Add description column to relay command table.

1 files changed, 35 insertions, 35 deletions

diff --git a/spec/tor-spec/relay-cells.md b/spec/tor-spec/relay-cells.md
index 8a0f2be..cc7ea88 100644
--- a/spec/tor-spec/relay-cells.md
+++ b/spec/tor-spec/relay-cells.md
@@ -32,41 +32,41 @@ enveloped relay message, encoded as follows:
 
 The relay commands are:
 
-| Command | Identifier  | Type
-| ------- | ----------  | ----
-|  1      | [BEGIN]     | **F**
-|  2      | [DATA]      | **F**/**B**
-|  3      | [END]       | **F**/**B**
-|  4      | [CONNECTED] | **B**
-|  5      | [SENDME]    | **F**/**B**, **C?**
-|  6      | [EXTEND]    | **F**, **C**
-|  7      | [EXTENDED]  | **B**, **C**
-|  8      | [TRUNCATE]  | **F**, **C**
-|  9      | [TRUNCATED] | **B**, **C**
-| 10      | [DROP]      | **F**/**B**, **C**
-| 11      | [RESOLVE]   | **F**
-| 12      | [RESOLVED]  | **B**
-| 13      | [BEGIN_DIR] | **F**
-| 14      | [EXTEND2]   | **F**, **C**
-| 15      | [EXTENDED2] | **B**, **C**
-| 16..18  | Reserved; see [prop339].
-| 19      | [CONFLUX_LINK][prop329]       | **F**, **C**
-| 20      | [CONFLUX_LINKED][prop329]     | **B**, **C**
-| 21      | [CONFLUX_LINKED_ACK][prop329] | **F**, **C**
-| 22      | [CONFLUX_SWITCH][prop329]     | **F**/**B**, **C**
-| 32      | [ESTABLISH_INTRO]      | **F**, **C**
-| 33      | [ESTABLISH_RENDEZVOUS] | **F**, **C**
-| 34      | [INTRODUCE1]           | **F**, **C**
-| 35      | [INTRODUCE2]           | **B**, **C**
-| 36      | [RENDEZVOUS1]          | **F**, **C**
-| 37      | [RENDEZVOUS2]          | **B**, **C**
-| 38      | [INTRO_ESTABLISHED]    | **B**, **C**
-| 39      | [RENDEZVOUS_ESTABLISHED] | **B**, **C**
-| 40      | [INTRODUCE_ACK]        | **B**, **C**
-| 41      | [PADDING_NEGOTIATE][circ-padding]  | **F**, **C**
-| 42      | [PADDING_NEGOTIATED][circ-padding] | **B**, **C**
-| 43      | [XON][prop324]  | **F**/**B**
-| 44      | [XOFF][prop324] | **F**/**B**
+| Command | Identifier  | Type         | Description
+| ------- | ----------  | ----         | -----------
+|  1      | [BEGIN]     | **F**        | Open a stream
+|  2      | [DATA]      | **F**/**B**  | Transmit data
+|  3      | [END]       | **F**/**B**  | Close a stream
+|  4      | [CONNECTED] | **B**        | Stream has successfully opened
+|  5      | [SENDME]    | **F**/**B**, **C?** | Acknowledge traffic
+|  6      | [EXTEND]    | **F**, **C** | Extend a circuit with TAP (obsolete)
+|  7      | [EXTENDED]  | **B**, **C** | Finish extending a circuit with TAP (obsolete)
+|  8      | [TRUNCATE]  | **F**, **C** | Remove nodes from a circuit (unused)
+|  9      | [TRUNCATED] | **B**, **C** | Report circuit truncation (unused)
+| 10      | [DROP]      | **F**/**B**, **C** | Long-range padding
+| 11      | [RESOLVE]   | **F**        | Hostname lookup
+| 12      | [RESOLVED]  | **B**        | Hostname lookup reply
+| 13      | [BEGIN_DIR] | **F**        | Open stream to directory cache
+| 14      | [EXTEND2]   | **F**, **C** | Extend a circuit
+| 15      | [EXTENDED2] | **B**, **C** | Finish extending a circuit
+| 16..18  | Reserved    |              | For UDP; see [prop339].
+| 19      | [CONFLUX_LINK][prop329]       | **F**, **C** | Link circuits into a bundle
+| 20      | [CONFLUX_LINKED][prop329]     | **B**, **C** | Acknowledge link request
+| 21      | [CONFLUX_LINKED_ACK][prop329] | **F**, **C** | Acknowledge CONFLUX_LINKED message (for timing)
+| 22      | [CONFLUX_SWITCH][prop329]     | **F**/**B**, **C** | Switch between circuits in a bundle
+| 32      | [ESTABLISH_INTRO]      | **F**, **C** | Create introduction point
+| 33      | [ESTABLISH_RENDEZVOUS] | **F**, **C** | Create rendezvous point
+| 34      | [INTRODUCE1]           | **F**, **C** | Introduction request (to intro point)
+| 35      | [INTRODUCE2]           | **B**, **C** | Introduction request (to service)
+| 36      | [RENDEZVOUS1]          | **F**, **C** | Rendezvous request (to rendezvous point)
+| 37      | [RENDEZVOUS2]          | **B**, **C** | Rendezvous request (to client)
+| 38      | [INTRO_ESTABLISHED]    | **B**, **C** | Acknowledge ESTABLISH_INTRO
+| 39      | [RENDEZVOUS_ESTABLISHED] | **B**, **C** | Acknowledge ESTABLISH_RENDEZVOUS
+| 40      | [INTRODUCE_ACK]        | **B**, **C** | Acknowledge INTRODUCE1
+| 41      | [PADDING_NEGOTIATE][circ-padding]  | **F**, **C** | Negotiate circuit padding
+| 42      | [PADDING_NEGOTIATED][circ-padding] | **B**, **C** | Negotiate circuit padding
+| 43      | [XON][prop324]  | **F**/**B** | Stream-level flow control
+| 44      | [XOFF][prop324] | **F**/**B** | Stream-level flow control
 
 [prop324]: ../proposals/324-rtt-congestion-control.txt
 [prop329]: ../proposals/329-traffic-splitting.md