JP2003078538A - Information transferring function switching system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an information transferring function switching system for preventing the consumption of the large amounts of IP address resources while facilitating countermeasures to an information transferring system using a short packet in a layer 2 level and an information transferring system using an SNMP function in a high rank level. SOLUTION: In network equipment having a short packet information transferring system functioning in a layer 2 level, a disconnection switch 4 is arranged between an LAN SW and a control monitoring part 26, and an IP address setting part 3 is arranged. At the time of validating an information transferring system using an SNMP function as necessary, an IP address is acquired by the short packet information transfer, and the disconnection switch 4 is switched so as to be connected so that the SNMP function can be made available. Thus, it is not necessary to preliminarily assign the IP address, and it is possible to execute high level information transfer by using the SNMP function as necessary.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information transfer function switching system, and more particularly to a technology for switching a function of transferring information such as control or alarm in a network device (LAN switch or the like) forming a wide area LAN.

[0002]

2. Description of the Related Art In recent years, local networks (LAN)
Ethernet (registered trademark: FujiXero)
x) is heavily used. This network method called Ethernet is currently ISO OSI (Open Syste).
In consideration of the (ms Interconnection) reference model, IEEE802.
The standard is defined as 3.

The OSI reference model is a standard model of a network system proposed by ISO (International Organization for Standardization).
It is divided into two layers and the roles and functions of each layer are defined. These seven layers are the first layer “physical (physical) layer”, the second layer “data link layer”, the third layer “network layer”, the fourth layer “transport layer”, and the fifth layer “session layer”. , A sixth layer “presentation layer”, and a seventh layer “application layer”, and each has a mechanism for providing a service to an upper layer. For example, in the physical layer of the first layer, electrical / mechanical specifications of transmission methods such as serial / parallel or optical / electrical are defined, and in the data link layer of the second layer, subnets such as Ethernet and IEEE802. The protocol is specified. In addition, TCP / IP, which is a standard protocol of the Internet,
IP (internet protocol) corresponds to the network layer of the third layer, and TCP (Transmission Control Protocol) corresponds to the transport layer of the fourth layer.

In the Ethernet defined in the data link layer of the second layer, all information flowing on the Ethernet is put in a packet called an Ethernet frame. FIG. 4 is a diagram showing a configuration example of an Ethernet frame, in which a preamble (7 bytes) and a start delimiter: SFD (1 byte) are provided at the beginning and the end of the frame, respectively.
s) and a frame check sequence: FCS (4 bytes). The preamble is used by the receiver to find the beginning of the signal and trigger the clock recovery
The start delimiter (SFD) indicates that the data frame below this is a data frame (MAC layer). The frame check sequence (FCS) is also used to check the validity of the content of the data frame by the CRC code.
Then, at the beginning of the data frame, a MAC (Media Access Control) address representing a transmission destination (destination) and a transmission source is arranged in 6 bytes, for example, the transmission destination address is FF.
-FF-FF-FF-FF-FF, it represents a broadcast.

The MAC address is a physical address uniquely assigned to each communication interface device such as a network card. For example, the MAC address of Ethernet is 6 bytes long, the first 3 bytes is a vendor code, and the IEEE manages / assigns it for each company. ing. Because it is managed like this,
There is no Ethernet card having the same physical address in the world, and different MAC addresses are all assigned.

By the way, in Ethernet, frames are transmitted and received based on this MAC address.
There are several types of Ethernet frame switching methods for devices such as LAN switches that form a network. Above all, in the fragment free method and the store and forward method,
It has a function to detect short packets (frame length is 64 bytes or less). Short packets are not transferred because the probability of error packet occurrence is high. Therefore, the fragment-free method transfers data after confirming 64 bytes from the beginning of the frame, and the store-and-forward method transfers data after accumulating and confirming from the beginning to the end.

On the other hand, as a protocol used for data communication within a company or between companies, the above-mentioned IP has come to be widely used due to the use of the Web for core business and the introduction of groupware. In the past, when building a corporate network (intranet), a dedicated line or a frame relay network was used to uniquely configure the network. In recent years, however, a telecommunications business generally called a carrier IP network services provided by individuals have come to be used. When using this IP network service, the connection (access line) to the access point of the carrier network is a high-speed leased line (digital access), an ATM leased line, or an ATM leased line, depending on the transmission speed required by the user (company or the like). Although frame relays and the like have been common, carriers have begun to appear that provide a LAN direct collection service (also called a wide area LAN service) that directly accommodates Ethernet, which is a user's LAN interface, with an optical fiber.

FIG. 5 is a diagram showing a configuration example of a system (wide area LAN) based on a general LAN direct collection service. The LAN direct collection service shown in this figure shows a situation in which a plurality of user LANs are accommodated via an access line (LAN extension connection) by a single station facility. Here, an optical fiber is used as the access line. 30 is used. The media converter 20 is provided at both ends of the optical fiber 30.
a and 20b are provided. This media converter is
It has an optical signal / electrical signal mutual conversion function, and specifically refers to one that converts TX and FX in Ethernet. Although not shown, on the electric side of the home media converter (MC) 20a, a plurality of terminal devices are connected to the H side.
It connects to UB etc., and the HUB is the media converter 20.
It is connected to a.

On the other hand, the station equipment side has a plurality of electric / optical converters (E / O CONV) facing the media converter 20a, and a control unit (CONT) for integrally controlling these E / O CONVs. Owned media converter 20
b. CONT of the media converter 20b
A monitor control terminal 40 is connected to the. The media converter 20b is a layer 2 switch (L2SW).
50 and a layer 3 switch (L3SW) 60 to connect to the carrier network 70.

The wide area LAN thus configured has the following features. That is, the media converter 20a
Is an optical fiber 30 that converts an electric signal of 100BASE-TX into an optical signal and outputs it as 100BASE-FX.
Connect to. 100BESE-FX uses single mode or multimode optical fiber cable,
It is used to enable long-distance connection that is impossible with TP (Unshielded Twist Pair) cables. For example, if the above-mentioned single mode optical fiber is used, it is possible to extend the communication distance to about 20 to 40 km in full duplex mode connection. On the other hand, the multimode optical fiber is an optical fiber cable that is cheaper than the single mode, and can connect up to about 400 m in the half-duplex mode and up to about 2 km in the full-duplex mode. In addition, since optical fiber cables are not easily affected by electromagnetic noise, in addition to being used for long-distance connections, optical fibers can be used to prevent the effects of noise in places where much noise is generated, such as in factories and research facilities. May be used.

The optical signal (100BASE-FX) arriving via the long-distance optical fiber 30 is re-generated by the media converter 20b on the side of the station equipment as an electric signal (100BAS).
It is converted to E-TX) and is sent to the carrier network 70 via the layer 2 switch 50 and the layer 3 switch 60.

Next, a configuration example of the media converter will be described with reference to FIG. The home-side media converter 20a shown in FIG. 6 includes an optical module 21, a physical layer device 22, a media conversion circuit 23, and a physical layer device 24.
And the transformers 25 are connected in tandem, and a control monitor 26 is connected to the media conversion circuit 23. The optical module 21 performs optical / electrical conversion, the physical layer devices 22 and 24 perform waveform shaping or code conversion and code rule conversion according to the transmission medium, and the media conversion circuit 23 performs the physical layer device 22.
In the communication performed between No. 24 and No. 24, the timing of the clock and the data are matched. The control monitoring unit 26
It is responsible for monitoring packets and transferring in-apparatus information, and is specifically composed of a CPU and firmware (F / W). In addition, the functional part which handles a layer 2 interface including a physical layer device is generally called a LAN SW.

Next, two information transfer functions used in the above-mentioned wide area LAN will be described. FIG. 7 shows TCP /
It is a figure which shows the example of an information transfer structure at the time of using the SNMP function in IP, and FIG. 8 is a figure which shows an example of the information transfer structure using a short packet. First, the example shown in FIG.
The figure shows a scene where monitoring and control are performed by NMP (Simple Network Management Protocol). The media converter 20a on the home side is used as an SNMP agent, and the management server 80 arranged in the central office connected to the carrier network 70 is used as an SNMP manager. . In addition,
The SNMP agent refers to the device on the control target side, whereas the SNMP manager is
Refers to the equipment on the management side. The SNMP agent has a management information database called MIB (Management Information Base) information, and the SNMP manager performs management by monitoring and controlling this MIB. Since SNMP is a protocol based on IP, it is necessary to use the SMNP manager and SN.
It is necessary to give an IP address to the MP agent. As described above, by using the information transfer by the SNMP function, it is possible to perform detailed management at the TCP / IP level.

By the way, the current mainstream IP address is IPv6.
4, which has a 32-bit address space,
There is a concern that exhaustion will occur due to the rapid increase in IP-related equipment. Therefore, depending on the carrier providing the wide area LAN service, simple information transfer as shown in FIG. 8 below is performed to manage the IP address without allocating it to the network device. The example shown in FIG. 8 is a configuration example in which information is transferred using short packets, and information is transferred between the home-side media converter 20a and the supervisory control terminal 40 of the office-side media converter 20b. Be seen. That is, the LAN SW (included in CONT in the station side media converter 20b) in each media converter has a function of detecting a short packet, intentionally creating a short packet and managing it. It carries the information and transfers it. Therefore, the short packet is always started only between the media converters arranged opposite to each other, and does not leak to the network or the like beyond the media converter.
In this way, since the transfer is performed based on the MAC address in the layer 2 level interface, it is not necessary to allocate the IP address.

[0015]

However, the above-mentioned two conventional information transfer methods have the following problems. In other words, in the information transfer method using the SNMP function, while advanced information transfer can be performed, IP addresses must be assigned to all target network devices. On the other hand, the information transfer method using short packets does not need to allocate an IP address, but can only perform simple information transfer. Furthermore, since it is necessary to determine in advance which information transfer method is to be supported and to incorporate the firmware (F / W) into the CPU part of the network device, pre-setting for the network device is also complicated.

The present invention has been made to solve such a problem, and is an information transfer method using a short packet at a layer 2 level and an information transfer method using an SNMP function at a higher level. It is an object of the present invention to provide an information transfer function switching method that is compatible with both of the above and does not consume a large amount of IP address resources.

[0017]

In order to solve the above problems, the invention according to claim 1 of the information transfer function switching system according to the present invention has a LAN SW for transferring a packet of a layer 2 interface, In addition, in a network device corresponding to the information transfer method that functions at the layer 2 level, it is provided between the control monitoring unit for performing information management based on a predetermined upper protocol, and the LAN SW and the control monitoring unit. A disconnection switch and an IP address setting unit that manages the setting of the IP address supplied by the information transfer method functioning at the layer 2 level are provided. If the information transfer method that works is enabled and the disconnection switch is opened, the information transfer method that works at the upper layer level is disabled. Characterized in that it functions as.

According to the invention of claim 2 of the information transfer function switching system of the present invention, in the information transfer function switching system of claim 1, the network device is a home-side media converter in a wide area LAN. It is characterized by

According to the invention of claim 3 of the information transfer function switching system of the present invention, in the information transfer function switching system of claim 1 or 2, the information transfer system functioning at the layer 2 level is: An information transfer method using short packets, and an information transfer method that functions at a higher layer level is an information transfer method using an SNMP function.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below based on the illustrated embodiments. FIG. 1 is a functional block diagram showing a configuration example when the information transfer system according to the present invention is applied to a media converter (home side). It should be noted that the same functional blocks as those of the media converter shown as the conventional example in FIG. 6 described above are denoted by the same reference numerals and the description thereof will be omitted.

The media converter 1 shown in this figure is provided with a LAN SW having a short packet communication unit 2 between the physical layer device 22 and the media conversion circuit 23, and further, based on the output from the short packet communication unit 2. IP address setting unit 3 for setting an IP address in control and monitoring unit 26, media conversion circuit 23 and control and monitoring unit 26
The connection / disconnection of the MII interface between and is connected to and disconnected from the short packet communication unit 2 based on a switching control signal. In addition, MI
I is the carrier-sensitive multiple access / collision detection (CSMA / CD) standard 80, which most of Ethernet conforms to.
Media independent interface (MI
I) An interface defined by the standard.

The operation of the media converter 1 shown in this example will be described with reference to FIGS. 2 and 3 below. Figure 2 shows the SNM
FIG. 4 is a sequence diagram showing an example of a procedure when the P function is valid, and FIG. 3 is a sequence diagram showing an example of a procedure when the SNMP function is invalid.

First, in FIG. 2, the disconnection switch of the home-side media converter is initially in the "open" state (disconnected), and a short packet is sent between the home-side media converter and the office-side media converter. It is assumed that information is being transferred. It should be noted that the short packet information transfer is always performed even in the case where "SNMP information transfer is effective", which will be described later. In addition, in the station side media converter, DHCP (Dynamic Host Configuration Protocol) is used.
A function for dynamically assigning an IP address is provided by using, for example, and each of the station-side media converters has some assignable IP addresses (in this case, a private IP address) (at least 1). Prepare) That is, this IP address can be shared by a plurality of home-side media converters.

First, in the media converter on the station side, it is judged whether or not the SNMP function is used.
P1>, if used (Yes), a “start packet” is transmitted to the home-side media converter by a short packet. Here, as the determination when using the SNMP function, for example, one of a plurality of home-side media converters connected to the station-side media converter is
If the frequency of alarm information indicating a failure is high due to constant short packet information transfer, the carrier side that maintains and operates the wide area LAN service should identify the cause of the failure in order to identify the cause of the failure. It is assumed that the side media converter temporarily performs advanced information transfer by the SNMP function to collect detailed information.

On the other hand, the "start packet" is received by the short packet communication unit 2 of the home-side media converter, the short packet communication unit 2 starts the connection switching sequence based on this, and the "start response" is sent to the station side media converter. A "packet" is transmitted <STEP2>. As a result, the home-side media converter is prepared to operate according to the procedure based on the predetermined connection switching sequence. Next, the station side media converter selects one of the IP addresses prepared in advance based on the reception of the "startup response packet" and transmits it to the home side media converter as an "IP address packet". The assigned IP address is registered in association with the assigned home-side media converter <STEP 3>.

Upon receiving the "IP address packet", the short packet communication unit 2 of the home-side media converter outputs it to the IP address setting unit 3, and the IP address setting unit 3 sends the IP address to the control monitoring unit 26. Set. At the same time, the short packet communication unit 2 transmits an "address setting completion packet" to the station side media converter <STEP4>. After receiving the "address setting completion packet", the station side media converter transmits a "switch (close) control packet" to the home side media converter to close the disconnection switch <STEP5.
>.

Upon receiving the "switch (close) control packet", the home-side media converter closes the disconnection switch 4 based on the switching control signal from the short packet communication unit 2 and also causes the station-side media converter to "switch complete packet". Is transmitted <STEP6>. This becomes a home-side media converter that has an IP address,
It can be treated as an NMP agent.

When the above procedure is performed, the state in which the information transfer by the SNMP function becomes possible is completed, and the supervisory control terminal 40 of the station side media converter or the management server of the central station which is a higher management station is used as the SNMP manager. And S
Performs advanced information transfer using the NMP function. In this way, by collecting more detailed information, it becomes possible to remotely pursue the cause of the failure. Even in this case, the short packet information is transferred between the home-side media converter and the office-side media converter.

Next, a procedure for invalidating the SNMP function of FIG. 3 will be described. For example, when the pursuit of the cause of the failure of the home-side media converter using the SNMP information transfer is completed, the SMNP manager sends the home-side media converter to the station-side media converter that accommodates the home-side media converter.
You will receive a notification that the SNMP function will be terminated. When the notification is received, the media converter on the station side receives S when judging whether or not the SNMP function is not used <STEP7>.
It is determined that the NMP function is not used (Yes), and the "start packet" is transmitted to the home media converter by the short packet information transfer.

When this "start packet" is received by the short packet communication unit 2 of the home-side media converter, the short packet communication unit 2 starts the disconnection switching sequence and at the same time sends the "start response packet" to the station side media converter. Send <STEP8>. After receiving the "start response packet", the station side media converter transmits a "switch (open) control packet" to open the disconnection switch to the home side media converter <STEP9>.

Upon receiving the "switch (open) control packet", the short packet communication unit 2 of the home-side media converter outputs a switching control signal to the disconnecting switch 4 to open the switch, thereby disconnecting. When the switch 4 opens the switch, the control monitoring unit 26 is switched to the media conversion circuit 23.
At the same time, the short packet communication unit 2 transmits a "switching completion packet" to the station side media converter <STEP10>. From this time, information transfer by the SNMP function cannot be performed. The IP address setting unit 3 of the home-side media converter resets (erases) the IP address set in the control monitoring unit 26 after the disconnection switch 4 is turned off <STEP 11>.

On the other hand, the station-side media converter deletes the registered assigned IP address based on the reception of the "switching completion packet" and returns the IP address to the assignable state <STEP12>. After completing the above procedure, SN
When the information transfer by the MP function is completed, the station side media converter notifies the SNMP manager of the completion.

As described above, the information transfer function switching method according to the present invention can always transfer information using short packets and, if necessary, transfer information using the SNMP function. According to this, it is not necessary to assign a fixed IP address to all the home-side media converters, and if a small number of IP addresses are given to the station-side media converter, the target to be assigned will be different in time. Since it is shared by a plurality of home-side media converters, it is possible to prevent a large amount of IP addresses from being consumed. Note that a fixed IP address can be assigned later to each home-side media converter by the above short packet information transfer by the next IPv6, and in that case, information transfer using the SNMP function is always performed. You can also respond to do it. In addition, the firmware (F
/ W) is equipped with a device compatible with both the information transfer method using the SNMP function and the information transfer method using the short packet, and the initial value may be set to the unused information transfer method using the SNMP function. , The presetting will be extremely simple.

In the embodiment of the present invention described above, a media converter is shown as an example of a network device to which the present invention is applied, but the present invention is not limited to this example, and a LAN SW function is provided. It can also be applied to a switching HUB, a router, and the like that it has.

[0035]

As described above, the information transfer function switching method according to the present invention can be applied to a network device equipped with a short packet information transfer method that operates at the layer 2 level.
An SNMP switch is provided between the LANSW and the control and monitoring unit, and an IP address setting unit is provided to configure the SNMP.
When the information transfer method by the function is made effective as needed, the IP address is acquired by the short packet information transfer, and the connection is switched by connecting the disconnection switch.
Since it operates to enable the NMP function, IP
It is not necessary to allocate an address in advance, and advanced information transfer by the SNMP function can be performed if necessary. Further, since the firmware (F / W) corresponding to both information transfer methods may be incorporated in the CPU part of the network device, the pre-setting for the network device becomes extremely easy.

[Brief description of drawings]

FIG. 1 is a functional block diagram showing a configuration example of a media converter using an information transfer function switching system according to the present invention.

FIG. 2 shows an information transfer function switching system according to the present invention,
It is a sequence diagram which shows the example of a procedure at the time of enabling an SNMP function.

FIG. 3 shows an information transfer function switching system according to the present invention,
It is a sequence diagram which shows the example of a procedure at the time of invalidating an SNMP function.

FIG. 4 is a diagram for explaining an Ethernet frame structure and a switching method for transferring the same.

FIG. 5 is a diagram showing a configuration example of a general LAN direct collection service (wide area LAN).

FIG. 6 is a functional block diagram showing a configuration example of a conventional media converter.

FIG. 7 is a diagram showing a configuration example of information transfer by an SNMP function in a wide area LAN system.

FIG. 8 is a diagram showing a configuration example of information transfer using short packets in a wide area LAN system.

[Explanation of symbols]

1 ... Media converter 2 ... Short packet communication unit 3 ... IP address setting section 4 ... Disconnection switch 20a ... Home side media converter 20b ... Station side media converter 21 ... Optical module 22 ... Physical layer device 23 ... Media conversion circuit 24 ... Physical layer device 25 ... Transformer 26 ... Control monitoring unit 30 ... Optical fiber (access line) 40 ... Supervisory control terminal 50 ... Layer 2 switch (L2SW) 60: Layer 3 switch (L3SW) 70 ... Carrier network 80 ... Management server

Claims (3)

[Claims] 1. A network device having a LAN SW for transferring a packet of a layer 2 interface and supporting an information transfer method that functions at the layer 2 level, manages information based on a predetermined upper protocol. Control and monitoring unit, a disconnecting switch provided between the LAN SW and the control and monitoring unit, and IP address setting for performing setting management of the IP address supplied by the information transfer method functioning at the layer 2 level. An information transfer method that functions at an upper layer level when the disconnection switch is closed, and an information transfer method that functions at an upper layer level when the disconnection switch is opened. An information transfer function switching method characterized by functioning to invalidate. 2. The information transfer function switching system according to claim 1, wherein the network device is a home-side media converter in a wide area LAN. 3. The information transfer method that functions at the layer 2 level is an information transfer method that uses short packets, and the information transfer method that functions at a higher layer level is S.
3. The information transfer function switching method according to claim 1 or 2, which is an information transfer method using an NMP function.