KR20150072879A - Apparatus of packet retransmission for advancing multimedia QoS and method for packet transmission - Google Patents

Apparatus of packet retransmission for advancing multimedia QoS and method for packet transmission Download PDF

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Publication number
KR20150072879A
KR20150072879A KR1020130160526A KR20130160526A KR20150072879A KR 20150072879 A KR20150072879 A KR 20150072879A KR 1020130160526 A KR1020130160526 A KR 1020130160526A KR 20130160526 A KR20130160526 A KR 20130160526A KR 20150072879 A KR20150072879 A KR 20150072879A
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KR
South Korea
Prior art keywords
packet
terminal
transmitted
retransmission
flow
Prior art date
Application number
KR1020130160526A
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Korean (ko)
Inventor
정현호
김봉기
박태민
황영헌
Original Assignee
주식회사 케이티
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
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Priority to KR1020130160526A priority Critical patent/KR20150072879A/en
Publication of KR20150072879A publication Critical patent/KR20150072879A/en

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L1/00—Arrangements for detecting or preventing errors in the information received
    • H04L1/12—Arrangements for detecting or preventing errors in the information received by using return channel
    • H04L1/16—Arrangements for detecting or preventing errors in the information received by using return channel in which the return channel carries supervisory signals, e.g. repetition request signals
    • H04L1/18—Automatic repetition systems, e.g. Van Duuren systems
    • H04L1/1867—Arrangements specially adapted for the transmitter end
    • H04L1/188—Time-out mechanisms
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/24—Traffic characterised by specific attributes, e.g. priority or QoS
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/28—Flow control; Congestion control in relation to timing considerations
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L47/00—Traffic control in data switching networks
    • H04L47/10—Flow control; Congestion control
    • H04L47/32—Flow control; Congestion control by discarding or delaying data units, e.g. packets or frames
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L63/00—Network architectures or network communication protocols for network security
    • H04L63/14—Network architectures or network communication protocols for network security for detecting or protecting against malicious traffic
    • H04L63/1441—Countermeasures against malicious traffic
    • H04L63/1466—Active attacks involving interception, injection, modification, spoofing of data unit addresses, e.g. hijacking, packet injection or TCP sequence number attacks

Abstract

According to the present invention, a device to retransmit a packet hijacks a packet transmitted from a web server to a terminal, and stores the hijacked packet by copying the same. The device also analyzes a packet flow transmitted to the web server from the terminal, identifies a retransmission request of the packet, and transmits the copied and stored packet to the terminal once the retransmission request of the packet is identified.

Description

[0001] The present invention relates to a packet retransmission apparatus for improving multimedia service quality and a packet transmission method using the same,

The present invention relates to a packet retransmission apparatus for improving multimedia service quality and a packet transmission method using the same.

In general, a receiving host that receives a signal sends an acknowledgment (ACK) to all the packets transmitted from the transmitting host to inform the receiving host of the acknowledgment of whether or not the packet has been received. At this time, the receiving host confirms the sequence number, transmits a duplicate acknowledgment when a loss occurs in the transmitted packet, and the transmitting host which received the duplicate acknowledgment retransmits all the packets from the lost packet again .

BACKGROUND ART [0002] With the recent increase in demand for multimedia streaming services (for example, YouTube, IPTV VoD, smart TV, etc.) in wireless terminals, the quality of the interval transmission of a wireless network has become important. Most multimedia streaming services are based on TCP (Transmission Control Protocol). When the quality of a network deteriorates or a DDoS attack occurs, packet loss occurs and TCP retransmission occurs repeatedly. The repetitive phenomenon of TCP retransmission increases the load on the network, thereby deteriorating the quality of perceived quality when the client watches a moving picture.

Accordingly, the present invention provides a packet retransmission apparatus and method for improving multimedia service quality by reducing the number of retransmission hops of a packet through a TCP retransmission proxy.

According to another aspect of the present invention, there is provided an apparatus for retransmitting packets,

A packet receiver for hijacking and receiving a packet transmitted from the web server to the terminal and receiving a response signal transmitted from the terminal to the web server; A flow analyzer for analyzing a packet flow for a response signal transmitted from the terminal to the web server and for determining whether to retransmit the packet based on the analysis result; A packet buffer for copying and storing the packet received by the packet receiver; And a packet transmission unit for transmitting the copied packet stored in the packet buffer to the terminal when the flow analysis unit determines retransmission of the packet.

And a timer for driving a timer for the stored packet when the packet copied to the packet buffer is stored and for requesting discard of the packet when the timer is completed, to the packet buffer.

And a flow information storage unit for storing the packet flow analyzed by the flow analysis unit.

According to another aspect of the present invention, there is provided a method for transmitting a packet in a packet retransmission apparatus,

Hijacking a packet transmitted from a web server to a terminal; Copying and storing the hijacked packet; Analyzing a packet flow transmitted from the terminal to the web server and confirming whether or not to request retransmission of the packet; And transmitting the copied and stored packet to the terminal when it is confirmed that the packet is requested to be retransmitted.

Confirming whether or not the retransmission is confirmed includes checking whether a packet flow including a sequence number of a packet transmitted from the web server to the terminal is transmitted; And confirming that the packet transmitted to the terminal is retransmitted when a packet flow including a sequence number of a packet transmitted to the terminal is transmitted before the transmitted packet.

The storing step may include driving a timer for the packet when the packet is copied and stored.

The step of hijacking the packet may include monitoring and hacking the TCP flow for all Internet traffic or specific service traffic transmitted and received from the front end of the edge router of the backbone network to the terminal,

If the quality of service device is connected to a router, the router may change the configuration of the router to physically pass the packet retransmission device to hijack the packet, or if the quality of service device is located in any server, It can be bypassed to an arbitrary server and allowed to pass through the packet retransmission device to monitor and hijack the TCP flow.

According to the present invention, it is possible to provide a fast retransmission response as the number of transmission hops decreases, and the load of the backbone network is reduced.

1 is an exemplary diagram of a network environment for improving multimedia service quality according to an embodiment of the present invention.
2 is a structural diagram of a packet retransmission apparatus according to an embodiment of the present invention.
3 is a flowchart of a packet transmission method according to an embodiment of the present invention.
4 is a flowchart illustrating a packet transmission method based on a packet retransmission apparatus according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

Throughout the specification, when an element is referred to as "comprising ", it means that it can include other elements as well, without excluding other elements unless specifically stated otherwise.

In this specification, a terminal includes a mobile station (MS), a mobile terminal (MT), a subscriber station (SS), a portable subscriber station (PSS) An access terminal (AT), and the like, and may include all or some of functions of a mobile terminal, a subscriber station, a mobile subscriber station, a user equipment, and the like.

In this specification, a base station (BS) is an access point (AP), a radio access station (RAS), a node B, a base transceiver station (BTS) Mobile Multihop Relay) -BS, and may include all or some of the functions of an access point, a radio access station, a Node B, a base transceiver station, and an MMR-BS.

In general, the web proxy distributes the load of the client's service request at the application layer (L7) and transmits the response page. However, in the embodiment of the present invention, the transmission layer L4 retransmits the packet instead.

In addition, the CDN (Content Delivery Network) service provides fast service by distributing contents (or application services) to major nodes of the network. However, in the embodiment of the present invention, will be. Hereinafter, an apparatus and method for improving multimedia service quality, which are different from the conventional art, will be described in detail with reference to the drawings.

1 is an exemplary diagram of a network environment for improving multimedia service quality according to an embodiment of the present invention.

1, the web server 200 provides a multimedia service to the terminal 400 through the base station 300 or the AP 300 '. At this time, a packet retransmission apparatus 100 for analyzing flow information of a packet in a network section between the web server 200 and the base station 300 or the AP 300 ', and copying the packet and retransmitting the packet to the terminal is located. The web server 200 and the AP 300 'or the base station 300 do not recognize the existence of the packet retransmission apparatus 100,

In the embodiment of the present invention, the packet retransmission apparatus 100 uses the TCP retransmission proxy apparatus as an example, but it is not necessarily limited thereto. In addition, the packet retransmission apparatus 100 can be installed anywhere in a network section. However, since deterioration in transmission quality of the network occurs in the access period and the wireless period, an access gateway node is suitable.

A structure of a packet retransmission apparatus 100 for hacking a packet in a network section and transmitting a packet that fails in transmission to the web server 200 will be described with reference to FIG.

2 is a structural diagram of a packet retransmission apparatus according to an embodiment of the present invention.

2, the packet retransmission apparatus 100 includes a packet reception unit 110, a flow analysis unit 120, a flow information storage unit 130, a packet buffer 140, a timer 150, and a packet transmission unit 160).

The packet receiving unit 110 hijacks and receives a packet transmitted from the web server 200 to the base station 300 or the AP 300 '. The method of hijacking a packet by the packet receiving unit 110 may be performed through various methods. In an embodiment of the present invention, hijacking is performed by any one of the following methods.

As a first method, the packet retransmission apparatus 100 is installed in the in-line manner in front of an edge router of a backbone network by a network operator so as to monitor and hijack a TCP flow for all Internet traffic or specific service traffic. It can hijack a packet without changing the configuration of an existing network node or client device.

In the second method, when the packet retransmission apparatus 100 is connected to the router by the network operator, it changes the setting of the router (for example, changes the port forwarding, routing policy, etc.). Then, the setting of the network node is changed so that the traffic physically passes through the packet retransmission apparatus 100, thereby hijacking the packet.

In the third method, the packet retransmission apparatus 100 is located in a server farm at a preset location, and the client traffic is bypassed to the server farm so as to pass through the packet retransmission apparatus 100 to monitor the TCP flow . As a last resort, a router or switch with an algorithm capable of hijacking packets can be implemented and operated.

The flow analysis unit 120 analyzes flow information of a packet hijacked by the packet reception unit 110. [ In addition, flow information about a response signal indicating whether a packet transmitted from the terminal 400 to the web server 200 is received or not is analyzed.

Then, the flow analysis unit 120 determines whether packet retransmission is necessary based on the analyzed flow. The method of confirming whether the flow analyzer 120 needs packet retransmission may employ a TCP packet retransmission algorithm and is not limited to any one method.

The flow information storage unit 130 stores and manages flow information analyzed by the flow analysis unit 120. Here, the flow information is information (e.g., session ID, etc.) necessary for TCP retransmission. Since the information is already known, detailed description will be omitted in the embodiment of the present invention. Also, the flow information includes a sequence number included in the TCP frame, and it is possible to confirm a packet requiring retransmission to the terminal 400 through the sequence number.

The packet buffer 140 copies the hijacked packet to the packet transmitter 160 when the packet receiver 110 hijacks the packet. At the same time, copied packets are stored and managed. Based on the analysis of the flow analysis unit 120, the packet transmission unit 160 transmits a packet stored for the packet requiring retransmission. In addition, when the predetermined period of time, that is, the life cycle has passed, the stored copied packets are discarded.

When the packet buffer 140 stores the copied packet, the timer 150 drives a timer for the packet. Here, the timer 150 sets a timer for a predetermined lifetime, and when the timer is completed, requests the packet buffer 140 to delete the timer-completed packet. To this end, the timer 150 stores and manages the identification information of the copied packet stored in the packet buffer 140 when the timer is driven.

The packet transmission unit 160 transmits the packet copied from the packet buffer 140 to the terminal 400 through the base station 300 or the AP 300 '. The packet transmitter 160 transmits a packet requiring retransmission in the packet buffer 140 to the base station 300 or the AP 300 'and transmits the packet to the terminal 400.

A packet transmission method for improving multimedia service quality through the packet retransmission apparatus 100 will be described with reference to FIGS. 3 and 4. FIG. FIG. 3 shows an overall flow of a packet transmitted from the web server 200 to the terminal 400, and FIG. 4 shows a detailed function performed by the packet retransmission apparatus 100 when a packet is transmitted.

FIG. 3 is a flowchart of a packet transmission method according to an embodiment of the present invention, and FIG. 4 is a flowchart of a packet transmission method based on a packet retransmission apparatus according to an embodiment of the present invention.

3, when the web server 200 transmits the packet 1 to the terminal 400, the packet retransmission apparatus 100 located between the web server 200 and the terminal 400 hijacks the packet 1 , The packet 1 is copied and stored. The web server 200 sequentially transmits the packets 2, 3, 4 and 5 to the terminal 400, and the packet retransmission apparatus 100 copies and stores the packets 2 to 5 as well as the packet 1.

At this time, when the terminal 400 normally receives the packet 1, the terminal 400 transmits an acknowledgment ACK 1 for the packet 1 to the web server 200. However, since the terminal 400 does not normally receive the packet 2 transmitted from the web server 200, the terminal 400 transmits ACK 1, which is an affirmative response to the packet 1, even if the terminal 3 normally receives the packet 3.

Accordingly, the packet retransmission apparatus 100 confirms the response signal transmitted from the terminal 400, analyzes the response signal, and transmits the packet 2 temporarily stored in the packet retransmission apparatus 100 to the terminal 400. Then, the timer is driven from the time when the packet is temporarily stored, and when the timeout occurs, the timeout packet is discarded.

That is, in the embodiment of the present invention, it is assumed that the packet retransmission apparatus 100 can monitor the traffic transmitted / received between the web server 200 and the terminal 400 between the end and the end. Accordingly, when there is a packet retransmission request from the terminal 400, the packet retransmission apparatus 100 can detect the request. At this time, the packet retransmission apparatus 100 can not detect the packet temporarily stored in place of the web server 200 To the terminal (400).

3, since the packet 2 is lost, the terminal 400 requests the retransmission of the packet 2 by continuously sending the ACK for the packet 1 to the web server 200. [ At this time, the terminal 400 can know the order of the packets through the sequence number in the TCP frame, and the details thereof are already known, and a detailed description will be omitted in the embodiment of the present invention. Accordingly, the packet retransmission apparatus 100 retransmits the packet 2 back to the terminal 400 through the sequence number in the TCP frame.

Referring to FIG. 4, a detailed procedure of the function of the packet retransmission apparatus 100 for confirming whether or not a packet to be transmitted is hijacked and a packet is to be retransmitted will be described with reference to FIG. In Fig. 4, transmission and reception of packet 1 will be described as an example.

As shown in FIG. 4, when the web server 200 transmits packet 1 (S100), the packet retransmission apparatus 100 hijacks packet 1 (S101). Then, the packet 1 is copied and stored in the packet buffer 140 (S102), and at the same time, the timer 150 is driven (S103). Packet 1 that the packet retransmission apparatus 100 has hijacked is transmitted to the terminal 400 in step S104 and may be transmitted in the packet transmission unit 160 and may be directly transmitted from the web server 200 to the base station 300 or AP And transmitted to the terminal 400 through the base station 300 '.

The terminal 400 transmits a response to the web server 200 informing that the packet 1 has been received securely in step S105 and the flow analysis unit 120 of the packet retransmission apparatus 100 transmits a response to the response transmitted from the terminal 400 And checks whether the response transmitted by the terminal 400 is an ACK for the packet 1. (S108, S109).

If the response is ACK, the terminal 400 transmits a response signal to the web server 200 (S108). However, if the response is not ACK or a response to a previously transmitted packet is transmitted rather than a response to a packet transmitted from the web server 200, the packet retransmission apparatus 100 transmits a packet that failed in packet transmission to the terminal 400 (S109).

The packet retransmission apparatus 100 transmits the packet 1 temporarily stored in the packet buffer 140 of the packet retransmission apparatus 100 to the packet transmission unit 160 To the terminal 400 via the network. Then, whether or not to respond to the retransmitted packet 1, the procedure after step S105 is repeated.

Meanwhile, after the step S109 or while the packets other than the packet 1 are being transmitted to the terminal 400, the timer 150 of the packet retransmission apparatus 100 checks whether the timer for the packet 1 is completed and becomes a timeout state (S110 ). If not, the packet 1 stored in the packet buffer 140 is maintained in a stored state (S112).

However, when the timeout state is reached, the packet buffer 140 discards the packet for packet 1 (S111). At this time, since the packet buffer 140 and the timer 150 store information about mutual packets together to check which packet the timer is driven, when the timer 150 is in the timeout state, To the packet buffer 140 to delete the temporarily stored packet.

Since the retransmission of the packet is performed in the packet retransmission apparatus 100, the path for retransmission of the packet does not go up to the web server 200, so the response can be shortened and quick response can be performed.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, It belongs to the scope of right.

Claims (9)

An apparatus for retransmitting packets,
A packet receiver for hijacking and receiving a packet transmitted from the web server to the terminal and receiving a response signal transmitted from the terminal to the web server;
A flow analyzer for analyzing a packet flow for a response signal transmitted from the terminal to the web server and for determining whether to retransmit the packet based on the analysis result;
A packet buffer for copying and storing the packet received by the packet receiver; And
And a packet transmitter for transmitting the copied packet stored in the packet buffer to the terminal when the flow analysis unit determines retransmission of the packet,
Gt; The method according to claim 1,
A timer for driving the stored packet when the packet copied to the packet buffer is stored, and a timer for requesting discard of the packet if the driven timer is completed,
Gt; 3. The method of claim 2,
A flow information storage unit for storing the packet flow analyzed by the flow analysis unit,
Further comprising: The method according to claim 1,
The packet retransmission apparatus is implemented as a TCP retransmission proxy apparatus, and is installed in an access gateway node. A method of transmitting a packet by a packet retransmission apparatus,
Hijacking a packet transmitted from a web server to a terminal;
Copying and storing the hijacked packet;
Analyzing a packet flow transmitted from the terminal to the web server and confirming whether or not to request retransmission of the packet; And
If it is confirmed that the packet is requested to be retransmitted, transmitting the copied packet to the terminal
Lt; / RTI > 6. The method of claim 5,
The method of claim 1,
Confirming whether a packet flow including a sequence number of a packet transmitted from the web server to the terminal is transmitted; And
Confirming that the packet transmitted to the terminal is retransmitted when a packet flow including the sequence number of the packet transmitted to the terminal is transmitted before the transmitted packet
Lt; / RTI > 6. The method of claim 5,
Wherein the storing step comprises:
When the packet is copied and stored, driving a timer for the packet
Further comprising: 8. The method of claim 7,
After confirming the retransmission,
Checking if a timer has timed out; And
If there is a timed-out timer, delete the packet stored for the timer
Lt; / RTI > 6. The method of claim 5,
Hijacking the packet comprises:
The service quality device may monitor and hijack the TCP flow for all Internet traffic or specific service traffic transmitted to and from the terminal in front of the edge router of the backbone network,
When the quality of service device is connected to a router, the router is configured so that traffic is physically passed through the packet retransmission device to hijack the packet,
Wherein when the quality of service device is located in a certain server, traffic transmitted to the terminal is bypassed to the arbitrary server and allowed to pass through the packet retransmission device, thereby monitoring and hacking the TCP flow.
KR1020130160526A 2013-12-20 2013-12-20 Apparatus of packet retransmission for advancing multimedia QoS and method for packet transmission KR20150072879A (en)

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Application Number Priority Date Filing Date Title
KR1020130160526A KR20150072879A (en) 2013-12-20 2013-12-20 Apparatus of packet retransmission for advancing multimedia QoS and method for packet transmission

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020130160526A KR20150072879A (en) 2013-12-20 2013-12-20 Apparatus of packet retransmission for advancing multimedia QoS and method for packet transmission

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KR20150072879A true KR20150072879A (en) 2015-06-30

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