home
***
CD-ROM
|
disk
|
FTP
|
other
***
search
/
HAM Radio 1
/
HamRadio.cdr
/
exam
/
g1emmnos
/
rspf.not
< prev
next >
Wrap
Text File
|
1990-09-04
|
3KB
|
62 lines
Date: Fri, 17 Aug 90 19:57:43 +0200
From: klemets@sics.se
Subject: RSPF implementation available
To: tcp-group@ucsd.edu
I have polished my implementation of RSPF a little bit. It is now
supposed to work with the latest versions of NOS. The implementation
follows version 2.1 of Fred Goldsteins specification.
The Radio Shortest Path First protocol works more or less in the
following way. 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 a RRH message is received, NOS will try to figure out if 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 elses neighbouring
nodes as well. Using this information, it is possible to calculate the
shortest path to any station on the network.
The protocol is described in detail in the RSPF 2.1 specification.
To activate RSPF, do the following.
Set the broadcast address for the ax0 interface:
ifconfig ax0 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, or the
routing entries will overwrite each other. Exactly how the broadcast
address 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.
Configure ax0 as an RSPF interface with quality 8 and a horizon of 32 (hops).
rspf interface ax0 8 32
Set the interval between RRH messages.
rspf rrhtimer 900
Define how long it takes until an idle link is suspected to be bad.
rspf suspecttimer 2000
Set the interval between routing updates.
rspf timer 900
I haven't really had the possibility to test this latest version of
RSPF, so it would be nice with some feedback. I am especially
interested in knowing if the implementation scales, if it is stable,
etc. RSPF is a rather complex protocol and the implementation is about
twice as large as RIP, so there may of course be bugs.
The code is available with anonymous ftp from sics.se. The filename is
archive/packet/ka9q/nos/rspf.arc. It will be necessary to change the
definition of a pair of functions in NOS from static to gloabl. You
will notice this when compiling the code.
Anders