1 files changed, 46 insertions, 0 deletions
diff --git a/doc/basic.texi b/doc/basic.texi
index cea33eaa8..05d72bc80 100644
--- a/doc/basic.texi
+++ b/doc/basic.texi
@@ -18,6 +18,7 @@ daemons.
 * Config Commands::             Commands used in config files
 * Terminal Mode Commands::      Common commands used in a VTY
 * Common Invocation Options::   Starting the daemons
+* Loadable Module Support::     Using extension modules
 * Virtual Terminal Interfaces:: Interacting with the daemons
 @end menu
 
@@ -372,6 +373,51 @@ Print program version.
 @end table
 
 
+@node Loadable Module Support
+@section Loadable Module Support
+
+FRR supports loading extension modules at startup.  Loading, reloading or
+unloading modules at runtime is not supported (yet).  To load a module, use
+the following command line option at daemon startup:
+
+@table @samp
+@item -M @var{module:options}
+@itemx --module @var{module:options}
+
+Load the specified module, optionally passing options to it.  If the module
+name contains a slash (/), it is assumed to be a full pathname to a file to
+be loaded.  If it does not contain a slash, the
+@code{@value{INSTALL_PREFIX_MODULES}} directory is searched for a module of
+the given name; first with the daemon name prepended (e.g. @code{zebra_mod}
+for @code{mod}), then without the daemon name prepended.
+
+This option is available on all daemons, though some daemons may not have
+any modules available to be loaded.
+@end table
+
+
+@subsection The SNMP Module
+
+If SNMP is enabled during compile-time and installed as part of the package,
+the @code{snmp} module can be loaded for the @command{zebra},
+@command{bgpd}, @command{ospfd}, @command{ospf6d} and @command{ripd} daemons.
+
+The module ignores any options passed to it.  Refer to @ref{SNMP Support}
+for information on its usage.
+
+
+@subsection The FPM Module
+
+If FPM is enabled during compile-time and installed as part of the package,
+the @code{fpm} module can be loaded for the @command{zebra} daemon.  This
+provides the Forwarding Plane Manager ("FPM") API.
+
+The module expects its argument to be either @code{netlink} or
+@code{protobuf}, specifying the encapsulation to use.  @code{netlink} is the
+default, and @code{protobuf} may not be available if the module was built
+without protobuf support.  Refer to @ref{zebra FIB push interface} for more
+information.
+
 
 @node Virtual Terminal Interfaces
 @section Virtual Terminal Interfaces