ELSA LANCOM Office Manual page 180

R34 Technical basics
If this router cannot establish a further connection to another remote station, all
other routes are propagated with the distance '16' in the RIPs. The '16' stands for
"This route is not available at the moment". If a router cannot establish a
connection, in addition to the present one, this may be due to one of the following
causes:
– Another connection has already been established on all the other channels (also
– The existing connection is using all B channels (channel bundling).
To take advantage of this function, enable the 'IP RIP' option (in ELSA LANconfig in the
'TCP/IP' configuration section on the 'Router' tab or in the
module
Routers with RIP capabilities dispatch the RIP packets approximately every 30 seconds.
The router is only set up to send and receive RIPs if it has a unique IP address. The IP RIP
module is deselected in the default setting using the IP address XXX.XXX.XXX.254.
Which information does the router take from received IP RIP packets?
When the router receives such IP RIP packets, it incorporates them in its dynamic routing
table, which looks something like this:
IP address
192.168.120.0
192.168.130.0
192.168.140.0
What do the entries mean?
IP addresses and network masks identify the destination network, the distance is taken
from the RIP information, the final column indicates the router which announced this
route. This leaves the 'Time'. The dynamic table thus shows how old the relevant route
is. The value in this column acts as a multiplier for the intervals at which the RIP packets
arrive. A '1', therefore, stands for 30 seconds, a '5' for about 2.5 minutes and so on. New
information arriving about a route is, of course, designated as directly reachable and is
given the time setting '1'. The value in this column is automatically incremented when
the corresponding amount of time has elapsed. The distance is set to '16' after 3.5
minutes (route not reachable) and the route is deleted after 5.5 minutes.
Now if the router receives an IP RIP packet, it must decide whether or not to incorporate
the route contained into its dynamic table. This is done as follows:
The route is incorporated if it is not yet listed in the table (as long as there is enough
space in the table).
ELSA LANCOM Office
via the LANCAPI or a/b ports).
menu for other configuration modes).
Netmask
255.255.255.0
255.255.255.0
255.255.255.0
Setup/IP Router-
Time Distance
1 2
5 3
1 5
Ver.0:26.08.99/Ver.14:04.04.00
Router
192.168.110.1
192.168.110.2
192.168.110.3