Test-Um NT750 - Manual (Page 12)

LanScaper
TM
3.3.3 Validate Link -
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4.1 Target Setup Sub-Menu -
This mode allows two LanScaper™ testers to be connected directly to each
other on a cable with no other equipment required. No special configuration of the testers is
required other than to put them into the test modes as described. This allows a cable run to be
verified after installation. One LanScaper™ is put into Validate Link mode (Validator), while the
other one is put into PING test with DHCP Off (PING Generator). The Validator will be locked in
NIC mode, generating link pulses that the PING Generator can receive to allow it to take on the
HUB cable configuration. Once the PING Generator detects the Link pulses, it will go into the
active PING state and start generating ARP packets, attempting to connect to both the manually
configured Target and Router IP addresses. The Validator will receive the ARP requests, and wait
until it gets several requests for the same IP address, while not receiving any responses from
another device to that IP address. The Validator will then assume that IP address, and respond to
the ARP. The PING Generator then starts to PING the IP address that the Validator has responded
to. The Validator responds to the PING, but modifies the packet instead of merely copying it, so
that the PING Generator can recognize when it is communicating with a Validator. When the PING
Generator recognizes the Validator's response, it will change it's PING status acronym display to
“Val”, and terminate the PING conversation to the other IP address it is configured for. Once this
negotiation is complete, the Validator will show a count of PINGs received, and the PING
Generator will display the normal PING status screens for monitoring the progress of the test.
The Validate Link test can also be used on an Ethernet installation with other active devices. Since
the Validator verifies that the IP address it will assume is not responding on the network, it will not
interfere with other devices on the LAN. The PING Generator must be setup in DHCP Off mode,
and its manual IP configuration must be setup to address IP addresses not in use on that LAN. For
example, the active Target address could be on the same LAN segment as MyIP. Or, the Router IP
address could be set to an un-used IP address on that LAN. The PING Generator could even be
setup with IP addresses that are not in use on that LAN, and still communicate with the Validator.
The Setup Mode is provided to set user selectable options and present
information that is useful to the user. Entering SETUP is done by pressing the center of the
CABLE/NTWRK buttons, which actually activates both buttons simultaneously. The estimated
battery life remaining is displayed briefly whenever SETUP mode is entered. The main select
menu is scrolled through using the up/down arrow buttons. There are several sub-menus that are
accessed by pressing the SEL button when the sub-menu title is displayed.
This is the sub-menu title screen for the selection and IP address
configuration of the four available Target IP address storage locations. Only one Target can be
active at a time for the PING test mode. Pressing the SEL button moves the LanScaper™ into the
Target selection screen. The up/down arrow buttons scroll through the five set able options. One of
the four stored target addresses can be selected, or the Target PING can be disabled. 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.
When one of the four Targets is displayed on the screen, the SEL button can be used to drop into the
edit IP address screen for that Target. The IP address is edited by moving the cursor left and right
using the left/right arrow buttons, and then changing the digit above the cursor using the up/down
arrow buttons. Note the IP address is displayed in the typical decimal dot format.
4.0 SETUP MODE