I’m having the chance to test a DOCSIS 3.0 system. (Internet + IPTV)
Right know I’m providing Docsis 1.1 and I’m still having analog signal (750Mhz).
We’re using all possible frequencies and we want to TEST System in the real environment just to see
How our networks responds to 256QAM.
I'm wondering if it’s possible that I can provision DOCSIS 1.1 with that DOCSIS 3.0 CMTS. (4 DS using Channel Bonding and 8 US).
That way I could sacrifice only 2 videos channels during the test and all internet (1.1) customers will still receive their service trough that system.
The Test enviroment is using CS2200 CMTS.
Regards.-
You must just use at least mixed-mode upstream modulation profiles to provide IUC for Short and Long Data Grants to D1.1 cable modem. In mixed-mode the upstream frequency bandwidth cannot be wider as 3.2MHz or a maximum symbolrate of 2.56MSymb/s.
And the downstream channels used as Primary Capable.
Hi!
Here are some config lines for the C2200 in D 1.1 mode:
interface qam 0/0
modulation 64qam <------- 256qam should also work (see below)
interleave 16
power 480
channel 0 frequency 114000000
no channel 0 shutdown
channel 1 frequency 120000000
channel 1 shutdown
no shutdown
service group 1
desc "Area 1"
qam 0/0/0
qam 0/0/1
upstream 1/0
service group 2
desc "Area 2"
qam 0/0/0
qam 0/0/1
upstream 1/2
interface docsis-mac 1
no shutdown
no dhcp-authorization
no early-authentication-encryption
no multicast-dsid-forward
no tftp-proxy
ip bundle 1
downstream 1 interface qam 0/0/0
downstream 2 interface qam 0/0/1
downstream 3 interface qam 0/1/0
downstream 4 interface qam 0/1/1
downstream 5 interface qam 0/2/0
downstream 6 interface qam 0/2/1
downstream 7 interface qam 0/3/0
downstream 8 interface qam 0/3/1
upstream 1 interface upstream 1/0/0
upstream 2 interface upstream 1/1/0
upstream 3 interface upstream 1/2/0
upstream 4 interface upstream 1/3/0
upstream 5 interface upstream 1/4/0
upstream 6 interface upstream 1/5/0
upstream 7 interface upstream 1/6/0
upstream 8 interface upstream 1/7/0
interface upstream 1/0
frequency 39900000
channel-width 3200000 <--- Cannot do 6400000 when running D1.1, hence 3200000
power-level 9
map-advance static 200
ingress-cancellation
logical-channel 0 profile 2 secondary-profile 1 <--- Need to use modulation profiles with TDMA, not A-TDMA
logical-channel 0 minislot 2
logical-channel 0 pre-equalization
no logical-channel 0 shutdown
no shutdown
interface upstream 1/2
frequency 39900000
channel-width 3200000
power-level 9
map-advance static 200
ingress-cancellation
logical-channel 0 profile 2 secondary-profile 1
logical-channel 0 minislot 2
no logical-channel 0 shutdown
no shutdown
Using 64 or 256QAM for downstream should really be decided based on the cable plant quality, but some really old D1.1 modems seem to have a problem with 256QAM, hence not adhering to the standard. 64QAM is the safe choice, but 256QAM should work and gives some 10 Mbps extra capacity in the downstream channel.
Good luck!
/Fredrik
a lot of thanks for your answers and also to show a config.
So what would be max download and upload using this config?
Hi!
Downstream should be 27 Mbps using 64QAM, and 39 Mbps using 256QAM.
Upstream with a 3,2 MHz channel width is 4.4 Mbps using QPSK and 8.8 Mbps using 16QAM.
I have attached a table describing this.
/Fredrik