The internetworked binary Transactional Transmission Protocol, or ib-TTP for short, is the second subprotocol of the internetworked binary master protocol. It provides one-and-done-style transactional bidirectional transmission of data between endpoints on a network such as the Worldwide Web, much like the original designs of HTTP, FTP and more.
Model
Like HTTP, ib-TTP has a client-server model where the client sends a request and the server responds with a response.
A request is laid out like so:
| Size
|
Name
|
Explanation
|
| 4
|
flags
|
Flags bitfield. See below for layout.
|
| 20
|
hash
|
SHA-1 checksum of previous data. Only present if flags.form is delta.
|
| 8
|
range_a
|
First bound of the request payload range. Only present if flags.form is ranged.
|
| 8
|
range_b
|
Second bound of the request payload range. Only present if flags.form is ranged.
|
| 4
|
authctx_ct
|
Number of authorisation contexts provided minus 1. Only present if flags.authed is 1.
|
| 4
|
uri_sz
|
Size of the request URI, denoted in octets.
|
| 8
|
payload_sz
|
Size of request payload, denoted in octets. Only present if flags.payload is 1.
|
| varies
|
authctxs
|
Authorisation contexts of the client's request. Only present if code.authed is 1.
|
| varies
|
uri
|
URI of resource being requested, excluding the protocol portion (e.g. http:). Example: //example.com/hello.jpeg. The encoding must be UTF-8.
|
| varies
|
payload
|
Payload contents. Only present if flags.payload is 1.
|
| Bit
|
Name
|
Explanation
|
| 0-2
|
method
|
Request method. (0=GET, 1=HEAD, 2=POST, 3=PUT, 4=PATCH, 5=DELETE, 6=OPTIONS, 7=TRACE)
|
| 3-4
|
form
|
What form the response is being requested in. (0=normal, 1=delta, 2=ranged, 3=test)
|
| 6
|
authed
|
Whether any authorisation contexts (credentials and/or behalves) have been sent as part of the request. At least one context must be sent for a request to be considered "authed".
|
| 7
|
payload
|
Whether the request has a payload or not.
|
| 8-31
|
reserved
|
Reserved. Must be zero.
|
Status codes
ib-TTP also has a grouped collection of status codes similar in function to the numeric status codes of HTTP. However, ib-TTP status codes are constrained into an 8-bit integer and are conventionally represented in octal. This is done since the 8-bit number is divided into 4 groups of 64 codes each according to the type of status code, causing the greatest digit to typify the response code at a glance.
| Code
|
Explanation
|
0o0XX
|
Successful codes
|
0o1XX
|
Neutral codes (includes redirects)
|
0o2XX
|
Negative/failure codes, client is at fault
|
0o3XX
|
Negative/failure codes, server is at fault
|
Successful codes
| Code
|
Name
|
Description
|
HTTP equiv.
|
0o000
|
OK
|
The request was successful.
|
200
|
0o001
|
No content
|
The response header may be informative, but no response body was given.
|
204
|
0o002
|
Partial content
|
Returned upon requests invoking the range field to request a certain part of a resource.
|
206
|
0o003
|
Created
|
The request succeeded, and a new resource was created as a result.
|
201
|
0o004
|
Accepted
|
The request has been received but not yet acted upon.
|
202
|
0o005
|
Non-Authoritative OK
|
The response is not necessarily the same as is available from the origin server, but is collected from a local or a third-party copy.
|
203
|
0o006
|
Reset content
|
Tells the client to reset the context from which they made the request.
|
205
|
Neutral codes
| Code
|
Name
|
Description
|
HTTP equiv.
|
0o100
|
Continue
|
An informational code telling the client to carry on with the request, or ignore this response if the request is finished.
|
100
|
0o101
|
Switch protocols
|
Used in response to the upgrade field of a request.
|
101
|
0o102
|
Processing
|
Server has received the request but does not yet have a response ready.
|
102
|
0o103
|
Further hints
|
To be used with the link response field, giving the client URIs to load resources from before the server sends its response.
|
103
|
0o104
|
Multiple choice
|
The request has more than one possible response, and the client must choose which one it wants.
|
300
|
0o105
|
Moved
|
The requested resource was moved to a new location. Strictly speaking this has the same semantics as HTTP 307 Moved Temporarily, as ib-TTP has no semantics for permanent moves.
|
301, 307
|
0o106
|
Strictly moved
|
This is the same as 0o105, except that the request method must be kept the same, i.e. a POST request made to URI A that returns 0o106 must cause a POST request to the URI it points to.
|
308
|
0o107
|
Not modified
|
This is used for caching purposes. It tells the client that the response has not been modified, so the client can continue to use the same cached version of the response.
|
304
|
Negative/failure codes, client
| Code
|
Name
|
Description
|
HTTP equiv.
|
0o200
|
Bad request
|
The server could not understand the request due to invalid syntax.
|
400
|
0o201
|
Unauthenticated
|
The client must first authenticate to proceed with their request.
|
401
|
0o202
|
Forbidden
|
The client does not have access rights to view the given resource.
|
403
|
0o203
|
Not found
|
No resource was found at the location the client specified.
|
404
|
0o204
|
Wrong method
|
The request method is known by the server but is not supported by the target resource. For example, an API may not allow calling DELETE to remove a resource.
|
405
|
0o205
|
Unacceptable
|
This response is sent when the web server, after performing server-driven content negotiation, doesn't find any content that conforms to the criteria given by the user agent.
|
406
|
0o206
|
Timeout
|
This response is sent on an idle connection by some servers, even without any previous request by the client. It means that the server would like to shut down this unused connection.
|
408
|
0o207
|
Conflict
|
This response is sent when a request conflicts with the current state of the server. You do realise this means war?
|
409
|
0o210
|
Length needed
|
Server rejected the request because the length request field is not defined and the server requires it.
|
411
|
0o211
|
Requirement failed
|
The client has indicated requirements in its request header which the server does not meet.
|
412
|
0o212
|
Payload too large
|
Request entity is larger than limits defined by server.
|
413
|
0o213
|
Headers too large
|
The server is unwilling to process the request because its header fields are too large.
|
431
|
0o214
|
URI too long
|
The URI requested by the client is longer than the server is willing to interpret.
|
414
|
0o215
|
Unsupported content format
|
The format of the requested data is not supported by the server, so the server is rejecting the request.
|
415
|
0o216
|
Range out-of-bounds
|
The range specified in the request cannot be fulfilled. It is often likely that the range is outside the size of the target URI's data.
|
416
|
0o217
|
Upgrade needed
|
The server refuses to perform the request using the current protocol but might be willing to do so after the client upgrades to a different protocol.
|
426
|
0o220
|
Requirement needed
|
The origin server requires the request to be conditional. This response is intended to prevent the 'lost update' problem, where a client GETs a resource's state, modifies it and PUTs it back to the server, when meanwhile a third party has modified the state on the server, leading to a conflict.
|
428
|
0o221
|
Too many requests
|
The user has sent too many requests in a given amount of time. This is also known as "rate limiting".
|
429
|
0o222
|
Unavailable for legal reasons
|
The user agent requested a resource that cannot legally be provided, such as a web page censored by a government.
|
451
|
Negative/failure codes, server
| Code
|
Name
|
Description
|
HTTP equiv.
|
0o300
|
Internal error
|
The server has encountered a situation it does not know how to handle.
|
500
|
0o301
|
Unimplemented
|
The request method is not supported by the server and cannot be handled.
|
501
|
0o302
|
Bad gateway
|
This error response means that the server, while working as a gateway to get a response needed to handle the request, got an invalid response.
|
502
|
0o303
|
Service unavailable
|
The server is not ready to handle the request. Common causes are a server that is down for maintenance or that is overloaded.
|
503
|
0o304
|
Gateway timeout
|
This error response is given when the server is acting as a gateway and cannot get a response in time.
|
504
|
0o305
|
Protocol version unsupported
|
The protocol version specified in the request is too new for the server to handle.
|
505
|
0o306
|
Loop detected
|
The server detected an infinite loop while processing the request.
|
508
|
