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we are using CASA CMTS.
We have 3 physically upstream interfaces(connectors), each of them has a "sub-interface". We have only 4 upstream frequencies.
I would like to know if is it ok, to put within the same MAC DOMAIN...different upstream channels..but on the same frequencies.

You should check the config bellow.
Can the upstream 1/2.0 and 1/2.1 be withib the same MAC DOMAIN...because they are on the same freq as 1/0.0 and 1/0.1?

interface docsis-mac 7
downstream 20 interface qam 4/3/0
downstream 21 interface qam 4/3/1
downstream 22 interface qam 4/3/2
downstream 23 interface qam 4/3/3
upstream 220 interface upstream 1/0.0/0 ---->freq 36,5 Mhz
upstream 221 interface upstream 1/0.1/0 ---->freq 45,6 Mhz
upstream 230 interface upstream 1/1.0/0 ---->freq 52,5 Mhz
upstream 231 interface upstream 1/1.1/0 ---->freq 60 Mhz
upstream 250 interface upstream 1/2.0/0 ---->freq 36,5 Mhz
upstream 251 interface upstream 1/2.1/0 ---->freq 52,5 Mhz
no mgmd ipv4 shutdown

Thanks in advance, vaitapu

This is a qualified yes, I

This is a qualified yes, I would need more information to determine if this is valid config or not...

On a Casa only a "service group" has the requirement to not have overlapping upstream frequencies. However, it is assumed that each "service group" corresponds to one Node/trunk. i.e. a CM can only transmit(upstream) on one service group. On the downstream side multiple Service Groups can be aggregated to one Docsis Mac (Mac Domain).

From your config it looks like you are trying to receive the same frequency 36.5 and 52.5 from the same node/trunk. This would not be allowed and would result in modems not using 1/0.0/0 && 1/1.0/0 && 1/2.0/0 && 1/2.1/0 because of self interference.
if your setup looks like the attachment, it will work.

File attachments: 

thanks for the quick reply.

If I understand correctly the configuration I'm using should work and it works...I have registered modems on all of US interfaces.
I also see that load balancing is working fine.

I don't notice any strange behaviour, except when I try to save config.

copy running-config startup-config fail.
The same frequency can not be configured to different channels in the same service group.

Thanks and BR, vaitapu

light (not verified)
No it would not work

Hello Vaitapu,

No, it would not work, you can't use the same freqs, on the interfaces that are bundled in the same service group, it will overlap one another,

Anyway, you can use the same freq on the interfaces that are part of the MAC-Domain but in different Service groups.


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