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kdavid
casa c100g

Hi all,

i decided to switch from our chinese mini cmtsses to something more professional - casa c100g

I am not a professional in docsis, but i cant find any manuals and example configurations on web for this device.

Is there anyone who can helsp me with manuals or som example configs.

I have also few question about casa c100.

1 - Does it support dynamic modulation for upstream to handle short noise changes on reverse path?

2- Is there any way to make RF Groups and join the to separate vlan? At this time i have One mini cmts per one village. SO now i want to have 1rf port or 32 channels DS/ 8 channels US joined to vlan and worl like a bridge.

Is there anyone who can helps me wit that beast?

Thank you
Sincerelly
Dave

kwesibrunee
What software version are you

What software version are you running? I can get you the appropriate documentation for your software release.

1. Yes you can specify a secondary Modulation profile for D3.0 modems. Casa also supports logical upstreams, where you can have 1 logical upstream at one modulation and/or width, and another logical upstream on a different modulation and/or width both centered at same frequency. That way you can move modems that have low SNR issues to lower modulation/width logical channels with Spectrum rules, rather than changing the modulation for everybody because a few modems have low SNR.

2. Casa C100G does not support Bridge mode (L2 VLANs) but it can do similar things with L3. You can configure multiple bundles and assign different mac Domains to the different IP Bundles, or you can add VRF if you need total isolation between IP Bundles.

I could get you an example config if you tell me what features you are looking for.

kdavid
Thank you for info... but

Thank you for info... but that is not good news for me that casa cant make bridge domain :( it will mess up my provisioning that is made now on mikrotiks or cisco asr where is dhcp server running.
Sincerelly
Dave

kwesibrunee
As long as your DHCP servers

As long as your DHCP servers have an IP that is reachable from the Casa ( you can create VLAN interfaces on the SMM interfaces to reach a VLANed network) you can use the cable helper-address to proxy all DHCP requests to the specified IP from either the primary address on the IP-Bundle or the secondary ip on the IP bundle, depending on whether you have cable dhcp-giaddr-primary set. So you should not have too much trouble.

kwesibrunee
Here is a barebones config

Here is a barebones config, you will need to supply the information in between < and >

File attachments: 
kdavid
Thank you for config file.

Thank you for config file.

With it i am able to connect the moden, but it receive only one IP fo CRM. For router it cant load ip.

When i add more IPs to ip-bundle the modem is not able to load config file.

interface ip-bundle 1
ip address 192.168.1.1 255.255.255.0
ip address 192.168.0.1 255.255.255.0 secondary
cable helper-address 10.0.0.1

For test i am using mikrotik dhcp. The mikrotik can ping modem IP, bude modem doesnt obtain IP to the wan interface (in case of one IP in ip bundle).

IP of casa is 10.0.0.2
IP of mikrotik is 10.0.0.1

Local network (nated and prerouted is ) 192.168.1.0/24 for internet and 192.168.0.0/24 for modems with config file

Can you helsp me pls?
Sincerelly
Dave

kwesibrunee
A little info on DHCP for

A little info on DHCP for DOCSIS

The CMTS acts as a L3 DHCP Proxy, meaning it forwards the L2 DHCP messages to a L3 endpoint, there are a few classes of devices that need to do this functionality, but to keep things simple lets think of it as two classes, CM and CPE. CPEs just need IP/SubnetMask/GW/DNS, CMs need the same (minus DNS) and special DHCP options like boot-file and next-server(tftp server).

If your using a single DHCP Server you need a way to differentiate between CMs and CPEs, you can do this a couple of ways:

option 1: CMs will always have the letters docsis followed by version number 1.0,1.1,2.0,3.0,3.1 in the vendor identifier of DHCPDISCOVER packets, if your dhcp server supports identifying CMS this way, you can point the CMs to the CM Subnet with the extra options, all other devices would go to the CPE subnet.

option 2: The CMTS can peek at the DHCP Discover packets looking for the docsis1.0, docsis2.0 etc in the vendor identifier and forward the dhcp packet to a different endpoint based on whether it is a CM or not. This is done by adding an identifier after the cable helper-address specifying whether it is a cable-modem or cpe. This requires two dhcp servers one for the cable-modems and one for the CPEs

When you have multiple Ips on your bundle you need a way to distinguish which IP to use as the giaddr (source network) of the DHCP request, the DHCP server will look at the giaddr and determine what pool to offer the device based on that. On the CMTS you can control which IP is set as the giaddr by adding the following statement to your docsis-macs (you have to do it to each one) dhcp-giaddr-primary -- this will select the first ip address on the IP-bundle as the giaddr, dhcp-giaddr-secondary -- this will select the first secondary ip-address on the IP bundle as the giaddr.

back on your DHCP server you need a way to combine networks/subnets together so that it listens on one subnet but gives an address from another.

using your config as an example
interface ip-bundle 1
ip address 192.168.1.1 255.255.255.0
ip address 192.168.0.1 255.255.255.0 secondary

if you had dhcp-giaddr-primary set on your docsis macs, DHCPDISCOVERs from CMs would be sent to your cable helper-address with a giaddr of 192.168.1.1, on you dhcp server it would look at its networks and if it had a 192.168.1.x and a pool on that network to hand off an IP. For a CPE the DHCPDISCOVERs would also be sent with a giaddr of 192.168.1.1 and on your dhcp server you would need a way to link the network 192.168.1.x with the network 192.168.0.x with a pool for 192.168.0.x. Some DHCP servers call this a shared-network.

I notice you have all non-routeable (private) Ips on your ip-bundle, unless your planning to NAT your customers this probably is not what you want. Typically most MSOs set up the ip-bundle with a non-routeable subnet for the modems and a routeable (public) ips for the CPEs

e.g.
interface ip-bundle 1
ip address 10.0.0.1 255.255.0.0
ip address secondary

Looking at the Microtik's dhcp server documentation, I am not sure it can be the dhcp server for both your CMs and CPEs. It does not appear to have the ability to combine networks needed to deploy typical docsis networks.

you could try setting up two dhcp servers on the microtik one for CMS and one for CPEs and then

interface ip-bundle 1
ip address 192.168.1.1 255.255.255.0
ip address 192.168.0.1 255.255.255.0 secondary
cable helper-address cable-modem
cable helper-address cpe

and see if that works.

Otherwise you may need a more flexible DHCP server, ISC dhcp server works well for this task and is open-source and I can surely give your a leg up on configuring it. the microtik could surely handle the CPE dhcp funtionality, or the CM dhcp functionality but probably not both.

Also important to note, Authorization in DOCSIS is typically done with DHCP (e.g. service level is controlled by what modem config is given, unauthorized modems are either not given an IP or given an IP with config that shuts network side of modem off) Microtiks DHCP server does not seem to have a notion of authorized / not authorized or the ability to easily change dhcp options to vary service levels for modems.

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