Hello everybody,

maybe this link will also help:

Link

regards,

wittmann

P.S. Sorry for my poor english ;)

What version of firmware do You have on TCM420? Maybe You have to upgrade it?

Hey Simon,

Did you ever this this problem fixed because im having the same issues right now :)
Hope you can post it on this forum, thanks

Martin
DK

Hi Simon,

don't get mixed up. The 2.7Mb is a very good result. This is the physical limmitation of Docsis.
OK Docsis 2.0 at qam64 equals 30Mb upstream theoretical, for the upstreamPORT. upstreamspeed of cablemodem is different of the upstreamport of your CMTS.

Try it, 5CM's at 2.7Mb =ok, 10CM's at2.7Mb = ok 20CM's at 2.7Mb = NOK

I have the same UBR, only i work with webstart modem's.

That's strange. Guess I have mixed the different Cisco CMTS names. Pardon for that. But since you have managed to get the 6Mbps, I might help you to get a bit more...

What do you mean about timeslot? Is that the same as minislotsize? In that case, have you tried with both 2 and 4 slots?

You can also try with some other settings in the configfile:

UsServiceFlow {
UsServiceFlowRef 2;
QosParamSetType 7;
MaxConcatenatedBurst 4566;
MaxTrafficBurst 4566;
}

Note the MaxConcatenatedBurst and MaxTrafficBurst. Try with 1522 * X values, and see what gives you the best result.

successfull tested a bandwith of 6MBit+ in the US
with a lower time slot and channel bw of 6,4 Mhz

You cannot go any higher than 2.7Mbps. There is an issue with the chipset, so it cannot transfere more than 2.7Mbps pr. session - even though you can go higher when transfering from multiple modems at the same time.

About the doc 2.0 flag: This is enabled by default, so you don't need to set this. You will only set it to 0, if you want to disable 2.0...

There are some issues with the TCM420 as well, but I'm pretty sure that is the case here. Let me know if you purchase another CMTS, and still can't get the US rate any higher...

here are the important config parts

ubr config:

cable modulation-profile 222 request 0 16 0 22 64qam scrambler 152 no-diff 64 fixed qpsk1 1 2048
cable modulation-profile 222 initial 5 34 0 48 64qam scrambler 152 no-diff 128 fixed qpsk1 1 2048
cable modulation-profile 222 station 5 34 0 48 64qam scrambler 152 no-diff 128 fixed qpsk1 1 2048
cable modulation-profile 222 a-short 6 76 6 22 64qam scrambler 152 no-diff 64 shortened qpsk1 1 2048
cable modulation-profile 222 a-long 8 231 0 22 64qam scrambler 152 no-diff 64 shortened qpsk1 1 2048
cable modulation-profile 222 a-ugs 8 231 0 22 64qam scrambler 152 no-diff 64 shortened qpsk1 1 2048

[cable interface]
cable tftp-enforce
no cable packet-cache
cable downstream annex A
cable downstream modulation 256qam
cable downstream frequency xxxxxxx
cable downstream channel-id 1
no cable downstream rf-shutdown
cable downstream rf-power 57
cable upstream 0 connector 4
cable upstream 0 frequency xxxxxxxx
cable upstream 0 docsis-mode atdma
cable upstream 0 channel-width 6400000 1600000
cable upstream 0 minislot-size 2
cable upstream 0 power-level 0
cable upstream 0 range-backoff 3 6
cable upstream 0 modulation-profile 222
cable upstream 0 equalization-coefficient

modem config:

Main
{
NetworkAccess 1;
BaselinePrivacy
{
AuthTimeout 10;
ReAuthTimeout 10;
AuthGraceTime 600;
OperTimeout 10;
ReKeyTimeout 10;
TEKGraceTime 600;
AuthRejectTimeout 60;
}
VendorSpecific
{
.
.
.
}
MaxCPE 5;
UsPacketClass
{
ClassifierRef 2;
ServiceFlowRef 2;
ActivationState 1;
IpPacketClassifier
{
DstPortStart 2727;
DstPortEnd 2727;

}
}
UsPacketClass
{
ClassifierRef 1;
ServiceFlowRef 2;
ActivationState 1;
LLCPacketClassifier
{
EtherType 0x030f16;
}
}
DsPacketClass
{
ClassifierRef 3;
ServiceFlowRef 4;
ActivationState 1;
IpPacketClassifier
{
IpProto 256;
DstPortStart 2427;
DstPortEnd 2427;
}
}
UsServiceFlow
{
UsServiceFlowRef 1;
QosParamSetType 7;
MaxRateSustained 10000000;
SchedulingType 2;
}
UsServiceFlow
{
UsServiceFlowRef 2;
QosParamSetType 7;
TrafficPriority 4;
SchedulingType 2;
}
DsServiceFlow
{
DsServiceFlowRef 3;
QosParamSetType 7;
MaxRateSustained 10000000;
}
DsServiceFlow
{
DsServiceFlowRef 4;
QosParamSetType 7;
TrafficPriority 4;
}
GlobalPrivacyEnable 1;
DocsisTwoEnable 1;
}

kind regards
Simon

@Simon,

have you set DOCSIS2.0 enable at configfile?

May be the problem in logical upstream channel settings?
Post UBR config here