X-Git-Url: http://www.git.cypherpunks.ru/?a=blobdiff_plain;f=doc%2Fsp.texi;h=e7f4895c67f43c539915046887c1252d2de573b2;hb=7f71f37675f61b4081ad6fef2a936f1c7eb620f9;hp=d6be2d927f7977aca6b750a2c22b2152ea6b1179;hpb=fb0b3a18e2f73d4bf36a5aa3aa1e976b4dd284e9;p=nncp.git

diff --git a/doc/sp.texi b/doc/sp.texi
index d6be2d9..e7f4895 100644
--- a/doc/sp.texi
+++ b/doc/sp.texi
@@ -12,6 +12,11 @@ high-delay links, so acknowledging of each received packet, like
 @url{https://en.wikipedia.org/wiki/XMODEM, XMODEM} does, causes
 unacceptable performance degradation.
 
+Internally it uses various timeouts and deadlines. One of them used
+extensively is 10 seconds default deadline timeout. You can override it
+with @env{$NNCPDEADLINE} environment variable, that could be useful with
+very high delay links.
+
 SP works on top of
 @url{http://noiseprotocol.org/noise.html#interactive-patterns,
 @code{Noise_IK_25519_ChaChaPoly_BLAKE2b}} protocol. Each Noise packet
@@ -61,6 +66,15 @@ just an unsigned integer telling what body structure follows.
 +------+
 @end verbatim
 
+@item PING
+    Dummy packet only used for determining workability of the connection.
+
+@verbatim
++------+
+| PING |
++------+
+@end verbatim
+
 @item INFO
     Information about the file we have for transmission.
 
@@ -145,7 +159,7 @@ just an unsigned integer telling what body structure follows.
 
 Typical peer's behaviour is following:
 
-@verbatiminclude sp.utxt
+@verbatiminclude sp.plantuml.txt
 
 @enumerate
 @item Perform @emph{Noise-IK} handshake:
@@ -173,7 +187,7 @@ payloads, then send all of remaining in the transport stage.
     Ignore it if it is too nice.
     @item If already downloaded file exists, then queue @emph{DONE}
     sending.
-    @item If @file{.seen} exists, then queue @emph{DONE} sending.
+    @item If @file{seen/XXX} exists, then queue @emph{DONE} sending.
     @item If @file{.part} exists, then queue @emph{FREQ} sending with
     corresponding offset.
     @end itemize
@@ -195,13 +209,20 @@ then run background integrity checker on it. If check succeeds, then
 delete @file{.part} suffix from file's name and send @emph{DONE} packet.
 
 @item When @emph{DONE} packet received, delete corresponding file.
+
 @item When @emph{HALT} packet received, empty file sending queue.
 
 @item Each second, node checks: are there any new @emph{tx} packets
 appeared and queues corresponding @emph{INFO} packets.
 
-@item If no packets are sent and received during @ref{CfgOnlineDeadline,
-onlinedeadline} duration, then close the connection. There is no
-explicit indication that session is over.
+@item Each minute, if no packets were sent, node sends @emph{PING}
+packet.
+
+@item If no non-PING packets are sent and received during
+@ref{CfgOnlineDeadline, onlinedeadline} duration, then close the
+connection. There is no explicit indication that session is over.
+
+@item If no packets are received during two minutes (two PING timeouts),
+then close the connection.
 
 @end enumerate