VoIP, Sip and QoS on Cisco CMTS

Hello,

I have a question about cisco cmts QoS and sip VoIP.
Im testing a voip setup on a 10k with non-eMTA SurfBoard 5100 and epc3000 modems.
Behind the modem there is conneted an router with ATA doing SIP.

Wer doing UGS-AD and it seems to be working, almost. The problems seems to be that the
call is just hanging there when its done. Its never deleted in the CMTS ?? there fore also res. bandwitdh in the CMTS maybe :-/ ?

Seems like the CMTS creates the UGS flow :
--
sh cable modem calls
001e.6bfc.62f4 172.20.11.198 C5/0/1/U1 3310 V
--
sh cable modem 001e.6bfc.62f4 qos
6858 US act 3310 BE 0 4096000 1600 0 0
8176 US act 1721 UGS_A 0 0 0 0 0
6837 DS act N/A BE 0 25000000 1600 0 0
8995 DS act N/A BE 3 128000 3044 0 0
--
sh inter ca5/0/1 service-flow 8176
8176 1721 001e.6bfc.62f4 10 10 10 sec(S) US act 1d12h
--

The docsis file SF is created like this:
--
/* VoIP upstream flow */
UsServiceFlow {
UsServiceFlowRef 2;
QosParamSetType 7;
SchedulingType 5; /* UGS_AD */
RequestOrTxPolicy 0x000001ff; /* see fig 1. */
UnsolicitedGrantSize 232; /* 232 for g.711 is OK g.729 = 92 */
NominalPollInterval 20000; /* nominal interval between successive unicast request */
ToleratedPollJitter 10000; /* microseconds that the unicast request interval may be delayed from the nominal periodic sched */
NominalGrantInterval 20000; /* Nominal Grant Interval set to 20000usec = 20 ms */
ToleratedGrantJitter 10000; /* max microseconds that the transmission opportunities may be delayed from the nominal periodic */
GrantsPerInterval 1; /* How many simultanious VoIP calls? */
}

DsServiceFlow {
DsServiceFlowRef 102;
QosParamSetType 7;
MaxRateSustained 128000;
TrafficPriority 3;
}

UsPacketClass {
ClassifierRef 2;
ServiceFlowRef 2;
ActivationState 1;
IpPacketClassifier {
IpProto 17; /* UDP */
IpDstAddr ;
IpDstMask 255.255.255.255;
DstPortStart 5061;
DstPortEnd 65535;
}
}

/* VoIP downstream acl */
DsPacketClass {
ClassifierRef 102;
ServiceFlowRef 102;
ActivationState 1;
IpPacketClassifier {
IpProto 17; /* UDP */
IpSrcAddr ;
IpSrcMask 255.255.255.255;
SrcPortStart 5061;
SrcPortEnd 65535;
}
}
--

Any one have some good info on this, plz let me know ;-)

Martin