prop224: Add a section on the number of introduction points

Acked-by: George Kadianakis <desnacked@riseup.net>
Signed-off-by: David Goulet <dgoulet@torproject.org>

1 files changed, 18 insertions, 1 deletions

diff --git a/proposals/224-rend-spec-ng.txt b/proposals/224-rend-spec-ng.txt
index 558cf1f..1fe738d 100644
--- a/proposals/224-rend-spec-ng.txt
+++ b/proposals/224-rend-spec-ng.txt
@@ -37,6 +37,7 @@ Table of contents:
             2.3.2. Hidden services and changing shared random values
         2.4. Hidden service descriptors: outer wrapper [DESC-OUTER]
         2.5. Hidden service descriptors: encryption format [ENCRYPTED-DATA]
+            2.5.1. Number of introduction points [NUM_INTRO_POINT]
     3. The introduction protocol
         3.1. Registering an introduction point [REG_INTRO_POINT]
             3.1.1. Extensible ESTABLISH_INTRO protocol. [EST_INTRO]
@@ -999,7 +1000,8 @@ Table of contents:
       able to contact the host. Recognized types are: 'password' and
       'ed25519'. See [INTRO-AUTH] below.
 
-     Followed by zero or more introduction points as follows:
+     Followed by zero or more introduction points as follows (see section
+     [NUM_INTRO_POINT] below for accepted values):
 
         "introduction-point" SP link-specifiers NL
 
@@ -1058,6 +1060,21 @@ Table of contents:
    Other encryption and authentication key formats are allowed; clients
    should ignore ones they do not recognize.
 
+2.5.1. Number of introduction points [NUM_INTRO_POINT]
+
+   This section defines how many introduction points an hidden service
+   descriptor can have at minimum, by default and the maximum:
+
+      Minimum: 0 - Default: 3 - Maximum: 20
+
+   A value of 0 would means that the service is still alive but doesn't want
+   to be reached by any client at the moment. Note that the descriptor size
+   increases considerably as more introduction points are added.
+
+   The reason for a maximum value of 20 is to give enough scalability to tools
+   like OnionBalance to be able to load balance up to 120 servers (20 x 6
+   HSDirs) but also in order for the descriptor size to not overwhelmed hidden
+   service directories with user defined values that could be gigantic.
 
 3. The introduction protocol