Network Essential Version A (LE) Practice Test

IPv6 compression relies on removing leading zeros in each 16‑bit block and replacing the longest run of all-zero blocks with a double colon (::) exactly once.

Starting with 0090:FEA0:00DA:F4A8:008A:0000:0000:0000, drop leading zeros in each block to get 90:fea0:da:f4a8:8a:0:0:0. The three trailing zero blocks form the longest consecutive zero sequence, so replace them with ::, yielding 90:fea0:da:f4a8:8a::. Using lowercase hex is fine, so 90:fea0:da:f4a8:8a:: is also correct.

The other forms don’t fully apply the compression rules: they either keep leading zeros, or merge separate blocks into a single hex segment, which isn’t allowed.