System Administration Guide: Resource Management and Network Services

Chapter 32 Setting Up a Leased-Line PPP Link (Tasks)

This chapter explains how to configure a PPP link that uses a leased line between peers. Major sections include the following:

Setting Up a Leased Line (Task Map)

Leased-line links are relatively easy to set up, in comparison with dial-up links. In most instances, you do not have to configure the CSU/DSU, dialing services, or authentication. If you do need to configure the CSU/DSU, refer to the manufacturer's documentation for aid with this complex task.

The task map in the next table describes all the tasks that are involved in setting up the basic leased-line link.

Note –

Some types of leased lines, such as Frame Relay that uses Switched Virtual Circuits (SVCs) or Switched 56 service, do require the CSU/DSU to “dial” the address of the opposite peer.

Table 32–1 Task Map for Setting Up the Leased-Line Link


Task	Description	For Instructions
1. Gather preconfiguration information	Gather data that is needed prior to setting up the link.	Table 30–4
2. Set up the leased-line hardware	Assemble the CSU/DSU and synchronous interface card.	How to Configure Synchronous Devices
3. Configure the interface card, if required	Configure the interface script to be used when the leased line is brought up.	How to Configure Synchronous Devices
4. Configure information about the remote peer	Define how communications between your local machine and the remote peer should work.	How to Configure a Machine on a Leased Line
5. Start up the leased line	Configure your machine so that it starts up PPP over the leased line as part of the booting process.	How to Configure a Machine on a Leased Line

Configuring Synchronous Devices on the Leased Line

The task in this section involves configuring equipment that is required by the leased-line topology that is introduced in Example—Configuration for a Leased-Line Link. The synchronous devices that are required to connect to the leased line include the interface and modem.

Prerequisites for Synchronous Devices Setup

Before you perform the next procedure, you must have the following items:

Working leased line that is installed at your site by the provider
Synchronous unit (CSU/DSU)
Solaris 9 operating environment release installed on your system
Synchronous interface card of the type that is required by your system

How to Configure Synchronous Devices

Physically install the interface card into the local machine, if it is necessary.

Follow the instructions in the manufacturer's documentation.

Connect the cables from the CSU/DSU to the interface and, if it is necessary, from the CSU/DSU to the leased-line jack or similar connector.

Configure the CSU/DSU, as instructed in the documentation from the manufacturer or network provider.

Note –
The provider from whom you rented the leased line might supply and configure the CSU/DSU for your link.

Configure the interface card, if necessary, as instructed in the interface documentation.

The configuration of the interface card involves the creation of a startup script for the interface. The router at LocalCorp in the leased-line configuration that is shown in Figure 30–2 uses an HSI/S interface card.

The following script hsi-conf starts up the HSI/S interface:
#!/bin/ksh /opt/SUNWconn/bin/hsi_init hih1 speed=1536000 mode=fdx loopback=no \ nrzi=no txc=txc rxc=rxc txd=txd rxd=rxd signal=no 2>&1 > /dev/null
hih1

Indicates that HSI/S is the synchronous port used

speed=1536000

Sets the speed of the CSU/DSU to 1536000

Where to Go From Here

Task	For Instructions
Configure the local machine on the leased line	How to Configure a Machine on a Leased Line

Configuring a Machine on the Leased Line

The task in this section explains how to set up a router to function as the local peer on your end of a leased line. The task uses the leased line that was introduced in Example—Configuration for a Leased-Line Link as an example.

Prerequisites for Configuring the Local Machine on a Leased Line

Before you perform the next procedure, you must have completed the following:

Set up and configured the synchronous devices for the link, as described in Configuring Synchronous Devices on the Leased Line
Obtained the root password for the local machine on the leased line
Set up the local machine to run as a router on the network(s) to use the services of the leased-line provider

How to Configure a Machine on a Leased Line

Become superuser on the local machine (router).

Add an entry for the remote peer in the router's /etc/hosts file.
# vi /etc/hosts # # Internet host table # 127.0.0.1 localhost 192.168.130.10 local2-peer loghost 192.168.130.11 local1-net 10.0.0.25 farISP
The sample /etc/hosts file is for the local router at the fictitious LocalCorp. Note the IP address and host name for the remote peer farISP at the service provider.

Create the file /etc/ppp/peers/peer-name to hold information about the provider's peer.

For the sample leased-line link, you create the file /etc/ppp/peers/farISP.

#vi /etc/ppp/peers/farISP
init '/etc/ppp/conf_hsi'
local
/dev/hih1
sync
noauth
192.168.130.10:10.0.0.25
nodefaultroute
passive
persist
noccp
nopcomp
novj
noaccomp

The following table explains the options and parameters that are used in /etc/ppp/peers/farISP.

Option	Definition
`init '/etc/ppp/conf_hsi'`	Starts up the link and configures the HSI interface by using the parameters in the script `/etc/ppp/conf_hsi`.
`local`	Tells the `pppd` daemon not to change the state of the Data Terminal Ready (DTR) signal and to ignore the Data Carrier Detect (DCD) input signal.
`/dev/hih1`	Gives the device name of synchronous interface.
`sync`	Establishes synchronous encoding for the link.
`noauth`	Disables authentication on the link.
`192.168.130.10:10.0.0.25`	Defines the IP addresses of the local peer and the remote peer, separated by a colon.
`passive`	Tells the `pppd` daemon on the local machine to go quiet after issuing maximum number of LCP Configure-Requests and wait for the peer to start.
persist	Tells the `pppd` daemon to try to restart the link after a connection ends.
`noccp, nopcomp, novj, noaccomp`	Disables the Compression Control Protocol (CCP), Protocol Field compression, Van Jacobson compression, and address and control field compression, respectively. Though these forms of compression accelerate transmissions on a dial-up link, they might slow down a leased line.

Create an initialization script that is called demand, which creates the PPP link as part of the booting process.

# cd /etc/ppp/
# vi demand
if [ -f /var/run/ppp-demand.pid ] &&
           /usr/bin/kill -s 0 `/bin/cat /var/run/ppp-demand.pid`
        then
                :
        else
                /usr/bin/pppd call farISP
        fi

The demand script contains the pppd command for establishing a leased-line link. The following table explains the contents of $PPPDIR/demand.

Code Sample	Explanation
`echo "Starting Solaris PPP 4.0\c"`	Displays “Starting Solaris PPP 4.0” during the booting process.
`if ps -e \| grep '\<pppd\ > /dev/null 2>&1 ; thenecho "\npppd daemon is still running"` `echo "or in the process of exiting"` `exit 0`	Search for an already existing `pppd` daemon. If `pppd` is found, then send out a message and exit the `demand` script.
`echo "\nEstablishing PPP session...\n"`	Display “Establishing PPP session” during booting.
`/usr/bin/pppd call farISP`	Run the `pppd` command by using the options that are in `/etc/ppp/peers/farISP`.

The Solaris PPP 4.0 startup script /etc/rc2.d/S47pppd invokes the demand script as part of the Solaris booting process. The following lines in /etc/rc2.dS47pppd search for the presence of a file that is called $PPPDIR/demand.

    if [ -f $PPPDIR/demand ]; then
                . $PPPDIR/demand
        fi

If $PPPDIR/demand is found, it is executed. During the course of executing $PPPDIR/demand, the link is established.

Where to Go From Here

If you have followed all the procedures in this chapter, you have completed the configuration of the leased-line link.

Task	For Instructions
Instruct users to start communicating with machines on the Internet or other network that is served by the remote peer	Have users run `telnet`, `ftp`, `rsh`, or similar commands to reach machines outside the local network.
Fix problems on the link	Fixing Leased-Line Problems for troubleshooting information.
Learn more about the files and options used in this chapter	Using PPP Options in Files and on the Command Line.

`hih1`	Indicates that HSI/S is the synchronous port used
`speed=1536000`	Sets the speed of the CSU/DSU to 1536000