CN1848795A - Method for realizing large data packet quick retransmission in real-time communication system - Google Patents

Abstract

A method for realizing quick retransmission of big data packet in real time communication system includes carrying NAT and firewall filter treatment in receiving buffer storage and setting up an index in high speed buffer at the same time, recording concrete information of stream and port required to be retransmitted, interrupting the processing program to seek high speed buffer when stream succeedent packet is arrived, sending out data packet in internal memory directly by relevant port according to information in high speed buffer with no necessary of copying data packet from internal memory to buffer.

Description

In real-time communication system, realize the method that big packet is transmitted fast

Technical field

The present invention relates to the router field, relate in particular to the method for the forwarding of the big packet of a kind of router.

Background technology

ReOS is the real-time communication system of HiPER series router.The ReOS system mainly operates on the embedded type CPU, as the Power PC of Motorola Inc., and ARM7 and ARM9 nuclear, MIPS nuclear, IntelXscale also may operate in the CPU etc. of the i386 compatibilities such as CPU of i386 compatibility.ReOS has realized that by CPU and external network interface chip the packet of the network equipment transmits and other management functions, and in present system, the forwarding of packet mainly realizes by CPU.

And a typical mid-range-and-low-end routers system is the CPU of kernel with ARM9, and is as follows in the flow process of the processing mode of ReOS:

1. the chip of network interface card is received the packet of Ethernet, this packet is placed on receives buffering, sends interrupt message to CPU then;

2.CPU receive after the interrupt message that CPU carries out task scheduling, call the task of needing processing;

3. this task copies packet in the internal memory to from receive buffer memory, handle accordingly, as decision abandons still forwarding through the firewall filtering module, perhaps handle and revise IP address and port through NAT, perhaps need to carry out flow control and be placed into queue queue etc.;

4. treated packet is forwarded to corresponding ports, perhaps abandons, perhaps forward the application program on upper strata to;

5. after the processing data packets that need forward finishes, newly-generated packet is delivered to corresponding transmission buffering.

In above step, the first step is than very fast, and second step need to begin CPU to intervene in a large number, and is more consuming time.Under this pattern, the forward efficiency of ReOS, at typical A RM9 kernel, dominant frequency is on the CPU of 166Mhz, the numerical value that bag is transmitted is 6000PPS (Packet Per Second), that is to say that per second can be transmitted 6000 bags when Bao Changwei 64 bytes.The throughput of no packet loss is at 2Mbps.

Under this disposal ability, when Bao Changwei 1518 bytes (the maximum bag of Ethernet is long), the quantity of the bag that per second can be transmitted is also below 5000.

But because the continuous development of network application, the user is also more and more higher to the requirement of access bandwidth.

Summary of the invention

The technical issues that need to address of the present invention have provided a kind of method that big packet is transmitted fast that realizes in real-time communication system, be intended to solve the above problems.

In order to solve the problems of the technologies described above, the present invention realizes by following steps:

Network interface card is received the packet that is sended over by other equipment;

Whether CPU has pending packet to the network interface card inquiry at set intervals;

If pending packet is arranged in the network interface card buffer memory, enters interrupt handling routine;

Interrupt handling routine is received first packet of " stream " that sends over, carries out flow process and transmits; Described " stream " is meant to have identical source address, destination address, source port, the packet of destination interface and agreement; Described flow process is transmitted and comprised: in receiving buffer memory this packet is carried out NAT, an index is set up in processing such as firewall filtering simultaneously in speed buffering, and the specifying information of this stream and the port that needs to transmit are noted;

When " stream " bag reaches subsequently the time, interrupt handling routine removes to search speed buffering, according to the information in the speed buffering packet is directly sent by the corresponding port, no longer the data of internal memory is copied to earlier and sends buffering;

Compared with prior art, the invention has the beneficial effects as follows: more than long 512 bytes of bag reach, reached two-way linear speed.

Description of drawings

Fig. 1 is the comparison diagram of the technology of the present invention and another " stream ";

Embodiment

Below in conjunction with accompanying drawing and embodiment the present invention is described in further detail:

Network interface card is received the packet that is sended over by other equipment;

Whether CPU has pending packet to the network interface card inquiry at set intervals;

If pending packet is arranged in the network interface card buffer memory, enters interrupt handling routine;

Interrupt handling routine is received first packet of " stream " that sends over, carries out flow process and transmits; Described " stream " is meant to have identical source address, destination address, source port, the packet of destination interface and agreement; Described flow process is transmitted and comprised: in receiving buffer memory this packet is carried out NAT, an index is set up in processing such as firewall filtering simultaneously in speed buffering, and the specifying information of this stream and the port that needs to transmit are noted;

When " stream " bag reaches subsequently the time, interrupt handling routine removes to search speed buffering, according to the information in the speed buffering packet is directly sent by the corresponding port, no longer the data of internal memory is copied to earlier and sends buffering.

Adopt the CPU poll and do not copy the mode of internal memory, the forwarding of parcel is increased, still the forward efficiency to big bag has improved a lot.More than long 512 bytes of bag reach, reached two-way linear speed.

Be that the present invention and the technology that adopts another " stream " compare (as shown in Figure 1) below:

The technology of another " stream " is to realize by following steps:

Network interface card is received the packet that is sended over by other equipment, enters interrupt handling routine;

Interrupt handling routine is received first packet of " stream " that sends over, carries out flow process and transmits; Described " stream " is meant to have identical source address, destination address, source port, the packet of destination interface and agreement; Described flow process is transmitted and is comprised: packet is copied in the internal memory from the network interface card buffer memory, carry out again handling through fire compartment wall as needs, perhaps handle etc., in speed buffering, set up an index simultaneously, the specifying information of this stream and the port that needs to transmit are noted through NAT;

When " stream " bag reaches subsequently the time, interrupt handling routine removes to search speed buffering, according to the information in the speed buffering, the bag content in the internal memory is copied to earlier send buffering, waits for the transmission of this port then.

Claims (1)

1. in real-time communication system, realize the method that big packet is transmitted fast for one kind, realize by following steps:

Network interface card is received the packet that is sended over by other equipment;

Whether CPU has pending packet to the network interface card inquiry at set intervals;

If pending packet is arranged in the network interface card buffer memory, enters interrupt handling routine;

Interrupt handling routine is received first packet of " stream " that sends over, carries out flow process and transmits; Described " stream " is meant to have identical source address, destination address, source port, the packet of destination interface and agreement; Described flow process is transmitted and comprised: in receiving buffer memory this packet is carried out NAT, an index is set up in processing such as firewall filtering simultaneously in speed buffering, and the specifying information of this stream and the port that needs to transmit are noted;

When " stream " bag reaches subsequently the time, interrupt handling routine removes to search speed buffering, according to the information in the speed buffering packet is directly sent by the corresponding port, no longer the data of internal memory is copied to earlier and sends buffering.

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