Cisco IE-4000 Software Configuration Manual page 939

Configuring IPv6 Unicast Routing
Configuring IPv6

In the ipv6 address interface configuration command, you must enter the ipv6-address and ipv6-prefix variables
with the address specified in hexadecimal using 16-bit values between colons. The prefix-length variable (preceded
by a slash [/]) is a decimal value that shows how many of the high-order contiguous bits of the address comprise
the prefix (the network portion of the address).
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