diff --git a/utils/Rtpengine.pm b/utils/Rtpengine.pm
index 2bc513727..4ab72a39d 100644
--- a/utils/Rtpengine.pm
+++ b/utils/Rtpengine.pm
@@ -2,9 +2,20 @@ package Rtpengine;
 
 use strict;
 use warnings;
+use Socket;
+use Socket6;
+use IO::Socket;
 use IO::Socket::IP;
 use Bencode;
 use Data::Dumper;
+use Net::Interface;
+use List::Util;
+use IO::Multiplex;
+use Time::HiRes qw(time);
+use SDP;
+use ICE;
+use DTLS;
+use RTP;
 
 sub new {
 	my ($class, $addr, $port) = @_;
@@ -16,7 +27,7 @@ sub new {
 		$self->{socket} = $addr;
 	}
 	else {
-		$self->{socket} = IO::Socket::IP->new(Type => SOCK_DGRAM, Proto => 'udp',
+		$self->{socket} = IO::Socket::IP->new(Type => &Socket::SOCK_DGRAM, Proto => 'udp',
 				PeerHost => $addr, PeerPort => $port);
 	}
 
@@ -55,7 +66,158 @@ sub answer {
 package Rtpengine::Test;
 
 sub new {
-	my ($class) = @_;
+	my ($class, $callback) = @_;
+
+	my $self = {};
+	bless $self, $class;
+
+	# detect local interfaces
+
+	my @intfs = Net::Interface->interfaces();
+
+	my @v4 = map {$_->address(&IO::Socket::AF_INET)} @intfs;
+	@v4 = map {Socket6::inet_ntop(&IO::Socket::AF_INET, $_)} @v4;
+	@v4 = grep {$_ !~ /^127\./} @v4;
+	@v4 or die("no IPv4 addresses found");
+
+	my @v6 = map {$_->address(&IO::Socket::AF_INET6)} @intfs;
+	@v6 = map {Socket6::inet_ntop(&IO::Socket::AF_INET6, $_)} @v6;
+	@v6 = grep {$_ !~ /^::|^fe80:/} @v6;
+	@v4 or die("no IPv6 addresses found");
+
+	$self->{v4_addresses} = \@v4;
+	$self->{v6_addresses} = \@v6;
+	$self->{all_addresses} = [ @v4, @v6 ];
+
+	# supporting objects
+
+	$self->{mux} = IO::Multiplex->new();
+	$self->{mux}->set_callback_object($self);
+
+	$self->{media_port} = 2000;
+
+	$self->{rtpe} = Rtpengine->new('localhost', 2223);
+	$self->{callid} = rand();
+
+	$self->{callback} = $callback;
+
+	return $self;
 };
 
+sub client {
+	my ($self, %args) = @_;
+	return Rtpengine::Test::Client->_new($self, %args);
+}
+
+sub run {
+	my ($self) = @_;
+
+	$self->{mux}->loop();
+}
+
+sub mux_input {
+	my ($self, $mux, $fh, $input) = @_;
+
+	my $peer = $mux->udp_peer($fh);
+}
+
+sub mux_timeout {
+	my ($self, $mux, $fh) = @_;
+
+	$self->{callback}->(time());
+
+	$mux->set_timeout($fh, 0.01);
+}
+
+
+package Rtpengine::Test::Client;
+
+sub _new {
+	my ($class, $parent, %args) = @_;
+
+	my $self = {};
+	bless $self, $class;
+
+	$self->{parent} = $parent;
+	$self->{tag} = rand();
+
+	# create media sockets
+	my @addresses = @{$parent->{all_addresses}};
+	@addresses = List::Util::shuffle @addresses;
+	my (@sockets, @rtp, @rtcp);
+
+	for my $address (@addresses) {
+		my $rtp = IO::Socket::IP->new(Type => &Socket::SOCK_DGRAM, Proto => 'udp',
+			LocalHost => $address, LocalPort => $parent->{media_port}++) or die($address);
+		my $rtcp = IO::Socket::IP->new(Type => &Socket::SOCK_DGRAM, Proto => 'udp',
+			LocalHost => $address, LocalPort => $parent->{media_port}++) or die($address);
+		push(@sockets, [$rtp, $rtcp]);
+		push(@rtp, $rtp);
+		push(@rtcp, $rtcp);
+		$parent->{mux}->add($rtp);
+		$parent->{mux}->add($rtcp);
+		$parent->{mux}->set_timeout($rtp, 0.01); # XXX overkill, only need this on one
+	}
+
+	$self->{sockets} = \@sockets;
+	$self->{rtp_sockets} = \@rtp;
+	$self->{rtcp_sockets} = \@rtcp;
+
+	$self->{main_sockets} = $sockets[0]; # for m= and o=
+	$self->{local_sdp} = SDP->new($self->{main_sockets}->[0]); # no global c=
+
+	$self->{local_media} = $self->{local_sdp}->add_media(SDP::Media->new(
+		$self->{main_sockets}->[0], $self->{main_sockets}->[1], 'RTP/AVP')); # main rtp and rtcp
+
+	return $self;
+}
+
+sub offer {
+	my ($self, $other) = @_;
+
+	my $sdp_body = $self->{local_sdp}->encode();
+	# XXX validate SDP
+
+	my $req = { command => 'offer', ICE => 'remove', 'call-id' => $self->{parent}->{callid},
+		'from-tag' => $self->{tag}, sdp => $sdp_body };
+
+	my $out = $self->{parent}->{rtpe}->req($req);
+
+	$other->offered($out);
+}
+
+sub offered {
+	my ($self, $req) = @_;
+
+	my $sdp_body = $req->{sdp} or die;
+	$self->{remote_sdp} = SDP->decode($sdp_body);
+	# XXX validate SDP
+	@{$self->{remote_sdp}->{medias}} == 1 or die;
+	$self->{remote_media} = $self->{remote_sdp}->{medias}->[0];
+}
+
+sub answer {
+	my ($self, $other) = @_;
+
+	my $sdp_body = $self->{local_sdp}->encode();
+	# XXX validate SDP
+
+	my $req = { command => 'answer', ICE => 'remove', 'call-id' => $self->{parent}->{callid},
+		'from-tag' => $other->{tag}, 'to-tag' => $self->{tag}, sdp => $sdp_body };
+
+	my $out = $self->{parent}->{rtpe}->req($req);
+
+	$other->answered($out);
+}
+
+sub answered {
+	my ($self, $req) = @_;
+
+	my $sdp_body = $req->{sdp} or die;
+	$self->{remote_sdp} = SDP->decode($sdp_body);
+	# XXX validate SDP
+	@{$self->{remote_sdp}->{medias}} == 1 or die;
+	$self->{remote_media} = $self->{remote_sdp}->{medias}->[0];
+}
+
 1;
diff --git a/utils/test3.pl b/utils/test3.pl
new file mode 100644
index 000000000..05130a939
--- /dev/null
+++ b/utils/test3.pl
@@ -0,0 +1,27 @@
+#!/usr/bin/perl
+
+use strict;
+use warnings;
+use Rtpengine;
+use Time::HiRes qw(time);
+
+my ($r, $a, $b);
+
+my $offer = time();
+my $answer = $offer + 3;
+
+my $answer_done = 0;
+my $cb = sub {
+	my ($now) = @_;
+	if ($now >= $answer && !$answer_done) {
+		$b->answer($a);
+		$answer_done = 1;
+	}
+};
+
+$r = Rtpengine::Test->new($cb);
+$a = $r->client();
+$b = $r->client();
+
+$a->offer($b);
+$r->run();