We are having extreme difficulty in obtaining more than 30Mb download on a DOCSIS 3 cable modem. Cisco 7225 Chassis, MC88v line cards.
4 bonded downstream channels. We are using dynamic bandwidth sharing. Here is the relevant part of the config for the bandwidth sharing:
The DOCSIS 3 modems are coming online in wideband mode (w-online).
interface Wideband-Cable1/0:0
cable bundle 100
cable bonding-group-id 100
cable dynamic-bw-sharing
cable rf-channel 0 bandwidth-percent 16
cable rf-channel 1 bandwidth-percent 16
cable rf-channel 2 bandwidth-percent 16
cable rf-channel 3 bandwidth-percent 16
!
interface Integrated-Cable1/0:0
cable bundle 100
cable dynamic-bw-sharing
cable rf-bandwidth-percent 80 remaining ratio 16
We dont know if it is a problem with the the CMTS config, with the Cable modem provisions or maybe both.
We are using US and DS service flows on the modem provisioning.
Is there somewhere I can get a good working, simple copy of a DOCSIS cable modem file?
Also, we need some guidance on turning on SNMP for our DOCSIS 3 cable modem. We have SNMP working for all our other modems. We use PHP scripts to query and diagnose our cable modems.
Thank you for your help in advanced.
Strange
Its common for people to have problems getting decent upload speeds, but not so common to have problems with the downloads.
What downstream modulation are you using? 256qam?
What about your DS service flows. Are you defining all the flow settings in your config file, or are you using service class names on the CMTS?
Also note, that sometimes if your US config isnt done right, this can prevent the DS from performing well. So as a worst case we might need to look at that too.
I dont think the "cable rf-bandwidth-percent" statements are the source of you problems, because when "cable dynamic-bw-sharing" is active, it allows the unused bandwidth to be shuffled around between narrow and wideband modems. (Well that is assuming you are on a testing CMTS. If you CMTS is live and carrying a lot of traffic then there might not be much bandwidth spare to shuffle.)
If you want to experiment to ensure its not a DBS issue, I would suggest trying settings like this :
On the wideband channels put bandwidth-percent 1 remaining ratio 100
On the integrated put bandwidth-percent 4 remaining ratio 100
With DOCSIS 3.0 modems, they disable SNMP access by default as a security precaution. You have to manually enable SNMP in your config file eg :
SnmpMibObject docsDevNmAccessStatus.1 Integer 4; /* createAndGo */
SnmpMibObject docsDevNmAccessIp.1 IPAddress x.x.x.0 ;
SnmpMibObject docsDevNmAccessIpMask.1 IPAddress 255.255.255.0 ;
SnmpMibObject docsDevNmAccessCommunity.1 String "your_public" ;
SnmpMibObject docsDevNmAccessControl.1 Integer 2; /* read */
SnmpMibObject docsDevNmAccessInterfaces.1 String "@" ;
SnmpMibObject docsDevNmAccessStatus.2 Integer 4; /* createAndGo */
SnmpMibObject docsDevNmAccessIp.2 IPAddress x.x.x.0 ; /* your management subnet */
SnmpMibObject docsDevNmAccessIpMask.2 IPAddress 255.255.255.0 ;
SnmpMibObject docsDevNmAccessCommunity.2 String "your_private" ;
SnmpMibObject docsDevNmAccessControl.2 Integer 3; /* readWrite */
SnmpMibObject docsDevNmAccessInterfaces.2 String "@" ;