Avaya M770 ATM Switch User’s Guide 307

Appendix G

Setting Address Prefixes to Match Hierarchical PNNI

Algorithm for Automatic Setting of ATM Prefixes

1 Identify a pre-assigned prefix, possibly given by an ATM Service Provider. If
none, use our factory prefix 39.00.00.00.00.00.00.00.00.00.00.00.00
2 List switches that exist in the network.
3 The user identifies the highest level (L) for the hierarchy.
— The level range is 1-104. It is recommended to use the range 8-96
— The recommended value should be a multiple of eight.
4 For all switches set the L/8 left-most bytes to be the same as those bytes in the
pre-assigned prefix.
5 Select a group of switches that will be in the same level peer group, start from
the higher level peer group (lower number), and go down the hierarchy (higher
numbers).
6 Determine at which level this peer group should reside and make this level L1.
— Never select a level that is higher (lower in number) than a level that was
previously selected.
7 For all the switches in a peer group (L1), set an unused level-index (1-255) to the
(L1)/8 byte and mark this index “used”.
8 Determine whether this is the lowest level. If so, set to each one of the switches
in the peer group an unused index for the next byte and mark this index ‘used”.
9 Repeat steps 5-8 until the user decides that the process ends.
10 At this point, all bytes up to the 13th are set to 0.
Example: 1 The pre-assigned prefix is 39.00.00.00.00.00.00.00.00.00.00.00.00
2 Here is the list of switches:
A, B, C, D, E, F, G
3 The highest level of the hierarchy (user input): 40
4 The first five (40/8) bytes of all prefixes will be: 39.00.00.00.00
5 The user selects switches: A,B,C,D to be together at level 48.
6 Assign the sixth (48/8=6) byte to be 1, mark the index 1 for byte six “used”.
— The prefix for switches A,B,C,D so far is: 39.00.00.00.00.01
7 The user selects switches A,B to be together at level 56
8 Assign the 7 byte to be 1, mark the index 1 for byte seven “used”.
The prefix for switches A,B is: 39.00.00.00.00.01.01
9 The user says it is the lowest level for switch A,B
— Assign the next byte (8) to the switches in the peer group.