Test-Um NT750 - Manual (Page 13)

LanScaper
TM
Each of the four decimal numbers separated by periods represents one hexadecimal byte of the four
byte IP address, and can only take on the values between 0-255. Each digit in the decimal number
can only be set to a value valid for that position. Thus, the high order digit in any of the decimal
numbers can only be set to 0, 1, or 2. In addition, each digit can only be set to a valid value in
relation to the low-order digits in that number. The high order digit can only be set to 2 if the low
order digits are less than 55. The desired IP address may have to be entered from right to left to
allow the low order digits to be set prior to the high order digit. Any IP address can be entered for a
Target, either on or off the LAN segment, even “reserved” IP addresses can be entered. This sub-
menu can be exited by pressing SEL (taking the tester back to the sub-menu title screen), or by
pressing CABLE or NTWRK to enter a test mode. Exiting this menu will leave the displayed
Target as the active one.
This is the sub-menu title screen for the IP address configuration of
the DHCP Off (Manual) PING test mode. The settings of these values interact with each other to
force the Router IP address to be accessible on the same LAN segment as the LanScaper™. An off-
LAN router cannot be addressed by the tester, and therefore is not a useful setup option. Pressing
the SEL button drops the tester into the manual IP configuration screens. The up/down arrow
buttons scroll through the options in this sub-menu. This sub-menu is exited by scrolling to the
“Sel to go to Main Menu” screen and pressing SEL, or by pressing CABLE or NTWRK to exit to a
test mode.
When one of the option screens is displayed, pressing the SEL button drops the tester into the edit
IP address screen for that option. Note that the tester's IP address, MyIP, can only be set to non-
reserved IP addresses. This is any address other than 0.0.0.0, or 224-255.x.x.x. MyIP is edited in a
similar fashion to the Target IP addresses described above. The Router IP address is also edited in a
similar fashion to the Target's. In addition, the Router IP address is forced to be on the same LAN
segment as MyIP. This means that the Netmask, whose bits define the LAN segment, is compared
with MyIP, and the bits that must be common between MyIP and the Router IP are forced to the
correct state. The check of the Router's address is done whenever MyIP, the Router IP, or the
Netmask are edited. The Netmask is a special set of numbers that are similar to an IP address, but
must be a string of 1's, from the highest order bit down, defining the bits that must match between
MyIP and any device it tries to access on the LAN segment. If the IP address bits match, the device
is on the LAN segment, and can be addressed directly. If they do not match, the tester must redirect
it's IP packet to the Router for forwarding. Editing the Netmask is limited to setting valid bit
combinations that allow for LAN segments with 5 to 253 possible devices.
This sub-menu allows the user to view the results of the most recent DHCP
negotiation between the LanScaper™ and a DHCP server. The values displayed cannot be
modified, only viewed to determine the configuration of the LAN segment under test. Pressing the
SEL button drops the tester into the DHCP display screens. The up/down arrow or SEL buttons
scroll through the screens in this sub-menu. The information obtained for each item in the sub-
menu can be viewed by pressing the SEL button. Any 000.000.000.000 entries mean that the last
DHCP server did not provide the requested information. If all entries are 000.000.000.000, the
most likely cause is that DHCP On mode was selected, but the LAN did not provide a DHCP
server. This sub-menu is exited by scrolling to the “Sel to go to Main Menu” screen and pressing
SEL, or by pressing CABLE or NTWRK to exit to a test mode.
4.2 PING Setup Sub-Menu -
4.3 Last DHCP -