[Abstract] describes the main characteristics of the terabit router, discusses the main technology it uses, and points out some existing problems.
Keywords: router digital communication packet switching
1 Introduction The Internet is placing higher and higher demands on network speed, and its amazing traffic growth has become a common concern for ISPs. The computing speed of the CPU increases at a rate that doubles every 18 months, while the bandwidth of the Internet increases at a rate four times that rate. The growth of IP traffic requires higher-performance routers, which is exactly the challenge that the next-generation router, the terabit router, has to deal with. The maximum traffic of M40 introduced by Juniper Networks can reach 20Gb / sec, Cisco's 12000 can reach 60Gb / sec, and Pluris' Pluris 2 000 can use a single box to reach 149Gb / sec, and through multi-box interconnection can reach 19.2Gb / sec Traffic.
Speed ​​is not the only problem faced by current routers, and software failure is also an important issue that plagues currently used routers. Cis co System's IOS code has flaws that cannot be ignored, especially in newer versions. The Danish telecommunications operator, Danish Telecom, encountered great difficulties when using IOSV1.2 multi-protocol label switching. Cisco System technicians also encountered multiple problems when testing the code, including storage leaks on the connection card. The connection card needs to be restarted from time to time, and sometimes the restart rate can reach once every 2 hours, and it can lose up to 20 seconds of data packets when the backup card is switched and activated.
There are also flaws in Cisco's RSP. The defect of RSP may cause the entire machine to be paralyzed, so that the router can no longer calculate the route or transmit the data packet. Even installing a spare RSP will not solve this problem. In the end, you can only restart the RSP or replace the board.
Although Cisco has overcome some of the problems in the 12000 series, Cisco's strategy is to launch a new generation of high-end routers in order to better solve the existing problems.
2 Some features of the terabit router The terabit server tries to solve the existing problems satisfactorily. Table 1 shows an overview of the products currently provided by the major terabit router providers.
The superiority of the terabit router is first manifested in its throughput performance. However, there is no unified and scientific scale for the measurement of throughput performance. Currently, there are four measures for the throughput performance of terabit routers:
· Measured by the speed of the internal bus of the router. Lucent's claimed throughput rate of 6.4 Tb / sec is based on this measurement method. However, criticism from Avici believes that this figure is not significant because Avici's internal bus speed has reached 32Tb / sec.
Calculate the number of data packets. The calculated number of data packets is a very effective number for measuring the switching speed of the router, but using data packets of different lengths will produce different measurement results.
Calculate according to the performance of the cluster.
Calculate based on the total I / O capacity of a machine disk of the router. This method is more feasible because customers buy I / O; it is also relatively simple, as long as the single line rate is multiplied by the number of interfaces on the machine disk. With this method, there is currently no router of the equipment manufacturer that has reached the tertiary level. Lucent can reach 159Tb / sec, and Pluris and Cisco can reach 149Tb / sec.
Scalability will be an important feature of terabit routers. At present, terabit routers use clustering technology to expand network capacity to achieve terabit data flow routing and switching capabilities per second. By clustering multiple machine disks into a logical whole, a complete router is formed.
In terms of hardware, terabit routers have made great innovations. For example, the Cisco12016 router can quickly and completely recover from hardware or power failures. Unplugging a circuit board from the system will not interrupt the operation of the system. Routers with redundant backup switching routes and power supply equipment comply with NEBS specifications, thus ensuring the function, safety and interoperability of the equipment. This specification is detailed and specific, and even includes resistance to earthquakes and vibrations in the office environment. Unlike G-bit routers, terabit routers use redundant spare modules to improve system reliability. Lucent's 64000 and Cisco's 12016 can be configured with spare I / O modules, switch modules, and route processors. When one of the modules fails, the traffic will be switched to the standby module. Each I / O block of Pluris 20000 is equipped with two switching modules. While improving reliability, it means that half of the equipment is idle before a certain module fails. The routing calculation and I / O functions of the terabit router can operate independently, which also means that if one of them fails, it will not affect the operation of the other system. Even if the route processor is unplugged, the system can perform data route exchange.
3 Problems with terabit routers Even so, there are still many problems with terabit routers, including software and hardware. For high-performance routers, semiconductor manufacturing and design technology is always a bottleneck. How to stabilize high-speed ASIC circuits and adapt to rapidly changing industry standards is a common problem for router manufacturers. Tellabs is the first manufacturer to provide multi-machine disk routers. It uses FPGA technology. However, compared with ASICs, FPGAs are much less scalable, which is why the throughput of Tellabs routers is lower than similar products.
At present, most terabytes cannot maintain the function of route calculation at the same time when the route processor is replaced. Before the standby route processor can work normally, it will take up to tens of seconds, and people usually expect a few milliseconds of preparation.
In addition, most terabit routers cannot meet the need to add a machine disk to increase the capacity of the router.
Router operating systems cannot always avoid software failures, which usually has serious consequences. It is expected that the fault tolerance of software will be improved, but Pluris believes that even if the fault tolerance of software is improved, a completely error-free software system is impossible. Router software upgrade will also affect the normal operation of the system. Juniper's M40 can process data packets while the software is being upgraded. And Lucent, Charlotte'sWeb and NortelNetworks can correctly transmit data packets when some software is updated.
The method of using memory is also important. For example, M40 runs on Unix and uses protected mode memory. When a process uses memory errors, it will not affect other processes.
4 Conclusion The future terabit router will evolve further. The new generation of routers at the bottom will seek to integrate with other network equipment, which means that it will integrate with optical communication equipment, that is, terabit routers will communicate with optical switching equipment through MPLS. This synthesis will allow network operators to more flexibly configure the network.
On the other hand, the router will give control of the network to the software, and the user can request the required network service. For example, a video conference data packet requires that resources be reserved for a video conference session. The key to achieving this goal is the system's rapid response to user commands. In this regard, Avici product performance far exceeds Cisco's similar products. Compared with Avici, Cisco 12016 has poor programming performance. Avici takes less than one second to complete commands, but Cisco 12016 often takes several minutes.
2 Grid Held. Cisco router performance test. Beijing: Mechanical Industry Press, 2000
3 Lucent Technologies (China) Co., Ltd. WaveStar LamdaRouter wavelength router appeared in China. World Telecommunications, Volume 13, Issue 10, October 2000
4 Anonymous author. The core of the new generation backbone network-high-end road appliances. Telecom Express, 2000.9
Keywords: router digital communication packet switching
1 Introduction The Internet is placing higher and higher demands on network speed, and its amazing traffic growth has become a common concern for ISPs. The computing speed of the CPU increases at a rate that doubles every 18 months, while the bandwidth of the Internet increases at a rate four times that rate. The growth of IP traffic requires higher-performance routers, which is exactly the challenge that the next-generation router, the terabit router, has to deal with. The maximum traffic of M40 introduced by Juniper Networks can reach 20Gb / sec, Cisco's 12000 can reach 60Gb / sec, and Pluris' Pluris 2 000 can use a single box to reach 149Gb / sec, and through multi-box interconnection can reach 19.2Gb / sec Traffic.
Speed ​​is not the only problem faced by current routers, and software failure is also an important issue that plagues currently used routers. Cis co System's IOS code has flaws that cannot be ignored, especially in newer versions. The Danish telecommunications operator, Danish Telecom, encountered great difficulties when using IOSV1.2 multi-protocol label switching. Cisco System technicians also encountered multiple problems when testing the code, including storage leaks on the connection card. The connection card needs to be restarted from time to time, and sometimes the restart rate can reach once every 2 hours, and it can lose up to 20 seconds of data packets when the backup card is switched and activated.
There are also flaws in Cisco's RSP. The defect of RSP may cause the entire machine to be paralyzed, so that the router can no longer calculate the route or transmit the data packet. Even installing a spare RSP will not solve this problem. In the end, you can only restart the RSP or replace the board.
Although Cisco has overcome some of the problems in the 12000 series, Cisco's strategy is to launch a new generation of high-end routers in order to better solve the existing problems.
2 Some features of the terabit router The terabit server tries to solve the existing problems satisfactorily. Table 1 shows an overview of the products currently provided by the major terabit router providers.
The superiority of the terabit router is first manifested in its throughput performance. However, there is no unified and scientific scale for the measurement of throughput performance. Currently, there are four measures for the throughput performance of terabit routers:
· Measured by the speed of the internal bus of the router. Lucent's claimed throughput rate of 6.4 Tb / sec is based on this measurement method. However, criticism from Avici believes that this figure is not significant because Avici's internal bus speed has reached 32Tb / sec.
Calculate the number of data packets. The calculated number of data packets is a very effective number for measuring the switching speed of the router, but using data packets of different lengths will produce different measurement results.
Calculate according to the performance of the cluster.
Calculate based on the total I / O capacity of a machine disk of the router. This method is more feasible because customers buy I / O; it is also relatively simple, as long as the single line rate is multiplied by the number of interfaces on the machine disk. With this method, there is currently no router of the equipment manufacturer that has reached the tertiary level. Lucent can reach 159Tb / sec, and Pluris and Cisco can reach 149Tb / sec.
Scalability will be an important feature of terabit routers. At present, terabit routers use clustering technology to expand network capacity to achieve terabit data flow routing and switching capabilities per second. By clustering multiple machine disks into a logical whole, a complete router is formed.
In terms of hardware, terabit routers have made great innovations. For example, the Cisco12016 router can quickly and completely recover from hardware or power failures. Unplugging a circuit board from the system will not interrupt the operation of the system. Routers with redundant backup switching routes and power supply equipment comply with NEBS specifications, thus ensuring the function, safety and interoperability of the equipment. This specification is detailed and specific, and even includes resistance to earthquakes and vibrations in the office environment. Unlike G-bit routers, terabit routers use redundant spare modules to improve system reliability. Lucent's 64000 and Cisco's 12016 can be configured with spare I / O modules, switch modules, and route processors. When one of the modules fails, the traffic will be switched to the standby module. Each I / O block of Pluris 20000 is equipped with two switching modules. While improving reliability, it means that half of the equipment is idle before a certain module fails. The routing calculation and I / O functions of the terabit router can operate independently, which also means that if one of them fails, it will not affect the operation of the other system. Even if the route processor is unplugged, the system can perform data route exchange.
3 Problems with terabit routers Even so, there are still many problems with terabit routers, including software and hardware. For high-performance routers, semiconductor manufacturing and design technology is always a bottleneck. How to stabilize high-speed ASIC circuits and adapt to rapidly changing industry standards is a common problem for router manufacturers. Tellabs is the first manufacturer to provide multi-machine disk routers. It uses FPGA technology. However, compared with ASICs, FPGAs are much less scalable, which is why the throughput of Tellabs routers is lower than similar products.
At present, most terabytes cannot maintain the function of route calculation at the same time when the route processor is replaced. Before the standby route processor can work normally, it will take up to tens of seconds, and people usually expect a few milliseconds of preparation.
In addition, most terabit routers cannot meet the need to add a machine disk to increase the capacity of the router.
Router operating systems cannot always avoid software failures, which usually has serious consequences. It is expected that the fault tolerance of software will be improved, but Pluris believes that even if the fault tolerance of software is improved, a completely error-free software system is impossible. Router software upgrade will also affect the normal operation of the system. Juniper's M40 can process data packets while the software is being upgraded. And Lucent, Charlotte'sWeb and NortelNetworks can correctly transmit data packets when some software is updated.
The method of using memory is also important. For example, M40 runs on Unix and uses protected mode memory. When a process uses memory errors, it will not affect other processes.
4 Conclusion The future terabit router will evolve further. The new generation of routers at the bottom will seek to integrate with other network equipment, which means that it will integrate with optical communication equipment, that is, terabit routers will communicate with optical switching equipment through MPLS. This synthesis will allow network operators to more flexibly configure the network.
On the other hand, the router will give control of the network to the software, and the user can request the required network service. For example, a video conference data packet requires that resources be reserved for a video conference session. The key to achieving this goal is the system's rapid response to user commands. In this regard, Avici product performance far exceeds Cisco's similar products. Compared with Avici, Cisco 12016 has poor programming performance. Avici takes less than one second to complete commands, but Cisco 12016 often takes several minutes.
references
1 Radian Perlman. Network interconnection: bridges, routers, switches and interconnection protocols. Beijing: Mechanical Industry Press, 2000 2 Grid Held. Cisco router performance test. Beijing: Mechanical Industry Press, 2000
3 Lucent Technologies (China) Co., Ltd. WaveStar LamdaRouter wavelength router appeared in China. World Telecommunications, Volume 13, Issue 10, October 2000
4 Anonymous author. The core of the new generation backbone network-high-end road appliances. Telecom Express, 2000.9
Wooden Wall Clock,Wood Wall Clock,Wooden Wall Clock Led,Natural Wood Wall Clock
Guangzhou Huanyu Clocking Technologies Co., Ltd. , https://www.findclock.com