Dialout Configuration for Livingston Routers

Configuration of a Livingston route for dialout access, either on demand or continuous, is not terribly complicated. Livingston Enterprises has gone to considerable lengths to make their interface as user friendly as possible and, thus far, has done a fair job of it.

This configuration requires setting up global parameters to take into account the on demand or continuous dial setup, configuring each of the ports that will be part of the group of lines dialing, and setting up a dialout location appropriate for the terminal server or router you are dialing into.

Interface Configuration

The example configuration below uses an ISDN connection as its dialout line. Except for the addition of the SPID and directory number, the configuration of asynchronous interfaces is identical. Note that a static netmask entry has also been added. The router is capable of derriving this information dynamically but having a static entry prevents the dynamic entry from dissappearing if the interface that has placed the netmask entry in the table becomes innactive.
[Note: When changing the SPID on an ISDN interface, the router must be rebooted for the change to take effect.]

Configuration of each of the dialout interfaces begins with specifying the network type for the port in question. In this case, its "dialout". The router normaly uses the address of ether0 as the local address for these connections however, for our configuration, we've hard-coded the port address and netmask. Since this is an "on demand" configuration, we want to prevent unnecessary traffic from passing out this interface. To that end, the ports have been configured to listen to RIP packets but not to transmit them. Since the local network has only one exit point, we also disabled routing on the ethernet interface. The one remaining task is to assign the port to a dial group. This is used in indeitifying which interfaces can be used to connect to the programmed location. Each port can be a member of only one group.

Dialout Location Configuration

Setting up a dialout location, using PAP as the authentication scheme, it not far removed from configuration of netusers for dialin. Once the location is added, various protocol options need to be set along with routing options. These include the protocol being used (PPP is the default), the MTU of the interace (1500 is the default), the IP address and netmask of the destination router, wether RIP packets are transmitted over the interface, and wether header compression is used.

The remaining parameters deal with setting up the connection, authentication, the number of ports that can be used, when additional interfaces are used, where to connect to, and when to tear down the connection.

Since this is not a dedicated connection, we've set the type to "on_demand" instead of "continuous". The difference being that an "on_demand" connection is only opened when traffic must pass out an interface associated with that location. A "continuous" connection establishes automatically, regardless of traffic levels and if disconnected, will sleep for 1 minute and then attempt to reestablish the connection automatically. If you only want to connect to the location once, or only occassionally, you could also specify "manual" as the type. This type of connection requires that someone log into the router and force the connection open. When it disconnects, it will not reconnect.

There can be any number of interfaces in the connection group. To have the unit make use of additional interfaces, set "maxports" to the desired value. Since the connection we are setting up is an ISDN connection, we also want it to use multilink PPP instead of PPP load balancing. When additional interfaces are brought up is determined by the traffic load on the established interface(s). The "high_water" mark is the number of bytes queued for an interface. When this threshold is reached, an additional interface will be put into use, if additional interfaces are availible.

On ISDN lines, there is often a unit charge associated with the line. Similarly, if a dialup is made over a long distance line, there is a unit charge for that. If no idle timeout is set, the connection would remain up until somethig in the network caused the connection to drop. This can lead to unnecessary bills and possibly job openings. To avoid this, set a timeout for the location to some reasonable value. In our case, 10 minutes.

All that remains is to set the phone number to dial and the username and password to pass to the corosponding host for authentication. It should be noted that the characters in the phone number are passed directly to the device attached to the interface. For an ISDN connection, the only characters permitted are numbers. Formatting the phone number as 555-5555 (using the dash character as a seperator) will cause the switch to reject the call.

Testing the Configuration

Debugging the connection is relatively straight forward. All the messages are, for the most part, self-explanatory. "set console" and then turn on debugging for the appropriate service. For PPP connections, use "set debug 0x51". For ISDN connections, use "set debug isdn on". This will allow you to view the negotiations as they happen. A connection can be forced by typing "dial pnet" (Or whatever your location name is. In this case, "pnet"). On multiport configurations, a second connection can be initiated by issuing a second dial command. The connections can be disconnected by resetting the appropriate interface. When you are satisfied with the configuration, "set debug off" and "reset console" to disable debugging and point the console output elsewhere.

Example Configuration

The following configuration was used on a Livingston Office Router, model OH-U and is an on demand ISDN dialout. Configuration for asynchronous dialout (using a standard modem) is not too dissimilar.

set sysname dialout-1
set password hello
add netmask 206.165.9.0 255.255.255.240
set address 206.165.9.241
set netmask 255.255.255.240
set broadcast high
set gate 206.165.11.201
set routing off
set default listen

set isdn-switch ni-1
set s1 network dialout
set s1 spid 60212345671111
set s1 directory 6021234567
set s1 address 206.165.9.241
set s1 netmask 255.255.255.240
set s1 routing listen
set s1 group 1

set s2 network dialout
set s2 routing listen
set s2 address 206.165.9.241
set s2 netmask 255.255.255.240
set s2 spid 60212345671111
set s2 directory 6021234567
set s2 group 1

add location pnet
set location pnet on_demand
set loc pnet proto ppp
set loc pnet mtu 1500
set loc pnet dest 206.165.11.201
set loc pnet netmask 255.255.255.0
set loc pnet routing listen
set loc pnet group 1
set loc pnet maxports 2
set loc pnet high_water 1000
set loc pnet idle 10
set loc pnet multilink on
set loc pnet username Pfoo
set loc pnet password abcdefg
set loc pnet telephone 5551234
set loc pnet compress on

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