Frame bursting in Computer Network

Frame bursting is a transmission technique used at the data link layer of the OSI model to increase the rate of transmission of data frames. It can be effectively deployed in Gigabit Ethernet networks to increase network throughput and is specified in the IEEE 802.11e QoS specification.

By this technique, a sender can transmit a series of frames in succession without surrendering control of the transmission medium. A set of smaller frames may be concatenated to form a large frame that is transmitted at one go, reducing overhead and improving efficiency.

How Frame Bursting Works

Standard Transmission (Without Frame Bursting)

Suppose a station needs to send three short frames, F1, F2, and F3 via a shared medium. For sending F1, the station contends for the medium for a time equal to DIFS (Distributed Inter-Frame Space). If no other station is transmitting, the station gets the channel. After the frame is sent, the station waits for a time equal to SIFS (Short Inter-Frame Space) for the acknowledgment. The process is repeated for frames F2 and F3.

The time wasted for DIFS is considerably high, particularly in situations where the data length is low and the number of stations contending for the transmission medium is low.

Frame Bursting Transmission

The sender and receiver acquire the channel for a given transmission time limit while contending for transmission of the first frame. The sender waits for DIFS only for transmitting frame F1. After the acknowledgment for F1 has been received, the sender does not need DIFS since the channel is already acquired. It waits for SIFS before transmitting the subsequent frames. This continues until the permissible total transmission time limit is reached.

Frame Aggregation with Frame Bursting

Frame bursting may be combined with frame aggregation. In this case, a concatenated sequence of multiple frames is transmitted instead of separate small frames. This eliminates the inter-frame gaps and overheads for headers completely, which is particularly suitable when frames contain small payload sizes.

Advantages

• Reduced contention overhead − Eliminates multiple DIFS waiting periods for successive frames.

• Improved throughput − More data transmission time relative to control overhead.

• Better bandwidth utilization − Particularly effective for small frame sizes with high control overhead.