PPS and BPS

Packet forwarding rate indicates the size of the packet forwarding capability of the switch. The Unit is generally PPS (packets per second). Generally, the packet forwarding rate of a switch ranges from dozens of KPPS to hundreds of mpps. Packet forwarding rate refers to the number of million packets (mpps) that the switch can forward per second, that is, the number of packets that the switch can forward simultaneously. Packet forwarding rate reflects the switch switching capability in units of data packets.

The backboard bandwidth of A vswitch is the maximum amount of data that can be transferred between the vswitch interface processor or interface card and the data bus. The backboard bandwidth indicates the total data exchange capability of a vswitch. The unit is Gbps. It is also called the switching bandwidth. The bandwidth of A vswitch ranges from several Gbps to hundreds of Gbps. The higher the bandwidth of A vswitch, the stronger the ability to process data, but the higher the design cost.

Therefore, the second-layer capability uses BPS, and the third-layer capability uses PPS to support the third-layer switching equipment. The manufacturers will provide the second-layer forwarding rate and the third-layer forwarding rate respectively.

In addition, let's talk about how PPS is calculated.

We know that the wire speed package for 1 gigabit port is 1.4881 mpps,
The wire speed packet forwarding rate of the 0.14881 Mbps port is mpps. This is an international standard, but how can we get it?
During the transmission process, the specific data packet will be preceded by 64 (Leading Character) preamble, which is a 64-byte data packet. Originally, there are only 512 bits, however, during transmission, there will actually be 512 + 64 + 96 = 672bit, that is to say, the length of a data packet is actually a 1000-bit gigabit port line rate packet forwarding rate = 672 Mbps/1.488095 = 1.4881 mpps, which is about 0.14881 mpps, and Mbit/s apart from 10 for mpps.

In the future, it will be very easy. In fact, simply multiply the PPS value in the device parameter by 672, and then it will be converted into a popular BPS concept that we can understand.
Generally, sales are changed to 672 to 500 to facilitate calculation and integer-based understanding.

After understanding this, I suddenly found that the selection of network devices was so simple. I only need to predict the total number of nodes in the network and the bandwidth and traffic requirements, then the required vswitch performance models and vro models are ready.
Note:
Many of the current devices are layer-3 switches. The parameters we see are for layer-3 and layer-2 modules respectively.
For example, the 6509 mentioned on the fourth floor is like this.
The data exchange capability is 720 Gbps, but the routing packet forwarding capability is 400 mpps. There is no conflict here. Because neither Data describes one thing.