1. Asynchronous Message Service (AMS) Prototype Status
Scott Burleigh
Jet Propulsion Laboratory,
California Institute of Technology
25 August 2005

2. AMS Continuum configuration MIB configuration service
Message space for
application Q, authority R
new zone
specification
zone
registration
registrar
location
query and
response
Zone A
Zone B
Registrar
Registrar
reconfig
messages
node
registration
heartbeat,
ack, reconfig
heartbeat,
ack, reconfig
application
messages
remote AMS
messages
Node Z
Node X
Node Y
(a new node)
RAMS
gateway
application
messages
application messages
application
messages

3. Example programs (1 of 2) #include "ams.h" static int runCatcher() {
AmsNode me;
AmsEvent event;
int cn, zn, nn, len, ct;
char *sname, *txt;
ams_register(NULL,NULL,NULL, 0, "amsdemo", "test", "301", "catch", &me);
ams_invite(me, "text", AmsPriorityStandard, AmsAssured);
while (1)
ams_get_event(me, AMS_BLOCKING, &event);
if (ams_get_event_type(me, event) == AMS_MSG_EVT) break;
else ams_recycle_event(me, event); }
ams_parse_msg(me, event, &cn, &zn, &nn, &sname, &len, &txt, &ct);
printf("%d received '%s'.\n", getpid(), txt);
ams_recycle_event(me, event);
ams_unregister(me);
return 0;

4. Example programs (2 of 2) static int runPitcher() { AmsNode me;
AmsEvent event;
AmsStateType state;
AmsChangeType change;
AmsPriority priority;
AmsDiligence diligence;
int zn, nn, textlen;
char buffer[80], *zname, *nname, *sname;
sprintf(buffer, "Hello from %d.", getpid());
textlen = strlen(buffer) + 1;
ams_register(NULL,NULL,NULL, 0, "amsdemo", "test", "301", "pitch", &me);
while (1)
ams_get_event(me, AMS_BLOCKING, &event);
ams_parse_notice(me, event, &state, &change, &zname, &zn,
&nname, &nn, &sname, &priority, &diligence);
ams_recycle_event(me, event);
if (state == AmsInvitationState)
printf("%d sending '%s'.\n", getpid(), buffer);
ams_send(me, 0, zn, nn, "text", textlen, buffer,
AmsReportNone, NULL, 0);
ams_unregister(me);
return 0; }
int main(int argc, char **argv)
if (fork() == 0) return runCatcher(); else return runPitcher();

5. Management Information Base
<?xml version="1.0" standalone="yes"?>
<ams_mib_load>
<ams_mib_init continuum_nbr="1" continuum_name="jpl" ptsname="dgr"/>
<ams_mib_add>
<csendpoint epspec="2357:loretta.jpl.nasa.gov"/>
<application name="amsdemo">
<role nbr="1" name="shell"/>
<role nbr="2" name="log"/>
<role nbr="3" name="pitch"/>
<role nbr="4" name="catch"/>
<role nbr="5" name="benchs"/>
<role nbr="6" name="benchr"/>
<subject nbr="1" name="text" desc="ASCII text"/>
<subject nbr="2" name="noise" desc="more ASCII text"/>
<subject nbr="3" name="bench" desc="numbered msgs"/>
</application>
<msgspace nbr="1" appname="amsdemo" authname="test">
<zone nbr="1" name="301"/>
<continuum nbr="2" name="apl" desc="Johns Hopkins APL"/>
</msgspace>
</ams_mib_add>
</ams_mib_load>

6. Initial Performance Statistics
Msgs/sec
Mbps
Msg Size
Msg Count
1 subscr
2 subscr 20
10 million
11560
8581
1.7
1.3
200
1 million
10124
6642
15.4
10.1
2000
100,000
4800
2529
73.2
38.6
20000
10,000
587
293
89.6
44.8
Publisher on a Pentium III, Red Hat 8.0 Linux.
Subscriber(s) on a second Pentium III, Fedora Core 3.
Underlying transport is TCP/IP over a 100 Mbps Ethernet switch.

7. GDS Sim
Spacecraft Sim
SPOF router
admin
VxWorks
RAMS gateway
RAMS gateway
SMC controller
libams
ION
ION
ION
libams
libams
DGR
IP MC
SPOF CLA (C)
SPOF CLA (S)
SPOF CLA (C)
DGR
DGR
UDP
TCP
TCP
TCP
UDP
(80)
(80)
UDP
SMC target
SMC controller
amsd
libams
libams
DGR
VxWorks
Msg queue
DGR
amsd
IP MC
DGR
UDP
Linux
UDP
DGR
UDP
UDP
Linux
Solaris
SMC target
libams
VxWorks
Msg queue
DGR
UDP
Cygwin or Interix
The Internet
SMC target
SMC controller
libams
libams
VxWorks
Msg queue
DGR
IP MC
DGR
UDP
UDP
SMC controller
libams
IP MC
DGR
firewall
firewall
UDP

8. What’s Done Automatic discovery and dynamic reconfiguration
Startup, shutdown, registration
Exchange of subscriptions and invitations
Application message flow
Publish/subscribe
Private messages (send/reply)
Clean interface to underlying transport systems. Two adapters implemented so far: TCP and DGR (datagram retransmission, a reliable UDP system).
Heartbeat exchange, detection of unannounced crash.

9. What’s Not Done Yet Test/debug failover among configuration servers
Non-trivial encryption; test/debug authentication and authorization
Periodic resynchronization
Other transport service adapters with other QOS features: vxWorks message queues, IP multicast, probably UDP
Remote AMS gateway
Port to Interix (Windows); port to Solaris; finish port to vxWorks

10. Other stuff for FY06
Dynamic updating of MIBs, e.g., in response to changes in an information model
Message marshalling/un-marshalling per message definitions in MIB
JMS wrapper (JNI interface)
LabView wrapper
Matlab wrapper
Tcl/Tk wrapper