JP3384288B2 - Information transfer method in storage type switching network. - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a storage device having a layer 2 processing unit for processing a layer 2 function and a layer 3 processing unit for processing a connectionless layer 3 function. TECHNICAL FIELD The present invention relates to an information transfer method in a storage-type switching network configured by connecting multiple type exchanges in multiple stages, and particularly to an information transfer method in a storage-type switching network capable of performing information transfer with high throughput and low delay. 2. Description of the Related Art Digital signal switching systems are broadly classified into circuit switching systems and store-and-switch systems, and the store-and-switch systems are further divided into packet-switching systems and message-switching systems. The system is a cell relay system (A
TM switch) and the frame relay method. 2. Description of the Related Art Conventionally, in a storage-type switching network including a storage-type switch having a connectionless layer 3 type function for correctly routing a packet from a source storage-type exchange to a destination storage-type exchange without setting a logical connection, ,
Packets are transferred hop-by-hop between storage switches. In this case, when the storage type exchange receives the packet, the storage type exchange analyzes the header of the packet in a functional block for processing the layer 3 function, and performs a process of transferring the packet to the next hop storage type exchange based on the result. . The layer 3 processing is usually performed by software. On the other hand, in an ATM-LAN environment, an ATM switch is internally provided as a router for processing an IP protocol, and packets are normally routed in the IP layer, which is Layer 3, but it is expected that the duration of the application is sufficiently long. In the case of such a packet, since a bypass path for bypassing the IP processing unit is established using an ATM switch, the packet is switched using VPI / VCI indicated in the cell header instead of routing at the IP level. Technology exists. The determination of the establishment of the bypass route is performed using information obtained from the port number indicating the upper application included in the header of the TCP corresponding to the layer 4. [0003] As described above, the layer 3 processing is performed by software in the conventional storage type exchange, and the bypass processing is used in the IP processing unit in the ATM-LAN environment. . However, layer 3 by software implemented in storage type exchanges
Since the processing is inferior in processing performance to the transfer processing performed by hardware, there is a possibility that the concentration of traffic causes a decrease in throughput and an increase in transfer delay, which may cause a bottleneck in the packet transfer processing. ATM-
The technology for bypassing the IP processing unit in a LAN environment is TC
Because it uses the property of TCP that can recognize the upper application in the P layer and the environment where the point-to-point layer 2 link is not set between the storage exchanges, It cannot be applied to a storage-type switching network composed of storage-type exchanges using other protocols. SUMMARY OF THE INVENTION An object of the present invention is to solve such a conventional problem and to provide an information transfer method in a storage type switching network capable of transferring information with high throughput and low delay independent of a protocol. [0004] In order to achieve the above object, an information transfer method in a storage type switching network according to the present invention comprises a storage type including a layer 2 processing unit, a layer 3 processing unit, and a switch therein. In the exchange, the layer 3 traffic passing through the exchange is constantly monitored for each combination of the preceding storage type exchange and the subsequent storage type exchange. The storage exchange (transit exchange) that has detected the traffic that satisfies the activation condition based on the layer 3 traffic performs a packet sweeping process, and thus temporarily suspends the transmission of the packet to the subsequent storage exchange to the preceding storage exchange. To instruct. After the end of the sweeping process, the relay exchange sets a path that bypasses the layer 2 processing unit and the layer 3 processing unit using the internal switch. Further, it instructs the upstream storage switch and the downstream storage switch to set a layer 2 link connecting the upstream storage switch and the downstream storage switch on the bypass path. In response to this, the upstream storage exchange sets up a layer 2 link with the downstream storage exchange, and thereafter sends packets destined for the downstream storage exchange to the bypass path, thereby forming a layer at the intermediate exchange. The transfer is performed by bypassing the 2 processing unit and the layer 3 processing unit. As a result, when there is a large amount of traffic to be transmitted, routing processing for each packet is not required, so that information transfer with high throughput and low delay can be performed. On the other hand, when the traffic is small and does not affect the layer 3 processing capability, the information transfer using the routing process for each packet is more efficient than the information transfer using the bypass route. Resources can be used effectively. When information is transferred on the bypass path, the switch constantly monitors the bypass traffic transferred on the bypass path set. If there is traffic that satisfies the release condition based on the traffic on the bypass path, the transit exchange instructs the upstream storage switch and the upstream storage switch that use the bypass path to release the layer 2 link on the bypass path. Upon receiving this, the upstream storage switch temporarily stops sending packets to the downstream storage switch, releases the layer 2 link set on the bypass path, and thereafter forwards packets addressed to the downstream storage switch to the relay switch. And is routed by the layer 3 processing unit of the transit exchange. This allows
When the traffic is small, it is possible to shift to the information transfer by the routing process for each packet, so that the line resources can be effectively used. Further, according to the information transfer method in the storage type exchange network of the present invention, the layer 3 passing through the storage type exchange is provided.
The traffic is constantly monitored for each combination of the upstream storage switch and the downstream storage switch. If there is traffic that satisfies the activation condition based on the layer 3 traffic, the packet destined for the downstream storage switch is directly stored in the downstream storage switch in the layer 2 processing unit that establishes the layer 2 link with the upstream storage switch. By transmitting the information to the layer 2 processing unit that has set up the layer 2 link with the type exchange, information transfer without using the layer 3 processing unit is performed. This allows
If there is a large amount of traffic to be transmitted, routing processing for each packet is not required, so that high-throughput and low-delay information transfer becomes possible. On the other hand, when information transfer bypassing the layer 3 processing unit is performed between the preceding level 2 processing unit and the subsequent layer 2 processing unit, the layer 3
The traffic that bypasses the processing unit is constantly monitored. When detecting traffic that satisfies the release condition based on the bypass traffic, the preceding layer 2 processing unit transfers the packet addressed to the subsequent storage type exchange to the layer 3 processing unit, and thereafter uses the layer 3 processing. Information transfer will be performed. This means that when traffic is light,
Since it is possible to shift to information transfer by a routing process for each packet, it is possible to effectively use line resources. Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a configuration diagram of a storage type exchange according to a first embodiment of the present invention. Here, an example is shown in which the information transfer method of the present invention is applied to a storage-type switching network constituted by connecting storage-type exchanges via ATM lines. 1 to 5, reference numerals 1 to 5 denote storage exchanges, reference numerals 2 and 3 denote storage exchanges that transmit packets to the storage exchange 1, reference numerals 4 and 5 denote storage exchanges that receive packets from the storage exchange 1, and reference numeral 6 denotes a storage exchange. 2 is an ATM line for transferring information from the storage type exchange 1 to the storage type exchange 1, 7 is an ATM line for transferring information from the storage type exchange 3 to the storage type exchange 1, and 8 is an ATM line from the storage type exchange 1 An ATM line 9 for transferring information in the direction of the exchange 4 and an ATM line 9 for transferring information in the direction from the storage type exchange 1 to the storage type exchange 5.
In FIG. 1, when the storage type exchange 2 and the storage type exchange 3 transfer information to the storage type exchange 4 or the storage type exchange 5 as a destination, packets are transferred via ATM lines 6 and 7, respectively. The storage type exchange 1 receiving the packet determines the destination from the packet header,
The packet is transferred to the storage type exchange 4 or the storage type exchange 5 via the M line 8 or the ATM line 9. Although not shown in the figure, layer 2 is an
U.T. Recommendation I. SSCOP (Se
rvice Specific Convergenc
e Protocol). FIG. 2 is a functional block diagram of the storage type exchange (transit exchange) shown in FIG. In FIG. 2, 11
Is an ATM switch, and 12 is a storage type exchange 2 in FIG.
1 and 3, an output line corresponding unit corresponding to the storage type exchanges 4 and 5 in FIG.
14 is a routing processing unit that performs layer 3 processing of all received packets, 15 is a traffic management unit that monitors traffic transferred by the storage type exchange 1, and 16 is an input on the ATM switch 11 based on the monitoring result of the traffic management unit. A switch control unit 17 for controlling the setting and release of a bypass path connecting the line corresponding unit 12 and the output line corresponding unit 13 is provided between stations for exchanging control information with the adjacent storage exchanges 2 to 5. It is a signal control unit. The input line handling unit 12 is provided with an ATM cell processing unit 12a for performing layer 1 processing and a link processing unit 12b for performing layer 2 SSCOP processing. The output line handling unit 13 has an ATM cell processing unit 13a for performing layer 1 processing.
And link processing unit 13 for performing SSCOP processing of layer 2
b. The traffic management unit 15 includes a layer 3 traffic management unit 15a for monitoring layer 3 traffic, and a bypass traffic management unit 15b for monitoring traffic transferred via a bypass route set using the ATM switch 11. Is provided. In FIG. 2, during execution of information transfer by routing processing in Layer 3, packets received by the input line handling unit 12 are transmitted to the ATM cell processing unit 12a and the link processing unit 12a.
b, the output line pair which reaches the routing processing unit 14 and is to be routed by the routing processing unit 14
After selecting the response unit 13, the data is passed through the link processing unit 13b and the ATM cell processing unit 13a and transferred to another storage type exchange (see the path indicated by the arrow A). During the execution of the information transfer on the bypass route, after passing through the ATM cell processing unit 12a,
The data is transferred to the output line handling unit 13 using the bypass route set on the ATM switch 11, and then transferred to another storage type exchange through the ATM cell processing unit 13a (see the path indicated by arrow B). FIG. 3 is an operation flowchart of a storage type exchange (transit exchange) for starting or canceling a bypass process, FIGS. 4 and 5 are operation flowcharts of a storage type exchange on the transmission side of a bypass path, and FIG. It is an operation | movement flowchart of the accumulation type exchange which becomes a receiving side of a path | route. In FIG. 3, the storage type exchange 1 normally has a layer 3
Since the packet transfer is performed by the routing process, the traffic transferred to the layer 3 is monitored for each route at this time, and it is always checked whether or not the monitored traffic satisfies the bypass process activation condition (step 110). If the traffic from the storage type exchange 2 to the storage type exchange 4 satisfies the condition for starting the bypass processing (step 120), the storage type exchange 1 performs the processing of sweeping out the packet addressed to the storage type exchange 4 to the storage type exchange 2. A request signal is transmitted (step 130). Next, it is confirmed that the processing of the packet transmitted from the storage type exchange 2 to the storage type exchange 1 for transfer to the storage type exchange 4 is completed (step 140). Selects a VPI / VCI to be used as a bypass path by the storage type exchange 2 and the storage type exchange 4 (step 150), and sets a bypass path on the ATM switch 11 using them (step 160). After setting the bypass path, a bypass processing start request indicating the VPI / VCI to be used is sent to the storage type exchange 2 and the storage type exchange 4 to complete the transition to the packet transfer using the bypass path. (Step 170). On the other hand, at the time of packet transfer using the bypass route, traffic transferred on the bypass route is monitored (step 1).
80) If the monitoring traffic satisfies the bypass processing release condition (step 190), a bypass processing release request is sent to the storage type exchange 2 and the storage type exchange 4 using the bypass route (step 20).
0). Upon receiving the bypass processing release notification from the storage type exchange 2 (step 210), the bypass path on the ATM switch 11 is released, and the flow shifts to packet transfer by layer 3 (step 220). The operation of the storage exchange 2 will be described with reference to FIGS. The storage exchange 2 sends a packet addressed to the storage exchange 4 to the storage exchange 1 (step 3).
10). When receiving the request signal of the packet sweeping process destined for the storage type exchange 4 from the storage type exchange 1 of the packet transmission destination (step 320), the storage type exchange 2 temporarily stops sending the packet addressed to the storage type exchange 4 (step 320). 330). Thereafter, when a bypass processing start request indicating a VPI / VCI to be used as a bypass route is received from the storage type exchange 1 (step 340), the designated VPI / VCI is made available (step 35).
0), SSC between the storage exchange 4 on the bypass path
In order to set the OP link, an SSCOP link setting request primitive (AA-setting-request) is transmitted (step 360). In response to this, the SSCOP link setting confirmation primitive (AA
-Setting-confirmation) (step 370),
The transmission of the packet to the storage switch 4 that has been temporarily stopped is restarted on the bypass path (step 380).
On the other hand, as shown in FIG. 5, when a bypass processing release request is received from the storage type exchange 1 at the time of packet transfer on the bypass path (step 390), the packet transmitted to the storage type exchange 4 transmitted through the bypass path is transmitted. Is temporarily stopped (step 400), and thereafter, the storage type exchange 4
A SSCOP link release request primitive (AA-release-request) is transmitted in order to release the SSCOP link set between (step 410). In response to this, if an SSCOP link release confirmation primitive (AA-release-confirmation) from the storage type exchange 4 is received (step 420), a packet for the storage type exchange 4 is transmitted to the storage type exchange 1 (step 420). Step 4
30). The operation of the storage exchange 4 will be described with reference to FIG. The storage exchange 4 receives the packet transmitted by the storage exchange 2 via the storage exchange 1 (step 510). Here, when a bypass processing start request indicating the VPI / VCI to be used on the bypass path is received from the storage type exchange 1 (step 520), first, the designated VPI / VCI is made usable (step 53).
0). SSCOP on the bypass route from the storage exchange 2
If the link setting instruction primitive (AA-setting-instruction) is received (step 540), the SS
The COP link setting response primitive (AA-setting-response) is transmitted (step 550), whereby the preparation for receiving the packet from the storage type exchange 2 via the bypass path is completed, and the packet is actually received (step 580).
On the other hand, when a bypass processing release request is received from the storage type exchange 1 while receiving a packet from the storage type exchange 2 via the bypass path (step 560), the SSCOP on the bypass path from the storage type exchange 2 is received. When the link release instruction primitive (AA-release-instruction) is received (step 570), the state transitions to a state in which a packet from the storage type exchange 2 is received via the storage type exchange 1 (step 510). As described above, in the present embodiment, the transition to packet transfer on the bypass route is performed based on the activation condition based on the traffic on the layer 3 and the release condition based on the traffic on the bypass route.
Since it is possible to shift to packet transfer by processing, high-throughput and low-delay information transfer independent of a protocol is possible. In the above description of the embodiment, the storage type exchanges are connected to each other by an ATM line, the internal switch is an ATM switch, the layer 2 used between the storage type exchanges is SSCOP, and the layer 2 processing is line compatible. Although performed by a processor, the present invention is not limited to this, and various changes can be made without departing from the gist. (Second Embodiment) FIG. 7 is a block diagram of a storage exchange according to a second embodiment of the present invention. The storage type exchange of FIG. 7 is the storage type exchange (transit exchange) shown in FIG.
1 is shown. In the figure, 21 is an ATM switch,
Reference numeral 22 denotes an input line corresponding unit corresponding to the storage type exchange 2 and storage type exchange 3 shown in FIG. 1, 23 denotes an output line corresponding unit corresponding to the storage type exchange 4 and storage type exchange 5 shown in FIG. A routing processing unit that performs layer 3 processing of all received packets; 25, a traffic management unit that monitors traffic transferred by the storage type exchange 1; 26, an input line corresponding unit 22 based on the monitoring result of the traffic management unit 25; A bypass layer 2 link management unit that controls setting and release of a bypass layer 2 link between the output line corresponding units 23. The input line corresponding unit 22 includes an ATM cell processing unit 22a that performs a layer 1 process,
And a link processing unit 22b for performing the SSCOP processing. In addition, the traffic management unit 25 includes a layer 3
Layer 3 traffic management unit 25 that monitors the traffic of
a, and a bypass traffic management unit 25b that monitors traffic transferred on the bypass layer 2 link. In FIG. 7, during execution of information transfer by routing processing in Layer 3, a packet received by the input line corresponding unit 22 passes through an ATM cell processing unit 22a and a link processing unit 22b and passes through a routing processing unit. 24, and the output processing unit 23 to be routed by the routing processing unit 24 is selected.
3b, the packet is transferred to another storage type exchange through the ATM cell processing unit 23a (see the route indicated by arrow A). During information transfer on the bypass layer 2 link, after passing through the ATM cell processing unit 22a and the link processing unit 22b in the input line corresponding unit 22, the output line is connected using the bypass layer 2 link. To the link processing unit 2
3b, the packet is transferred to another storage type exchange through the ATM cell processing unit 23a (see the route indicated by arrow C). The operation of the storage type exchange of FIG. 7 will be described with reference to the flow of FIG. Here, in FIG. 1, the operation when the layer 3 traffic from the storage type exchange 2 to the storage type exchange 4 satisfies the bypass processing start condition in the storage type exchange 1 and the traffic on the bypass layer 2 link is bypassed The operation of the storage exchange 1 when the processing cancellation condition is satisfied will be described. In FIG. 8, the storage type exchange 1 normally performs packet transfer by layer 3 routing processing. At this time, traffic for transferring layer 3 is monitored for each route, and the monitored traffic is bypassed. It is always checked whether or not the start condition is satisfied (step 610). When the traffic from the storage type exchange 2 to the storage type exchange 4 satisfies the bypass processing activation condition (step 620), the storage type exchange 1
Performs a packet sweeping process in the link processing unit 22b of the input line corresponding unit 22 (step 630). When the sweep processing of the link processing unit 22b is completed (step 64)
0), a bypass layer 2 link is set between the link processing unit 22b of the input line corresponding unit 22 and the link processing unit 23b of the output line corresponding unit 23 (Step 650). Thereafter, the input line corresponding unit 22 sends the packet from the storage type exchange 2 to the storage type exchange 4 to the bypass layer 2 link. On the other hand, at the time of packet transfer by the layer 2 link for bypass, the traffic to be transferred on the layer 2 link for bypass is monitored (step 660), and if the monitored traffic satisfies the bypass processing release condition, (Step 670) The packet processing is performed by the link processing unit 22b of the input line corresponding unit 22 (Step 680). When the sweep processing of the link processing unit 22b is completed (step 690), the layer 2 link for bypass is released (step 700). Thereafter, the input line corresponding unit 22 sends a packet from the storage type exchange 2 to the storage type exchange 4 to the routing processing unit 24. In the above-described embodiment, while the storage type exchanges are connected to each other by an ATM line, a plurality of layer 2 processing units exist inside the storage type exchange, and these are connected to the ATM.
Although the connection is made by a switch, the present invention is not limited to such an embodiment, and various changes can be made without departing from the scope of the invention. For example, in the second embodiment, the connection is made via the internal switch 21.
The internal switch 21 is not indispensable, and can be realized by, for example, a method using an internal bus. Also,
In the present invention, a three-stage storage type exchange network is described. Of the two transit exchanges when four or more stages are connected, in the first embodiment (see FIG. 2), both of the present invention are the present invention. Is required, and in the second embodiment (see FIG. 7), there is no problem whether only one of them is applied or both are applied. As described above, according to the present invention,
In a method independent of a specific protocol, information transfer by routing processing in Layer 3 is performed in accordance with an activation condition based on traffic in Layer 3, and Level 3 is performed in lower layers.
It is possible to shift to information transfer that bypasses processing, and to shift from information transfer that bypasses lower layers to information transfer by routing processing in layer 3 according to a release condition based on traffic that is bypassed in lower layers. As a result, there is an effect that information transfer with high throughput and low delay becomes possible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a storage-based switching network showing a first embodiment of the present invention. FIG. 2 is a functional block diagram of the storage type exchange (transit exchange) shown in FIG. FIG. 3 is an operation flowchart of the storage type exchange (relay exchange) shown in FIG. 1; FIG. 4 is a part of an operation flowchart of the originating storage type exchange shown in FIG. 1; FIG. 5 is another part of the operation flowchart of the originating storage type exchange. FIG. 6 is an operation flowchart of the destination storage type exchange shown in FIG. 1; FIG. 7 is a functional block diagram of a storage exchange (transit exchange) showing a second embodiment of the present invention. FIG. 8 is an operation flowchart of the storage exchange shown in FIG. 7; [Description of Signs] 1-5: Storage type exchange, 6-9: ATM line, 11: ATM switch in storage type exchange, 12: Input line corresponding part in storage type exchange, 12a: ATM in input line corresponding part A cell processing unit, 12b: a link processing unit in an input line corresponding unit, 13: an output line corresponding unit in a storage type exchange, 13a: an ATM cell processing unit in an output line corresponding unit, 13b: a link processing unit in an output line corresponding unit, Reference numeral 14: a routing processing unit in the storage type exchange 15: a traffic management unit in the storage type exchange 15a: a layer 3 traffic management unit in the traffic management unit 15b: a bypass traffic management unit in the traffic management unit 16: a storage type exchange , A switch control unit in the inside, 17 ... an inter-station signal control unit in the storage type exchange, 21 ... an ATM switch in the storage type exchange, 22 ... storage type exchange 22a: ATM cell processing unit in the input line corresponding unit, 22b: Link processing unit in the input line corresponding unit, 23: output line corresponding unit in the storage type exchange, 23a: output line corresponding unit ATM cell section, 23b ... link processing section in output line corresponding section, 24 ... routing processing section in storage type exchange, 25 ... traffic management section in storage type exchange, 25a ... layer 3 traffic management section in traffic management section, 25b ... Bypass traffic management section in the traffic management section, 26 ... Layer 2 link management section for bypass in the storage type exchange.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-9-172457 (JP, A) Kazuho Miki et al., IP Data Communication over Public ATM Networks, IEICE Technical Report SSE 97-54, 1997 July 25 (58) Field surveyed (Int.Cl. ⁷ , DB name) H04L 12/56

Claims (1)

(57) [Claim 1] A layer 1 processing unit for processing a layer 1 function for transferring information between adjacent storage type exchanges.
And a layer 2 processing unit for processing a layer 2 function, and a layer 3 for processing a connectionless layer 3 function for routing a packet from the originating storage exchange to the destination storage exchange without setting a logical connection. a processing unit, a contact Keru information transfer method configured storage type switching network accumulation type exchanger having an internal switch by multistage connection for connecting switching the input lines and output lines, the accumulation of first and second stages The relay exchange, which is a specific storage type exchange that relays the type exchange, is transmitted through the above-mentioned layer 1 to 3 processing units.
Layer 3 traffic to be relayed is constantly monitored for each combination of the upstream storage switch and the downstream storage switch, and the internal switch is switched to the layer 1 for traffic satisfying the activation condition based on the layer 3 traffic. place
Connected to processing section, on the internal switch, set the bypass <br/> path that bypasses the layer 2 processing section and the layer 3 processing section, the control signal to the pre-stage storage-type switch and the subsequent accumulation type exchanger When the storage switches of the preceding and subsequent stages receive the control signal, each of the layer 2 processing units performs the relay switching.
Transfer information via the bypass route set in the exchange
The layer 2 link and set between the pre-stage storage-type switch and the subsequent accumulation type exchanger, and later directed from the front storage-type switch to the subsequent storage-type exchange packets for performing the above
Via the bypass path of the transit exchange on the layer 2 link
Shifts into the form to be transferred, then the transit exchange has set upper fangs Ipa scan route is traffic to be transferred from the preceding stage storage-type switch on the bypass path to the subsequent storage-type switch constantly monitors for the release satisfy traffic based on traffic on the bypass path, sends a release request control signal to the pre-stage storage-type exchanger and subsequent accumulation type exchanger, upper Fang Ipa scan through Upon receiving the release request control signal, the upstream and downstream storage exchanges release the layer 2 link set on the bypass path. Wherein the packet destined for the type exchange is routed in the layer 3 processing unit of the transit exchange and transferred to the subsequent storage type exchange. Information transfer method in.