Move ACK frame block counts up a section

quicwg · Jan 7, 2017 · f192883 · f192883
1 parent 5c8221b
commit f192883
Showing 1 changed file with 25 additions and 23 deletions.
diff --git a/draft-ietf-quic-transport.md b/draft-ietf-quic-transport.md
@@ -931,9 +931,11 @@ An ACK frame is shown below.
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |                  Largest Acked (8/16/32/48)                 ...
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|        Ack Delay (16)         |     Ack Block Section (*)   ...
+|        Ack Delay (16)         |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|                     Timestamp Section (*)                   ...
+|[Num Blocks(8)]|             Ack Block Section (*)           ...
++-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
+|   NumTS (8)   |             Timestamp Section (*)           ...
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 ~~~
 {: #ack-format title="ACK Frame Format"}
@@ -947,26 +949,33 @@ The fields in the ACK frame are as follows:
 * Ack Delay: Time from when the largest acked, as indicated in the Largest Acked
   field, was received by this peer to when this ack was sent.
 
+* Num Blocks (opt): An optional 8-bit unsigned value specifying the number of
+  additional ack blocks (besides the required First Ack Block) in this ACK
+  frame.  Only present if the 'N' flag bit is 1.
+
 * Ack Block Section: Contains one or more blocks of packet numbers which have
   been successfully received.  See {{ack-block-section}}.
 
+* Num Timestamps: An unsigned 8-bit number specifying the total number of
+  <packet number, timestamp> pairs in the Timestamp Section.
+
 * Timestamp Section: Contains zero or more timestamps reporting transit delay of
   received packets.  See {{timestamp-section}}.
 
 
 ### Ack Block Section {#ack-block-section}
 
-The Ack Block Section contains between one and 256 blocks of packet numbers
-which have been successfully received.  If the `N` bit in the Type field is 0,
-the Num Blocks field is absent and only the First Ack Block length is present.
-If the `N` bit is 1, the Num Blocks field indicates how many additional blocks
-follow the First Ack Block Length field.
+The Ack Block Section contains between one and 256 blocks of packet numbers 
+which have been successfully received. If the Num Blocks field is absent, only 
+the First Ack Block length is present in this section. Otherwise, the Num Blocks 
+field indicates how many additional blocks follow the First Ack Block Length 
+field. 
 
 ~~~
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|[Num Blocks(8)]|      First Ack Block Length (8/16/32/48)    ...
+|              First Ack Block Length (8/16/32/48)            ...
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |  [Gap 1 (8)]  |       [Ack Block 1 Length (8/16/32/48)]     ...
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -981,10 +990,6 @@ follow the First Ack Block Length field.
 
 The fields in the Ack Block Section are:
 
-* Num Blocks (opt): An optional 8-bit unsigned value specifying the number of
-  additional ack blocks (besides the required First Ack Block) in this ACK
-  frame.  Only present if the 'N' flag bit is 1.
-
 * First Ack Block Length: An unsigned packet number delta that indicates the
   number of contiguous additional packets being acked starting at the Largest
   Acked.
@@ -1000,23 +1005,23 @@ The fields in the Ack Block Section are:
 
 ### Timestamp Section {#timestamp-section}
 
-The Timestamp Section contains between zero and 255 measurements of packet
-delay. This information can be used by a sender to better estimate the RTT of
-the connection.
+The Timestamp Section contains between zero and 255 measurements of packet 
+receive time deltas. This information can be used by a sender to better estimate 
+the RTT of the connection. 
 
 ~~~
  0                   1                   2                   3
  0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|   Num TS(8)   | [Delta LA (8)]|
++-+-+-+-+-+-+-+-+
+| [Delta LA (8)]|
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-|                [Time Since Largest Acked (32)]                |
+|                [First Timestamp (32)]                |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |[Delta LA 1(8)]| [Time Since Previous 1 (16)]  |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |[Delta LA 2(8)]| [Time Since Previous 2 (16)]  |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
-                             ...
+                       ...
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
 |[Delta LA N(8)]| [Time Since Previous N (16)]  |
 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
@@ -1025,17 +1030,14 @@ the connection.
 
 The fields in the Timestamp Section are:
 
-* Num Timestamps: An unsigned 8-bit number specifying the total number of
-  <packet number, timestamp> pairs following, including the First Timestamp.
-
 * Delta Largest Acked (opt): An optional 8-bit unsigned packet number delta
   specifying the delta between the largest acked and the first packet whose
   timestamp is being reported.  In other words, this first packet number may
   be computed as (Largest Acked - Delta Largest Acked.)
 
 * First Timestamp (opt): An optional 32-bit unsigned value specifying the time
   delta in microseconds, from the beginning of the connection to the arrival
-  of this packet.
+  of the packet indicated by Delta Largest Acked.
 
 * Delta Largest Acked 1..N (opt, repeated): (Same as above.)