Bit, byte, BPS, BPS, PPS, and Gbps

Bit, byte, BPS, BPS, PPS, and Gbps

The smallest unit in computer memory. In binary computer systems, each bit can represent a digital signal of 0 or 1.

Byte

The unit of bytes, which generally indicates the unit of storage media size. a B (usually capital B to indicate byte) can represent a character (~ Z), number (0 ~ 9), or symbol (,.?! % & +-*/), But the Chinese text requires two bytes.

1 byte = 8 bits
1 kb = 1024 bytes
1 MB = 1024 KB
1 GB = 1024 MB
Note: When the computing storage medium is large, it needs to be converted to the Npower of 2 (1kb
= 2 ^ 10 bytes ).

BPS

"Bits per second" is commonly used to indicate the transmission rate of data machines and network communication. For example, the gigabitethernet Port:
5 minute input rate 38410000 bits/sec, 6344 packets/sec
382410000 bits/sec = 382.41 Mbps
Therefore, it is often said that fast Ethernet can achieve 100 MB of transmission, in fact, the actual transfer file size is only 10 MB = MB
Note: When calculating the transmission rate, you can directly use 1000 for conversion (1 MB =
1000 kb = 1000,000 bit ).

BPS

"Byte per second" computers generally display speed at BPS, but sometimes it will be confused with the transmission rate. For example, the bandwidth claimed by ADSL is 1 Mbps.
But in practice, the download speed is not 1 MB, only 1 Mbps/8 = 128 Kbps

That is to say, B, which is related to the transmission speed, generally refers to bit.
Capacity-related B generally refers to byte.

PPS-packet forwarding Rate

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.

Gbps-backboard bandwidth

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.

You can determine the bandwidth availability of a vswitch backboard from the following two aspects:
1. (capacity of all ports × number of ports × 2) less than or equal to the bandwidth of the backboard, enabling full-duplex non-blocking switching. This proves that the switch has the conditions to maximize the data exchange performance.
2. Full configuration throughput (mpps) =
The number of fully configured GE ports x 1. 488 mpps. The theoretical throughput of One gigabit port when the packet length is 64 bytes is 1.488 mpps.

GE port theoretical Throughput-1.488 mpps

The minimum packet length for Ethernet transmission is 64 bytes. The packet forwarding speed is measured by the number of 64 bytes of data packets (minimum packet) sent per unit time.

For Gigabit Ethernet, the calculation method is as follows:
1000 Mbps/(64b + 8B + 12B) × 8bit) = 1.488095pps
Note: When the Ethernet frame is 64 byte, the fixed overhead of the 8 byte leading character and the 12 byte frame gap must be considered.
In Ethernet, each frame header must contain an 8-byte leading character, which is used to tell the listener that data is coming. Then, there must be a frame gap between each frame in the Ethernet, that is, after each frame is sent, wait for a while before another frame is sent. In the Ethernet standard, the minimum value is 12 bytes, however, the frame gap may be larger than 12 bytes in practice. Here I use the minimum value. Each frame has a fixed overhead of 20 bytes. (In addition, the 20 bytes of information cannot be captured by the packet capture software)

Therefore, the packet forwarding rate of a full-duplex Gigabit Ethernet port when forwarding 64 bytes of packets is 1.488 mpps.

The following is a packet forwarding rule for common Ethernet ports:

1. 10 Gigabit Ethernet: 14.88 mpps
2. ge Ethernet: 1.488 mpps
3. 0.1488 Mbps Ethernet: mpps

From: [http://www.zhaocs.info]