ADTRAN Total Access 5000 Deployment Manual page 117

• Ethernet frames between 513 and 1024 bytes, inclusive:
• Ethernet frames 1025 bytes or larger:
The equations above assume that the NetVanta is not adding an extra tag to the customer
traffic (ie. when the customer traffic is tagged, and the customer edge tag is not being
preserved). In any case where the customer tag is preserved (the most likely scenario), and the
NetVanta 838 is simply stacking the provisioned service provider tag (s‐tag) to the customer
tag (if present), the calculation must account for the additional 4 bytes for the s‐tag, as follows:
• For Ethernet frames 512 bytes or smaller:
• For Ethernet frames between 513 and 1024 bytes, inclusive:
• Ethernet frames 1025 bytes or larger:
To determine the EFM bonding group bandwidth that needs to be provisioned so that the
customerʹs commissioned rate is provided, divide the customer rate by this percentage:
Required EFM Group Rate = (Customer Commissioned Rate) / (% Utilization.
Following are example calculations for customer throughput percentage, given a fixed frame
size, assuming the NetVanta 838 is adding a VLAN tag:
• For 64 byte Ethernet frames (worst case scenario):
• For an 8 Mbps bonding group, the actual throughput would be:
• If a customer is sold a 4 Mbps service, the required EFM group size calculation would be:
• For 1500 byte Ethernet frames:
• For an 8 Mbps bonding group, the actual throughput would be:
• If a customer is sold a 4 Mbps service, the required EFM group size calculation would be:
Another point of reference is the EFM bonding group utilization percentage that is seen
assuming uniform distribution of frame sizes, from 64 to 1518 bytes. This value is 96.0%
assuming the service provider VLAN tag is being added to the customer traffic. Assuming
uniform traffic size, the EFM group would need to be a factor of 1.042 greater than the
commissioned customer rate to provide the full customer rate.
The service provider is best suited to decide what traffic model it wants to use for network
planning, but the tools above should allow them to suitably determine the EFM Group
bandwidth needed to provide the customerʹs full traffic rate.
65K510DEP08-1A
% Utilization = (Frame Size) / (Frame Size + 16) x (64/65)
% Utilization = (Frame Size) / (Frame Size + 24) x (64/65)
% Utilization = (Frame Size) / (Frame Size + 12) x (64/65)
% Utilization = (Frame Size) / (Frame Size + 20) x (64/65)
% Utilization = (Frame Size) / (Frame Size + 28) x (64/65)
% Utilization = (64) / (64 + 12) x (64/65) = 82.9%
8 Mbps x .829 = 6.632 Mbps
(4 Mbps) / (.829) = 4.825 Mbps
% Utilization = (1500) / (1500 + 28) x (64/65) = 96.7%
8 Mbps x .967 = 7.736 Mbps
(4 Mbps) / (.967) = 4.137 Mbps
Section 4, EoCu Provisioning - Create an EFM Bonding Group
4-13