node  860  belonging to the third domain  803  (S 900 ). The frame may comprise address information and a payload. A destination IP address of the frame may be configured as 192.168.2.12 which is the IP address of the end node  860 , and a source IP address of the frame may be configured as 192.168.0.11 which is the IP address of the end node  810 . The destination MAC address of the frame may be configured as M 8  which is the MAC address for the first domain  801  among MAC addresses of the gateway  880 , and the source MAC address of the frame may be configured as M 1  which is the MAC address of the end node  810 . The end node  810  may transmit the frame to the switch  800  through the port P 1  (S 910 ). 
         [0103]    The switch  800  may receive the frame from the end node  810 . Since the frame is received through the port P 1 , the switch  800  may identify that the frame has been transmitted from the end node  810  connected to the port P 1 . Additionally or alternatively, the switch  800  may identify that the frame has been transmitted from the end node  810  by checking the source MAC address of the received frame. The switch  800  may identify the destination of the frame by checking the destination MAC address of the received frame (S 920 ). Since the destination MAC address of the frame is M 8  which is the MAC address for the first domain  801  among MAC addresses of the gateway  880 , the switch  800  may identify that the destination of the frame is the gateway  880 . Accordingly, the switch  800  may transmit the frame to the gateway  880  through the port P 8  (S 930 ). Here, since the switch  800  does not support layer-3 functions, the switch  800  cannot identify IP addresses in the frame, and thus the switch  800  may identify the destination and source of the frame by using the destination MAC address and source MAC address of the frame. 
         [0104]    The gateway  880  may receive the frame from the switch  800 . The gateway  880  may identify, based on the source MAC address (e.g., the source MAC address configured as M 1 ) or the source IP address (e.g., the source IP address configured as 192.168.0.11), that the source of the frame is the end node  810 . Also, the gateway  880  may identify the destination of the frame by checking the destination MAC address or the destination IP address of the received frame (S 940 ). Since the destination MAC address of the frame is configured as M 8  for the first domain  801  among MAC addresses of the gateway  880 , the gateway  880  may identify the destination of the frame is the gateway  880 . Also, since the destination IP address of the frame is configured as 192.168.2.12 which is the IP address of the end node  860 , the gateway  880  may identify that the final destination of the frame is the end node  860  belonging to the third domain  803 . 
         [0105]    The gateway  880  may reconfigure the MAC addresses of the frame by considering the final destination of the frame and the domain to which the final destination belongs (S 950 ). For example, in a case that a domain to which a communication node corresponding to the destination MAC address of the frame belongs is different from a domain to which a communication node corresponding to the destination IP address of the frame belongs, or in a case that a domain to which the source of the frame (e.g., the end node  810 ) belongs is different from a domain to which the final destination of the frame (e.g., the end node  860 ) belongs, the gateway  880  may reconfigure the MAC addresses of the frame. The gateway  880  may change the destination MAC address of the frame from M 8  to M 6  which is the MAC address of the end node  860 , and the source MAC address of the frame from M 1  to M 10  which is the MAC address for the third domain  803  among MAC addresses of the gateway  880 . Here, the IP addresses of the frame may not be changed. The gateway  880  may transmit the frame whose MAC addresses have been changed to the switch  800  through the port P 8  (S 960 ). 
         [0106]    The switch  800  may receive the frame from the gateway  880 . Since the frame is received through the port P 8 , the switch  800  may identify that the frame has been transmitted from the gateway  880  connected to the port P 8 . Additionally or alternatively, the switch  800  may identify that the frame has been transmitted from the gateway  880  by checking the source MAC address of the received frame. The switch  800  may identify the destination of the frame by checking the destination MAC address of the received frame (S 970 ). Since the destination MAC address of the frame is M 6  which is the MAC address of the end node  860  belonging to the third domain  803 , the switch  800  may identify that the destination of the frame is the end node  860 . Accordingly, the switch  800  may transmit the frame to the end node  860  through the port P 6  (S 980 ). 
         [0107]    The end node  860  may receive the frame from the switch  800 , and identify that the destination of the frame is the end node  860  by checking the destination MAC (or, IP) address of the received frame. Accordingly, the end node  860  may decode the payload included in the frame (S 990 ). 
         [0108]    Hereinafter, a vehicle network divided by gateways and an external network will be described. Here, the external network may be a network located externally from a vehicle. 
         [0109]      FIG. 10  is a block diagram illustrating a fourth exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied. 
         [0110]    As shown in  FIG. 10 , gateways  1010  and  1020 , switches  1030 ,  1040 , and  1050 , and end nodes  1031 ,  1032 ,  1041 ,  1042 ,  1051 ,  1052 , and  1053  may constitute a vehicle network. A diagnostic apparatus  1060  may constitute an external network, and belong to a first domain  1001 . Also, the diagnostic  1060  may perform diagnostic functions and reprogramming functions for the vehicle network. The switch  1030  and end nodes  1031  and  1032  may belong to a second domain  1002 , and communication nodes belonging to the second domain  1022  may form a local interconnect network (LIN). The gateway  1020 , switch  1040 , switch  1050 , end node  1041 , end node  1042 , end node  1051 , end node  1052 , and end node  1053  may belong to a third domain  1003 . The switch  1040 , end node  1041 , and end node  1042  may form a CAN-based network. The switch  1050 , end node  1051 , end node  1052 , and end node  1053  may form an Ethernet-based network. 
         [0111]    The gateway  1010  may support communications among the plurality of domains  1001 ,  1002 , and  1003  in the manner identical to or similar with that of the gateway  880  explained with reference to  FIG. 8  and  FIG. 9 . For example, the gateway  1010  may include a single NIC, and accordingly have a single physical MAC address. Also, the gateway  1010  may configure MAC addresses for respective domains. Since the gateway  1010  supports three domains  1001 ,  1002 , and  1003 , the gateway  1010  may further generate two virtual MAC addresses. The gateway  1010  may use the physical MAC address for communications with the communication nodes belonging to the first domain  1001 , a first virtual MAC address for communications with the communication nodes belonging to the second domain  1002 , and a third virtual MAC address for communications with the communication nodes belonging to the third domain  1003 . Through this, the vehicle network can be separated from the external network so that security of the vehicle network can be guaranteed. 
         [0112]      FIG. 11  is a block diagram illustrating a fifth exemplary embodiment of a vehicle network topology to which a port based VLAN technology is applied. 
         [0113]    As shown in  FIG. 11 , each of switch  1100  and gateway  1130  may support communications among a plurality of domains  1001 ,  1002 , and  1003  in the manner identical to or similar with that of the switch  800  and the gateway  880  explained referring to  FIG. 8  and  FIG. 9 . The switch  1100  may support layer-2 functions, and the gateway  1130  may include a single NIC. A diagnostic apparatus  1110  may perform diagnostic functions and reprogramming functions for the vehicle network, and belong to the first domain  1001 . An end node  1120  may belong to the second domain  1002 . 
         [0114]    The gateway  1130  may have a single physical MAC address, and may configure MAC addresses for respective domains. Since the gateway  1010  supports two domains, the gateway  1130  may further generate a virtual MAC addresses. The gateway  1130  may use the physical MAC address for communications with the diagnostic apparatus  1110  belonging to the first domain, and the virtual MAC address for communications with the end node  1120  belonging to the second domain. Also, the gateway  1130  may configure IP addresses for respective domains. For example, the gateway  1130  may obtain an IP address generated based on a dynamic host configuration protocol (DHCP) from the diagnostic apparatus  1110 , and use the obtained IP address as the IP address for the first domain. 
         [0115]    The methods according to embodiments of the present disclosure may be implemented as program instructions executable by a variety of computers and recorded on a computer readable medium. The computer readable medium may include a program instruction, a data file, a data structure, or a combination thereof. The program instructions recorded on the computer readable medium may be designed and configured specifically for the present disclosure or can be publicly known and available to those who are skilled in the field of computer software. Examples of the computer readable medium may include a hardware device such as ROM, RAM, and flash memory, which are specifically configured to store and execute the program instructions. Examples of the program instructions include machine codes made by, for example, a compiler, as well as high-level language codes executable by a computer, using an interpreter. The above exemplary hardware device can be configured to operate as at least one software module in order to perform the operation of the present disclosure, and vice versa. 
         [0116]    While the embodiments of the present disclosure and their advantages have been described in detail above, it should be understood that various changes, substitutions and alterations may be made herein without departing from the scope of the disclosure.