Optix OSN1500 VCTRUNK Bearer Bandwidth Calculation

Calculate the theoretical bandwidth of Ethernet services that can be carried by one VCTRUNK of an Ethernet single board, so as to determine the level and number of channels of bandwidth that need to be bound for actual services.

Bandwidth = number of channels bound to the VCTRUNK × net loading rate of the bound particles × encapsulation efficiency of the encapsulation protocol × (Ethernet frame length + frame gap length )/Ethernet frame length.

The net charge rate of VC-12 is 2.176 Mbit/s and that of VC-3 is 48.384 Mbit/s, and the frame gap length is fixed at 20 bytes.

GFP encapsulation efficiency should be categorized into two cases:

When the GFP protocol uses FCS32 as the checksum field, the GFP encapsulation efficiency is Ethernet frame length/ (Ethernet frame length + 12 bytes overhead).

When the GFP protocol does not attach a checksum field, the GFP encapsulation efficiency is Ethernet frame length / (Ethernet frame length + 8 bytes overhead).

Description:

When the Ethernet board uses GFP protocol to encapsulate Ethernet services, whether to use the parity field or not can be controlled by setting the parameter "Parity Field Length". By default, FCS32 is used as the checksum field. According to the above data, it can be calculated that if the Ethernet board adopts the default GFP protocol parameter setting, when the Ethernet frame length is 1500 bytes, the theoretical bandwidth of VCTRUNK of 5VC-12 level channels is 10.938Mbit/s; when the Ethernet frame length is 64 bytes, the theoretical bandwidth is 12.025Mbit/s.

In practice, the level and number of channels required can be roughly estimated according to one VC-12 channel carrying 2Mbit/s and one VC-3 channel carrying 48Mbit/s. For example, if 10Mbit/s is required to be carried on a VC-12 channel, it can be roughly estimated according to the number of channels required. For example, if you need to carry 10Mbit/s Ethernet service, you can consider binding 5VC-12 level channels for VCTRUNK.