Buck Rogers K4ABT Návod k obsluze Strana 35

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The Packet Radio 2 N 1 Handbook by Buck Rogers K4ABT
Section 1; Packet Radio “The BasicsSection 2; The X1J4 System Node Operator’s (SNO) Handbook
Section II; TheNET X1J4 System Node Operators Handbook __ Page 35
Chapter 14 Section II
ROUTE QUALITY ANALYSIS:
For each route in its routing table, TheNET X1 maintains a route quality value in the range 255 (best) to 0 (worst). This
allows it to keep alternate routes in order of quality, and to select the best available route to a destination. A route quality
value can best be visualized as a fraction (the value divided by 256) which quantifies the speed and reliability of a particular
route in comparison to a theoretically perfect route (an infinitely fast and perfectly error-free path) of quality 256.
For example, a route of quality 230 can be thought of as being "90% perfect" in speed and reliability (230/256 = 0.90). The
quality of each frequency used by a TheNET X1 node is established by the sysop of the node. As a starting point, we
suggest the following values to be used as baud/quality/parameters:
Baudrate Description Quality % Perfect
9600-baud RS232 wire interconnect (2-port) 255 99%+
9600-baud RS232 satellite interconnect (2-port) 252 98%
9600-baud RS232 wire interconnect (3-port) 248 97%
9600-baud HDLC isolated inter-node backbone 240 94%
1200-baud HDLC isolated inter-node backbone 224 88%
1200-baud HDLC user-accessed frequency 192 75%
1200-baud HF frequency 180 70% (Not recommended)
300-baud HDLC HF frequency 128 50%
The quality of a multi-segment route is simply the product of the qualities of each individual segment, where quality values
are treated as fractions with an implicit denominator of 256. For example, a four-segment route that consists of two 9600-
baud RS232 interconnect segments (quality 255) and two 1200-baud HDLC backbone segments (quality 224) has a
calculated quality of 194 (255/256 times 255/256 times 224/256 times 224/256 equals 194/256). Quality calculations are
rounded to the nearest 256th.
In practice, I have found that path quality for a 1200 baud neighbor node should be locked at 192 and path quality for a
9600 baud backbone neighbor node should be locked at 240.
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