Abstract:
There are provided a QoS Ethernet switch and a flow QoS processing method using the same. More particularly, there is provided a technology that can easily ensure IP service quality at low cost by introducing IP flow QoS function to an Ethernet switch.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the priorities of Korean Patent Application Nos. 10-2008-0124007 filed on Dec. 8, 2008, and 10-2009-0030244 filed on Apr. 8, 2009, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein by reference. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The present invention relates to a QoS Ethernet switch and a flow QoS processing method using the same, and more particularly, to a QoS Ethernet switch and a flow QoS processing method using the same that can easily ensure IP service quality at low cost by introducing IP flow QoS function to an Ethernet switch. 
         [0004]    2. Description of the Related Art 
         [0005]    Currently, most network services have evolved into IP-based services. Also, much of the traffic passing through Ethernet switches is IP traffic, such trend is predicted to only increase in the future. 
         [0006]    In general, the network performance of IP networks depends on the performance of lower-layer networks used to establish connections between routers. Currently, the most deployed technology to establish connections between routers in IP networks is Ethernet technology. Equipment that provides QoS per IP flow is required to ensure the quality of IP services. Current Ethernet switches do not support QoS and only transmit traffic by operating IEEE 802.1p-based priority queues, irrelevant to IP flows, while being unable to provide IP flow recognition and QoS support. 
         [0007]    In order to ensure QoS in IP networks, IP routers (S-series, Sable Networks) have been released and are being partially used in the networks. These flow QoS routers manage traffic per IP flow and provide QoS support such as a bandwidth guarantee per IP flow. 
         [0008]    However, routers are generally more expensive than Ethernet switches. It is also difficult to change existing routers to flow QoS routers due to complex IP network operation management. Furthermore, in terms of costs, it is very difficult to change all existing routers to flow QoS routers. 
       SUMMARY OF THE INVENTION 
       [0009]    An aspect of the present invention provides a flow QoS Ethernet switch and a flow QoS processing method using the same that can easily ensure IP service quality at low cost by introducing IP flow QoS function to an Ethernet switch. 
         [0010]    According to an aspect of the present invention, there is provided a flow QoS Ethernet switch including: a packet switch performing Ethernet layer switching; and a plurality of flow QoS line cards located at an input terminal or an output terminal of the packet switch and providing QoS for IP flows passing through the packet switch. 
         [0011]    Each of the flow QoS line cards may include: a classifier transmitting packets to an IP flow QoS engine or a transmitter according to whether the packets input through an external interface or the packet switch are IP packets subject to flow QoS; an IP flow QoS engine receiving the IP packets subject to flow QoS from the classifier and applying per-flow QoS to the IP packets; and a transmitter transmitting the packets transmitted from the classifier or the IP flow QoS engine to the packet switch or the outside. 
         [0012]    Each of the flow QoS line cards may further include a flow QoS traffic information DB storing information about traffic subject to flow QoS, and the classifier may classify the traffic subject to flow QoS with reference to the flow QoS traffic information DB. 
         [0013]    Each of the flow QoS line cards may further include a flow QoS profile information DB storing a flow QoS profile, and the IP flow QoS engine may apply per-flow QoS to the IP packets subject to flow QoS with reference to the flow QoS profile information DB. 
         [0014]    According to another aspect of the present invention, there is provided a flow QoS processing method using an Ethernet switch supporting IP flow QoS, the method including: determining whether packets input through an external interface or a packet switch correspond to traffic subject to flow QoS; determining whether the input packets are IP packets when the input packets correspond to traffic subject to flow QoS; accessing flow QoS profile information about the IP packets subject to flow QoS; and applying flow QoS to the IP packets subject to flow QoS according to the flow QoS profile information. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    The above and other aspects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which: 
           [0016]      FIG. 1  is a configuration view illustrating a network to which flow QoS Ethernet switches are applied according to an exemplary embodiment of the present invention; 
           [0017]      FIG. 2  is a configuration view illustrating a flow QoS Ethernet switch according to an exemplary embodiment of the present invention; 
           [0018]      FIG. 3  is a detailed configuration view illustrating the flow QoS line card, shown in  FIG. 2 ; and 
           [0019]      FIG. 4  is a flow chart illustrating a flow QoS process of the flow QoS line card, shown in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0020]    Exemplary embodiments of the present invention will now be described in detail with reference to the accompanying drawings. The invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the shapes and dimensions may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or like components. 
         [0021]    It will be understood that when an element is referred to as being “connected with” another element, it can be directly connected with the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly connected with” another element, there are no intervening elements present. In addition, unless explicitly described to the contrary, the word “comprise” and variations such as “comprises” or “comprising,” will be understood to imply the inclusion of stated elements but not the exclusion of any other elements. 
         [0022]      FIG. 1  is a configuration view illustrating a network to which flow QoS Ethernet switches are applied according to an exemplary embodiment of the invention. 
         [0023]    According to this embodiment, flow QoS Ethernet switches  100 , providing QoS for IP flows in order to ensure IP service quality, perform L2 (Ethernet) layer switching and at the same time, and provide end-to-end IP flow QoS by adjusting packet transmission priority with respect to IP packets through per-flow management and queuing mechanisms. 
         [0024]    As shown in  FIG. 1 , the flow QoS Ethernet switches  100  according to this embodiment are connected between routers  200  according to the related art that only support best-effort service and provide end-to-end IP flow QoS. Though not shown in  FIG. 1 , pieces of equipment, such as Ethernet switches and multiService provisioning platform (MSPPs) according to the related art, may be located between the QoS Ethernet switches  100 . 
         [0025]    As such, when the network is configured using the flow QoS Ethernet switches  100  and the routers  200  according to the related art, the routers  200  perform IP packet routing, and the flow QoS Ethernet switches  100  switch Ethernet layers and provide IP flow QoS. 
         [0026]      FIG. 2  is a configuration view illustrating a flow QoS Ethernet switch according to an exemplary embodiment of the invention. 
         [0027]    As shown in  FIG. 2 , a flow QoS Ethernet switch  100  according to this embodiment includes a plurality of flow QoS line cards  110  and a packet switch  120 . 
         [0028]    The flow QoS line cards  110  are included to provide QoS for IP flows. The configuration and function thereof will be described below in detail with reference to  FIG. 3 . 
         [0029]    The packet switch  120  performs general Ethernet layer switching, which can be implemented by the technology known in the related art. Thus, a detailed description of the packet switch  120  will be omitted. 
         [0030]      FIG. 3  is a detailed configuration view illustrating the flow QoS line card, shown in  FIG. 2 . 
         [0031]    In  FIG. 3 , except for the configuration for Ethernet switching that is provided for a general Ethernet switch, a configuration for providing QoS for IP flows will be only described in detail according to an exemplary embodiment of the invention. 
         [0032]    The flow QoS line card  110  includes a classifier  111 , an IP flow QoS engine  112 , a transmitter  113 , a flow QoS traffic information DB  114  and a flow QoS profile information DB  115 . 
         [0033]    The classifier  111  determines whether packets being input correspond to traffic subject to flow QoS and whether or not the input packets are IP packets. The classifier  111  transmits the input packets to the IP flow QoS engine  112  when the input packets are IP packets subject to flow QoS or otherwise transmits the input packets to the transmitter  113 . 
         [0034]    Here, the classifier  111  may classify the traffic subject to flow QoS with reference to information on traffic subject to flow QoS that is stored in the flow QoS traffic information DB  114 . Here, identifiers, used for traffic classification, may be defined as source and destination MAC addresses when the flow QoS Ethernet switch  100  including the flow QoS line cards  110  is merely an L2 Ethernet switch. Alternatively, the identifiers may be defined as a C-tag, an S-tag, route information of PBT/MPLS-TP and a combination thereof in a metro Ethernet, which is the Internet via Ethernet in a LAN environment. 
         [0035]    The IP flow QoS engine  112  receives the IP packets subject to flow QoS from the classifier  111  and processes the packets per flow. Specifically, the IP flow QoS engine  112  applies per-flow QoS with reference to flow QoS profiles stored in the flow QoS profile information DB  115 . 
         [0036]    The IP flow QoS engine  112  may be implemented by borrowing the configuration and function used in the flow QoS router according to the related art. The flow QoS router only performs per-flow packet processing of the IP packets according to the related art, while the IP flow QoS engine  112  can manage the entire Ethernet frame including the IP packets in units of IP flows according to this embodiment. 
         [0037]    The transmitter  113  outputs the traffic transmitted from the classifier  111  or the IP flow QoS engine  112  to the packet switch  120  or to the outside. 
         [0038]    The above-described packet flow may be equally applied to the flow QoS line cards  110  at both, or any one of the input and output terminals of the flow QoS Ethernet switch  100 . 
         [0039]      FIG. 4  is a flow chart illustrating a flow QoS process in the flow QoS line card, shown in  FIG. 3 . 
         [0040]    First, when packets arrive at the flow QoS line card  110  through an external interface or the packet switch  120  in operation S 400 , the classifier  111  determines whether the input packets correspond to traffic subject to flow QoS according to information set beforehand, that is, information stored in the flow QoS traffic DB  114  in operation S 401 . 
         [0041]    As a result of the determination, when the packets are not traffic flow subject to QoS, the classifier  111  transmits the packets directly to the transmitter  113  without passing them through the IP flow QoS engine  112  so that the packets are then transmitted through the packet switch or the external interface in operation S 407 . 
         [0042]    On the other hand, when the packets correspond to traffic subject to flow QoS, the classifier  111  determines whether the packets are IP packets in operation S 402  and transmits the packets to the IP flow QoS engine  112  when the packets are IP packets in operation S 403  or otherwise transmits the packets to the transmitter  113 . 
         [0043]    Then, the IP flow QoS engine  112  having received the IP packets, which are subject to flow QoS, accesses flow QoS profile information set beforehand in operation S 404 . When there is a flow QoS profile with respect to the transmitted packets in operation S 405 , the IP flow QoS engine  112  applies flow QoS to the packets according to the flow QoS profile in operation S 406 . 
         [0044]    The IP packets having been applied with flow QoS are transmitted to the packet switch or the external interface through the transmitter  113  in operation S 407 . 
         [0045]    As set forth above, according to exemplary embodiments of the invention, IP service quality can be increased by changing general Ethernet switches to flow QoS Ethernet switches supporting IP flow QoS in an IP network according to the related art. 
         [0046]    Furthermore, costs can be reduced and applicability can be increased by changing general Ethernet switches to flow QoS Ethernet switches as compared with the case in which general routers are changed to flow QoS routers. 
         [0047]    While the present invention has been shown and described in connection with the exemplary embodiments, it will be apparent to those skilled in the art that modifications and variations can be made without departing from the spirit and scope of the invention as defined by the appended claims.