JP2002247067A - Band controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a band controller capable of dynamically controlling band allocation of a network according to quality and quantity of a flowing frame. SOLUTION: The band controller 200 is provided with an interface 104 to be connected to a local area network and a function to monitor the frame flowing in the network, to check a UDP port number to be used by an RTP session by analyzing an ITU-T recommendation logical channel opening frame when the frame is received, to request a repeater 204 to secure a band to the frame the transport layer protocol of which is UDP and the port number of which is the UDP port number and to request the repeater 204 to release the secured band when an H.245 logical channel conclusion frame is received.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION Claim 1 of the present invention relates to RTP
Reserve the bandwidth required for the session at the start of the session,
The present invention relates to a band control device that controls a relay device to be released at the end of a session.

A second aspect of the present invention is the same as the first aspect, except that the RT that transfers the sound rather than the RTP frame that transfers the moving image.
The present invention relates to a band control device that controls a relay device to relay a P frame preferentially.

[0003] Claim 3 of the present invention, in addition to Claim 1 or 2, provides a relay apparatus for relaying an RTP frame having a longer delay time preferentially over an RTP frame having a shorter delay time for frame transmission. The present invention relates to a band control device to be controlled.

A fourth aspect of the present invention relates to a band control device for controlling a relay device so as to secure a band corresponding to a traffic amount of each protocol of an IP frame flowing through a network.

[0005] Claim 5 of the present invention relates to a bandwidth control device for controlling a relay device so as to secure a bandwidth corresponding to a traffic amount for each ToS field of an IP header of an IP frame flowing in a network.

[0006]

2. Description of the Related Art In recent years, private networks (intranets) using Internet technology have been constructed at many companies and universities, and are used for various information exchanges such as mails and bulletin boards. Furthermore, in recent years, in addition to data communication as described above, cases in which an in-house telephone or a TV conference system that needs to transfer voices and moving images in real time using an intranet are gradually increasing. RTP is used for real-time transfer of audio and moving images over an IP network.

[0007] As various types of information communication such as voice and moving images are mixed on an IP network, a technology for guaranteeing the communication quality QoS of the network becomes important. In particular, in voice and video communications, frame relay delay, jitter, and frame discards caused by network congestion and the like cause sound interruption and deterioration of sound quality and image quality.

[0008] In recent years, many techniques have been studied for guaranteeing communication quality in an IP network, and a function of assigning priorities to communication types and relaying frames according to their priorities, and a function for ascertaining a specific communication. Relay devices (routers, switching hubs, etc.) having a function of guaranteeing a certain minimum bandwidth have been commercialized.

As a condition for determining a communication type, a port number indicating an upper layer protocol of a transport layer or a ToS field of an IP header is often used. ToS
The field is an 8-bit field provided in the IP header, and specifies a priority, a processing method, and the like. In order to use this ToS field to set more detailed communication quality, a method (Diff-Serv) in which the usage of the ToS field is redefined has been studied, and compatible products have already been marketed.

Here, the terms used in this specification will be briefly described.

ITU-T (International Telecommunication)
tion Union, Telecommunication Standardization Secto
r): International Telecommunication Union Telecommunication Standardization Sector ITU-T Recommendation H. 245: A control protocol for multimedia communication in the H series (recommendation on non-telephone signal transmission lines) of the ITU-T recommendation. H.323: LAN terminal that communicates audio and video among H series of ITU-T recommendation. 225: One of H series of ITU-T recommendation RFC (Request for Comments): Standard recommendation document by Internet Architecture Committee RTP (Realtime Transport Protocol): RFC188
Protocols for real-time data transmission of audio and video defined in 9 and 1890 UDP (User Datagram Protocol): Transport layer protocol defined in RFC768 PT (Payload Type): Identifies the type of payload (information section) IP (Internet Protocol): RFC791 (RFC76
Protocol for establishing a communication path between computers defined in 0) ICMP (Internet Control Message Protocol): RFC
Protocol for error control specified in 792 ToS (Type of Service): Type of service, RFC
Defined in 1349 QoS (Quality of Service): Quality of service provided by network Diff-Serv (Differentiated Services): RF
Stipulated in C2474 SNMP (Simple Network Management Protocol): Simplified network management protocol, specified in RFC1157 TCP (Transmission Control Protocol): RFC79
Transport layer protocol defined in 3 These terms are all described in publicly known documents, and a detailed description thereof will be omitted in this specification.

[0012]

First, the problem to be solved by claim 1 will be described. The port number used in the RTP session for transferring audio and video is
In the case of an IP telephone or a TV conference, ITU-T Recommendation H. 2
Since it is dynamically determined by negotiation between the sender and the receiver according to the 45 protocol, it is difficult to set the RTP communication quality in the relay device in advance. A method of setting a terminal that uses RTP, such as an IP telephone or a TV conference terminal, to use a specific port number can be considered. Also, a method of fixing the IP address of the terminal and setting the communication quality for the IP address can be considered.
Each time a terminal is added or the IP address is changed, the router settings must be changed. In addition, the method of setting manually by a human as described above is not only time-consuming, but also may cause a setting error. Also, if the terminal using the RTP has a function of designating the priority in the ToS field, the relay device can perform band guarantee and priority control based on the ToS field. Applications are still few.

Next, the problem to be solved by claim 2 will be described. As described above, it is important to ensure real-time performance in the transfer of audio and moving images, but in particular, audio has a greater influence on communication quality than moving images. The video is
Even if the communication quality is slightly reduced, the frame rate is reduced and the image quality is reduced, but in the case of voice, conversation may not be established. In addition, since a moving image has a much larger amount of information than a sound, a sufficient band of sound can be secured by slightly lowering the priority of the moving image. Therefore, when the network is congested, it is desirable to process audio frames with priority over moving images. However, since the router or the switching hub does not analyze whether the data content of the relayed RTP frame is audio or video, it is difficult to distinguish between voice and video.

Next, the problem to be solved by claim 3 will be described. It is important to reduce the delay time in the transfer of audio and video, and in the case of audio, the allowable delay time is said to be 150 milliseconds to 200 seconds.
When communicating with a terminal that is geographically distant, the transmission time of a frame becomes longer, so that the delay time becomes longer than when communicating with a nearby terminal. That is, the delay time varies depending on the distance to the communication partner. Therefore, RT between short-range terminals having a small delay time
RT between long distance terminals having a longer delay time than P frame
It is desirable to preferentially process P frames to reduce the difference in delay time due to distance. However, since the router or the switching hub does not analyze the time from the source terminal to the destination terminal of the frame to be relayed, they cannot be distinguished.

Next, a problem to be solved by claim 4 will be described. In a network in which a plurality of types of communications coexist, it is necessary to distribute the limited transmission capacity fairly to some extent. However, when only the priority control is performed, there is a possibility that only a frame having a high priority uses up all the bandwidth of the network. For example, voice should generally have higher priority than other data,
It is necessary to guarantee a minimum bandwidth for file transfer.
In order to set the minimum guaranteed bandwidth, it is necessary to grasp the normal traffic amount (maximum value, average value) of the file transfer, and the effect becomes small if the setting is far from normal. For example, it is assumed that the average traffic volume of file transfer uses 5% of the entire network bandwidth. In this case, if the minimum guaranteed bandwidth of the file transfer is set to 3% of the entire bandwidth of the network, the communication quality of the file transfer is slightly lower than usual, but not significantly deteriorated even in the case of congestion. On the other hand, if the minimum guaranteed bandwidth for file transfer is set to 1% of the entire bandwidth of the network, the communication quality of file transfer becomes significantly worse than usual during congestion. vice versa,
If the minimum guaranteed bandwidth of the file transfer is set to 30% of the entire bandwidth of the network, the communication quality of the file transfer is guaranteed even at the time of congestion, but the communication quality of voice may be deteriorated. However, the traffic volume for each protocol is not always constant and changes every day, and it takes time and effort for an administrator to manually change the settings of routers and switching hubs periodically.

Next, the problem to be solved by claim 5 will be described. Similarly to the problem to be solved by claim 4, when priority control is performed in accordance with the value of the ToS field, there is a possibility that only high-priority frames may use up the entire bandwidth of the network. It is necessary to guarantee the minimum bandwidth for.
In order to set the minimum guaranteed bandwidth, it is necessary to grasp the normal traffic volume for each priority in the ToS field. However, the traffic volume for each priority in the ToS field is not always constant and changes every day, and it takes time and effort for the administrator to manually change the settings of the router and the switching hub periodically.

It is an object of the present invention to solve the above-mentioned problems and to provide a bandwidth control device capable of dynamically controlling the bandwidth allocation of a network according to the quality and quantity of flowing frames.

[0018]

In order to achieve the above object, the invention according to claim 1 has an interface for connecting to a local area network, monitors frames flowing through the network, and establishes an ITU-T recommended logical channel. When a frame is received, the frame is analyzed to check a UDP port number used by the RTP session, and a bandwidth is reserved for a frame whose transport layer protocol is UDP and whose port number is the UDP port number. Makes a request to the relay device, 24
When a five logical channel termination frame is received, a function is provided for requesting the relay device to release the reserved band.

Further, according to the invention of claim 2, in addition to claim 1, when an RTP frame is received, the RTP frame is analyzed to check a UDP port number,
It checks whether the type of data transferred by the RTP session is audio or video from the value of the PT field of the header, and preferentially relays the RTP frame that transfers audio over the RTP frame that transfers video. In order to make a request to the relay device.

According to a third aspect of the present invention, in addition to the first or second aspect, when an RTP frame is received, an ICMP echo request frame is transmitted to a source IP address and a destination IP address of the frame. Receiving the response frame, calculating the delay time required for frame transmission from the source terminal to the destination terminal from the round trip time, and giving priority to an RTP frame having a longer delay time than an RTP frame having a shorter delay time. And a function to make a request to the relay device to relay to the relay device.

The invention according to claim 4 has an interface for connecting to a local area network, receives all IP frames flowing through the network, and determines the traffic volume for each transport layer protocol and transport layer port number. It has a function of measuring and requesting the relay device to secure a band according to the measured traffic amount.

According to a fifth aspect of the present invention, in addition to the fourth aspect, instead of the transport layer protocol and the transport layer port number, the traffic volume of each ToS field of the IP header is measured, and the measured traffic volume is measured. And a function to make a request to the relay device to secure a band corresponding to the bandwidth.

[0023]

An embodiment of the present invention will be described below in detail with reference to the accompanying drawings.

As shown in FIG. 1, a bandwidth control device 100 according to the present invention includes a CPU 101, a volatile memory 10
2, nonvolatile memory 103, MAC control LSI 104,
It is composed of a port 105 connected to a network. The non-volatile memory 103 stores the program according to the present invention and network configuration information (IP address, various setting information, etc.). The program is CPU 101
To be executed.

FIG. 2 shows a network using the band control device 100 according to the present invention. In FIG. 2, reference numerals 200 and 201 denote band control devices according to the present invention, and 202 and 20.
3 is an Ethernet (registered trademark) LAN (Local Area Net)
work local communication network), 204 and 205 are routers, 20
6 to 209 are terminals such as personal computers, 210 to 202 are business phones, and 213 is a PBX (Private Branch eXcha).
nge private branch exchange), 214 is VoIV (Voice over Int)
215 is an IP telephone, 216 is the Internet or a dedicated line.

ITU-T Recommendation H.2, which is currently most widely used as a protocol for IP telephones and TV conferences, is described. The outline of the communication procedure of H.323 is shown below (see FIG. 3). 300 in FIG.
And 301 are H.264 such as IP phones. 323 terminals. (1) First, ITU-T Recommendation H. 225 TCP connection is established (302). (2) If the calling terminal 300 is H.264. 225 setup
(Setup) A message is transmitted (303). (3) When the called terminal 301 is in the H.264 mode. 225 Connect
nect) Send a message (304). (4) ITU-T Recommendation H. A TCP connection of H.245 is established (305). (5) If the calling terminal 300 is H.264. An open logical channel (Open Logical Channel) message of H.245 is transmitted (306). This message contains the UDP port number used in the next RTP session. (6) If the called terminal 301 is H. 245 open logical channel Ack message is transmitted (30
7). This message contains the UDP port number used in the next RTP session. (7) The calling terminal 300 and the called terminal 301 mutually transmit RTP frames including voice and video (30).
8 and 309). (8) When ending the session, one of the terminals is 245 Close Logic Channel
al Channel) message is transmitted (310). (9) The other terminal is H. Then, a close logical channel Ack message of H.245 is transmitted (311). (10) H. The RTP connection of H.245 is disconnected (312). (11) H. A release message of 225 is transmitted (313). (12) H. 225 Release Complete (Release C
omplete) message is sent (314). (13) H. The TCP connection of H.225 is disconnected (315).

An embodiment of the present invention will be described with reference to FIG.

The bandwidth control device 200 monitors all frames flowing through the LAN 202 connected to the Ethernet port. When the H.245 open logical channel message or the open logical channel Ack message is received, the frame is analyzed to extract the source IP address, the destination IP address, the UDP port number used by the RTP session, and store the combination in the memory. Register in the above management table. Thereafter, when the bandwidth control device 200 receives the UDP frame,
The source IP address, destination IP address,
A UDP port number is extracted, and it is checked whether or not a combination matching these exists in the management table on the memory. If the combination does not exist, no processing is performed. If the combination exists, the router 2
04, source IP address, destination IP address, UD
A request is made to secure a certain bandwidth for a frame whose P port number matches the above combination. The protocol used for the request to the relay device (router 204) is SN
It may be MP or another protocol. Thereby, the band of the RTP session is secured.

After that, the bandwidth control device 200 24
When the closed logical channel message or the closed logical channel Ack message of No. 5 is received, the frame is analyzed to extract the source IP address, the destination IP address, and the UDP port number used by the RTP session. Check if it exists in the management table. If the combination does not exist, no processing is performed. If the combination exists, delete the combination from the management table,
It requests the router 204 to release the bandwidth reserved for the frame whose source IP address, destination IP address, and UDP port number match the above combination. As a result, it is possible to prevent the bandwidth of the RTP session that has already been completed from being continuously wasted.

Next, a second embodiment of the present invention will be described.

When the band control device 200 receives the RTP frame, it analyzes the frame, extracts the source IP address and the destination UDP port, and transfers the RTP session based on the value of the PT field of the RTP header. It is checked whether the type of data to be performed is audio or moving image. If the video is a moving image, the router 204 is requested to change the priority of a frame whose source IP address, destination IP address, and UDP port number match the combination registered in the management table to a lower priority. I do. In the case of voice, the source I
A request is made to change the priority of a frame whose P address, destination IP address, and UDP port number match the combination registered in the management table to a higher priority. As a result, the priority of the RTP frame for transmitting the audio can be higher than the priority of the RTP frame for transmitting the moving image.

Next, a third embodiment will be described.

When receiving the RTP frame, the bandwidth control device 200 analyzes the frame and extracts a source IP address, a destination IP address, and a UDP port number. Next, the band control device 200 sends the ICM to the source terminal.
The P echo request frame is transmitted, and the transmission time is recorded in the memory. When the ICMP echo response frame is received from the source terminal, the round trip time is calculated from the difference between the reception time and the transmission time. A similar process is performed on the destination terminal. After checking the round trip time between the source and the destination, the sum of the two round trip times is defined as the round trip time from the source terminal to the destination terminal. This time is approximately equal to twice the frame relay delay time from the source terminal to the destination terminal. When the calculated delay time is small, the priority of the frame whose source IP address, destination IP address, and UDP port number match the combination of the frames registered in the management table is given to the router 204. Request a lower setting change. If the calculated delay time is large, the priority of the frame whose source IP address, destination IP address, and UDP port number match the combination of the frames registered in the management table is given to the router 204. Request a higher setting change. As a result, the priority of an RTP frame between terminals having a long delay time can be made higher than that of an RTP frame between terminals having a short delay time.

Next, a fourth embodiment will be described.

The bandwidth control device 200 monitors all frames flowing through the LAN 202 connected to the Ethernet port, measures the traffic volume for each transport layer protocol and transport layer port number, and stores the statistical information in a memory. To record. Band control device 200
Periodically updates the statistical information recorded in the memory and requests the router 204 to allocate a bandwidth proportional to the traffic amount to each protocol. As a result, it is possible to secure a large amount of bandwidth for a protocol with a small amount of traffic and avoid wasting the transfer capacity of the relay device, to maximize the transfer capacity, and to make it suitable for each protocol even during congestion. Bandwidth can be allocated, and it is possible to avoid that only the communication quality of a specific protocol is significantly degraded.

Next, a fifth embodiment will be described. The bandwidth control device 200 measures the traffic volume for each ToS field of the IP header, and records the statistical information on the memory. The bandwidth control device 200 periodically updates the statistical information recorded on the memory,
A request is made to allocate a band proportional to the traffic amount to each ToS. As a result, a bandwidth corresponding to the traffic amount for each ToS field is secured, so that an appropriate bandwidth is allocated to each ToS even during congestion, and a specific ToS
It is possible to avoid that only the communication quality of S significantly deteriorates.

According to the present invention, as described in the above embodiment, the processing of bandwidth monitoring and bandwidth control may be implemented in a relay device such as a router or a switching hub.

[0038]

The present invention exhibits the following excellent effects.

(1) According to the configuration of claim 1, it becomes possible to control the relay apparatus so that a band required for the RTP session is secured at the start of the session and released at the end of the session. As a result, a band required for the RTP session is secured, so that the communication quality of voice and moving images can be guaranteed. Further, since the reserved band is released at the end of the session, it is possible to prevent the network band from being wastefully reserved.

(2) According to the configuration of the second aspect, it becomes possible to control the relay device so that the RTP frame for transferring the voice is relayed with priority over the RTP frame for transferring the moving image. As a result, the RTP frame that transfers audio is relayed with higher priority than the RTP frame that transfers moving images, so that high sound quality can be maintained even during network congestion.

(3) According to the configuration of claim 3, it is possible to control the relay device such that the RTP frame having a longer delay time is relayed with higher priority than the RTP frame having a shorter delay time for frame transmission. Become. As a result, an RTP frame having a longer delay time is relayed with higher priority than an RTP frame having a shorter delay time required for frame transmission. it can.

(4) According to the configuration of claim 4, it becomes possible to control the relay apparatus so as to secure a band corresponding to the traffic amount of each protocol of the IP frame flowing through the network. As a result, I
Since the bandwidth according to the traffic amount for each protocol of the P frame is secured, a large amount of bandwidth is secured for a protocol with a small traffic amount to avoid wasting the transfer capacity of the relay device and maximize the transfer capacity. Can be withdrawn. In addition, even when congestion occurs, an appropriate bandwidth is allocated to each protocol, and it is possible to avoid that only the communication quality of a specific protocol is significantly deteriorated.

(5) According to the configuration of claim 5, it becomes possible to control the relay apparatus so as to secure a band corresponding to the traffic amount for each ToS field of the IP header of the IP frame flowing through the network. As a result, a bandwidth corresponding to the traffic amount for each ToS field of the IP header of the IP header of the IP frame flowing in the network is secured, so that even during congestion, an appropriate bandwidth is allocated to each ToS, and only the communication quality of a specific ToS is Significant deterioration can be avoided.

(6) It is possible to save the trouble of the administrator setting the communication quality of the relay device.

[Brief description of the drawings]

FIG. 1 is a hardware configuration diagram of a band control device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a network using the bandwidth control device of the present invention.

FIG. FIG. 323 is a diagram of a communication procedure in H.323.

[Explanation of symbols]

 Reference Signs List 101 CPU 102 Volatile memory 103 Nonvolatile memory 104 MAC control LSI 105 Port 200, 201 Band control device 202, 203 Ethernet LAN 204, 205 Router according to the present invention

Claims (5)

[Claims] 1. An interface for connecting to a local area network, which monitors a frame flowing through the network and, when an ITU-T recommended logical channel opening frame is received, analyzes the frame and uses it for an RTP session. Check the UDP port number, make sure that the transport layer protocol is UDP and the port number is UDP
A request is made to the relay device to secure a band for the frame that is the port number, and A bandwidth control device having a function of requesting a relay device to release a reserved bandwidth when a 245 logical channel termination frame is received. 2. When an RTP frame is received, the RTP frame is analyzed to check a UDP port number, and further, the RTP frame is analyzed based on a value of a PT field of the RTP header.
It checks whether the type of data transferred by the session is audio or moving image, and requests the relay device to relay the RTP frame for transferring audio preferentially over the RTP frame for transferring moving image. 2. The bandwidth control device according to claim 1, further comprising a function of performing the following. 3. When an RTP frame is received, an ICMP echo request frame is transmitted to a source IP address and a destination IP address of the frame, and a response frame is received. To calculate the delay time required for frame transmission from the terminal to the destination terminal, and make a request to the relay device to relay an RTP frame with a longer delay time preferentially over an RTP frame with a shorter delay time 3. The bandwidth control device according to claim 1, wherein: 4. An interface having an interface for connecting to a local area network, wherein all I
It has a function of receiving a P frame, measuring a traffic volume for each transport layer protocol and a transport layer port number, and requesting the relay device to secure a bandwidth corresponding to the measured traffic volume. A band control device characterized by the above-mentioned. 5. Instead of the transport layer protocol and transport layer port number, the IP header To
5. The bandwidth control device according to claim 4, further comprising a function of measuring a traffic volume for each S field and requesting the relay device to secure a bandwidth corresponding to the measured traffic volume.