diff --git a/src/osmo_ss7_sup.erl b/src/osmo_ss7_sup.erl
index 2e34b41..ed31cb5 100644
--- a/src/osmo_ss7_sup.erl
+++ b/src/osmo_ss7_sup.erl
@@ -31,7 +31,9 @@
 init(Args) ->
 	LinksChild = {ss7_links, {ss7_links, start_link, []},
 		     permanent, 2000, worker, [ss7_links]},
-	{ok,{{one_for_one,60,600}, [LinksChild]}}.
+	RouteChild = {ss7_routes, {ss7_routes, start_link, []},
+		     permanent, 2000, worker, [ss7_routes]},
+	{ok,{{one_for_one,60,600}, [LinksChild, RouteChild]}}.
 
 % Add a m3ua link to this supervisor
 add_mtp_link(L=#sigtran_link{type = m3ua, name = Name,
diff --git a/src/ss7_links.erl b/src/ss7_links.erl
index 5e98b3b..75617f5 100644
--- a/src/ss7_links.erl
+++ b/src/ss7_links.erl
@@ -39,20 +39,20 @@
 
 -record(slink, {
 	key,		% {linkset_name, sls}
-	name,
-	linkset_name,
+	name,		% name of the link
+	linkset_name,	% name of the linkset to which we belong
 	sls,
-	user_pid,
-	state
+	user_pid,	% Pid handling MTP-TRANSFER primitives
+	state		% (down | up | active)
 }).
 
 -record(slinkset, {
-	name,
-	local_pc,
-	remote_pc,
+	name,		% name of the linkset
+	local_pc,	% local point code
+	remote_pc,	% remote point code
 	user_pid,
-	state,
-	links
+	state,		% (down | up_inactive | active)
+	active_sls	% list of Sls of currently active links
 }).
 
 -record(service, {
@@ -218,7 +218,8 @@
 				{FromPid, _FromRef}, S) ->
 	#su_state{linkset_tbl = Tbl} = S,
 	Ls = #slinkset{local_pc = LocalPc, remote_pc = RemotePc,
-		       name = Name, user_pid = FromPid},
+		       name = Name, user_pid = FromPid,
+		       state = down, active_sls=[]},
 	case ets:insert_new(Tbl, Ls) of
 	    false ->
 		{reply, {error, ets_insert}, S};
@@ -270,6 +271,7 @@
 	    [Link] ->
 		NewLink = Link#slink{state = State},
 		ets:insert(LinkTbl, NewLink),
+		propagate_linkstate_to_linkset(LsName, Sls, State),
 		{reply, ok, S}
 	end;
 
@@ -322,3 +324,32 @@
 
 code_change(_OldVsn, State, _Extra) ->
 	{ok, State}.
+
+% update the active_sls state in a linkset after a link state chg
+propagate_linkstate_to_linkset(LsName, Sls, State) ->
+	case ets:lookup(ss7_linksets, LsName) of
+	     [Ls = #slinkset{}] ->
+	       #slinkset{active_sls = ActSls, remote_pc = Dpc} = Ls,
+		case State of
+		    active ->
+			% add Sls to list (unique)
+			ActSls2 = lists:usort([Sls|ActSls]);
+		    _ ->
+			% del Sls from list
+			ActSls2 = lists:delete(Sls, ActSls)
+		end,
+		% compute the linkstate state
+		case ActSls2 of
+		    [] ->
+			LsState = up_inactive,
+			ss7_routes:delete_route(Dpc, 16#ffff, LsName);
+		    _ ->
+			LsState = active,
+			ss7_routes:create_route(Dpc, 16#ffff, LsName)
+		end,
+		ets:insert(ss7_linksets,
+			   Ls#slinkset{active_sls = ActSls2,
+					state = LsState});
+	    _ ->
+		{error, ets_lookup}
+	end.
diff --git a/src/ss7_routes.erl b/src/ss7_routes.erl
new file mode 100644
index 0000000..70fd5c9
--- /dev/null
+++ b/src/ss7_routes.erl
@@ -0,0 +1,128 @@
+% Internal SS7 route database keeping
+
+% (C) 2011 by Harald Welte <laforge@gnumonks.org>
+%
+% All Rights Reserved
+%
+% This program is free software; you can redistribute it and/or modify
+% it under the terms of the GNU Affero General Public License as
+% published by the Free Software Foundation; either version 3 of the
+% License, or (at your option) any later version.
+%
+% This program is distributed in the hope that it will be useful,
+% but WITHOUT ANY WARRANTY; without even the implied warranty of
+% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+% GNU General Public License for more details.
+%
+% You should have received a copy of the GNU Affero General Public License
+% along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+-module(ss7_routes).
+-behaviour(gen_server).
+
+-include_lib("osmo_ss7/include/mtp3.hrl").
+
+% gen_fsm callbacks
+-export([init/1, handle_call/3, handle_info/2, terminate/2, code_change/3]).
+
+% our published API
+-export([start_link/0]).
+
+% client functions, may internally talk to our sccp_user server
+-export([create_route/3, delete_route/3]).
+-export([dump/0]).
+-export([route_dpc/1]).
+
+-record(ss7route, {
+	remote_pc_mask,		% {remote_pc, remote_pc_mask}
+	linkset_name
+}).
+
+-record(sr_state, {
+	route_tbl
+}).
+
+% initialization code
+
+start_link() ->
+	gen_server:start_link({local, ?MODULE}, ?MODULE, [], [{debug, [trace]}]).
+
+init(_Arg) ->
+	RouteTbl = ets:new(ss7_routes, [ordered_set, named_table,
+			     {keypos, #ss7route.remote_pc_mask}]),
+	process_flag(trap_exit, true),
+	{ok, #sr_state{route_tbl = RouteTbl}}.
+
+% client side API
+
+% all write operations go through gen_server:call(), as only the ?MODULE
+% process has permission to modify the table content
+
+create_route(RemotePc, RemoteMask, LinksetName) ->
+	gen_server:call(?MODULE, {create_route, {RemotePc, RemoteMask, LinksetName}}).
+
+delete_route(RemotePc, RemoteMask, LinksetName) ->
+	gen_server:call(?MODULE, {delete_route, {RemotePc, RemoteMask, LinksetName}}).
+
+% the lookup functions can directly use the ets named_table from within
+% the client process, no need to go through a synchronous IPC
+
+route_dpc(Dpc) ->
+	% this was generated by ets:fun2ms() on the shell
+	Match = [{#ss7route{remote_pc_mask={'$1','$2'},linkset_name='$3'},
+			  [{'==',{'band',Dpc,'$2'},'$1'}],
+			    ['$3']}],
+	case ets:select(ss7_routes, Match) of
+	    [Name|_] ->
+		{ok, Name};
+	    _ ->
+		{error, no_route}
+	end.
+
+dump() ->
+	List = ets:tab2list(ss7_routes),
+	dump_routes(List).
+
+dump_routes([]) ->
+	ok;
+dump_routes([Head|Tail]) when is_record(Head, ss7route) ->
+	dump_single_route(Head),
+	dump_routes(Tail).
+
+dump_single_route(#ss7route{remote_pc_mask = {Pc, Mask},
+			    linkset_name = Name}) ->
+	io:format("Dest PC ~p/~p -> Linkset ~p~n",
+		  [Pc, Mask, Name]).
+
+% server side code
+
+handle_call({create_route, {RemotePc, RemoteMask, Name}},
+				{_FromPid, _FromRef}, S) ->
+	#sr_state{route_tbl = Tbl} = S,
+	R = #ss7route{remote_pc_mask = {RemotePc, RemoteMask},
+		      linkset_name = Name},
+	case ets:insert_new(Tbl, R) of
+	    false ->
+		{reply, {error, ets_insert}, S};
+	    _ ->
+		{reply, ok, S}
+	end;
+
+handle_call({delete_route, {RemotePc, RemoteMask, _Name}},
+				{_FromPid, _FromRef}, S) ->
+	#sr_state{route_tbl = Tbl} = S,
+	ets:delete(Tbl, {RemotePc, RemoteMask}),
+	{reply, ok, S}.
+
+handle_info(Info, S) ->
+	error_logger:error_report(["unknown handle_info",
+				  {module, ?MODULE},
+				  {info, Info}, {state, S}]),
+	{noreply, S}.
+
+terminate(Reason, _S) ->
+	io:format("terminating ~p with reason ~p", [?MODULE, Reason]),
+	ok.
+
+code_change(_OldVsn, State, _Extra) ->
+	{ok, State}.