![Practical Byzantine Fault Tolerance ,[object Object],[object Object]](https://image.slidesharecdn.com/paperreview2-1-110516173748-phpapp01/85/PBFT-1-320.jpg)
![Outline ,[object Object],[object Object],[object Object],[object Object],[object Object]](data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7)
Recomendados
Más contenido relacionado
La actualidad más candente
La actualidad más candente (20)
Similar a PBFT
Similar a PBFT (17)
Último
Último (20)
PBFT
- 8. Algorithm: Client Request: o, t, c Reply: v, t, c, i, r
- 22. Implementation
- 23. Performance
Notas del editor
- independent node failures: nodes don’t depend on each other, host different implementations of the service
- to detect corrupted messages signature m signed by node i digests produced by hash-function, we sign just a digest replicas know all pub key to verify
- Linearizability: service behaves like a centralized implementation, executes operations atomically one at the time.
- Client waits for f+1 replies form different replicas with the same result, this is the result of the operation. Replicas:- Deterministic- Start in the same state=> total order for the execution on all non-faulty replicas
- 2nd case: if replica hasn’t processed the request yet, it relays the request to the primary. If the primary doesn’t multicast the request, it will eventually be suspected by replicas, then view change.
- Non-deterministic case : additional phase:- primary obtains proposed authenticated values, concat. 2f+1 of them with the request, start 3phase for this message;- replicas choose the value deterministically (for example, median).
- Requests are not included in pre-prepare message to keep them small. Pre-prepare message are used as a proof that the request was assigned sequence number n in view v in view changes. The last condition prevents a faulty primary from exhausting the space of sequence numbers by selecting a very large one. If doesn’t accept — does nothing. Otherwise enters next phase.
- n — seq number of last request whose execution reflected in the state d — digest of the state The checkpoint protocol is used to advance the low and high water marks (which limit what messages will be accepted). k is big enough so that replicas do not stall waiting for a checkpoint to become stable. For example, if checkpoints are taken every 100 requests, might be 200.
- n is the sequence number of the last stable checkpoint known to i C is a set of (2f+1) valid checkpoint messages proving the correctness of s P_m for each request m that prepared at i with a sequence number higher than n new_view starts when 2f view-changes received