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RSPF
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1991-09-18
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==== NOSview [137]
rspf
====
RSPF is the Radio Shortest Path First protocol. Each node that
runs RSPF tries to figure out which other nodes are its
neighbours. They do so by listening for Router-to-Router-Hello
(RRH) messages sent by other RSPF nodes. When such an RRH
message is received, NOS will determine whether the link is bi-
directional by pinging the other station.
All neighbour nodes might not be running RSPF, but they are
discovered by monitoring changes in the ARP table.
The quality of the AX.25 link is assessed by comparing the number
of sent and received AX.25 frames on the channel from the
particular node. The routing table broadcasts contain not only a
list of the originating nodes' neighbours, but a list of
everybody else's neighbouring nodes as well.
Using this information, it is possible to calculate the shortest
path to any station on the network.
To activate RSPF, do the following:
1. Set the broadcast address for the interface (e.g. with the
command 'ifconfig tnc0 broadcast 44.255.255.255'). This
automatically creates a routing entry for 44.255.255.255 in the
routing table. If you intend to use RSPF on more than one
interface, the interfaces must be given different broadcast
addresses, otherwise the routing entries will overwrite each
other. Exactly how the broadcast looks like is of minor concern
to NOS, since any IP datagram sent inside an AX.25 frame for
"QST" is regarded as a broadcast datagram.
2. Configure the interface as an RSPF interface with quality 8
and a horizon of 32 hops (e.g. 'rspf interface tnc0 8 32').
3. Set the interval between RRH messages (e.g. 'rspf rrhtimer
900').
4. Define how long it takes until an idle link is suspected bad
(e.g. 'rspf suspecttimer 2000).
5. Set the interval between routing updates (e.g. 'rspf timer
900').
The RSPF commands are now described.
_________________________________________________________________
rspf interface [<interface> <quality> <horizon>]
_________________________________________________________________
Display or set an RSPF interface. The command 'rspf interface'
without parameters displays existing interface settings.
<interface> is the required interface RSPF should use.
<quality> is from 1 to 127
<horizon> is from 1 to 255 hops
>> Example: rspf interface tnc0 8 32
_________________________________________________________________
rspf maxping [<n>] Default: 5
_________________________________________________________________
Display or set the maximum number of times to ping.
>> Example: rspf maxping 10
_________________________________________________________________
rspf message ["<message_string>"]
_________________________________________________________________
Display or set the RSPF message string.
>> Example: rspf message "RSPF routing in use. RIP disabled"
_________________________________________________________________
rspf mode [vc | datagram | none]
_________________________________________________________________
Display or set the preferred mode for RSPF.
>> Example: rspf mode datagram
_________________________________________________________________
rspf routes
_________________________________________________________________
Display the RSPF routing table.
>> Example of 'rspf routes' display output:
.............................................................
: Local routing update: :
: Reporting Router: ns9bob Seq 32769 Subseq 0 links 1 :
: horizon 32 ERP factor 0 cost 8 adjacencies 3 :
: ns9ken/32 :
: ns9jim/32 :
: region42/24 :
:...........................................................:
_________________________________________________________________
rspf rrhtimer [seconds] Default: 0
_________________________________________________________________
Display or set the Router-to-Router Hello (RRH) message interval.
>> Example: rspf rrhtimer 900
_________________________________________________________________
rspf status
_________________________________________________________________
Display the current RSPF status.
>> Example of 'rspf status' display output:
...........................................................
: Bad checksum 0 Bad version 0 Not RSPF interface 0 :
: RRH in 10 RRH out 12 Update in 3 Update out 6 :
: Non-adjacency update 0 Old node report 1 Polls sent 0 :
: Addr Cost Seq Heard Timer TOS State :
: ns9ken 8 515 0 622/1999 16 OK :
: ns9liz 8 0 0 442/1999 0 OK :
:.........................................................:
_________________________________________________________________
rspf suspecttimer [seconds] Default: 0
_________________________________________________________________
Display or set the time limit for an idle link to be suspected to
be bad.
>> Example: rspf suspecttimer 2000
_________________________________________________________________
rspf timer [seconds] Default: 0
_________________________________________________________________
Display or set the interval between routing updates.
>> Example: rspf timer 900