WO2011050542A1

WO2011050542A1 - Router constructing method supporting hierarchy of video quality

Info

Publication number: WO2011050542A1
Application number: PCT/CN2009/074738
Authority: WO
Inventors: 李挥; 李硕彦; 李锐源; 庄少然; 李烽; 陈曦; 陈钦树; 李亦宁; 潘凯
Original assignee: 深圳市利德嘉实业有限公司; 北京大学深圳研究生院; 上海北京大学微电子研究院
Priority date: 2009-10-31
Filing date: 2009-10-31
Publication date: 2011-05-05

Abstract

A router constructing method supporting hierarchy of video quality is provided in the present invention. The method includes the following steps: S1: priorities are set according to the kinds of data packets at an input line card, and for the video bit-stream data packets which have been hierarchically encoded, during they are cut into cells for packet switching, priority codes are allocated to the corresponding cells according to the levels of bit-streams encoded hierarchically by the video resolution; S2: a packet switching structure performs route forwarding according to the output destination addresses of the cells; S3: an output line card recombines the cells to form data packets, and then continue to forward them at wire-speed or transmit them by links; S4: N×N routing structure is formed, its inputs and outputs are divided into M line groups, and each line group is made up of G input or output ports, i.e. N=M×G; S5: a central control unit performs access admission control for the long-time-continued streams.

Description

Router construction method supporting video quality grading

Technical field

The present invention relates to the field of communications, and more particularly to a router construction method for supporting video quality grading composed of a plurality of switching units for multi-level interconnection, which is proposed for the current high-speed video application and video grading coding technology of the Internet.

Background technique

Internet traffic is growing at a high rate. In 2006, Henry Kafka, chief network architect of BellSouth Telephone Company of the United States, said at the National Fiber Optic Communications Engineers Conference that broadband home users currently download an average of 2 gigabytes (GB) of data per month, with file downloads. The popularity will reach 9 GB per household per month; Internet TV users will download 224 GB per month, while HD video users will download about 1 terabyte of data (1000G) per month.

Behind the composition of high-speed growth traffic is a major change in the composition of the flow. From the application layer and the transport layer, around 2000, typical TCP-based traffic such as Web HTTP access, email SMTP, etc. accounted for more than 90%; other domain name services DNS, routing protocol RIP, network management SNMP, etc. The UDP application accounts for about 5%; a small number of network control protocols such as ICMP, IGMP, EGP, IGP, and OPSF traffic account for about 3%. Today, when real-time video interaction, streaming media and other applications start to dominate the network, UPD accounts for about 50%. It can be predicted that the era of Internet TV, high-definition video, and high-speed mobile video of 3G and 3G will dominate the video stream. The status is more than 90% of UDP video traffic.

All in all, real-time and interactive audio and video will be the mainstream of future network services. The proportion of data files will drop to less than 10% within 5 to 10 years.

In addition, with the tremendous growth of Internet services, there are more and more requirements and applications for video transmission on IP network (Internet Protocol) networks with different rates and heterogeneous networks with different transmission characteristics. In this context, video grading coding is becoming more and more important, and its application is very extensive. Here, the Scalability of video coding refers to the adjustability of the code rate, that is, the video data is compressed only once, but Multiple frame rates, spatial resolutions, or video quality are decoded to support a variety of different application requirements for multiple types of users. For example, MPEG-4 implements Temporal Scalability through the video object layer (VOL, Video Object Layer) data structure, Spatial Scalability and mixed grading of support time and airspace. Each hierarchical code has at least two layers of VOL, the lower layer is called the base layer, and the upper layer is called the enhancement layer. The base layer provides basic information about the video sequence, and the enhancement layer provides a higher resolution of the video sequence.

The present invention provides a router system and a construction method for supporting video quality grading of hyper-scale streaming media.

The technical solution adopted by the present invention to solve the technical problem is to provide a router construction method for supporting video quality classification, which includes the following steps: S1: setting a priority according to the type of the data packet at the input line card, and having the hierarchical coding Video stream packets, when they are divided into cells for packet switching, are given corresponding cell priority coding according to the level of their video hierarchical code stream; S2: packet switching structure according to cell output destination The address is routed and forwarded; S3: The output line card reassembles the cell to form a data packet and continues to be forwarded by the line rate or sent by the link; S4: A routing structure constituting Ν Ν, whose input and output are divided into a line group Each line group consists of G input or output ports, ie N = MxG; S5: The central control unit performs access control for long-lasting streams.

A further technical solution adopted by the present invention to solve the technical problem is as follows: In the step S2, when a cell contends for an internal port or an outgoing resource, the low priority cell will be blocked and discarded without being cached.

A further technical solution adopted by the present invention to solve the technical problem is as follows: In the step S5, the central control unit performs resource reservation control, but does not perform input/output pairing scheduling for each input/output port per cell slot.

A further technical solution adopted by the present invention to solve the technical problem is: the input line card determines the classification according to the header information of the newly arrived data packet, and the video coding data of different levels of the same stream is marked as different levels of cells. .

A further technical solution adopted by the present invention to solve the technical problem is: the packet switching structure is composed of a multi-level interconnection network partially sorted from a routing hub, and the cells are sorted according to their target output port addresses and priorities, and each The level blocks cells that exceed their line group forwarding capabilities by priority. A further technical solution adopted by the present invention to solve the technical problem is: the output line card completes reassembly of the data packet, and when the cell is exchanged to the output port, the addressing bit is cancelled during the addressing process. After consumption, the cell control information mainly has the remaining active flag bits and priority flag bits, and the corresponding processor in the output line card removes the remaining control information bits and reassembles the cells into data packets. A further technical solution adopted by the present invention to solve the technical problem is to provide a router system supporting video quality grading, comprising a plurality of input line cards, a plurality of output line cards, a cell switching structure, and a central control unit. The input line card sets a corresponding priority according to the type of the data packet on the input port, and then divides the video code stream data packets that have been hierarchically coded into cells for exchange, and according to the video hierarchical coded stream The level is given the corresponding cell priority. The packet switching structure performs routing and forwarding according to the output destination address of the cell, and the output line card reassembles the cell to form a data packet and then continue to be forwarded by the line rate or sent by the link.

A further technical solution adopted by the present invention to solve the technical problem is: the packet switching structure may be partially ordered from a multi-level interconnection network of a routing hub, and the cells are sorted according to their target output port addresses and priorities, and each The level blocks cells that exceed their line group forwarding capabilities by priority. The further technical solution adopted by the present invention to solve the technical problem is: the output line card completes the reassembly of the IP data packet, and when the cell is exchanged to the output port, the addressing bit is consumed in the addressing process, and the cell control The information mainly has active flag bits and priority flag bits, and the corresponding processor in the output line card removes the remaining control information bits and reassembles the cells into data packets. The router system and the construction method supporting the video quality classification of the invention can realize a super-large-scale streaming media router structure, and the number of expandable ports is N>10000, and the bandwidth per port is lOOMbits per second. The streaming media that supports video hierarchical coding immediately discards the advanced enhanced coding portion of the media stream when the burst load traffic overloads the router switch fabric, while completely retaining the lower level basic level code stream. Quasi-circuit-switched architecture, no queuing delay, zero jitter. Access control is only allowed for newly arrived flows, but not with matching scheduling per slot. The cells are distributed and self-routing, and there is no resource bottleneck.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of a packet-cutting cell of a router construction method supporting video quality classification of the present invention.

2 is an 8x8 network of a router construction method capable of supporting video quality classification according to the present invention. Schematic diagram of the network principle. 3 is a schematic diagram of cell reassembly of a router construction method supporting video quality grading according to the present invention. detailed description

The following is a detailed description of the present invention in conjunction with the specific preferred embodiments. It is to be understood by those skilled in the art that the present invention can be delineated or replaced without departing from the spirit and scope of the invention.

With the changes in the above applications and technologies, the network's main device routers must evolve from current "data" routers to "streaming" routers. Table 1 compares streaming routers with traditional data routers.

Table 1 Comparison of "Streaming Media" Router and "Data" Router The present invention provides a router construction method supporting video quality grading, which includes the following steps:

S1: setting a priority according to the type of the data packet at the input line card, and dividing the data packets of the video code stream that has been hierarchically coded into the cells for packet switching, according to the video hierarchical coded stream The level of the corresponding cell priority encoding;

S2: The packet switching structure performs routing and forwarding according to the output destination address of the cell;

S3: The output line card reassembles the cells, and after forming the data packet, continues the line speed forwarding or Link transmission

S4: A routing structure constituting Ν Ν ,, whose input and output are divided into M line groups, each line group consisting of G input or output ports, that is, N = MxG;

S5: The central control unit performs access control for long-lasting streams.

In the step S2, when the cell contends for the internal port or the outgoing resource, the low priority cell will be blocked and discarded without being cached.

In the step S5, the central control unit performs resource reservation control, but does not perform input/output pairing scheduling for each input/output port per cell slot.

The input line card determines its classification according to the header information of the newly arrived data packet, and the video coding data of different levels of the same stream is marked as cells of different levels.

The packet switching structure is composed of a multi-level interconnection network partially ordered from a routing hub, the cells are sorted according to their target output port addresses and priorities, and the packets exceeding the forwarding capability of the line group are blocked by priority at each level. yuan. The router input line card determines its classification based on the header related information of the newly arrived packet.

The output line card completes the reassembly of the IP data packet. When the cell is exchanged to the output port, the addressing bit is consumed in the addressing process, and the cell control information mainly has the active flag bit and the priority flag bit. The corresponding processor in the output line card removes these remaining control information bits and reassembles the cells into packets.

The present invention provides a router system that supports video quality grading, comprising a number of input line cards, a number of output line cards, a cell switching structure, and a central control unit. The input line card sets a corresponding priority according to the type of the data packet on the input port, and the video stream data packet that has been hierarchically encoded is divided into video stream coded streams when they are divided into the cells for exchange. The level is given to the corresponding cell priority, and the packet switching structure performs routing and forwarding according to the output destination address of the cell. The output line card reassembles the cells to form a data packet and continues the line rate forwarding or transmission by the link.

1. Input line card

The main function of the input line card is to set the corresponding priority according to the type of the data packet at the input port. In particular, the video stream packets that have been hierarchically encoded are further divided into cells for exchange, and according to which The level of the video grading code stream is given the corresponding cell priority.

As shown in FIG. 1, the input line card can divide a packet into a plurality of small cells, and add m+n+1 bits of control information Ipm-l ... p0dld2 before each input cell. Dn, where the first bit is the active bit, pm-ΐ ... ρθ is the priority bit, and dld2...dn is the addressing bit. Taking m=3 as an example, the packet priority is set to level 8. The group priority list is as follows:

The proportion of high-priority data packets in the network is extremely low, and the occupied bandwidth is negligible. Streaming media occupies the largest traffic in network transmission. In the streaming media, the basic layer data and audio data of the video are the most important information. The biggest feature of the streaming media information is its strong real-time performance. Therefore, when designing the streaming router, priority will be given when the bandwidth is limited. Its high priority packet is sent. The video base layer and audio are set to a higher priority, which of course is to preferentially guarantee the transmission of the base layer and audio information of the video packet. The user can decode a video image having a general image quality through the received video base layer. When the bandwidth is sufficient, the user can receive the enhancement layer information (El, E2, E3) of the video image within the image decoding delay range, so that a clear high quality video image can be reconstructed.

2. Packet switching structure

If each routing node in an interconnected network uses in-band control to set its connection state, the network implements self-routing exchange. For an interconnect consisting of 2x2 routing nodes, the input signal can be sorted using a 2x2 sequencer according to the following 2-bit sequence:

10 < 00 < 11.

In a 2nx2n interconnect network, each input signal has a routing flag consisting of one active bit and the next n address bits. Each address bit represents an output selection at a particular level of routing node and is consumed when passing through a routing node of a certain level. Using such a route tagging method, the 2x2 sequencer sorts its input signals in an equivalent manner as follows: "To 0 destination address"<"idle"<"to 1 destination address".

In a multi-level interconnection network with an online group size of R, if each node is a 2Rx2R hub, and its input signals are sorted according to the following 2-bit sequence: 10 < 00 < 11 , the self-routing mechanism can be used to control signal routing. .

This achieves the goal of routing the maximum number of 0 target addresses (corresponding to 1 target address) to its R 0-outputs (corresponding, 1-output).

A routing unit takes the first two bits from each input cell as an in-band control signal. It is assumed that an active bit is generated on an active input port, followed by an address bit and a non-control bit. The address bits indicate the choice made between the two outputs of the unit. At the same time, the idle packet is a string of 0 bits. Therefore, the in-band control signals for the destination address of the 0 destination address, the packet to the 1 destination address, and the idle packet are 10, 11 and 00, respectively. In this case, the basic linear ordering of the routing unit translates to:

"To 0 destination address" < "idle" < "to 1 destination address".

The following table shows the connection status of a routing unit.

When a network contains a large number of switching nodes, the speed of switching control throughout the network depends on its degree of distribution. In distributed control, each packet should carry an in-band control signal as its prefix when entering the switching node, so that the switching decision of the node depends only on the in-band control signal carried by the input packet. In a packet switched network, an in-band control mechanism is self-routing, and control signals for packets entering a switching node are determined only by the I/O address of the packet.

In broadband applications, the control signals of packets entering a switching node need to contain as few bits as possible, so that the exchange decision process can be performed very quickly.

When a packet enters the network, its prefix for in-band control is its binary destination address dld2...dn. Bit dj indicates the choice of the jth level unit between the two outputs, and is The j-level exchange control is consumed. The parallel/cross state of the switching unit is determined only by the first bit of the two input packets. When two packets contend for the same output port of the switching unit, one of the packets will be misrouted or blocked. Usually an application allows for an empty input, so the in-band control signal actually contains an "active bit" at the forefront for distinguishing between idle packets 00... 0 of unloaded data, so the in-band control signal is usually

The basis of this mechanism is the self-routing destination address-oriented sequence of the network: for example, the Omega network is a monotonic sequence of 1, 2, ..., n. For a general 2ηχ2η榕tree type network with γ(1)=1, γ(2)=2, ..., γ(η)=η, the mechanism can be generalized as follows: A target address is binary (dld2... dn) The grouping uses the binary control stream lp^ ...pod^d^) ... d^) as a prefix. Therefore, the format of the entire packet entering the switching network is: In-band control signal data

_Lp ₂ p _lPo d ₍₁₎ d ₍₂₎ such as an ATM unit or an IP packet

Before the bit stream reaches the jth stage, the data segment (1γ(1)(1γ(2)...(1γ(ΐ-1) has been consumed, so the first control bit of the two cells is lpsPiPodyG), j The level exchange control reads only these two bits in the packet.

Switching control can be described by a finite state automaton with three states: initial, parallel, and crossed states. Its initial state is arbitrary, with a tentative connection state parallel, or cross. The automaton's excitation signal contains the first five bits from each of the two synchronized input data (= Ορ ₂ ριροΟ, 1ρ ₂ ριροΟ or 1ρ ₂ ριρ ₀ 1 Two data inputs are combined to form 9*2 ³ = 81 different According to the excitation, the switching unit copies the active bit and the priority bit at the active output, and respectively latches the connection state into parallel or cross according to the state of the automaton parallel or cross. After that, the successive bits are only The single unit passes through the switching unit in the latched connection state. When both the first and last two bits of the input signal are "10" or "11", the output contention is generated. The output contention can be differently arbitrated. The solution is to either deflect (ie misroute) or block one of the packets. An additional stimulus for the automaton comes from the frame clock that is not data input. It resets the unit to its initial state, and the following table shows the self-routing unit. Automaton behavior in . Excitation ^ dog state = initial state = parallel state = cross

Op ₂ piPoO and 0 ρ' ₂ ρΊρΌ0 outputs 0 and 0;

0 Ρ2Ρ1Ρ0Ο and 1 ρ' ₂ ρΊρΌ0 outputs 1 and 0; V

0 P2P1P0O and 1 ρ' ₂ ρ'ιρ' ₀ 1 Output 0 and 1; V

1 P2P1P0O and 0 ρ' ₂ ρΊρΌ0 outputs 1 and 0; V

1 P2P1P0O and 1 ρ' ₂ ρΊρΌ0 Output contention arbitration Ρ2ΡιΡο<ρ'2ρΊρΌ Ρ2ΡιΡο >ρ'2ρΊρΌ

1 P2P1P0O and 1 ρ' ₂ ρ'ιρ' ₀ 1 outputs 0 and 1; V

1 P2P1P0I and 0 ρ' ₂ ρΊρΌ0 outputs 0 and 1; V

1 P2P1P0I and 1 Ρ'2Ρ'ιΡ'οΟ Outputs 1 and 1; V

1 P2P1P0I and 1 Ρ'2Ρ'ιΡ'ο1 Output contention arbitration Ρ2ΡιΡο> ρ'2ρΊρΌ P2P1P0 <Ρ'2Ρ'ιΡ'ο Frame clock state <~ initial; here the output contention arbitration uses the output high priority cell, A policy for dropping low priority cells. In the actual VLSI implementation of cell control, in order to bin the logic, for the first bit from one input, there is a tendency to process only one of them at a time.

3. Output line card

The main function of the output line card is to complete the reassembly of the data packet. When the cell is switched to the output port, the addressing bit is consumed in the addressing process. The cell control information mainly has the active flag bit and the priority flag bit, and the corresponding processor in the output line card removes the remaining control. The information bits then reassemble the cells into packets. The router system and the construction method supporting the video quality classification of the invention can realize a super-large-scale streaming media router structure, and the number of expandable ports is N>10000, and the bandwidth per port is 100 Mbits per second. The streaming media supporting video hierarchical coding immediately discards the advanced enhanced coding part of the media stream when the burst load traffic overloads the router switching structure, and completely retains the level enhanced code stream. Quasi-circuit-switched architecture, no queuing delay, zero jitter. Access control is only allowed for newly arrived flows, but not with matching scheduling per slot. The cells are distributed and self-routing, and there is no resource bottleneck.

Claims

Claim

A router construction method supporting video quality grading, comprising the steps of:

S1: setting a priority according to the type of the data packet at the input line card, and dividing the video code stream data packets that have been hierarchically coded into the cells for packet switching, according to the video hierarchical coded code stream The level is given a corresponding cell priority encoding;

S3: The output line card reassembles the cells, and after forming the data packet, continues the line speed forwarding or is sent by the link;

S4: A routing structure constituting N X N, whose input and output are divided into M line groups, each line group consisting of G input or output ports, that is, N = MxG;

S5: The central control unit performs access control for long-lasting streams.

2. The method for constructing a router for supporting video quality grading according to claim 1, wherein in the step S2, when a cell contends for an internal port or an outgoing resource, a low priority cell is to be used. Block the drop and not cache.

3. The method for constructing a router for supporting video quality grading according to claim 1, wherein in the step S5, the central control unit performs resource reservation control, but does not perform input/output ports per cell slot. Input and output pairing scheduling.

4. The method for constructing a router for supporting video quality grading according to claim 1, wherein the input line card determines its classification according to the header information of the newly arrived data packet, and the video of different resolution levels of the same stream. Encoded data, marked as cells of different levels.

5. The method according to claim 1, wherein the packet switching structure is partially ordered from a multi-level interconnection network of a routing hub, and the cell outputs a port address according to its destination. And prioritize the cells, and block the cells that exceed their line group forwarding capabilities by priority at each level.

6. The method of constructing a router for supporting video quality grading according to claim 1, wherein said output line card performs reconstruction of an IP data packet, and when the cell is exchanged to an output port, the addressing bit is addressed. After the process is exhausted, the cell control information mainly has active flag bits and priority flag bits, and the corresponding processor unit in the output line card removes the remaining control information bits and reassembles the cells into data packets.

7. A router system supporting video quality grading, characterized in that it comprises: a plurality of input line cards, a plurality of output line cards, a cell switching structure, and a central control unit, said input line card being at the input port according to The type of the packet is set to the corresponding priority, and the video quality has been The size-coded video stream packets are given a corresponding cell priority according to the level of the video-graded code stream when they are sliced into cells for exchange, and the packet switching structure is based on the output destination address of the cell. Route forwarding is performed, and the output line card reassembles the cells to form a data packet and then continues to be forwarded by the line rate or sent by the link.

8. The router system for supporting video quality grading according to claim 7, wherein the input line card determines its classification according to the header information of the newly arrived data packet, and the video coding data of different levels of the same stream, Cells marked as different levels.

9. The router system for supporting video quality grading according to claim 7, wherein said packet switching structure is formed by a multi-level interconnection network partially ordered from a routing hub, and the cell outputs a port address according to a target thereof. The priorities are sorted, and cells that exceed their line group forwarding capabilities are blocked by priority at each level.

10. The router system for supporting video quality grading according to claim 7, wherein said output line card completes reassembly of the data packet, and when the cell is exchanged to the output port, the addressing bit is in the addressing process. After being consumed, the cell control information mainly has active flag bits and priority flag bits, and the corresponding processor in the output line card removes the remaining control information bits and reassembles the cells into data packets.