User Manual

Basic Remote Networking IP Address Negotiation
4-6
Note: The default site configuration is listed in Table 4-1 on page 4-3.
When an incoming caller is allocated a temporary site, the name of the site is based on the port receiving
the call. For example, an incoming call to port 3 may be allocated a temporary site named Port3.
4.2.7 Using Sites for Outgoing Connections
Note: The SCS does not support outgoing remote node connections.
A site must be configured for each outgoing LAN to LAN connection. This site controls when and how the
SCS will call the remote location, what protocols to use, and when to terminate the connection.
Outgoing sites are typically named for the remote router that the SCS will call; for example, if a site is used
for outgoing connections to a remote router in Dallas, the site used for the connection might be named
dallas. This site could also be used for incoming calls; if the router in Dallas needed to call the first SCS, it
could use dallas to make the connection.
4.3 IP Address Negotiation
By default, sites use “unnumbered” interfaces for IP. The IP address of the Ethernet connected to the SCS
will be used as the IP address on all SCS serial ports. This reduces the amount of configuration and
eliminates the need to allocate a separate IP network for each port.
When the SCS receives an incoming connection request (remote node or LAN to LAN), an IP address is
negotiated for the caller. The address agreed upon depends on the caller’s requirements; some don’t have a
specific address requirement, while others must use the same IP address each time they log into the SCS.
Note: PPP negotiation is covered in Chapter 7, PPP.
The SCS can also be used to connect to a dialup network such as Earthlink, where the network will then
assign you a nameserver and an IP address. For this functionality, the nameserver of the SCS should be set
to 0.0.0.0 (with the Set/Define IP Nameserver command) and the SCS should be set to accept dynamic IP
addresses (with the Define Site IP Address Dynamic command).
For a complete discussion of IP address assignment (including configuration instructions), see IP Addresses
on page 6-1.
4.4 IP Routing
The following sections discuss IP routing issues as they pertain to remote networking. For a complete
discussion of IP routing, refer to Chapter 6, IP.
When a packet is received from or generated for a remote network, the SCS will check its routing table to
determine the most efficient route to the destination. If the SCS does not have a route to a remote network,
it cannot send the packet to the destination.
The entries in the routing table are one of three types: