This read-only 4-byte value is the IPX network number this interface belongs to, and it reads as 00000000 if the unit has not yet determined its network number. An admin checks this to confirm the unit has successfully joined an IPX network segment, since an all-zero value indicates it hasn't yet resolved one. For example, seeing 00000000 shortly after boot but a real network number moments later confirms the unit picked up its IPX network assignment during startup.