Bound Registers

In the interval labelling scheme, the addressing space is divided in intervals defined by an upper and lower limits called bounds. Each bound is coded on 2 bytes called mbound (Most Significant Byte) and lbound (Less Significant Byte) since we allow 2 byte headers. The user must load these bounds registers according to the topology of the network. In an addressing space coded on 16 bits, we obtain 65536 different destinations for a packet. Since there are 8 bounds registers, we divide this space into 8 intervals. An example is given on table 5.1. A header whose value stands in interval [53699,...,65535] [0,...,501[ falls in interval 7. If it belongs to [501,...,2570[, it stands in interval 0 and so on. In case of 1 byte headers the value of the lbound is unused.

Table 5.1: Exemple of interval bound table
interval number mbound[7:0] lbound[7:0] #dec

00000001 11110101 501

1 00001010 00001010 2570

2 00010100 11000011 5315

3 00111111 10000011 16259

4 01101001 10001000 27016

5 10001111 01000000 36672

6 11001000 00100101 51237

7 11010001 11000011 53699

**Table 5.1:** Exemple of interval bound table
interval number	mbound[7:0]	lbound[7:0]	#dec
	00000001	11110101	501
1	00001010	00001010	2570
2	00010100	11000011	5315
3	00111111	10000011	16259
4	01101001	10001000	27016
5	10001111	01000000	36672
6	11001000	00100101	51237
7	11010001	11000011	53699

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