WCCP uses bits to create and distribute buckets. Using HASH assignment, what are the maximum number of bits used?

Question

Options

• A4
• B7
• C8
• D32
• E256

• A
  15% (9)
• B
  2% (1)
• C
  73% (43)
• D
  3% (2)
• E
  7% (4)

Explanation

WCCP v2's HASH assignment method uses an 8-bit hash of the destination IP address (or other fields) to map packets into one of 256 buckets - 8 is the correct maximum bit count because 2^8 = 256 covers the full bucket space, which is then distributed among available cache engines.

Why the distractors are wrong:

• A (4): Only 4 bits would yield just 16 possible values - far too coarse for WCCP's 256-bucket design.
• B (7): 7 bits gives 128 values; close but not the standard - WCCP uses the full 8-bit hash.
• D (32): 32 bits is the size of a full IPv4 address; WCCP hashes down to 8 bits, it doesn't use the raw address bit-for-bit.
• E (256): 256 is the number of buckets produced by the 8-bit hash, not the number of bits themselves - a common trap.

Memory tip: Think "1 byte = 8 bits = 256 buckets." WCCP HASH uses exactly one byte's worth of hash output to fill all 256 buckets. If you remember 256 buckets, just work backwards - log₂(256) = 8 bits.

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