Table size change

draft-ietf-quic-qcram.md

@@ -224,15 +224,15 @@ represented as an 8-bit prefix string literal.
 
 ### Duplicate {#indexed-duplicate}
 
-Duplication of an existing entry in the dynamic table starts with the '00'
-two-bit pattern.  The index of the existing entry is represented as an integer
-with a 6-bit prefix. Table indices are always non-zero; a table index of zero
+Duplication of an existing entry in the dynamic table starts with the '000'
+three-bit pattern.  The index of the existing entry is represented as an integer
+with a 5-bit prefix. Table indices are always non-zero; a table index of zero
 MUST be treated as a decoding error.
 
 ~~~~~~~~~~ drawing
      0   1   2   3   4   5   6   7
    +---+---+---+---+---+---+---+---+
-   | 0 | 0 |      Index (6+)       |
+   | 0 | 0 | 0 |    Index (5+)     |
    +---+---------------------------+
 ~~~~~~~~~~
 {:#fig-index-with-duplication title="Duplicate"}
@@ -243,6 +243,31 @@ entries which are frequently referenced, both to avoid the need to resend the
 header and to avoid the entry in the table blocking the ability to insert new
 headers.
 
+### Dynamic Table Size Update
+
+A dynamic table size update signals a change to the size of the dynamic table.
+
+~~~~~~~~~~ drawing
+  0   1   2   3   4   5   6   7
++---+---+---+---+---+---+---+---+
+| 0 | 0 | 1 |   Max size (5+)   |
++---+---------------------------+
+~~~~~~~~~~
+{:#fig-size-change title="Maximum Dynamic Table Size Change"}
+
+A dynamic table size update starts with the '001' 3-bit pattern, followed by the
+new maximum size, represented as an integer with a 5-bit prefix (see Section
+5.1 of [RFC7541]).
+
+The new maximum size MUST be lower than or equal to the limit determined by the
+protocol using QCRAM.  A value that exceeds this limit MUST be treated as a
+decoding error.  In HTTP/QUIC, this limit is the value of the
+SETTINGS_HEADER_TABLE_SIZE parameter (see [QUIC-HTTP]) received from the
+decoder.
+
+Reducing the maximum size of the dynamic table can cause entries to
+be evicted (see Section 4.3 of [RFC7541]).
+
 ## HEADER_ACK Frames {#feedback}
 
 HEADER_ACK frames on the control stream carry information used to ensure