Well, we now have our uBR 'live' and running alongside our LANcity stuff
with no obvious conflicts either RF or network-wise. The HFC plant is a
very tight plant in both directions with no major issues there either.
Levels are optimum most everywhere and the SB5120's we've put into
the field seem very happy in just about any location in a 20 node HFC
architecture. So...
Next batch of issues:
Upstream speeds --
The LANcity modems consistently outperform the DOCSIS modems at
what is supposed to be the same service level -- particularly on the
upstream -- in side-by-side tests. While downstream speeds are a bit
closer all the way up to around 6~7Mbps, the DOCSIS modems hit an
upstream wall at 1.3Mbps regardless of their actual configuration. All
is as it should be up TO that upstream service level. Where do I start
checking for that type of bottleneck? Since the plant is clean and tight,
my guess would be the uBR? But what am I looking for there and/or
what parts of the config should I post for assessment? (BTW, I'm only
testing DOCSIS 1.0 currently.)
CPE address binding to cable modem MAC--
How and where would I do this in my dhcpd.conf host entries?
Entry convention for SNMP filters in cable modem config file--
What's the 'easiest way' with the simplest editor to add SNMP
filterering to the modem config file? I have several editors, none
of which I like very much, and each one seems to use a slightly
different method for the function. Doesn't seem
to be a quick and dirty copy/paste method and I'm not at all a
very experienced Linux user, so haven't even messed with the
sourceforge docsis editor/encoder/decoder, tho I guess I'll hafta
learn it sooner or later if it will correctly compile on a CentOS 5.3
box. Will it?
Anyway, we're making progress, but have a deadline for deploying
around 60 DOCSIS modems for a pilot program in conjunction with
a College network that we serve -- and I'm getting a little nervous.
As always, thanks for the continued assistance.
Kind regards,
Poge
Upstream problems ....
sounds suspiciously like a channel width issue post the ubr config for the relevant cable blade
the output from
show cable modem xxxx.xxxx.xxxx verbose where xxxx.xxxx.xxxx is the mac address would be helpful
also show cable modem xxxx.xxxx.xxxx qos while running your speed test can help as well.
Editor wise.... there is really not a "Good" editor for entering in snmp filters that I have found, I usually tough it out once and then reuse that same file as the template for new files. For that first time I like to use Arris' PacketAce.
> post the ubr config for the relevant cable blade
************************************************************
Same performance situation on all 3 active blades. I did change channel
width to 3200000 (and mini-slot went to 2) with no change in upstream performance.
Still maxxed out at 1.3Mbps.
************************************************************
interface Cable3/0
ip address 208.66.214.1 255.255.255.0 secondary
ip address 10.1.0.1 255.255.0.0
cable bundle 1 master
cable downstream annex B
cable downstream modulation 64qam
cable downstream interleave-depth 32
cable downstream channel-id 0
cable upstream 0 frequency 39008000
cable upstream 0 power-level 0
cable upstream 0 channel-width 1600000
cable upstream 0 minislot-size 4
cable upstream 0 modulation-profile 1
cable upstream 0 s160-atp-workaround
no cable upstream 0 shutdown
cable upstream 1 frequency 39008000
cable upstream 1 power-level 0
cable upstream 1 channel-width 1600000
cable upstream 1 minislot-size 4
cable upstream 1 modulation-profile 1
cable upstream 1 s160-atp-workaround
no cable upstream 1 shutdown
cable upstream 2 frequency 39008000
cable upstream 2 power-level 0
cable upstream 2 channel-width 1600000
cable upstream 2 minislot-size 4
cable upstream 2 modulation-profile 1
cable upstream 2 s160-atp-workaround
no cable upstream 2 shutdown
cable upstream 3 frequency 39008000
cable upstream 3 power-level 0
cable upstream 3 channel-width 1600000
cable upstream 3 minislot-size 4
cable upstream 3 modulation-profile 1
cable upstream 3 s160-atp-workaround
no cable upstream 3 shutdown
cable upstream 4 frequency 39008000
cable upstream 4 power-level 0
cable upstream 4 channel-width 1600000
cable upstream 4 minislot-size 4
cable upstream 4 modulation-profile 1
cable upstream 4 s160-atp-workaround
no cable upstream 4 shutdown
cable upstream 5 frequency 39008000
cable upstream 5 power-level 0
cable upstream 5 channel-width 1600000
cable upstream 5 minislot-size 4
cable upstream 5 modulation-profile 1
cable upstream 5 s160-atp-workaround
cable upstream 5 shutdown
cable dhcp-giaddr policy
cable helper-address 10.10.1.3
no keepalive
!
interface Cable4/0
no ip address
cable bundle 1
cable downstream annex B
cable downstream modulation 64qam
cable downstream interleave-depth 32
cable downstream channel-id 1
cable upstream 0 frequency 39008000
cable upstream 0 power-level 0
cable upstream 0 channel-width 1600000
cable upstream 0 minislot-size 4
cable upstream 0 modulation-profile 1
cable upstream 0 s160-atp-workaround
no cable upstream 0 shutdown
cable upstream 1 frequency 39008000
cable upstream 1 power-level 0
cable upstream 1 channel-width 1600000
cable upstream 1 minislot-size 4
cable upstream 1 modulation-profile 1
cable upstream 1 s160-atp-workaround
no cable upstream 1 shutdown
cable upstream 2 frequency 39008000
cable upstream 2 power-level 0
cable upstream 2 channel-width 1600000
cable upstream 2 minislot-size 4
cable upstream 2 modulation-profile 1
cable upstream 2 s160-atp-workaround
no cable upstream 2 shutdown
cable upstream 3 frequency 39008000
cable upstream 3 power-level 0
cable upstream 3 channel-width 1600000
cable upstream 3 minislot-size 4
cable upstream 3 modulation-profile 1
cable upstream 3 s160-atp-workaround
no cable upstream 3 shutdown
cable upstream 4 frequency 39008000
cable upstream 4 power-level 0
cable upstream 4 channel-width 1600000
cable upstream 4 minislot-size 4
cable upstream 4 modulation-profile 1
cable upstream 4 s160-atp-workaround
no cable upstream 4 shutdown
cable upstream 5 frequency 39008000
cable upstream 5 power-level 0
cable upstream 5 channel-width 1600000
cable upstream 5 minislot-size 4
cable upstream 5 modulation-profile 1
cable upstream 5 s160-atp-workaround
no cable upstream 5 shutdown
!
interface Cable5/0
no ip address
cable bundle 1
cable downstream annex B
cable downstream modulation 64qam
cable downstream interleave-depth 32
cable downstream channel-id 2
cable upstream 0 frequency 39008000
cable upstream 0 power-level 0
cable upstream 0 channel-width 1600000
cable upstream 0 minislot-size 4
cable upstream 0 modulation-profile 1
cable upstream 0 s160-atp-workaround
no cable upstream 0 shutdown
cable upstream 1 frequency 39008000
cable upstream 1 power-level 0
cable upstream 1 channel-width 1600000
cable upstream 1 minislot-size 4
cable upstream 1 modulation-profile 1
cable upstream 1 s160-atp-workaround
no cable upstream 1 shutdown
cable upstream 2 frequency 39008000
cable upstream 2 power-level 0
cable upstream 2 channel-width 1600000
cable upstream 2 minislot-size 4
cable upstream 2 modulation-profile 1
cable upstream 2 s160-atp-workaround
no cable upstream 2 shutdown
cable upstream 3 frequency 39008000
cable upstream 3 power-level 0
cable upstream 3 channel-width 1600000
cable upstream 3 minislot-size 4
cable upstream 3 modulation-profile 1
cable upstream 3 s160-atp-workaround
no cable upstream 3 shutdown
cable upstream 4 frequency 39008000
cable upstream 4 power-level 0
cable upstream 4 channel-width 1600000
cable upstream 4 minislot-size 4
cable upstream 4 modulation-profile 1
cable upstream 4 s160-atp-workaround
no cable upstream 4 shutdown
cable upstream 5 frequency 39008000
cable upstream 5 power-level 0
cable upstream 5 channel-width 1600000
cable upstream 5 minislot-size 4
cable upstream 5 modulation-profile 1
cable upstream 5 s160-atp-workaround
no cable upstream 5 shutdown
!
Also, here are the cable qos entries...
*******************************************************
fastether transmit store_and_forward enable
cable qos profile 8
cable qos profile 8 tos-overwrite 0xFF 0x0
cable qos profile 10
cable qos profile 10 tos-overwrite 0xFF 0x0
cable qos profile 10 grant-size 1500
cable qos profile 12 guaranteed-upstream 100000
cable qos profile 12 tos-overwrite 0xFF 0x0
no cable qos permission create
no cable qos permission update
cable qos permission modems
cable time-server
ip subnet-zero
*******************************************************
> show cable modem xxxx.xxxx.xxxx verbose where xxxx.xxxx.xxxx is the mac
> address would be helpful
*******************************************************
MAC Address : 0013.7118.8cc4
IP Address : 10.1.0.4
Prim Sid : 31
QoS Profile Index : 9
Interface : C3/0/U0
sysDescr :
Upstream Power : 0.00 dBmV (SNR = 26.62 dBmV)
Downstream Power : 0.00 dBmV (SNR = ----- dBmV)
Timing Offset : 1760
Initial Timing Offset : 1760
Received Power : 0.00
MAC Version : DOC2.0
QoS Provisioned Mode : DOC1.0
Enable DOCSIS2.0 Mode : Y
Phy Operating Mode : tdma
Capabilities : {Frag=N, Concat=Y, PHS=N, Priv=BPI}
Sid/Said Limit : {Max Us Sids=0, Max Ds Saids=0}
Optional Filtering Support : {802.1P=N, 802.1Q=N}
Transmit Equalizer Support : {Taps/Symbol= 0, Num of Taps= 0}
Number of CPE IPs : 1(Max CPE IPs = 1)
CFG Max-CPE : 1
Flaps : 43(Jan 17 00:39:25)
Errors : 0 CRCs, 0 HCSes
Stn Mtn Failures : 0 aborts, 28 exhausted
Total US Flows : 1(1 active)
Total DS Flows : 1(1 active)
Total US Data : 191689 packets, 55182030 bytes
Total US Throughput : 0 bits/sec, 0 packets/sec
Total DS Data : 200337 packets, 190299777 bytes
Total DS Throughput : 0 bits/sec, 0 packets/sec
Active Classifiers : 0 (Max = NO LIMIT)
DSA/DSX messages : permit all
Total Time Online : 4d22h8m
That SNR upstream sure doesn't seem right since this modem is on my
bench here in my office. Hmmmm.... Modem web interface says 37dB at
a transmit level of 54dBmV as does the Motorola Stormwatch app. No
FEC errors. There is some dropped outbound traffic indicated, but
not a bunch. So I presume the 26dB is then at the uBR at ref'd 0dBmV?
**********************************************************************
> also show cable modem xxxx.xxxx.xxxx qos while running your speed test can help
> as well.
**********************************************************************
Typical DS from the particular server for this qos..
oberlin-uBR7246#sh cable modem 0013.7118.8cc4 qos
Sfid Dir Curr Sid Sched Prio MaxSusRate MaxBrst MinRsvRate Throughput
State Type
63 US act 31 BE 1 3072000 1522 0 151926
64 DS act N/A BE 0 5120000 3044 0 4243032
**********************************************************************
Upstream..., always in the 1.3 neighborhood.
oberlin-uBR7246#sh cable modem 0013.7118.8cc4 qos
Sfid Dir Curr Sid Sched Prio MaxSusRate MaxBrst MinRsvRate Throughput
State Type
63 US act 31 BE 1 3072000 1522 0 1382177
64 DS act N/A BE 0 5120000 3044 0 30519
oberlin-uBR7246#sh cable modem 0013.7118.8cc4 qos
Sfid Dir Curr Sid Sched Prio MaxSusRate MaxBrst MinRsvRate Throughput
State Type
63 US act 31 BE 1 3072000 1522 0 1299677
64 DS act N/A BE 0 5120000 3044 0 26302
oberlin-uBR7246#sh cable modem 0013.7118.8cc4 qos
Sfid Dir Curr Sid Sched Prio MaxSusRate MaxBrst MinRsvRate Throughput
State Type
63 US act 31 BE 1 3072000 1522 0 1385290
64 DS act N/A BE 0 5120000 3044 0 29492
********************************************************************
> Editor wise.... there is really not a "Good" editor for entering in snmp filters
> that I have found, I usually tough it out once and then reuse that same file as
> the template for new files.
That seems to be the case and is the general plan.
> For that first time I like to use Arris' PacketAce.
Sounds like the favorite of most folks. I'm scrounging for it
Poge
Looks like the culprit is
cable upstream X channel-width 1600000
with a channel width of 1.6 mhz you are limited to half of the bandwidth on each upstream channel try changing it to
cable upstream X channel-width 3200000
and check your speeds again that should give you about 4.2-4.5 Megs of total bandwidth on each upstream with the MC 16C cards you have compared to the 2-2.5 megs you have currently.
Please note that is going to use more spectrum so make sure you have the upstream in a place where it can double in size without interfering with adjacent carriers, we use 4 Mhz spacing on our plant.
Poge, stop me if I'm wrong, but isn't Lancity 6 meg wide on the upstream as well as the downstream?
the modems you have can do docsis 2.0 with 6.4Mhz wide on the upstream and depending on the modulation and modem file, you can beat that 7 meg your looking for on the upstream. drop me an email and we can talk some more
Have a good weekend
~Carl
> Poge, stop me if I'm wrong, but isn't Lancity 6 meg wide on the upstream as well as the downstream?
Yeah, at 4QAM (qpsk) squeezed through a shared 10meg /half-duplex interface with ~100 or so other modems! ;-)
> the modems you have can do docsis 2.0 with 6.4Mhz wide on the upstream
The CMTS can't with the MC16C blades.
> drop me an email and we can talk some more
Thanks.
Poge
DOCSIS 1.0 config file will only yield ~1.3 mbps up
I'm actually sniffing around 1.8Mbps at a 3.2MHz channel width at 16QAM. Still rather sobering reality considering the 'spec' of 10.24 (9 in reality) Mbps upstream throughput advertised for 1.0 and 1.1.
May indeed be. Switched back to 3200000 and picked up around 500k on a
fairly consistent basis, but shouldn't it be somewhere around 5Mbps even
at QPSK? Still barely getting a whiff of 2Mbps. Looks like 16QAM is maybe
where I need to go?