WO2014083961A1

WO2014083961A1 - Packet transfer control device and communications system

Info

Publication number: WO2014083961A1
Application number: PCT/JP2013/078399
Authority: WO
Inventors: 一範小澤
Original assignee: 日本電気株式会社
Priority date: 2012-11-29
Filing date: 2013-10-11
Publication date: 2014-06-05

Abstract

A packet transfer control device that, in order to avoid deterioration in Quality of Experience (QoE), connects a terminal via a network, and transfers packets storing media data, by using a request from the terminal, said packet transfer control device comprising a congestion detection unit that detects network congestion and a transfer control unit that, if the congestion detection unit has detected network congestion, notifies at least either a partner terminal or the terminal itself of a request to reduce the rate for media data.

Description

Packet transfer control device and communication system

The present invention relates to a packet transfer control device that performs packet transfer while controlling communication quality for each packet, and a communication system including the same.

In recent years, the capacity and speed of mobile networks have been increased, and systems such as LTE (Long Term Evolution) and EPC (Evolved Packet Core) have begun to be introduced.
In conventional communication systems, circuit switching for voice calls and videophone calls and packet switching for sending data are configured as separate systems. On the other hand, in the LTE / EPC system, voice call data, videophone data, content distribution data, and so-called data signals (application data, document data, photo data, etc.) flow together on the same packet communication path. Features. Furthermore, as mobile terminals, the spread of so-called smart devices such as smartphones and tablets as well as conventional so-called Galapagos mobiles is accelerating.
Thereby, in the LTE / EPC system, a packet with a huge amount of data that cannot be compared with the conventional communication system flows through the packet communication path.
Therefore, in the LTE / EPC system, it is necessary to perform packet transfer rate control. For example, Japanese Patent Laying-Open No. 2004-320452 (Patent Document 1) discloses a packet transfer control device that performs packet transfer rate control.
The packet transfer control device disclosed in Patent Document 1 includes a line congestion state determination unit, a transfer rate control determination unit, and a packet processing unit. The line congestion state determination unit determines whether the backbone line is congested based on the accumulated packet total amount that is the accumulated value of the packet size for a plurality of packets. When determining that the backbone line is in a congested state, the transfer rate control determination unit selects one or more IP (Internet Protocol) flows having a hop count value lower than the threshold value. The packet processing unit determines whether the IP flow selected by the transfer rate control determination unit is a TCP (Transmission Control Protocol) packet. In the case of a TCP packet, the packet processing unit performs the following three types of packet processing. Apply.
Specifically, 1) In the case of an outgoing packet from the server, the CE (Consultation Experience) bit of ECN (Explicit Connection Notification) is set in the TCP header. 2) In the case of a reply packet returned from the client, the advertisement window size of the TCP header is reduced and changed. 3) In the case of an acknowledgment (Ack) packet, the transmission timing of the packet to the backbone line is delayed. If it is not a TCP packet, the packet is discarded.

JP 2004-320452 A ([0051] to [0057])

Until now, in packet transfer control devices (for example, EPC P-GW: Packet data network Gateway or S-GW: Serving Gateway), QCI (Quality Class Id) is used as a parameter for controlling QoS (Quality of Service). Parameters such as (Maximum Bit Rate) and GBR (Guaranteed Bit Rate) are set, and QoS is controlled for each packet.
However, since the network bandwidth of the entire LTE / EPC system varies temporally depending on the temporal variation of the traffic volume, QCI (Quality Class Identifier), MBR (Maximum Bit Rate), GBR (Guaranteed Bit Rate) Transfer control by setting parameter values such as (Rate) is not sufficient, and in the worst case, a problem relating to quality of experience (QoE) degradation such as the screen being frozen at the terminal or the sound being interrupted has occurred.
Furthermore, in the future, when the network is congested in a situation where it is started as a real-time communication service such as a high-quality voice VoIP (Voice Over IP) or a high-resolution videophone using the packet communication path of the LTE / EPC system, There is a risk of problems regarding QoE degradation on the terminal side, such as sound being interrupted at the terminal during a voice call by VoIP, or video being disturbed or frozen at the terminal during a videophone call.
The packet transfer control device disclosed in Patent Document 1 discloses a technical idea of selecting one or more IP flows having a hop count value lower than a threshold when the backbone line is congested. Not too much. That is, Patent Document 1 does not recognize the above-described problem relating to the deterioration of QoE.
An object of the present invention is to provide a packet transfer control device capable of avoiding QoE degradation.

One aspect of the present invention is a packet transfer control device for connecting a terminal via a network and transferring a packet storing media data in response to a request from the terminal, the congestion detecting unit detecting congestion of the network, A transfer control unit for notifying at least one of the partner terminal and the own terminal of a request to reduce the rate of the media data when the congestion detection unit detects congestion.

According to the present invention, it is possible to avoid a congestion state even when the traffic changes significantly compared to the statistical value.

FIG. 1 is a block diagram showing a connection configuration of a communication system according to the first embodiment of the present invention.
FIG. 2 is a block diagram showing a configuration of a packet transfer control device used in the communication system shown in FIG.
FIG. 3 is a block diagram showing a configuration of a rate control unit used in the packet transfer control device shown in FIG.
FIG. 4 is a block diagram showing a connection configuration of a communication system according to the second embodiment of the present invention.
FIG. 5 is a block diagram showing a configuration of a packet transfer control device used in the communication system shown in FIG.
FIG. 6 is a block diagram showing a configuration of a mobile terminal used in the communication system shown in FIG.

Hereinafter, embodiments and operations of the present invention will be described in detail with reference to the drawings.
[First Embodiment]
FIG. 1 is a block diagram showing a configuration of a communication system according to the first embodiment of the present invention. Here, a configuration in which the mobile LTE / EPC packet network 150 is used as the network is shown.
Further, in the communication system of FIG. 1, a packet transfer control device 190 (to be described later) shows a configuration using P-GW (Packet data network Gateway) or S-GW (Serving Gateway) or both. The mobile terminal is assumed to be a so-called Galapagos mobile phone, a smartphone, or a tablet.
The communication system of FIG. 1 shows an example in which user A communicates with a partner user (not shown).
In the communication system of FIG. 1, a user A uses a portable terminal 170 </ b> _ <b> 1 via a mobile network 150 and an IMS (IP Multimedia Subsystem) network 130 via a counterpart network (not shown). (Not shown) and VoIP (Voice Over IP) voice communication. A TV phone may be used in place of the voice communication (voice call), but in FIG.
As an example of congestion detection, FIG. 1 shows a configuration for detecting congestion by receiving congestion information by ECN (Explicit Congestion Notification) for an upstream packet sent from a terminal. Here, when the outdoor LTE radio base station apparatus (eNodeB apparatus) 194 detects a congestion state in the wireless network, the ECN field of the IP (Internet protocol) header portion of the uplink packet from the eNodeB apparatus to the packet transfer control apparatus 190 It is assumed that the packet transfer control device is notified of the congestion state by setting a predetermined value for the packet transfer control device.
In the communication system of FIG. 1, when the mobile terminal 170_1 sends out the IP address and RTP (real-time transport protocol) port number of the destination terminal from the mobile terminal 170_1 as a connection request signal for a voice call, the connection request signal is , A SIP (Session Initiation Protocol) server 110 disposed in an IMS (IP Multimedia Subsystem) network 130, and a PCRF (Policy and Charging Rules Function) 191 at least via the eNodeB device 194 and the packet transfer control device 190, respectively. Forwarded to one side. Further, the mobile terminal 170_1 adds at least one parameter of parameters such as voice call traffic, desired QoS class, MBR (Maximum Bit Rate), GBR (Guaranteed Bit Rate) to the connection request signal, and the parameter is added. The connection request signal thus made can be notified to at least one of the SIP server 110 and the PCRF device 191 via the packet transfer control device 190.
The SIP server 110 receives a connection request signal for a voice call and sends a connection request signal to a partner terminal (not shown) via a partner network (not shown). When the SIP server 110 receives the Ack signal from the counterpart terminal, the SIP server 110 sends the Ack signal to the portable terminal 170_1 via the packet transfer control device 190 and the eNodeB device 194. When this is received by the portable terminal 170_1, control signals for voice call are exchanged. Here, not only the IP address and RTP port number of the mobile terminal 170_1 but also at least one of the parameters of voice call traffic, desired QoS class, MBR (Maximum Bit Rate), GBR (Guaranteed Bit Rate) from the counterpart terminal. Can also be sent out. These parameters can be transmitted not only to the SIP server 110 but also to the PCRF device 191.
The PCRF device 191 inputs the voice call traffic, the IP address of the portable terminal 170_1, and the port number from the packet transfer control device 190 for at least one of the upstream and downstream directions. If necessary, the PCRF device 191 also inputs parameters such as a desired QoS class, MBR (Maximum Bit Rate), GBR (Guaranteed Bit Rate), etc. from the packet transfer control device 190 as QoS information.
Next, the PCRF device 191 generates a QoS parameter for QoS control. The QoS parameter for QoS control is at least one of QCI (Quality Class Identifier) which is a value for identifying a QoS class, ARP (Allocation and Retention Priority) indicating the priority of resource reservation and retention, MBR, and GBR. is there. Here, the MBR and the GBR are used as they are when received from the packet transfer control device 190, and are generated by the PCRF device 191 when there is no reception.
The PCRF device 191 generates at least one of these four types of QoS parameters for each of the uplink direction and the downlink direction, and sends the generated parameter to the packet transfer control device 190. For the mobile terminal 170_1, since the traffic is a voice call, specifically, the QoS parameter values are, for example, QCI = 1 (Conversational Voice), ARP = 2, GBR = 12, for both uplink and downlink. .2 kbps and MBR = 22.8 kbps are set. Here, as an example, assuming that an AMR-NB (Adaptive Multi-Rate Narrowband) audio codec is used in a mobile terminal, the above parameter values are used. As another configuration, an AMR-WB (Adaptive Multi-Rate Wideband) audio codec can be used. In this case, the value of GBR can be changed.
Next, the configuration of the packet transfer control device 190 will be described with reference to FIG. As shown in FIG. 2, the packet transfer control device 190 includes a packet transfer unit 176, a transfer control unit 188, a congestion detection unit 200, a control unit 211, and a rate control unit 230.
In FIG. 2, the control unit 211 relays a control signal from the mobile terminal 170_1 to the SIP server 110, and relays a control signal and an Ack signal from the SIP server 110 to the mobile terminal 170_1. In addition, the control unit 211 inputs at least one of four types of QoS parameters of QCI, ARP, MBR, and GBR for each traffic data from the PCRF device 191.
Here, in the first embodiment, since two types of traffic, that is, voice call traffic and Web content download data traffic, are generated, the control unit 211 controls the uplink and downlink directions of the voice call traffic. At least one of the four types of QoS parameters and at least one of the four types of QoS parameters for the downlink direction of the download data traffic are input from the PCRF device 191. The control unit 211 sends these QoS parameters to the rate control unit 230.
The congestion detection unit 200 checks the ECN (Explicit Congestion Notification) field of the IP header for the upstream packet sent from the eNodeB device 194 via the packet transfer unit 176. When the ECN field has a predetermined value, the congestion detection unit 200 recognizes that the downlink direction from the eNodeB device 194 to the portable terminal is in a congestion state, and controls downlink congestion detection information indicating the recognition result. Output to the unit 211 and the rate control unit 230. The control unit 211 sends the congestion detection information to the PCRF device 191 in FIG.
When the congestion detection information is input from the control unit 211 in FIG. 2, the PCRF device 191 in FIG. 1 checks the QoS parameter for the portable terminal 170_1 currently connected to the eNodeB device 194.
As described above, the QoS parameters of the portable terminal 170_1 are QCI = 1 (Conversational Voice), ARP = 2, GBR = 12.2 kbps, and MBR = 22.8 kbps for both uplink and downlink.
On the other hand, since the downlink direction is congestion detection as the congestion information, the PCRF device 191 determines that the QoS parameter for the portable terminal 170_1 is to be changed based on this information, and sets the change flag = 1. . Here, as an example, the mobile terminal 170_1 is changed to QCI = 1 (conversational voice), ARP = 2, GBR = 6.7 kbps, MBR = 12.2 kbps, and the PCRF device 191 performs QoS related to the mobile terminal 170_1. The parameter and the change flag are sent to the control unit 211 of the packet transfer control device 190.
Returning to FIG. 2, the rate control unit 230 inputs congestion detection information from the congestion detection unit 200, and inputs a QoS parameter and a change flag from the control unit 211.
Here, the configuration of the rate control unit 230 will be described with reference to FIG. The rate control unit 230 includes a congestion identification unit 231, a flag identification unit 232, a QoS parameter identification unit 233, and a rate change setting unit 234.
In FIG. 3, the congestion identification unit 231 receives the congestion detection information, identifies that congestion has occurred in the downstream direction, and sends the identification result to the rate change setting unit 234.
The flag identifying unit 232 inputs a change flag related to the QoS parameter for the mobile terminal 170_1, recognizes that there is a change in the QoS parameter for the mobile terminal 170_1, and instructs the rate change setting unit 234 to change the rate setting for the mobile terminal 170_1. To send.
The QoS parameter identification unit 233 inputs the QoS parameter for the mobile terminal 170_1, and recognizes that the GBR and MBR are changed (reduced) among the QoS parameters. Then, the QoS parameter identification unit 233 sends these QoS parameters to the rate change setting unit 234.
The rate change setting unit 234 creates an instruction to reduce the rate based on the voice communication based on the input values from the congestion control unit 231, the flag identification unit 232, and the QoS parameter identification unit 233. Specifically, for the uplink direction, the rate change setting unit 234 gives an instruction to change the rate of the audio codec transmitted from the mobile terminal 170_1 to a rate equal to or less than the rate of the uplink GBR by using a downlink signal to the mobile terminal 170_1. It sends it to the transfer control unit 188 (FIG. 2) for notification. Here, as an example, the rate after reduction is set to 6.7 kbps.
Furthermore, it is necessary to reduce the rate of the voice codec transmitted from the counterpart terminal to the portable terminal 170_1, and the rate change setting unit 234 sends an instruction to change to a rate equal to or lower than the downlink GBR to the uplink to the counterpart terminal. The data is sent to the transfer control unit 188 (FIG. 2) for notification by a signal. Here, as an example, the rate after reduction is set to 6.7 kbps.
In this way, the rate change setting unit 234 outputs these uplink and downlink rate reduction requests to the transfer control unit 188 in FIG.
The transfer control unit 188 in FIG. 2 sends an instruction signal for controlling transfer to the packet transfer unit 176 in accordance with the changed GBR and MBR for the downstream packet to the mobile terminal 170_1. Further, the transfer control unit 188 instructs the mobile terminal 170_1 to use a downstream packet so as to reduce the audio codec transmission rate to 6.7 kbps. For example, when SIP / SDP (Session Description Protocol) is used, the “b =” field of the SDP portion is set to 6.7 kbps. Alternatively, 6.7 kbps can be set in the CMR (Codec Mode Request) field in the RTP payload format header of the RTP packet.
On the other hand, the transfer control unit 188 sends to the packet transfer unit 176 an instruction signal for controlling transfer in accordance with the changed GBR and MBR for the uplink packet. Furthermore, the transfer control unit 188 gives an instruction to the partner terminal using the uplink packet so as to reduce the transmission rate of the voice codec to 6.7 kbps. For example, when SIP / SDP is used, the “b =” field of the SDP portion is set to 6.7 kbps. Alternatively, 6.7 kbps can be set in the CMR field in the RTP payload format header of the RTP packet.
The packet transfer unit 176 in FIG. 2 inputs an instruction signal from the transfer control unit 188, and controls transfer to the portable terminal 170_1 according to the changed GBR = 6.7 kbps and MBR = 12.2 kbps. Further, the packet transfer unit 176 instructs the mobile terminal 170_1 to use the downstream packet so as to reduce the audio codec transmission rate to 6.7 kbps. For example, when SIP / SDP is used, the “b =” field of the SDP portion is set to 6.7 kbps. Alternatively, 6.7 kbps can be set in the CMR field in the RTP payload format header of the RTP packet.
Further, the packet transfer unit 176 transfers the packet according to GBR = 6.7 kbps and MBR = 12.2 kbps for the uplink packet. Further, the packet transfer unit 176 gives an instruction to the partner terminal using the uplink packet so as to reduce the transmission rate of the voice codec to 6.7 kbps. For example, when SIP / SDP is used, the “b =” field of the SDP portion is set to 6.7 kbps. Alternatively, 6.7 kbps can be set in the CMR field in the RTP payload format header of the RTP packet.
Although the description of the configuration of the first embodiment of the present invention has been completed above, various modifications are possible.
In the first embodiment, a case where a voice call is made has been described. However, for example, a TV phone can be handled with the same configuration. It can also be applied to audio signals.
In the first embodiment, ECN information is used to detect congestion, but other information can also be used.
Although the congestion detection unit 200 and the rate control unit 230 are built in the packet transfer control device 190, they can be external devices.
Further, the function of the PCRF device 191 can be built in the packet transfer device 190.
The mobile network 150 may be a 3G network, and the packet transfer control device 190 may be an SGSN (Serving GPRS Support Node) or a GGSN (Gateway GPRS Support Node).
The packet transfer control device 190 can be realized by a program executed by a computer. That is, the packet transfer control device 190 may be composed of a packet transfer control processor (not shown) and a storage device (not shown). The storage device stores a packet transfer control program. In this case, the packet transfer control processor performs the above-described packet transfer control operation according to the packet transfer control program stored in the storage device.
Next, effects of the first exemplary embodiment of the present invention will be described.
According to the first embodiment of the present invention, when the bandwidth of the LTE / EPC network temporally varies depending on the temporal traffic variation, the conventional QoS parameter control method avoids this. It becomes possible to avoid the congested state that was difficult. As a result, there is an effect that it is possible to avoid QoE (Quality of Experience) degradation such as sound being interrupted or screen being frozen at a terminal for a preferential user. Furthermore, even if a service such as a high-quality VoIP or a high-resolution TV phone is started in the future using the packet communication path of the LTE / EPC system, it is possible to avoid deterioration of QoE on the terminal side. .
[Second Embodiment]
Next, the configuration of a communication system according to the second embodiment of the present invention will be described with reference to FIG. As will be described later, the illustrated communication system is different only in the packet transfer control device, and the other configuration is the same as the configuration of the communication system according to the first embodiment shown in FIG. Accordingly, reference numeral 190A is assigned to the packet transfer control device.
FIG. 5 is a block diagram showing a configuration of the packet transfer control device 190A. In FIG. 5, the constituent elements having the same numbers as those in FIG. 2 perform the same operations as those in FIG.
The packet transfer control device 190A is the same as the packet transfer control device 190 shown in FIG. 2 except that the bandwidth measuring unit 205 is added and the operation of the congestion detection unit is changed as will be described later. It has a configuration. Accordingly, reference numeral 210 is assigned to the congestion detection unit.
In FIG. 5, the bandwidth measuring unit 205 calculates at least one bandwidth of the network to which the mobile terminal 170_1 is connected at the time of session connection or at predetermined time intervals.
The bandwidth measuring unit 205 uses the transmission packet from the packet transfer unit 176 and the return packet from the mobile terminal 170 to determine the upstream bandwidth and the downstream bandwidth for the network connected to the mobile terminal 170. At least one is measured. In the present embodiment, a configuration in the case of measuring both upstream and downstream bands will be described.
First, the bandwidth measuring unit 205 instructs the packet transfer unit 176 to send a plurality of specific packets (probe packets) at a predetermined timing. In accordance with the instruction, the packet transfer unit 176 sends a plurality of specific packets to the portable terminal 170_1 at a timing when the instruction is received, and continuously transmits in a predetermined order in time.
Here, the plurality of packets indicates two or more packets. The sending order is a predetermined order. For example, packets are sent in order from a packet having a small data size to a packet having a large data size. Further, the time interval between the packet and the next packet is a predetermined time interval. Here, for example, RTP / UDP (user datagram protocol) / IP is used as the protocol.
Next, the packet transfer unit 176 receives a reply packet from the portable terminal 170_1 as a result of sending the plurality of packets.
Here, the reply packet includes, for example, the packet number received by the portable terminal 170_1 below the threshold with respect to the differential delay, the data size of the packet, the time when the packet was transmitted from the server, and the packet. Include information such as the time received by the mobile terminal.
The packet transfer unit 176 obtains, from the return signal received from the mobile terminal 170_1, the packet number that the mobile terminal 170_1 has received below the delay difference threshold, the transmission time from the server, and the reception time information at the mobile terminal. These are extracted and output to the bandwidth measuring unit 205.
The bandwidth measuring unit 205 receives the above information from the packet transfer unit 176 and calculates the network bandwidth.
The bandwidth measuring unit 205 receives the packet number, the packet data size, the transmission time of the packet from the server, and the reception time of the packet at the portable terminal at the portable terminal 170_1 below the delay difference threshold. The downstream band W_d is calculated according to the following equation (1).
D (N) / W_d = R (N) -R (N-1) (1)
In the above equation (1), D (N) represents the data size of the Nth packet transmitted from the packet transfer unit 176. Here, N and D (N) indicate the number and data size of a packet that can be received by the first portable terminal 170_1 below the delay difference threshold value, respectively. R (N) is the reception time at the portable terminal 170_1 of the Nth packet sent from the server, and R (N-1) is the first portable of the (N-1) th packet sent from the server. The reception times at terminal 170_1 are respectively shown.
Next, the bandwidth measuring unit 205 smoothes the downstream bandwidth measurement value W_d temporally according to the following equation (2) to calculate B (n) _d.
B (n) _d = (l−β) * B (n−1) _d + βW_d (2)
Here, B (n) _d indicates a downstream band measurement value after smoothing at the nth time, and β is a constant in a range of 0 <β <1. Note that the time direction smoothing according to the equation (2) may not be performed if unnecessary.
Next, the mobile terminal 170_1 sends a plurality of specific packets to the packet transfer control device 190A in a predetermined order at any timing after the connection request or when the reply signal is transmitted. Thus, the upstream band is measured in the packet transfer control device 190A. Here, the plurality of packets indicates two or more packets. The sending order is a predetermined order. For example, packets are sent in order from a packet having a small data size to a packet having a large data size. Further, the time interval between the packet and the next packet is a predetermined time interval. Here, for example, RTP / UDP / IP is used as the protocol.
The bandwidth measuring unit 205 receives a plurality of packets sent from the portable terminal 170_1 from the packet transfer unit 176, and receives the packet number that is received below the threshold of the delay difference, the data size of the packet, the mobile phone of the packet Information on the transmission time from the terminal and the reception time of the packet at the packet transfer unit 176 is input, and the upstream bandwidth W_u is calculated according to the following equation (3).
D (M) / W_u = P (M) -P (M-1) (3)
Next, the bandwidth measuring unit 205 smoothes the bandwidth measurement value W_u in the upstream direction temporally according to the following equation (4) to calculate B (n) _u.
B (n) _u = (l−β) * B (n−1) _u + βW_u (4)
The packet transfer unit 176 sends information necessary for network bandwidth measurement to the portable terminal 170_1 only at the time of session connection or at predetermined time intervals starting from the time of session connection and the time of session connection. A response signal is received from the mobile terminal.
The bandwidth measuring unit 205 calculates B (n) _d and B (n) _u, for example, at predetermined time intervals, and sends them to the congestion detection unit 210.
The congestion detection unit 210 performs the following determination to detect congestion.
1) Downlink bandwidth calculation B (n) _d ≧ If GBR + α in the downlink direction of a voice call by the mobile terminal 170_1, the congestion detection unit 210 does not change any of the downlink QoS parameters for the mobile terminal 170_1. This is transmitted to the PCRF device 191 in FIG. 4 via the control unit 211. Here, α is a margin, and a predetermined value is used.
2) When B (n) _d <GBR + α in the downlink direction of a voice call, the congestion detection unit 210 detects congestion and notifies the PCRF device 191 of the congestion information.
3) Concerning the uplink direction, the congestion detection unit 210 determines the same as in 1) and 2) above, and notifies the PCRP device 191 whether or not congestion has been detected.
Returning to FIG. 4, when the congestion detection information is input from the congestion detection unit 210 of FIG. 5, the PCRP apparatus 191 checks at least one of the user profile information and the QoS parameter for the portable terminal 170_1.
As described above, the QoS parameters for the portable terminal 170_1 are QCI = 1 (Conversational Voice), ARP = 2, GBR = 12.2 kbps, MBR = 22.8 kbps in both uplink and downlink, but input congestion detection information. Therefore, for example, the PCRP device 191 changes GBR = 6.7 kbps and MBR = 12.2 kbps in both uplink and downlink, and sends the changed QoS parameter to the packet transfer control device 190A. Specifically, the PCRP apparatus 191 sends the changed QoS parameter to the rate control unit 230 via the control unit 211 of FIG.
FIG. 6 is a block diagram illustrating a configuration of the mobile terminal 170_1. The portable terminal 170_1 includes a packet transmission / reception unit 250, an audio codec 253, a rate setting unit 254, and a delay difference determination unit 255.
In FIG. 6, the packet transmitting / receiving unit 250 generates a reply packet for the received probe packet and sends the generated reply packet to the network. Here, the reply packet is generated as follows, for example.
The packet transmission / reception unit 250 receives each of the plurality of probe packets transmitted from the packet transfer unit 176 in FIG. 5 and outputs the received packet to the delay difference determination unit 255.
The delay difference determination unit 255 measures the delay time T (n) for each packet by the following equation (5).
T (n) = R (n) -S (n) (5)
Here, T (n), R (n), and S (n) indicate the delay time of the nth packet, the reception time of the nth packet, and the transmission time of the nth packet, respectively. .
Further, the delay difference determination unit 255 calculates the delay difference τ (n) between the packets by the following equation (6).
τ (n) = T (n) −T (n−1) (6)
Here, τ (n) represents the delay difference of the nth packet.
Next, the delay difference determination unit 255 uses τ (n) to determine whether or not the delay difference exceeds a predetermined threshold value. If τ (n) ≧ Th3, the delay difference determination unit 255 determines that the delay difference has exceeded the threshold value in the nth packet. Here, Th3 is a predetermined threshold value. Then, the delay difference determining unit 255 outputs the packet number N immediately after the delay difference exceeds the threshold value to the packet transmitting / receiving unit 250.
The packet transmission / reception unit 250 receives the packet number N from the delay difference determination unit 255, the packet number N immediately after the delay difference exceeds the threshold, the data size of the Nth packet, the (N−1) th The data size of each packet, the reception time and transmission time of each packet are stored in the payload of the reply packet, and then transmitted to the packet transfer control device 190A via the eNodeB device 194 in FIG.
Here, the threshold value Th3 may be determined in advance, or may be determined each time after looking at a series of values of τ (n).
Also, other methods can be used as the discrimination method. For example, T (n) may be compared with a threshold value, and n when the threshold value is exceeded may be set to N.
In FIG. 6, the rate setting unit 254 receives the reduced audio codec rate from the packet transmission / reception unit 250 and sets the rate in the encoder of the audio codec 253. Here, it is assumed that the rate setting unit 254 reads the numerical value of 6.7 kbps set in the CMR field of the SDP or RTP payload header, and sets 6.7 kbps in the audio codec 253. Here, as described above, AMR is used as the audio codec 253.
This is the end of the description of the configuration of the second exemplary embodiment of the present invention, but various modifications are possible.
For example, another algorithm can be used as the band measurement algorithm in the band measurement unit 205 of FIG. In the above embodiment, the bandwidth measuring unit 205 calculates the bandwidth based on the response signal from the mobile terminal, but the bandwidth measuring unit 205 measures the amount of delay with the mobile terminal and based on this, It can also be calculated.
The bandwidth measuring unit 205 does not measure the bandwidth by sending a probe packet for bandwidth measurement from the packet transfer unit, but uses a response signal from the mobile terminal without using the probe packet. It can also be used. In this case, the delay difference determination unit 255 in FIG. 6 is unnecessary.
In the second embodiment, the bandwidth measurement unit 205, the congestion detection unit 210, and the rate control unit 230 are built in the packet transfer control device 190A, but at least one of them may be an external device. it can.
The packet transfer control device 190A can be realized by a program executed by a computer. That is, the packet transfer control device 190A may be composed of a packet transfer control processor (not shown) and a storage device (not shown). The storage device stores a packet transfer control program. In this case, the packet transfer control processor performs the above-described packet transfer control operation according to the packet transfer control program stored in the storage device.
Next, effects of the second exemplary embodiment of the present invention will be described.
According to the second embodiment of the present invention, when the bandwidth of the LTE / EPC network temporally varies depending on the temporal traffic variation, the conventional control method using the QoS parameters can be avoided. It becomes possible to avoid the congested state that was difficult. As a result, there is an effect that it is possible to avoid QoE (Quality of Experience) degradation such as sound being interrupted or screen being frozen at a terminal for a preferential user. Furthermore, even if a service such as a high-quality VoIP or a high-resolution TV phone is started in the future using the packet communication path of the LTE / EPC system, it is possible to avoid deterioration of QoE on the terminal side. .
Although the present invention has been described with reference to the embodiments, the present invention is not limited to the above embodiments. Various changes that can be understood by those skilled in the art can be made to the configuration and details of the present invention within the scope of the present invention.
A part or all of the above-described embodiment can be described as in the following supplementary notes, but is not limited thereto.
(Appendix 1)
A packet transfer control device for connecting a terminal via a network and transferring a packet storing media data in response to a request from the terminal,
A congestion detection unit for detecting congestion of the network;
When the congestion detection unit detects congestion of the network, a transfer control unit that notifies a request to reduce the rate of the media data to at least one of the partner terminal and the own terminal;
A packet transfer control device comprising:
(Appendix 2)
The packet transfer control device according to appendix 1, wherein the congestion detection unit extracts congestion information from an upstream packet and detects congestion of the network.
(Appendix 3)
The packet transfer control device according to appendix 2, wherein the congestion detection unit extracts the congestion information by checking an ECN field of an IP header portion of the uplink packet.
(Appendix 4)
Based on a reply response signal from the terminal to the packet sent from the packet transfer control device, further comprising a bandwidth measuring unit that calculates the bandwidth of the network as a calculated value,
The packet transfer control device according to appendix 1, wherein the congestion detection unit detects congestion of the network based on the calculated value.
(Appendix 5)
The packet transfer control device according to appendix 4, wherein the bandwidth measuring unit calculates the bandwidth of the network at the time of session connection or at a predetermined time interval.
(Appendix 6)
The packet transfer control device according to any one of appendices 1 to 5, wherein the media data includes at least one of audio data, video data, and audio.
(Appendix 7)
A communication system including the packet transfer control device according to any one of supplementary notes 1 to 6 and the terminal connected to the packet transfer control device via the network.
(Appendix 8)
A PCRF device for changing the QoS parameter for the terminal and generating a changed QoS parameter and a change flag when the congestion detection unit detects congestion of the network;
The packet transfer control device further includes a rate control unit that creates an instruction to reduce a rate in response to the changed QoS parameter and the change flag,
8. The communication system according to appendix 7, wherein the transfer control unit notifies at least one of the partner terminal and the own terminal of a request to reduce the rate for the media data in response to an instruction to reduce the rate.
(Appendix 9)
The communication system according to appendix 8, wherein the QoS parameter is at least one of QCI, ARP, MBR, and GBR.
(Appendix 10)
A packet transfer control method in a packet transfer control device for connecting a terminal via a network and transferring a packet storing media data in response to a request from the terminal,
A congestion detection step of detecting congestion of the network;
A transfer control step of notifying at least one of the partner terminal and the own terminal of a request to reduce the rate of the media data when congestion of the network is detected;
A packet transfer control method including:
(Appendix 11)
11. The packet transfer control method according to appendix 10, wherein the congestion detection step detects congestion of the network by extracting congestion information from an upstream packet.
(Appendix 12)
12. The packet transfer control method according to appendix 11, wherein the congestion detection step extracts the congestion information by checking an ECN field of an IP header part of the uplink packet.
(Appendix 13)
Based on a reply response signal from the terminal to the packet transmitted from the packet transfer control device, further comprising a bandwidth measurement step of calculating the bandwidth of the network as a calculated value,
The packet transfer control method according to appendix 10, wherein the congestion detection step detects congestion of the network based on the calculated value.
(Appendix 14)
14. The packet transfer control method according to appendix 13, wherein the bandwidth measurement step calculates the bandwidth of the network at the time of session connection or at a predetermined time interval.
(Appendix 15)
15. The packet transfer control method according to any one of appendices 10 to 14, wherein the media data includes at least one of audio data, video data, and audio.
(Appendix 16)
A computer-readable recording medium recorded with a packet transfer control program for transferring a packet storing media data in response to a request from the terminal to a computer connected to the terminal via a network, the packet transfer control program comprising: To the computer,
A congestion detection procedure for detecting congestion of the network;
A transfer control procedure for notifying at least one of the partner terminal and the own terminal of a request to reduce the rate of the media data when congestion of the network is detected;
A computer-readable recording medium for executing

DESCRIPTION OF SYMBOLS 110 SIP server 130 IMS network 140 Internet network 145 Web server 150 Mobile network 170_1 Portable terminal 176 Packet transfer part 188

Transfer control part

190, 190A Packet transfer control apparatus 191 PCRF apparatus 194 eNodeB apparatus 205

Bandwidth measurement part

200, 210 Congestion detection part 211 Control unit 230 Rate control unit 250 Packet transmission / reception unit 253 Audio codec 254 Rate setting unit 255 Delay difference determination unit This application is based on Japanese Patent Application No. 2012-260636 filed on November 29, 2012 And the entire disclosure is incorporated herein.

Claims

A packet transfer control device for connecting a terminal via a network and transferring a packet storing media data in response to a request from the terminal,
A congestion detection unit for detecting congestion of the network;
When the congestion detection unit detects congestion of the network, a transfer control unit that notifies a request to reduce the rate of the media data to at least one of the partner terminal and the own terminal;
A packet transfer control device comprising:
2. The packet transfer control device according to claim 1, wherein the congestion detection unit extracts congestion information from an upstream packet and detects congestion of the network.
3. The packet transfer control device according to claim 2, wherein the congestion detection unit extracts the congestion information by checking an ECN field of an IP header portion of the uplink packet.
Based on a reply response signal from the terminal to the packet sent from the packet transfer control device, further comprising a bandwidth measuring unit that calculates the bandwidth of the network as a calculated value,
The packet transfer control device according to claim 1, wherein the congestion detection unit detects congestion of the network based on the calculated value.
The packet transfer control device according to claim 4, wherein the bandwidth measuring unit calculates the bandwidth of the network at the time of session connection or at predetermined time intervals.
The packet transfer control device according to any one of claims 1 to 5, wherein the media data includes at least one of audio data, video data, and audio.
A communication system including the packet transfer control device according to any one of claims 1 to 6 and the terminal connected to the packet transfer control device via the network.
A PCRF device for changing the QoS parameter for the terminal and generating a changed QoS parameter and a change flag when the congestion detection unit detects congestion of the network;
The packet transfer control device further includes a rate control unit that creates an instruction to reduce a rate in response to the changed QoS parameter and the change flag,
The communication system according to claim 7, wherein the transfer control unit notifies a request for reducing the rate of the media data to at least one of a partner terminal and a local terminal in response to an instruction to reduce the rate.
The communication system according to claim 8, wherein the QoS parameter is at least one of QCI, ARP, MBR, and GBR.
A packet transfer control method in a packet transfer control device for connecting a terminal via a network and transferring a packet storing media data in response to a request from the terminal,
A congestion detection step of detecting congestion of the network;
A transfer control step of notifying at least one of the partner terminal and the own terminal of a request to reduce the rate of the media data when congestion of the network is detected;
A packet transfer control method including: