Q: Why do I need to specify an X in the address for the line descriptions of my network server?
A: Line descriptions to be used with network servers use a local adapter address that you specify when you create the line description. This address must contain an X in the last position for a token-ring adapter or an X in the second to last position for an Ethernet adapter. For example, a valid token-ring address would be 40001234567X. Any system identifying the address, such as PCs using the FSIOP as a communications adapter, should consider the X to be a zero. The X reserves the other 15 addresses (400012345671-40001234567F) for internal AS/400 and FSIOP functions.
Because the AS/400 has only one domain name, all FSIOPs residing in the same AS/400 participate in the same domain, even if the FSIOPs do not exist on the same LAN. This allows you to have and manage several LANs as if they were physically connected.
LAN Server/400 provides an interconnection between the AS/400 system's FSIOPs that reside on different physical LANS. This is possible because of the 15 reserved addresses created by the X in the locally administered address. The interconnection allows for users of any of these disjointed LANs to access data managed by any of the FSIOPs residing in the AS/400.
While this capability is provided, it is not tuned for performance. Therefore, when superior performance is critical and you have disjointed LANs, you should install one or more bridges to connect the LANs.
- Jan Glowacki