| Name | Size (bytes) | Description |
|---|---|---|
| opcode | 1 | Numeric code indicating type of message |
| version | 1 | Version of the protocol being used |
| length | 2 | Total length of packet |
| reqnum | 4 | Request number assigned by client |
| authenticator | 8 | Authentication information (future) |
| senderid | 4 | Identification (host id) of sender |
| Opcode | Name | Description |
|---|---|---|
| 1 | Query | Query a cache to determine hit/miss |
| 2 | Hit | Cache has a copy of the queried object |
| 3 | Miss | Cache does not have a copy of the queried object |
| 4 | Err | Some type of error occurred at the server |
| 5 | Send | Send object to client (retrieve if necessary) |
| 6 | SendA | Send/validate object to client (retrieve if necessary) |
| 7 | DataBeg | Denotes the beginning of object data |
| 8 | Data | Denotes the next segment of object data |
| 9 | DataEnd | Denotes the final segment of object data |