Abstract: The Internet current capacity’s swift growth, proposed to the backbone network transmission a higher request, we developed the total turnover rate to reach as high as 1.28T for this reason the bit high performance IPv4/v6 router. This router provides 2.5GPOS, the 10GPOS,100M ethernet, the 1000M ethernet, the 10GLAN ethernet, connections and so on 10GWAN ethernet, may facilitate the network. This article introduced briefly this router’s gross structure, and deep research 2.5GPOS has met oral plate’s design with to realize.
Key word: Router; Synchronized light network; Synchronized digit series; Embedded
1. Introduction
As Internet’s key position, the router is being quicker toward the speed, the grade of service to be better and the change develops in the integrated management three directions. Now chip speed every 18 months turn, but Internet’s current capacity is every six months turns. Everybody also with emphasis manifests to the router research in enhances the router in the processing speed, continued proposed the kilomegabit exchange router (GSR, Gigabit Switch Router) and too the position exchange router (TSR, Terabit Switch Router).
Is approved gradually along with the IP core status, IP over ATM, then ATM over SDH way by IP direct over SDH way substitution. The transmission speed also very quickly (622Mbps) jumps from OC-12 to OC-48 (2.5Gbps). The POS technology already widely used in the backbone network, but the POS connection becomes a high-end router essential part.
I develop T bit router, the system total turnover rate may reach 1.28Tbps, peak value exchange capacity is 2.4Tbps, but each port may achieve 10G the repeater speed. In order to achieve 10G the repeater speed, this router has used 4 group 2.5GPOS connections. The article described the 2.5GPOS connection e architecture design and the performance demand analysis in second, elaborated in detail in third the software architecture’s design with realizes.
2. Hardware gross structure design
This router e architecture by the line interface subsystem, the repeater processing subsystem, the light back board exchange network sub-system and the internal communication subsystem four major part is composed. After the connection receives the data packet, first judges this package’s destination address whether for this router, is delivers for the veneer software and gives master control processing by the internal communication subsystem; Otherwise fills internal Baotou, an indication package of type, the agreement type, the goal rack number, the port number, information and so on connection number, gives the repeater processing subsystem by the coaxial cable, retransmits again from the light back board to the goal connection. The package which connection transmits Bao who the extension He this router sends out, carries on after road processing transmits again.
2.1 performance demand analysis
1) acts according to the former router the experience, usually in the hardware FPGA high speed channel work is quite stable under the 2.5Gbps speed. On A data-in speed 10Gbps, 4 2.5Gbps high speed channels may pass to the data the repeater processing module. But, the line interface module’s function realizes the request: After the data wraps in passes through the line interface input processing module processing, must add on 128 bit namely 16 byte the internal labels. Considers the limiting case, A receives is 40 byte ultra short packages, that B output’s data’s limiting speed is: [10Gbps× (40 byte 16 byte)] /40 byte=14Gbps. Therefore, we design use two group 2.5Gbps the high speed channels to pass on A receive in the 10Gbps data 1/4 are the 2.5Gbps data to the repeater processing module. Then, B maximum output speed for 2.5Gbps×8=20Gbps, completely satisfies B to transmit orally the belting leather wide request.
2) in the even input service model and under the balanced output model condition, the hypothesis fixed-length grouping service intensity Lamda is 0.95, to control the grouping the loss probability is smaller than 10-8, may calculate the Output queue which needs to group cushioning capacity S approximately is 650 groupings. Counts in the significance the IP grouping statistical length is 508 bytes. Considered the internal grouping label attaches 24 bytes, need the cushion the IP grouping byte count are equally 532 byte total cushioning capacities for 650×532×8=2766400 (Bits), namely approximate is the 2.8MBits cushioning capacity.
3) the book system’s connection speed must achieve 10Gbps, if each package is 40 bytes, then the limit table look-up speed was by now:
Regarding input table look-up module another target for a table capacity. Calculated according to the ultimate capacity that T bit router has 8 racks, each rack 8 ports, each port 8 connections, each connection’s IPv4 unicast multicast, the IPv6 unicast multicast address grand total has 64. Then a limit table capacity is 8*8*8*64=32768 (32k) the strip. Achieves these two design target is this module design difficulty. Finally, we have chosen section of CAM, has the 64K strip table item, the table look-up speed can achieve 100MSPS. Such target definitely may achieve this module the request.
2.2 subsystem function division and module design
The following chart shows, 4 2.5G line interface subsystem may divide into the electro-optic and the string and transforms the module, the link level processing module, to output the FPGA processing module, to input the FPGA processing module, the agreement text to deliver the buffer module, the input table look-up module and the clock processing module. Is convenient for the description, is called The book system and the router exterior connection, processes subsystem’s connection with the repeater to be called B, is called G with the light back board subsystem’s connection, is called F with the veneer processor’s connection, is called J with the clock subsystem’s connection.
When from router exterior receive data, the electro-optic and the string and transform the module to be responsible to receive 4 group 2.5Gbit/s serial light signal from A, transforms 16 group difference 622Mhz electrical signal; Delivers carries on link level processing by the link level processing module. The link level processing module withdraws the ppp text from the SDH frame, then gives inputs the FPGA processing module. Inputs the FPGA processing module in view of an input package of type, to inputs this aircraft IP address table table look-up which the table look-up module saves, carries on by-pass processing, if this text’s goal delivers for this router master control, otherwise retransmits to B. Outputs the FPGA processing module to be responsible to receive master control after-crops agreement Bao Hecong the system light back board retransmits G data packet, after the closed circuit, gives the link level processing module. The link level processing module after road’s ppp text seal in the SDH frame, and transforms by the electro-optic and the string the module to transform the light signal to transmit. The clock processing module provides the overall situation clock and for this module the clock which withdraws from the line outputs this module to the clock board.
3. The software gross structure design with realizes
MPC860 is based on the PowerPC structure communication controller. It is not only the integrated microprocessor, moreover many peripheral device’s functions also integrates in together. MPC860 has the storage control unit, its storage control unit’s function is very strong, may support each kind of memory, including each kind of new DRAM and Flash, and may realize with memory’s seamless connection.
Embedded real-time operating system VxWorks which (Wind River) promotes by the US National customs River Company because of uses in Mars debarkation vehicle being renowned in one’s time. VxWorks is a set has the micro essence, the high performance, the expandable operating system, supports the widespread network service agreement, and can act according to the user the demand combination, the fluctuation. In addition its outstanding development environment Tornado, caused it to become the embedded operating system’s first choice. Chooses MPC860 to add on embedded strong real-time operating system VxWorks definitely to be possible to buy full veneer processing the performance demand.
The figure above has demonstrated the veneer software gross structure. The veneer operating system is uses VxWorks, the veneer processor uses MPC860. The router has the different type line to meet the oral plate, each seed grafting oral plate needs to complete many same functions, may place these same functions in an independent module to realize, reduces the redundancy work. The board level support module provides with master control services and so on between software’s correspondence, task management, memory management and timer management for the veneer application; But the veneer application for the line interface veneer software module, completes veneer repeater processing.
The veneer software mainly completes the function includes: To various types veneer hardware’s initialization and the disposition, receive the veneer control command which and processes of master control after-crops, completes the software and hardware program load, the ethernet meets the oral plate to move IPv4 the ARP agreement, the maintenance and to the master control circular ARP information, the agreement data (source/target address for this router grouping) receives and dispatches, maintains the router connection address message, error message processing, the record text reports, the service performance statistical data collection and reporting, maintain correspondence connection between the veneer and the master control board.
According to these functions, divides into the veneer software the initialization module, the master control demand processing module, the connection chip monitoring and the service performance statistics module, the news distribution module, wraps the transmission module, reports the receive module, the self-checking module, the CAM table maintenance module, the tool function module. When normal operation establishes four duties: The master control processing duty, the statistical duty, the contract award duty, receives a package of duty.
Its data processing flow like figure to the right: The veneer hardware receives this router package, reads in inputs FIFO, receives the package of duty read-out package, seals in the definition internal data structure, in the transfer board level support module’s transmission function issues master control; Master control after-crops Bao Ze by news distribution module processing, the agreement bawyo for the contract award duty, reads in again outputs FIFO, then transmits, controls Bao Ze to hand over master control processing module processing, completes to the corresponding function.
Because this connection needs to achieve 10G the speed, between various duties must have stable and high speed alternately machine-made. The VxWorks operating system corresponded for the duty has provided many mailing addresss, including sharing memory, signal quantity, news formation and pipeline, Sockets and long-distance transfer and so on. The news formation allows the length to variable, the number invariable news formation, may satisfy between the multi-duties to correspond. The VxWorks Wind essence may use based on the priority grab type task scheduling and the rotation dispatch unifies, must therefore certainly establish various duties the priority, if the memory duty’s priority must be higher than the master control processing duty, the master control processing duty must be higher than receives the contract award the duty. But must establish various duties in advance to the same priority’s duty the execution time, otherwise first will obtain CPU the duty to monopolize, hinders other character movement. In brief, must certainly understand VxWorks fully in the software design the working mechanism, not only otherwise cannot design the benefit high procedure, instead will hinder VxWorks the effective movement.
4. Concluding remark
Fast growth’s network and Internet traffic proposed a higher demand to the existing network foundation structure, also has stimulated the high performance network connections development. This article introduced briefly the turnover rate reaches as high as the 1.28T bit high performance router, and studied its 2.5GPOS connection to realize the technology, first might penetrate to the POS technology in realizes with the application in research, next might enrich the router interface function, increased the router connection the flexibility, the enhancement router compatibility, so that the more widespread use network resource, realized the network system and the construction evolution, provided the technical mentality which for the high performance router’s development and the following development might use for reference.
Reference:
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