Functional Address

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The Token-Ring network architecture provides bit-specific functional addresses for widely used functions, such as Ring Parameter Server or Configuration Report Server. Ring stations use functional address masks to identify these functions.

The specified address is OR'ED with the currently specified functional addresses, and the resultant address is set as the functional address for the device. Functional addresses are encoded in a bit-significant format, thereby allowing multiple individual groups to be designated by a single address.

For example, if function G is assigned a functional address of C0.00.00.08.00.00 (hex), and function M is assigned a functional address of C0.00.00.00.00.40 (hex), then ring station Y, whose node contains function G and M, would have a mask of C0.00.00.08.00.40 (hex). Ring station Y would receive packets addressed to either function G or M or to an address like C0.00.00.08.00.48 (hex) because that address contains bits specified in the mask.

Note: The LANE device driver forces the first 2 bytes of the functional address to be C0.00 (hex). In addition, bits 6 and 7 of byte 5 of the functional address are forced to 0.

The NDD_ALTADDRS and TOK_RECEIVE_FUNC flags in the ndd_flags field are set.

Because functional addresses are encoded in a bit-significant format, reference counts are kept on each of the 31 least significant bits of the address. Reference counts are not kept on the 17 most significant bits (the C0.00 (hex) of the functional address and the functional address indicator bit).