Issue
JACE 645 Ethernet ports usage
Environment
JACE 645 Network Controller
Cause
JACE 645 has 2 Ethernet ports.
Resolution
LAN1 is the primary network port for the JACE645. As per the JACE Install and Startup Guide, LAN2 (secondary port) can be used in the following scenarios.
Intended usage (of LAN2) is for:
- Isolating a "driver's" Ethernet traffic from the primary (LAN1) interface.
OR
- In some cases, LAN2 may be set up with a standard, fixed, IP address that is used only by a company's service technician, when on site. This allows access to the JACE without disconnecting it from the customer's network, or without connecting the technician's service PC to the customer's network (which might go against local IT security policies).
Note that only one LAN port can be set as DHCP. If enabling LAN2, you typically specify another (network) static IP address and the appropriate subnet mask.
Also note the following:
- If enabling both LAN ports, note that the LAN1 IP address and LAN2 IP address must be on different subnets, otherwise the ports will not function correctly. For example, with a typical "Class C" subnet mask of 255.255.255.0, setting Interface 1=192.168.1.99 and Interface 2=192.168.1.188 is an invalid configuration, as both addresses are on the same subnet.
- A JACE does not provide IP routing or bridging operation between different Interfaces (LAN ports, GPRS, dialup).
- All of this also applies to the "third interface" provided by the "WiFi option" if installed in a JACE (at the time of this document, available for a JACE-700 only). However, it is likely the WiFi interface will be used as the primary interface in most cases (no LAN cabling available to the JACE).
