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UGS Service Flow without PacketCable and dQOS

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UGS Service Flow without PacketCable and dQOS

Hello everybody,

i've got a problem. I need a Service Flow in Upstream for Voice (listening on TOS-Bit 118) and i will taking UGS as Scheduling Type. If i set SchedulingType from 2 (BE) to 6 (UGS) the CM can't registration on CMTS (Failure: reject(c)). We don't use PacketCable-Devices and can't use the dQoS-Feature from Pktc.

I'm trying with admission control, scheduling-type-entry at upstream and so on but nothing is help. I'm afraid the UGS Service Flow can only give from the CMTS to the CM but how can i requesting this flow without dQoS from Pktc?

My CMTS at Lab is a uBR7114E, but we use CMTS from uBR7111 up to uBR10012.

The Current-IOS on the CMTS at Lab is 12.3(17a)BC2

UGS Service Flow without PacketCable and dQOS

I'm testing a CM with a config file with Service Flow Scheduling Type 5 (Unsolicited Grant Service) and DQOS on both US and DS, but CMTS (Juniper G1 docsis 1.1) reject it. I don't know why. Maybe there is something more to be configured like Unsolicited Grant Size or Grants per Interval.
If anybody could help us.


Anonymous (not verified)
UGS Service Flow without PacketCable and dQOS

Nearly half a year ago we`ve tested DQOS with same results.
What we received in reply to our request from vendor is:

to use DQoS you should add to your config file special MIB, which dedicate to the TMs. This MIB call CallPFeatureSwitch and has a lot of value. i've attched example of config file to the TMs. If you want more informatoin about this mib you can find it on the diagnostic page on the TM.


11 (SNMP MIB Object) = %Integer = 1209672
11 (SNMP MIB Object) = %Integer = 4


May be it helps you ;)

UGS Service Flow without PacketCable and dQOS

Hello everybody,

first, my problem with the Reject(c) is solved. I was using the wrong respectively forgott mandatory values the configfile for the UGS SchedulingType. (DOCSIS 1.1 Specs, CM-SP-RFIv1.1-C01-050907, page 158)

Now i'm looking resume to establishment dynamic ServiceFlows, else every new CM who is registering on CMTS with UGS-ServiceFlow is "nailing up" my upstream.

nelson2006.chen (not verified)
How did you solve reject(c)?

I had same problem,How did you solve reject(c)?
Did both CMTS and CM must setting UGS parameter ?

Taiwan engineer

Here is an example

So, after a couple of years I need a static UGS ServiceFlow again and i've realized that I didn't have a copy of the first success. I found the solution again after some trys and reading the spec and will post it here to have a backup for the future.

Here is the ServiceFlow for the Configfile for normal registration:

UsServiceFlowRef 13;
QosParamSetType 7; /* Prov-, Adm-, Act-QoSParameterSet */
SchedulingType 6; /* UGS */
RequestOrTxPolicy 0x000001ff;
UnsolicitedGrantSize 232; /* 232 Byte per Interval */
GrantsPerInterval 1;
NominalGrantInterval 20000; /* Value in Microseconds, 20ms */
ToleratedGrantJitter 1000; /* Value in Microseconds, 1ms */

If you want to use the ServiceFlow on a diagnostic cable modem with the dsx-menu use the QosParamSetType 6 (without the Bit for Prov-QosParameterSet).

232Byte = 1856Bit every 20ms results in 92800bps

Attention! If you use a static UGS-ServiceFlow with infinite ActQosParamsTimeout (0) the CMTS will reserve this rate/resource until the cable modem isn't registered anymore! So use it only for debugging!

In my case I need the static UGS for some Lab- and Securitytests.

Have fun!

UGS Service Flow without PacketCable and dQOS

Dear Mr. wittmann could you please send me that sample of config file that you used for the CM that is not rejected from the CMTS?


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