Description: This attribute indicates the set of services that this entity primarily offers. The value is a sum. This sum initially takes the value zero, then, for each layer, L, in the range 1 through 7, that this node performs transactions for, 2 raised to (L-1) is added to the sum. For example, a node which performs primarily routing functions would have a value of 4 (2^(3-1)). In contrast, a node which is a host offering application services would have a value of 72 ((2^4-1) + 2^(7-1)). Note that in the context of the Internet suite of protocols, values should be calculated accordingly: layer 1 - physical (for example, repeaters) layer 2 - datalink/subnetwork (for example, bridges) layer 3 - internet (for example, IP gateways) layer 4 - end-to-end (for example, IP hosts) layer 7 - applications (for example, mail relays) For systems including OSI protocols, layers 5 and 6 may also be counted.