hi all,
I have a question about the bandwidth of the wideband interface on the ubr10k PRE4 with mc20x20 cards with 8x4 channel bonding. My config is similar to that given by mbowe here https://docsis.org/forums/docsis-chat/8x4-channel-bonding and the network has d2.0 and d3.0 modems. I achieve max DS speed on the modem of about 370Mb which seems to be ok. Unfortunately, I noticed that when the total traffic on the WB interface exceeds 200Mb (from the available 400Mb) the speed on the modem drops by almost half.
Is it normal for such a configuration, i.e. 4 primary channels and 4 common ones, or something else, maybe the PRE4 bottleneck
Best Regards
So you have 4 x mac-domains each with 4 direct DS, plus 1 set of 4 DS spanned across those 4 mac domains?
Keep in mind that this allows bursts up to 8 DS speed, but if the card is heavily loaded it is only going to permit the equivalent capacity of 5 DS channels per mac-domain
Is that what is going wrong for you?
To keep an eye on this I would recommend graphing the utilization of all DS channels, like discussed here
https://docsis.org/comment/4542#comment-4542
Thank you for your answer.
Is there a way to bypass this limitation so as to have a consistently 8 DS performance regardless of the WB interface load?
What does, for example, 16DS bonding look like in the 4 direct plus 12 spanned configuration or does the bandwidth also drop to about 5 DS under heavy load?
There are only 20 physical channels on the card.
You have to carve it up in a way that suits your application.
4 mac-domains of 4 direct DS = 16 channels
1 set of 4 spanned DS = 4 channels
total of 20 channels
if all 4 mac domains are under heavy load, the 4 spanned channels will be getting hammered by 4 mac-domains = about 1 channel of bandwidth to each mac-domain
so in offpeak times, each mac domain might get 8DS of capacity
but in peak times, each mac domain might only have about 5DS capacity
Some other variations are mentioned here :
https://www.docsis.org/comment/5866#comment-5866
OK I understand. However, I want maximum performance for 8x4 channel bonding and can use the entire card for it. Will I have more throughput when creating 2 x mac-domains with 8x primary DS per domain than for a 4xprimary + 4xspanned configuration? If so, should the DS configuration for the first mac-domain look similar to this?
......
interface Cable5/0/0
downstream Integrated-Cable 5/0/0 rf-channel 0-3
downstream Integrated-Cable 5/0/4 rf-channel 0-3
..........
.........
!
interface Cable5/0/4
no cable mtc-mode
no cable packet-cache
cable upstream max-ports 0
!
and all integrated interfaces of these cable interfaces:
interface Integrated-Cable5/../..
cable bundle xyz
cable rf-bandwidth-percent 1 remaining ratio 100
!
..........
..........
It sounds like you want to avoid using any spanned channels
(due to the uncertainty of how much bandwidth they will provide peak vs offpeak)
You could setup 1 mac-domain of 20DS
Configure each mac-domain:
* 5 x 4DS bonding groups
* plus 4 x overlapping 8DS bonding groups
* plus 5 x overlapping 16DS bonding group
* Up to 8 US
Gotchas :
* you have at least 12 US channels stranded/idle
You could setup 1 mac-domain of 16DS
Configure each mac-domain:
* 4 x 4DS bonding groups
* plus 2 x 8DS bonding groups
* plus 1 x 16DS bonding group
* Up to 8 US
Gotchas :
* you have 4 DS channels stranded/idle
* you have at least 12 US channels stranded/idle
You could setup 2 mac-domains of 8DS
Configure each mac domain:
* 2 x 4DS bonding groups
* plus 1 x 8DS bonding group
* up to 8 US
Gotchas :
* No 16way DS bonding
* you have 4 DS channels stranded/idle
* you have at least 4 US channels stranded/idle
If you don't have many/any DOCSIS 1.x or 2.0 modems, then don't make all your DS channel primary.
Each primary channel has several Mbps of overhead.
I recommend making only every 4th or 8th DS channel primary.
Eg for the 2 mac domains with 8 DS each it could look like this with every 4th primary
controller integrated-cable 5/0/0
rf-channel 0 freq 1
rf-channel 1 freq 2
rf-channel 2 freq 3
rf-channel 3 freq 4
controller integrated-cable 5/0/1
rf-channel 0 freq 5
rf-channel 1 freq 6
rf-channel 2 freq 7
rf-channel 3 freq 8
controller integrated-cable 5/0/2
rf-channel 0 freq 1
rf-channel 1 freq 2
rf-channel 2 freq 3
rf-channel 3 freq 4
controller integrated-cable 5/0/3
rf-channel 0 freq 5
rf-channel 1 freq 6
rf-channel 2 freq 7
rf-channel 3 freq 8
! setup mac-domain #1
interface Cable5/0/0
! channels put here are made primary
downstream Integrated-Cable 5/0/0 rf-channel 0
downstream Integrated-Cable 5/0/1 rf-channel 0
! configure primary channel
interface integrated-cable 5/0/0:0
cable bundle xyz
cable rf-bandwidth-percent 1 remaining ratio 100
! configure primary channel
interface integrated-cable 5/0/1:0
cable bundle xyz
cable rf-bandwidth-percent 1 remaining ratio 100
! configure bonding groups
int wide 5/0/0:0
! 4way #1
cable bundle xyz
cable rf-channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/0:1
! 4way #2
cable bundle xyz
cable rf-channel controller 1 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/0:10
! 8way
cable bundle xyz
cable rf-channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel 3 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 3 bandwidth-percent 1 remaining ratio 100
! configure mac-domain #2
interface cable 5/0/1
! channels put here are made primary
downstream Integrated-Cable 5/0/2 rf-channel 0
downstream Integrated-Cable 5/0/3 rf-channel 0
interface integrated-cable 5/0/2:0
cable bundle xyz
cable rf-bandwidth-percent 1 remaining ratio 100
interface integrated-cable 5/0/3:0
cable bundle xyz
cable rf-bandwidth-percent 1 remaining ratio 100
int wide 5/0/1:0
cable bundle xyz
cable rf-channel controller 2 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/1:1
cable bundle xyz
cable rf-channel controller 3 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/1:10
cable bundle xyz
cable rf-channel controller 2 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 3 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 3 bandwidth-percent 1 remaining ratio 100
thank you again. Yes, I am looking for the most efficient 8x4 configuration at high load, even at the cost of not using a few DS/US. Please latest hint. Does anything change in the configuration when there are only D3.0 modems on the network?
ps.
in the example for !configure mac-domain #2 it should probably be:
interface Cable5/0/2 and int wide5/0/2:0 etc. instead of 5/0/1
2020 card can have up to 5 mac domains
* interface cable 5/0/0
* interface cable 5/0/1
* interface cable 5/0/2
* interface cable 5/0/3
* interface cable 5/0/4
You can use from 1 to 5 of these, it doesnt matter which ones you decide to use
In my example I used :
* int c5/0/0 (containing channels from controller integrated-cable 5/0/0 and 5/0/1)
* int c5/0/1 (containing channels from controller integrated-cable 5/0/2 and 5/0/3)
If you prefer you could do this :
* int c5/0/0 (containing channels from controller integrated-cable 5/0/0 and 5/0/1)
* int c5/0/2 (containing channels from controller integrated-cable 5/0/2 and 5/0/3)
If you do not have any D2.0 modems, and don't have many/any 4x4 modems, I would make only every 8th channel primary.
ie my example :
interface cable 5/0/0
downstream Integrated-Cable 5/0/0 rf-channel 0
! dont put any other controllers/channels here
interface cable 5/0/1
downstream Integrated-Cable 5/0/2 rf-channel 0
! dont put any other controller/channels here
Other tips
* You should keep the DS channel frequencies adjacent/contiguous
* On the upstream, use atdma mode not tdma-atdma mode
----
And for extra mind bending, the interface wideband-cable numbering actually has nothing to do with the mac-domains
in my example I had these mac-domains
interface cable 5/0/0
interface cable 5/0/1
and I named the widebands like this
interface wideband-cable 5/0/0:x
interface wideband-cable 5/0/1:x
But the widebands dont have to be named like that.
They are not actually linked to the mac domain in any way.
The wideband interface is just a "container" for the physical RF channels.
I could have put all my widebands into 5/0/4:x and everything still works exactly the same.
eg
int wide 5/0/4:0
cable rf-channel controller 0 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 0 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 0 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 0 channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/4:1
cable rf-channel controller 1 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/4:2
cable rf-channel controller 2 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/4:3
cable rf-channel controller 3 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/4:10
cable rf-channel controller 0 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 0 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 0 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 0 channel 3 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 1 channel 3 bandwidth-percent 1 remaining ratio 100
int wide 5/0/4:11
cable rf-channel controller 2 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 2 channel 3 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 0 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 1 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 2 bandwidth-percent 1 remaining ratio 100
cable rf-channel controller 3 channel 3 bandwidth-percent 1 remaining ratio 100