Existing challenges of White Box Switches
For the need for new types of business affairs and network development, the white box exchange machine has been in the device opening and drainage and network.
Programmable ASIC chips are expensive and the data plane is not widely programmable. The commercial programmable ASIC chip represented by Tofino not only has the network programmable advantages of FPGA and NPU, but also does not reduce the high performance of the ASIC chip. It is a milestone node in the future network innovation and development. Because of this, the investment in programmable ASIC chips is huge, and the market price is expensive. Only large-scale data centers will be equipped in batches. At the same time, the focus of current network evolution lies in the centralized control of logic, and the programmable data plane is still in the academic exploration stage. Most infrastructure networks still use fixed-function chips, and use OpenFlow control plane programmable white-box switches to reduce costs and open up The internet.
(2) The chip interface specifications are different, and the chip interfaces in the industry are not unified. For traditional chip interfaces, SAI is supported by OCP standardization and natively equipped by SONiC, and is strongly supported by downstream Internet service providers of switches; OpenNSL comes from Broadcom, an upstream chip giant of switches, with a high industry penetration rate and a solid foundation; switchdev is a Linux kernel component, supported by the Linux Foundation and the DentOS operating system, intends to directly replace various traditional chip interfaces with kernel mode drivers. For network programmable chip interfaces, OpenFlow, P4Runtime, and P4 are all from ONF, and they occupy an important position in the academic development of network programmable. Among them, OpenFlow has achieved a balance between academic innovation and industrial development. Great recognition; and NPL is still only a supporting language for Broadcom programmable chips. In short, there are currently many chip interface specifications, each with its own advantages and disadvantages, and no integration and unity have been formed in the industry.
The development of the white box switch industry is backward, and the network equipment has not been fully white boxed. On the one hand, OpenFlow makes little changes to switches and is accepted by mainstream suppliers. In addition, programmable chips are expensive. The current white box switches are mainly OpenFlow switches equipped with fixed-function chips. On the other hand, fixed-function chips make Open-Flow switches mainly suitable for switch scenarios with simple functions and high bandwidth, but it is difficult to meet the needs of routers and firewalls with complex logic functions in data centers, etc.
Future direction
At present, the development of new services and networks has put forward an urgent demand for white-box switches. The academic and industrial circles are also vigorously promoting the development of white-box switch technology and industrial ecology. According to the existing development trends and existing challenges, the following future development can be drawn direction.
(1) Network programming heterogeneity
If the price of programmable ASIC chips remains high, the white box switch can adopt a heterogeneous architecture combining multiple chips for high-performance network programmable. In addition to the CPU chip being responsible for computing, in order to speed up data forwarding, a dedicated switch is equipped with an additional ASIC chip. Similarly, white-box switches can also be combined with FPGA, NPU and other programmable chips for heterogeneous network programmable.
(2) Chip interface language
When an ASIC chip forms its own network instruction set like a CPU, various chip interfaces may also be abstracted into programming languages like a general-purpose programming language. The current chip interface specifications are complicated, and ASIC has not yet formed a consistent network instruction set, resulting in different levels of chip interface abstraction. In the future, developers use the chip interface language to define network functions, and then compile and convert them into network command programs through a target-specific compiler, and send them to the ASIC chip to execute the commands to complete the configuration of the switch. Or
(3) Generalization of network equipment
Traditional network equipment includes optical transceivers, switches, routers, firewalls, etc. White box switches can realize the generalization of network equipment, and a single white box switch can be used as a variety of network equipment. With the emergence of OpenFlow, white-box switches can behave like routers, switches, firewalls or other network middleware, and at the same time, programmable ASIC chips can make white-box switches maintain high performance and multi-function, and can fully adapt to various networks device scene. In this way, in the future, white box switching opportunities will be more powerful and generalized, and will be gradually and widely deployed in various network infrastructures.
