True or False: assuming that the server participates in the peer to peer exchange (as in the equation above), peer to peer download will always be faster than or the same speed as client/server download. Explain your answer
Try an answer before revealing the guidance below.
Key Concepts
- Term-by-term comparison
- F/us ≤ NF/us
- Extra upload capacity from peers
- Lower bounds
Answer Approach
- Compare each term of D_p2p with the client-server terms.
- Check whether adding peer upload capacity can ever increase a term.
- Identify when the two are equal.
Full Answer
Answer status: Draft answer (unofficial). Revision notes, not an official marking scheme.
True (according to the model). F/dmin appears in both. F/us ≤ NF/us for N ≥ 1, and NF/(us + Σui) ≤ NF/us because peer upload rates are non-negative. So every term of D_p2p is no larger than the largest term of D_cs, and D_p2p ≤ D_cs. They are equal when peers contribute no upload capacity or when F/dmin dominates both. (In practice, overheads and peer churn that the model ignores can make P2P slower.)
NF/(us + Σui) ≤ NF/usF/us ≤ NF/usShortcuts: K concepts · A approach · F answer · R reviewed · B bookmark · ← / → previous / next