📄 rfc907.txt
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allow more than one Notification to be outstanding, each is
assigned a unique Notification ID. The Notification
Acknowledgment returned by the user host to the service host must
contain the Notification ID.
The general format of every setup message is:
<DATAGRAM MESSAGE HEADER>
<OPTIONAL INTERNET HEADER>
<SETUP MESSAGE HEADER>
<SETUP MESSAGE BODY>
The service host accepts setup requests in either Internet or
non-Internet format. Replies from the service host will be in
the same form as the request, that is, Internet requests get
Internet replies, and non-Internet requests get non-Internet
replies.
The format of the combined datagram message header and setup
message header is illustrated in Figure 6. The body of the setup
messages depends on the particular setup message type. Stream
request and reply messages are described in Section 6.1. Group
request and reply messages are described in Section 6.2. To
simplify the presentation in both of these sections, the setup
messages are assumed to be exchanged between a local host and
SIMP even though Internet group and stream setups are supported
(see Figure 6). The format of notifications, which consists of
only a single word beyond the basic setup header, is shown in
Figure 7. Since the SIMP does not retain the optional Internet
header information that can be included in setup requests,
Internet notifications are not supported. The format of
acknowledgment messages associated with request/reply and
notification setups is illustrated in Figure 8.
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RFC 907 Host Access Protocol
July 1984 Specification
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
0-5 | DATAGRAM MESSAGE HEADER |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
6-N | <OPTIONAL INTERNET HEADER> |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
N+1 | SETUP TYPE | SETUP CODE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
N+2 | SETUP CHECKSUM |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
N+3 | SETUP ID |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Figure 6 . SETUP MESSAGE HEADER
0-5 Datagram Message Header. Each setup message begins
with the six word datagram message header (see Section
3).
6-N Internet Header (Optional). These fields, when
present, conform to the DoD Standard Internet Protocol
(IP). The Internet header size is a minimum of 10
words but can be longer depending on the use of
optional IP facilities. (Internet notification
messages are not supported.)
N+1[8-15] Setup Type. This field determines the type of setup
message.
0 = Acknowledgment
1 = Request
2 = Reply
3 = Notification
N+1[0-7] Setup Code. For requests, this field identifies the
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RFC 907 Host Access Protocol
July 1984 Specification
Request Type.
1 = Create group address
2 = Delete group address
3 = Join group
4 = Leave group
5 = Create stream
6 = Delete stream
7 = Change stream parameters
8 = Reserved
For Replies, this field provides the Reply Code. Some
of the Reply Codes can be returned to any setup
request and others are request specific.
0 = Group or stream created
1 = Group or stream deleted
2 = Group joined
3 = Group left
4 = Stream changed
5 = Reserved
6 = Bad request type
7 = Reserved
8 = Network trouble
9 = Bad key
10 = Group address/stream ID nonexistent
11 = Not member of group/creator of stream
12 = Stream priority not being accepted
13 = Reserved
14 = Reserved
15 = Illegal interval
16 = Reserved
17 = Insufficient network resources
18 = Requested bandwidth too large
19 = Reserved
20 = Reserved
21 = Maximum messages per slot not consistent with
slot size
22 = Reply lost in network
23 = Illegal reliability value
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RFC 907 Host Access Protocol
July 1984 Specification
For Notifications, this field contains the
Notification Type.
0 = Stream suspended
1 = Stream resumed
2 = Stream deleted
3 = Group deleted by host
4 = Group deleted by SIMP
5 = All streams deleted
6 = All groups deleted
For Acknowledgments, this field contains the
Acknowledgment Type.
0 = Reply acknowledgment
1 = Notification acknowledgment
N+2[0-15] Setup Checksum. The checksum covers the three setup
message header words and the setup message body data
words. Setups received with bad checksums must be
discarded.
N+3[0-15] Setup ID. This field is assigned by the host to
uniquely identify outstanding requests (Request ID)
and by the service host to uniquely identify
outstanding notifications (Notification ID).
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RFC 907 Host Access Protocol
July 1984 Specification
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
0-5 | DATAGRAM MESSAGE HEADER |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
6 | 3 | NOTIFICATION TYPE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
7 | SETUP CHECKSUM |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
8 | NOTIFICATION ID |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
9 | NOTIFICATION INFO |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Figure 7 . NOTIFICATION MESSAGE
0-5 Datagram Message Header (see Section 3).
6[8-15] Setup Type = 3 (Notification).
6[0-7] Notification Type.
0 = Stream suspended
1 = Stream resumed
2 = Stream deleted
3 = Group deleted by host
4 = Group deleted by SIMP
5 = All streams deleted
6 = All groups deleted
7[0-15] Setup Checksum. Covers words 6-9.
8[0-15] Notification ID.
9[0-15] Notification Information. This field contains the
16-bit group address in the case of a group
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RFC 907 Host Access Protocol
July 1984 Specification
notification (types 3 and 4) and the 10-bit host
stream ID (right justified) in the case of a stream
notification (types 0-2). This field is zero for
Notification Types 5 and 6, which pertain to ALL
streams and groups, respectively.
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RFC 907 Host Access Protocol
July 1984 Specification
15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
0-5 | DATAGRAM MESSAGE HEADER |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
6 | 0 | ACK TYPE |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
7 | SETUP CHECKSUM |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
8 | SETUP ID |
+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+--+
Figure 8 . SETUP ACKNOWLEDGMENT
0-5 Datagram Message Header.
6[8-15] Setup Type = 0 (Acknowledgment).
6[0-7] Acknowledgment Type.
0 = Reply acknowledgment
1 = Notification acknowledgment
7[0-15] Setup Checksum. Covers words 6-8.
8[0-15] Setup ID. This is either a Request ID or a
Notification ID.
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RFC 907 Host Access Protocol
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6.1 Stream Setup Messages
Hosts use streams to support high duty cycle applications
and applications requiring a one satellite hop network
transmission delay. Host streams must be set up before stream
data messages can flow. The stream setup messages defined by HAP
are Create Stream Request, Create Stream Reply, Delete Stream
Request, Delete Stream Reply, Change Stream Parameters Request,
and Change Stream Parameters Reply. The use of these messages is
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