Synchronous LAN to LAN Configuration

Figure 5-1 shows a single synchronous PPP link used to connect two local area networks (LANs). Two hosts (epic and odyssey) running Solstice PPP act as routing gateways between the two networks. Both hosts request authentication using the Password Authentication Protocol (PAP).

Figure 5-1 Synchronous LAN to LAN Configuration

The simplest, and most efficient, way to implement this configuration establishes a point-to-point IP connection between the gateways epic and odyssey. Each host can use its primary IP address as the source address of the point-to-point IP interface.

The two hosts act as IP routers in this configuration; therefore, the file /etc/gateways must exist on each host so that IP datagrams are routed correctly.

In this example, both hosts use one of the onboard serial ports (zsh) to make the link; however, the same link could be established using some other serial device.

PPP Configuration File (ppp.conf) for epic:

ifconfig ipdptp0 plumb
ifconfig ipdptp0 epic odyssey netmask 255.255.255.0 mtu 1500 up

sync_path
    ip_interface              ipdptp0
    unix_device               zsh0
    expect_authentication     pap
    expect_pap_id             odyssey_id
    expect_pap_passwd         odyssey_passwd
    send_authentication       pa
    send_pap_id               epic_id
    send_pap_passwd           epic_passwd

PPP Configuration File (ppp.conf) for odyssey:

ifconfig ipdptp0 plumb
ifconfig ipdptp0 odyssey epic netmask 255.255.255.0 mtu 1500 up

sync_path
    ip_interface           ipdptp0
    unix_device            zsh0
    expect_authentication	 pap
    expect_pap_id        	 epic_id
    expect_pap_passwd       epic_passwd
    send_authentication  	 pap
    send_pap_id         	  odyssey_id
    send_pap_passwd     	  odyssey_passwd

Link Configuration Files (link.conf) for epic and odyssey:

sync_device            syncdev0
    unix_device        zsh0
    line_speed         19200
    tx_clock           baud
    rx_clock           rxc