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Multiple CMTS on one node

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Multiple CMTS on one node

Hi all.

I have HFC in small village with 2 nodes. 50 modems / each. I am using mini cmts based on broadcom chipset.

The big cons of mini cmts is that it have only 1 physical port for US. It means that the noise from one node is shared with all nodes.

We bought another CMTS thats US port we want to connect to another node.

Question is.... Is possible to have 2x16 Channels in same shared downstream (2 CMTS on different freq range), but one node will be connected only to one node. Not shared.

How can CMs know that which 16channel bundle is for the right upstream bundle?
How to prevent that to connect CMs from node1 to node2 DS?


Downstream Freq config

Thinking you have two options.
1st is different optical transmitter for the 2nd node with only the 2nd cmts downstream 16 Qams.
2nd option is in the modem files. in the optional encoding, docsis 1.0 encodings in Excentis config editor is the option to add downstream frequency configuration. for node 1 add freq 5710000 and for node 2 add freq 745000000 as an example. so from cmts 1 one of the downstream frequencies and 2nd cmts 2 since it's different frequencies. so two modems for basic 1 with freq A and basic 2 with freq B
benefit of option 1 is faster registration time


cmts1 connects to node 1
cmts2 connects to node 2
This is safe and reliable option

both CMTS connect to both nodes DS and US (with no overlapping DS and US frequencies)
Doesnt help solve your noise issues.
Might not get even balance of modems across both systems. Although you can add commands to the CM config file to lock a particular customer to a particular CMTS (DS frequency)

both CMTS connected to both nodes DS (with no overlapping DS frequencies)
CMTS1 connects to node 1 US
CMTS2 connects to node 2 US
Modems might be a bit slower to register, since they may initially connect to the "wrong" CMTS

Get rid of mini CMTS and buy yourself a surplus bigger unit with more DS and US ports
You can buy bigger system like Cisco uBR10K with 20x20 cards, dirt cheap

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