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Author Panden; Xu Peixia;
British writer Penden; Xia Department of Electronic Engineering and Information Science; China University of Science and Technology; Hefei; 230027; China);
Author: Department of Electronic Engineering and Information Science, China University of Science and Technology; 230027;
Collection and processing of literature source data, data collection and journal; Processing, editorial office mailbox, 04, 2003
Journal honor: summary of the main contents of Chinese core journals: CJFD, the source journal of ASPT.
Chinese keyword switched router; General operating system; Router operating system;
English keyword switch router; General operating system; Router operating system;
This paper presents a scheme to transplant the general operating system and its upper routing software to the switching router platform. This scheme can shield the architectural differences between the switching router and the traditional router, so as to transplant the general operating system and its upper routing software to the platform of the switching router. At the same time, it takes into account the requirements of data communication and management and maintenance, and provides the upper-layer routing software with the same interface as the traditional router, so that the routing software based on the general operating system can be quickly transplanted to the switched router without losing scalability. The practical application proves that the scheme has good flexibility and compatibility.
A new scheme of porting general operating system and its routing software to switching router is proposed. This scheme shields the architectural differences of application layer software between traditional routers and switching routers, so that the general operating system and its routing software can be supported on the switching router platform. This solution is also considered as a requirement of data communication and control functions. Provides the same access and control methods as traditional routers. ...
Supported by National 8 63 Program (863-3 17-0 199)
Docnki: Sun: SJCJ.0.2003-04-0 17
Classification number TN9 15.05
The most important job of a router is to forward IP packets according to IP packet headers and routing filtering rules. Other functions include the maintenance of routing tables and router systems. In fact, the router can be regarded as a special computer designed for IP network routing requirements. With the evolution of Internet-borne services, the Internet's requirements for router performance are constantly improving. On the exchange road
Look at this.
Article number:100429037 (2003) 0420450205.
Implementation of Switching Router Operating System Based on Universal Operating System
Pan Deng, Xu Peixia
(Department of Electronic Engineering and Information Science, China University of Science and Technology, Hefei, 230027)
Abstract: This paper puts forward a scheme to transplant the general operating system and its upper routing software to the switched router platform. This scheme can be shielded upward.
The difference between the switched router and the traditional router architecture, so as to transplant the general operating system and its upper routing software to the switched router.
On the platform; At the same time, it takes into account the requirements of data communication and management and maintenance, and provides the upper routing software with the same interface as the traditional router, thus making
Routing software based on general operating system can be quickly transplanted to switched routers without losing its scalability. The practical application has confirmed this point.
This scheme has good flexibility and compatibility.
Keywords: switched router; General operating system; Router operating system
China Library Classification Number: TN 915105; TP393 document id: a
Fund Project: Supported by the National 863 Program (86323 1720 1299).
Date of receipt: 2003203229; Revision date: 20032062 15
Switch router operating system based on
Universal operating system
PA N D eng，X U P ei2x ia
(Department of Electronic Engineering and Information Science,
China University of Science and Technology, Hefei, 230027.
Abstract: A new solution to support general operating system and its operation is proposed.
The switch rou ter is ready. This solution highlights the architectural differences between tradition and modernity.
Rou ter and sw itch rou ter are suitable for two application levels, so they can support general operations.
Both systems and their operation are on the software platform. This solution is also considered to be
Requirements for broadband data communication and control functions and the same access methods
And control are provided as traditional routers, so the routing of the two routers is common.
The operating system can quickly switch router platforms through the upgrade tool.
Flexibility. Practice has proved that the scheme has good compatibility and flexibility.
Keywords: switch router; General operating system; Conventional operating system
cite
The most important work of a router is based on the header and route of an IP packet,
Filtering rules forward IP packets. Other features include the dimensions of the routing table.
Protection and maintenance of router system. In fact, routers can be regarded as
A special computer designed for IP network routing needs.
With the evolution of services carried by the Internet, the Internet is very important for routing.
The performance requirements of equipment are also improving. In a switched router, data packets
Most processing, such as forwarding, has moved to port-centric.
Hardware, only the generation and maintenance of routing rules, network management
Complex work such as management and system maintenance is still done by software.
All right.
In fact, the operating systems used by routers can be divided into three categories.
Class: (1) A special operating system represented by Cisco's IO S often
Found in network backbone nodes; (2) embedding represented by V xWo rk s.
Embedded system, common in small offices? Home access equipment; (3)
If a common operating system is adopted, it is set at the backbone node and user access.
This kind of equipment is available on all equipment. For example, the routing products of Juniper are adopted.
Use L inux as the operating system. Various paths on a common operating system
Network management software has been developed for a long time, and its function, performance
Performance, stability and upgrade flexibility are excellent, but these softwares are still
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Data acquisition and processing
Journal of data acquisition and application. process
Document 18
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However, it is developed for the traditional router architecture and cannot be used directly.
Used in the new router architecture. This paper proposes that in the general operating system
Insert an intermediate layer in the driver stack of the system, so that the system kernel and
The upper layer software such as routing and network management running on it shields the lower layer.
The particularity of hardware, thus combining the upper software with the high-speed hardware platform.
Put them together. This scheme has been applied to high-speed edge routers.
The system has good practicability and expansibility.
1 Switched router and traditional router in the body
Differences in system structure
The router works in the third layer of the network, and its processing work mainly
Covers the next three layers of the seven-layer model, including: physical interface processing, number
According to link layer processing, network layer routing lookup, forwarding and queuing.
Management [1]. In the traditional router architecture, the hardware part
Only physical layer processing is realized, and the rest work needs to consume system calculation.
Resource completion: including CPU cycle, memory capacity and bus bandwidth.
And so on, so the performance is also limited by these resources. In switched routing
In a router, the routing processor only handles system maintenance and routing table maintenance.
A small amount of work, data flow processing is done by relatively independent hardware.
Success is no longer limited by system computing resources, so its performance is far better than that of.
Traditional router [2]. As shown in figure 1.
(A) the traditional router architecture
(b) Switched router architecture
Figure 1 Logical Structure of Router
As far as architecture is concerned, traditional routers and switching routers
There are obvious differences: in traditional routers, all physical interfaces
Directly connected to the bus, the kernel can access it directly through the bus.
Some interfaces; In a switching router, only the control card is direct.
Attached to the bus, the kernel must access each one indirectly through the control card.
An interface. This causes the driver to represent the network interface in the operating system kernel.
The difference between moving objects and moving objects: In traditional routers, there are several networks in the kernel.
Network devices drive object instances, and each instance is directly maintained through the bus.
A port that provides basic operations for the kernel and its upper software.
Seek support. In a switched router, the public network device driver
Dynamic objects cannot directly maintain ports, nor can they support system kernel and
Upper layer software operation. Therefore, the characteristics of switching router architecture
This particularity makes it impossible for general operating system and upper software to be directly applied.
There are two solutions to this problem: (1) modifying the kernel a lot.
And the source code of various related software adapted to the new architecture. this
This method has the disadvantages of large development workload, long cycle and strong limitations.
Point, lost the flexibility of using general operating system; (2) When driving
A middle layer is added to the stack to support what ordinary network-driven objects can do.
Support all operations, so that the system kernel and upper software basically
It can run on the switching router without modification. This is Ben.
The middle layer scheme proposed in this paper. This scheme overcomes the first method.
The complexity of the law, on the basis of maintaining flexibility, can be quickly
Transplanting the general operating system and upper software to the switched router.
On the hardware platform of.
2 Intermediate layer design
The functions of the middle layer include data communication and control. from
Considering data communication, the function of each port is equivalent to that of a traditional port.
The network interface in the router, so every physical port is included.
There should be a corresponding network driver instance in the kernel. In this way, we can support each other.
This upper-layer software runs to meet the needs of data communication function.
Considering the control function, we should put every possible
Logical operations are mapped into hardware operations; Ability to communicate with multiple devices.
Communication. The upper application includes system maintenance, routing software and network management software.
Pieces; The lower device includes a processing engine and a port. Tool with control function
Body implementation is related to hardware platform. Considering that multiple applications may be simultaneously
Operating a hardware device, an application can also operate multiple devices at the same time.
Equipment, support for multiple concurrent operations must be considered when implementing.
Hold on.
Based on the above considerations, the middle layer consists of the control card driver module and the intermediate frequency.
Dry network drive instance. In fig. 2 (a, b), they are given respectively.
The structure and driving mode of traditional router and the method proposed in this paper
Position and driving mode of intermediate layer.
No.4 Panden et al.: Implementation of Switching Router Operating System Based on General Operating System 45 1
Fig. 2 Location and driving mode of intermediate layer
As the core of the middle layer, the control card driver module maintains control.
All ports on the card, memory mapping, interrupts and circular buffer queues.
Resources. It realizes data channel and control channel. Downward direct drive
The dynamic control card communicates with each port and the processing engine; Right side, one side
The interface of control channel is provided by kernel call trap; another
Aspect provides a data channel interface for virtual network driver instances. Fictitious/virtual
For each physical port in the operating system kernel, the network driver instance is real.
Now is an example of a network driver. They work on the basis of the control card driver module.
Basically, it does not directly control the hardware, so it is called virtual network to drive reality.
For example. The virtual network driver instance encapsulates the information provided by the control card driver module.
Data transmission function, and provide a common network for the kernel and upper software.
The same calling interface of the network driver instance. The data communication is given below.
Implementation scheme of channel and control channel.
The function and implementation of 2 1 1 data channel
Virtual network driver instances and physical ports are in one-to-one correspondence.
The functions of the kernel data transceiver include three aspects:
(1) The packets sent to the virtual network driver instance should be sent by the
Which corresponds to the port output;
(2) The packets received by this port are also driven by this virtual network.
Submit the dynamic instance to the system kernel;
(3) The middle layer can also stream virtual network driver instances.
Control operation to avoid data loss caused by congestion.
Note that the switching structure in fig. 2 (b) is switched in fixed-length cells.
Data, the format of which is shown in Figure 3, in which the cell header occupies 4 bytes and the packet
Includes processing engine number and port number fields. For collection? Sender, processing leader
The engine number and port number are the source port and destination port of the cell, respectively.
The corresponding value of the mouth.
According to the system structure shown in fig. 2 (b), it can be known that it is triggered by processing.
The engine number and port number can determine the physical location of the port. Control card driver
The dynamic module maintains the virtual network in its internal driving information array.
Correspondence between driver instances and ports.
Figure 3 Data Unit Structure
When sending data, the virtual network driver instance receives data from the kernel network department.
Get the data to be sent separately and a pointer to the instance itself.
Submitted to the control card driver module together. On the one hand, the control card drives
Through this pointer, the module can drive the virtual network instance.
Flow control settings; On the other hand, according to the virtual network, the control card driver module
The network drive instance pointer looks up the drive information table to obtain the physical information of the target port.
Location information, including processing engine number and port number. Port physical bit
The aggregate information will be filled into all the data packets to be sent.
In the cell header. The control card driver module sends the cell to.
The exchange structure, the exchange structure and the processing engine are respectively based on the processing index.
The engine number and port number forward the cell to the destination port. The last port
Recover the original data from the received cell and send it out.
When receiving data, the port will also split the data into several cells.
Upload step by step. Considering the cyclic priority mechanism of the switching structure, I
The process of uploading data packets may be affected by data from other ports.
Stealing. Therefore, the control card driver module presses the received cell according to the source.
Port location information (including processing engine number and port number) is saved to
In different buffers. When all the letters related to the data packet are received
Element, the control driver module can reorganize the data and according to the source port
The position information is refer to that driving information table to obtain a corresponding virtual point to the port.
A pointer to an instance of the virtual network driver, thereby activating the virtual network driver.
Instance receives data. Virtual network driver instance slave control card driver module
Block, which is called in the normal way of the network driver.
The net if- rx interface submits data to the kernel. Data transceiver implementation structure
As shown in figure 4.
It is worth noting that in a switched router, the processing engine
What is exchanged through the switching structure is IP packets; In the general operating system,
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Fig. 4 Implementation structure of data transceiver
Network drivers usually process frames at the link layer. I.e. control card drive module
The data formats of data channel pairs are different. Therefore, in
When sending data, the control card driver module needs to get the link frame from the link frame.
Extract IP packets from and forward them to the port; When receiving data, the opposite is true.
The IP packet from the port is encapsulated by the link frame and then submitted upwards. for
For example, it is necessary to restore the physical grounding of the source station and the target station.
Address, load type and frame check [3]. For Ethernet carrying IP packets
Obviously, the physical address of the target station and the payload type of the frame [4] are known.
Yes The operating system used in the implementation is L inux, which is based on virtual.
Setting in the network driver source code can make the kernel not frame.
Check [5]. So only that physical address of the source station is unknown. If you need something hard,
Given the real physical address of the source station, the complexity of hardware is increased.
Degree; If the source physical address in the control card driver module is forged, then
It may lead to confusion in kernel ARP management. To simplify hardware setup
In the design, the source physics is forged in the control card driver module.
Address method, while modifying the virtual network driver source code, overloading.
Frame header processing function [6]. In this way, the kernel ARP table will not be forged.
Address, which accesses and refreshes ARP records through the query port.
Realize.
Function and Implementation of 2 12 Control Channel
The communication of control functions is also based on units, whose operations include
Maintenance management and table synchronization. Maintenance management is mainly to carry out a variety of
Inquiries are usually completed through several two-way communication. Every communication has it
The payload is only a few bytes and can be carried by a cell. but
Table synchronization is to copy the table maintained by the upper software to the related hardware.
Including ARP table, routing and classification table, etc. Table synchronization operations include
And a large amount of data transmission needs to be carried by multiple cells. control function
It's all about the equipment, so it's all under control? The feedback unit further
Physical location information of the target device must be included.
In practice, all upper-layer applications and devices
The multiplex control channel based on control communication is characterize in that:
(1) Different applications may access the same device at the same time;
(2) Applications can also access multiple devices at the same time;
(3) The operation of the same application program of the same device usually
Continuous.
In order to support this multiplexing operation, all the bearer control information and inverse
The header of the feed includes not only the physical location and operation of the target hardware.
In addition to instructions, it also includes command type and application type information. Control? counter
The feeder cell structure is shown in fig. 5.
Figure 5 Control? Feedback unit structure
Figure 5: Processing the engine number and port number to determine the device.
Location; Accept? The sending elements are the total destination of the source port of the cell.
The corresponding value of the port of; Command codes are defined between devices and applications.
Assign a code to each possible operation; Application program code in control card driver
Predefined between dynamic modules and upper-level applications. Each possible application is divided into
Match a code. These applications include network management, route maintenance and hardware dimension.
Protection and ARP information acquisition, etc.
The upper application starts control through the kernel call trap (IOCTL).
Channel operation, while giving the physical location and command class of the target device.
Type code and application type code. The control card driver module sends these letters.
The information is filled into the control unit and then sent to the equipment. The equipment puts these
Copy the code directly into the feedback cell, and then add feedback.
Information. The control card driver module allocates a cycle for each application.
Buffer, which queues the received feedback according to the application type.
Medium. The upper application reads the feedback from its corresponding circular buffer.
Cell, and then according to the physical location information in the cell, command code.
The original command corresponding to the feedback can be determined, so that the feedback data can be analyzed.
Handle it properly. In this way, the control of various control functions is realized.
Multiplexing of channels. As shown in fig. 6.
Panden et al.: Implementation of Switched Router Operating System Based on Universal Operating System 453
Fig. 6 Implementation structure of control communication
3 Conclusion theory
In view of the traditional router architecture and switched router body
Differences between architecture, common operating system and routing developed on it
Software cannot be directly applied to switching routers. This paper puts forward
Sandwich scheme can effectively solve this problem. Comprehensive review of the programme
Considering the requirements of data communication and management and maintenance, it provides the upper layer.
The interface is basically consistent with the original model, and the routing software is used in
Without losing its flexibility and scalability, it can be directly applied to
In a switched router. Although this scheme is only on a specific platform
It has been implemented on a specific operating system, but it is not difficult to see that this
This kind of thinking has no special dependence on the operating system, and it is entirely possible.
Transplant to other general operating systems. The scheme proposed in this paper has been adopted.
National 863 Project High-speed Edge Practical Integrated Access System
Good practical results have been achieved in the development of routers. This article is for the country.
The software development of high performance router puts forward an efficient and fast way.
This scheme has a good application prospect.
References:
[1] Li Shuhang se J F, Ro ss KW Computer Network: Top 2
Dawn app roach featuring the Internet. A ddison
W esley Longman publishing house, 200 1. 332~ 34 1.
[2] Liang Alei, et al. Router architecture and its development [J]. Small-scale
Computer system, 200 1, 8: 943 ~ 945.
[3] The framework of media access control. IEEE standard
802 13, 1998.36~ 40.
4. Charles Ning He. RFC 894: transmission standard 2
Transmission of IP datagram on ethernet.
1984 1 1~ 2.
[5] bovet d p. Understanding L inux kernel [M ].O reil2
Law Press, 2002. 683~ 685
[6] Rubini A. L inux device driver. Edit ion [M] for the second time.
O'Reilly Publishing House, 200 1. 455~ 458
About the author: Pan Deng (19772), male, Ph.D. candidate, research direction: Internet.
Architecture and network security, e2mail:mail.ustc.edu.cn Penden;
Xu Peixia (194 12), female, professor, doctoral supervisor, research direction: audio and video.
Coding, nonlinear processing, next generation network.
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