JP3778446B2 - Ethernet switch - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention generally relates to an Ethernet switch (hereinafter also referred to as an L2 switch) that becomes a connection point when an Ethernet leased line network and an Ethernet switched network are connected, and more specifically, a VLAN identifier (hereinafter referred to as an L2 switch). , Which is also referred to as VLAN-ID) as an identifier of a logical interface, and relates to an Ethernet switch that connects an Ethernet leased line network and an Ethernet switched network in a network network interface (hereinafter also referred to as NNI) system. .
[0002]
In this specification, the registered trademark “Ethernet” is frequently referred to, but the indication that it is a registered trademark is omitted in each reference part to avoid complication.
[0003]
In this specification, the connection by the NNI system means a connection in which lines are multiplexed, and a user network interface (hereinafter also referred to as UNI) to be described later is a physical connection for each user. Means a connection to which a line is assigned.
[0004]
[Prior art and problems to be solved by the invention]
When a plurality of providers providing Ethernet services connect their networks, UNI connection is a common connection form. However, the NNI connection with higher accommodation efficiency is often used as the connection form of the dedicated line service using the SONET / SDH system instead of the Ethernet system. The connection form is different in this way because the SONET / SDH system is a one-to-one connection form that connects two bases, whereas the Ethernet system is basically a network-to-network (between multiple bases) connection. This is due to the difference in form. The SONET / SDH system is a “transmission service” using a multiplexing device, whereas the Ethernet system is a “switching service” using an L2 switch. However, even in the Ethernet system, a one-to-one leased line connection form is possible, and there are actually companies that provide an Ethernet leased line service.
[0005]
In the Ethernet system, NNI connection is also possible when connecting dedicated line networks or connecting switched networks. However, when connecting a dedicated line network and an exchange network, the conventional technique can be configured only by a UNI connection.
[0006]
FIG. 1 shows an Ethernet frame multiplexing method using the VLAN function. In one physical line connecting the Ethernet device 101 and the Ethernet device 102, the Ethernet frame belonging to the VLAN 100 used by the user A and the Ethernet frame belonging to the VLAN 200 used by the user B are the VLAN 100 and the VLAN 200. Multiplexed using the VLAN-ID. Here, the VLAN-ID is an identifier uniquely assigned to each VLAN. A trunking method for logically distinguishing Ethernet frames flowing in one physical line with reference to the VLAN-ID assigned as in the example of FIG. 1 is defined in IEEE 802.1Q. An operator providing an Ethernet service assigns a unique VLAN-ID to each user, and uses the assigned VLAN-ID to logically multiplex Ethernet frames in one physical line, thereby improving efficiency. Can provide services well.
[0007]
The Ethernet devices 101 and 102 distinguish the Ethernet frame by treating the VLAN-ID included in the header of each Ethernet frame as “ID for identifying the user”, that is, “user identifier”. Therefore, when the same user (for example, user A) uses a plurality of different Ethernet dedicated lines and these Ethernet dedicated lines are connected to each other, the VLAN-ID for user A has a plurality of Ethernets. If uniqueness is not maintained between the dedicated lines, Ethernet frames are not exchanged even between the same user A. In other words, in order to connect the networks of a plurality of operators that provide Ethernet services to each other and ensure user connectivity among these operators, even between different operators, It is necessary that a VLAN-ID is uniquely assigned to each user.
[0008]
FIG. 2 illustrates a problem that occurs when different VLAN-IDs are assigned to the same user in each provider when connecting the two operators. It is assumed that the VLAN A ID VLAN100 is assigned to the user A in the Ethernet network of the operator A, and the VLAN 200 ID VLAN 200 is assigned to the same user A in the Ethernet network of the operator B. Between the Ethernet device 201 on the operator A side and the Ethernet device 202 on the operator B side, an Ethernet frame is logically multiplexed on one physical line and sent as in the case of FIG. In this case, even if an Ethernet frame including VLAN 100 as VLAN-ID is sent from the Ethernet network by the operator A to the Ethernet network by the operator B, the VLAN 100 does not mean the user A in the Ethernet network by the operator B. Therefore, this Ethernet frame is not transmitted to the VLAN 200 used by the user A. Conversely, when an Ethernet frame is transmitted from the carrier B side to the carrier A, communication is impossible for the same reason.
[0009]
Thus, in the case of one-to-one and network-to-network, the VLAN-ID match is a connection condition. However, the situation is different for a one-to-one network. Next, this problem will be examined with reference to FIG.
[0010]
FIG. 3 shows the NNI connection between the network of the provider (left side) providing the Ethernet leased line service and the network of the provider (right side) providing the Ethernet switching service. Hereinafter, for the sake of simplicity, these operators are referred to as a leased line operator and an exchange operator. The Ethernet device 301 on the leased line provider side and the L2 switch 302 on the exchange provider side are connected by a single physical line. On the leased line provider side, the same user has a contract with two sites, site A (VLAN 100) and site B (VLAN 200). The end point is a connection point 302 with the exchange operator. On the exchange operator side, the same user as that on the leased line operator side makes a contract at one site of the site C (VLAN 300).
[0011]
Since the leased line provider on the left side of FIG. 3 provides the Ethernet leased line service, not the Ethernet exchange service, when the same user contracts two lines, different VLANs, VLAN 100 and VLAN 200, are provided. An ID needs to be assigned to each contracted line. Since no exchange service is provided, the same VLAN-ID cannot be assigned to exchange Ethernet frames. Therefore, the exchange of the Ethernet frame is performed in the L2 switch 302 of the exchange operator. However, the VLAN-ID included in the Ethernet frame transmitted from the leased line provider side is different, such as VLAN 100 and VLAN 200, depending on from which location the transmission source is the same user. Therefore, the exchange frame L2 switch 302 cannot exchange the Ethernet frame.
[0012]
As shown in FIG. 4, a connection form that can be taken in such a case as shown in FIG. 4 is that an Ethernet multiplexer (multiplexer / demultiplexer) 402 is arranged at the stage before connection to the L2 switch of the exchange operator, and multiplexing is performed. This is a UNI system in which separate physical interfaces are allocated to the L2 switch 403 on the exchange operator side for each individual line on the leased line operator side after release of the network. In this configuration, the Ethernet frame logically multiplexed by the leased line provider side Ethernet device 401 of FIG. 4 and transmitted to the switching provider side is demultiplexed by the multiplexer 402, and the frame from the base A is removed. And the frame from the base B are transmitted to the L2 switch 403 on the exchange operator side through physically separate ports. That is, there are as many output ports on the exchange operator side of the multiplexing apparatus 402 as the number of contract lines in the leased line operator. In the example of FIG. 4, the number of output ports is two. However, if the number of contracted lines in the leased line provider increases, the number of output ports increases. Installing a large number of physically separate output ports is inefficient and management costs cannot be ignored.
[0013]
Here, a logical multiplex section is between the dedicated provider side Ethernet device 401 and the multiplexer 402, and a UNI section is between the multiplexer 402 and the switching provider side L2 switch 403. When viewed from the multiplexer 402, the left side is the network side and the right side is the user side. Further, when viewed from the L2 switch 403, the right side is the network side and the left side is the user side.
[0014]
[Means for Solving the Problems]
The reason why such physical processing is necessary is that the existing equipment such as the leased line provider side Ethernet equipment 401 and the switching company side L2 switch 403 treats the VLAN-ID as a “user identifier”. is there. It is inefficient and costly to physically provide separate ports for the number of contracted lines. On the other hand, in the present invention, the connection between the Ethernet private line network and the Ethernet switching network is realized by using the NNI system which has better accommodation efficiency than the UNI system. Therefore, in the present invention, a new approach is adopted in which the VLAN-ID is not used as a “user identifier” but as a “logical interface identifier”.
[0015]
According to the present invention, when an Ethernet switching network in which an Ethernet frame identified by VLAN-ID is exchanged is connected to an Ethernet leased line network in which the Ethernet frame identified by VLAN-ID is transmitted, the connection point An Ethernet switch is provided. The Ethernet exchange includes means for recognizing a VLAN-ID included in an Ethernet frame from an Ethernet leased line network as a logical interface identifier, and means for assigning a VLAN-ID in the Ethernet exchange network to the recognized logical interface. Is included. Thereby, it becomes possible to connect the Ethernet private line network and the Ethernet switching network by the NNI system.
[0016]
The present invention can also be regarded as a method for controlling an Ethernet switch as defined in the appended claims.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an example of the NNI connection according to the present invention will be described with reference to FIG. FIG. 5 shows the NNI connection between the leased line operator (left side) and the exchange operator (right side) as in the case of FIGS. 3 and 4. The Ethernet device 501 on the leased line provider side and the L2 switch 502 on the exchange provider side are connected by a single physical line, and on the leased line provider side, the same user is connected to the base A (VLAN 100) and the base B (VLAN 200) is contracted at two sites, and the end point is a connection point with the switching company. On the switching company side, the same user as the leased line side contracts at one site of site C (VLAN 300). It is the same as in the case of FIG. 3 and FIG.
[0018]
However, in the configuration of FIG. 5, a device corresponding to the multiplexing device 402 of FIG. 4 is not used. Instead of using the multiplexing device, the VLAN-ID is interpreted differently from the conventional one in the L2 switch 502 on the exchange operator side. This is the central idea in the present invention.
[0019]
Even in the case shown in FIG. 5, the connection between the leased line provider side Ethernet device 501 and the switching provider side L2 switch 502 is performed by Ethernet frame multiplexing according to IEEE 802.1Q by one physical interface. This is the same as in the case of FIG. 3 or FIG. However, unlike the conventional apparatus, the L2 switch 502 on the exchange operator side shown in FIG. 5 replaces the VLAN-ID of the Ethernet frame from the leased line network with the identifier of the logical interface. And an exchange unit 502b that interprets the VLAN-ID as an identifier of the user inside the exchange operator.
[0020]
The Ethernet frame sent from the leased line provider side includes VLAN-IDs (VLAN 100, VLAN 200, etc.) individually assigned to each user base on the leased line connected to the Ethernet equipment 501 on the leased line provider side. When the Ethernet frame is transmitted to the L2 switch 502 on the exchange operator side, the interface unit 502a, which is the first part of the L2 switch 502, specifies the VLAN-ID included in the frame as “the logical interface. Interpreted as “identifier”.
[0021]
Considering the configuration according to the prior art again, as shown in FIG. 4, with respect to the Ethernet frame from the leased line operator side, the multiplexing device 402 demultiplexes the frame, for each VLAN-ID of the Ethernet frame. The data is output to the L2 switch 403 via physically different ports (that is, physical interfaces). On the other hand, in the configuration example according to the present invention illustrated in FIG. 5, the configuration corresponding to the physical interface in FIG. 4 is not provided in the interface unit 502 a without providing a physically separate configuration for each VLAN-ID. It is implemented as a logical interface inside the switch 502.
[0022]
In order to specifically explain the processing of the Ethernet frame according to the present invention, the Ethernet frame AB transmitted from the base A on the leased line provider side to the base B on the leased line provider side shown in FIG. Think about the process. Here, the Ethernet frame AB means an Ethernet frame transmitted from the base A to the base B. Conversely, an Ethernet frame BA means an Ethernet frame transmitted from the base B to the base A. As described above, the leased line operators providing the base A and the base B do not perform the Ethernet frame exchange service. Therefore, the Ethernet device 501 on the leased line provider side does not exchange the Ethernet frames. I will not. Accordingly, the Ethernet frame AB transmitted from the site A is transmitted to the L2 switch 502 on the exchange operator side through the Ethernet device 501 on the leased line operator side. In the interface unit 502a of the L2 switch 502, the VLAN 100 that is the VLAN-ID included in the header of the Ethernet frame AB is recognized as an identifier of the logical interface of the L2 switch 502. In the switching unit 502b of the L2 switch 502, a VLAN 300 that is a VLAN-ID on the Ethernet switching network side is assigned to the recognized logical interface. Next, as in the case of the conventional L2 switch, the interface for the site B is determined according to the exchange operation of the Ethernet frame AB. The frame AB is transmitted from the L2 switch 502 to the leased line network side in accordance with the VLAN 200 that is the VLAN-ID on the leased line provider side.
[0023]
Next, consider an Ethernet frame CA transmitted from the base C of the Ethernet switching network toward the base A of the leased line network. This Ethernet frame CA is exchanged according to the exchange operation of the conventional L2 switch, and is transmitted from the L2 switch 502 to the dedicated line side as in the case of the Ethernet frame AB. Even in the case of the connection according to the present invention, the L2 switch 502 performs the conventional processing for the Ethernet frame from the Ethernet switching network side.
[0024]
【The invention's effect】
According to the present invention, when an Ethernet leased line network and an Ethernet switched network are connected, a VLAN-ID from the leased line network is handled as an identifier of a logical interface, so that an NNI connection form that is impossible in the prior art is achieved. As a result, the accommodation efficiency in the interconnection of Ethernet service providers is improved, and the operational load and equipment cost are reduced.
[Brief description of the drawings]
FIG. 1 is a diagram showing an Ethernet frame multiplexing method using VLAN.
FIG. 2 is a diagram illustrating a case where VLAN-IDs do not match when connecting two business operators.
FIG. 3 is a diagram showing a problem when an Ethernet leased line operator and an Ethernet exchange operator are connected by a network / network interface method.
FIG. 4 is a diagram showing a state of a network / network interface connection between an Ethernet leased line operator and an Ethernet exchange operator that can be realized in the prior art.
FIG. 5 is a diagram showing a state in which a network / network interface connection is established between an Ethernet leased line operator and an Ethernet exchange operator by performing VLAN-ID processing according to the present invention.

Claims (2)

An Ethernet switch that becomes a connection point when an Ethernet switching network in which an Ethernet frame identified by a VLAN identifier is exchanged is connected to an Ethernet private network through which the Ethernet frame identified by the VLAN identifier is transmitted. ,
Means for recognizing a VLAN identifier contained in an Ethernet frame from the Ethernet leased line network as an identifier of a logical interface;
Means for assigning a VLAN identifier in the Ethernet switching network to the logical interface;
The Ethernet exchange is characterized in that the Ethernet leased line network and the Ethernet exchange network can be connected by a network network interface system. When an Ethernet switching network in which an Ethernet frame identified by a VLAN identifier is exchanged is connected to an Ethernet leased line network in which the Ethernet frame identified by the VLAN identifier is transmitted, the Ethernet switching network serving as a connection point is controlled. A method,
Recognizing a VLAN identifier contained in an Ethernet frame from the Ethernet leased line network as an identifier of a logical interface;
Assigning a VLAN identifier in the Ethernet switched network to the logical interface;
A control method for an Ethernet switch, characterized in that it makes it possible to connect an Ethernet leased line network and an Ethernet switching network by a network / network interface system.

Images