As one of the 10 Gigabit Ethernet transmission media, the biggest difference between the 10 Gigabit copper cable and the previous twisted pair is that it needs to solve the influence of alien crosstalk (AXT). Alien crosstalk is considered to be the most important noise source of 10 Gigabit Ethernet. With statistical randomness, the harm caused by it cannot be eliminated by the DSP (Digital Signal Processor) on the network equipment. With the increase of 10G port shipments, the corresponding port cost will also be greatly reduced, resulting in a lower and lower cost advantage between 10GBase-T and 10GBase-SR. In addition, due to factors such as the shortage of copper resources, the continuous call for optical access to copper, and the changes in data center network requirements and architecture, the application of 10 Gigabit copper cabling systems also has considerable challenges. These challenges mainly come from three. Aspects: copper itself, equipment factors, and network application and architecture factors.
Influencing Factors of 10G Copper Cable Itself
The frequency corresponding to the copper cable when transmitting 10 Gigabit data reaches 500MHz. The transmission performance at such a high frequency is very sensitive to external interference. Therefore, the problem to be solved by the 10 Gigabit copper cable must include two parts: the cable itself. Crosstalk (NEXT), crosstalk (AXT) from adjacent cable pairs. NEXT can be eliminated by designing appropriate lay lengths for different pairs, which is a very mature technology. AXT comes from the same wire pair between different cables. This kind of interference cannot be eliminated by designing the appropriate laying distance, which requires special design of the wiring structure, such as increasing the diameter of the cable and increasing the spacing between the distribution frame modules. Or use shielding technology to eliminate. The figure below is the structure of the 10G copper cable.
According to the layer twist characteristics of the same outer diameter circle, there are 6 other cables around each cable that have the most serious influence on it (generally only the influence of the surrounding 6 cables needs to be considered), as shown in Figure 3. Therefore, the test is also different from the traditional test method. When selecting an unshielded 10 Gigabit copper cable cabling system, it is necessary to pass the “6+1” test to ensure that the entire system meets the requirements of 10 Gigabit transmission.
The comprehensive cabling system only accounts for 5%~10% of the entire weak current project, so whether to choose a 10 Gigabit copper cabling system or an optical cable cabling system depends on the equipment ports selected for the project. However, which ports a device uses depends on many factors, two of the most important being cost and power consumption.
Under the current circumstances, 10GbE ports based on 10GBase-T still have considerable cost advantages. However, with the substantial increase in shipments of 10 Gigabit optical ports and the continuous maturity and improvement of technology, its price will have a significant increase. decline. For example, the MellanoxSX1016 in the latest price announced by Mellanox, the cost of a 1U 64-port 10GbE switch has dropped to $188 per port, so the cost advantage of 10 Gigabit copper cables as a transmission medium will gradually weaken.
The port energy consumption of 10G-T based 10GBase-T 10G copper cable connector reaches 5W/port, while the energy consumption of optical port SFP+ under the same transmission capacity is only 1.5W/port, and the energy consumption of optical port is only copper port. 30%, as shown in Figure 7. According to experience, every unit of port energy consumption saved will bring 2.6 units of other supporting energy consumption to the entire data center. A data center with 10,000 ports can save as much as 870,000 yuan in electricity bills every year. In terms of port energy consumption, SFP+ has an absolute advantage in terms of current port energy consumption.
Network Application and Architecture Factors
With the gradual commercialization of the application of new technologies such as cloud computing and virtualization, network applications have higher and higher requirements for the speed of data traffic. The cabling system of the next-generation data center will mainly focus on 40G/100G. The currently officially released standard IEEE Several different interface modes are specified in 802.3ba, but the method based on multimode fiber will gradually become the mainstream in local area networks and data centers.
With the increasing density of single cabinets in data centers, cloud computing data centers will generally adopt the ToR (Top of Rack) network architecture. The copper cabling will be greatly reduced, the data center cabling system will be mainly composed of optical cables, and the pre-connected optical cables are consistent with the rapid deployment of the data center industrialization concept and will be more widely used.
With the further increase of bandwidth requirements for network applications, the ToR architecture of data center cabling and container data centers are widely used, and 10G copper cables will face severe challenges. The increase in 10G port shipments, on the one hand, can increase the demand for 10G copper cables, and on the other hand, the accompanying cost reduction of 10G fiber ports will gradually reduce the cost advantage of 10GBase-T, thus affecting the 10GBase-T cost advantage. Sustainable demand growth for mega copper cables.