EXFO FTB-800 Series for FTB-1 - Manual (Page 168)

Test Setup - Test Configurator, Timer, and System
158 FTB-700G/800 Series
MAC/IP/UDP

Interface ID Coupled, available when the Source Global IPv6
Address mode is Static, allows to couple the interface ID of the
Global address to the Link-Local source address.
Enabled (default): Only the 64 bit (MSB) prefix ID in the IPv6
address is configurable, and the 64 bit (LSB) Interface ID is not
configurable (read-only).
Disabled: The 64 bit (MSB) Prefix ID and 64 bit (LSB) Interface ID
in the IPv6 address are configurable.

Prefix Mask, available with Static mode, allows to specify a prefix
that defines the subnet. The accepted range is
0000:0000:0000:0000:0000:0000:0000:0000 to
FFFF:FFFF:FFFF:FFFF:0000:0000:0000:0000. For example:
Global Address: 2001:0DB8:0001:0002:02AA:00FF:FE11:1111
Prefix Mask: FFFF:FFFF:FFFF:0000:0000:0000:0000:0000
Corresponding Prefix: 2001:0DB8:0001.

Default Gateway allows the configuration of the default gateway
address to forward packets outside the subnet.

Mode
Automatic (default) allows automatic selection of the default
gateway.
Static allows entering the default gateway IP address.

Address, available with Static mode, allows to enter the IP address
of the Default Gateway. The accepted range is from
0000:0000:0000:0000:0000:0000:0000:0000 to
FE80:0000:0000:0000:FFFF:FFFF:FFFF:FFFF. The default address
is FE80:0000:0000:0000:0000:0000:0000:0000.