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Limit of BNG subscribers in ASR 9000

Level 1
Level 1


I need help to validate the total number of BNG subscribers (PPPoE) supported in a ASR-9010 chassis.

In this network scenario, we have one ASR-9010 with the following configuration:

1x A9K-RSP-440-SE
1x A9K-MOD-160-SE
2x A9K-MPA-8x10GE

NOTE: We will associate subscribers to a MOD.

I know the MOD-160 has four Thyphoon NPUs and that each NPU supports 32K subscribers, totaling 128K. Then, we found out that there is a limitation to 64K subscribers, from the MOD-160 connection to the backplane.

We will be upgrading the MOD-160 module to the maximum number of supported subscribers possible.

Searching for another module, I found out the A9K-MOD400-SE.

I noticed that the MOD-400 has two Tomahawk NPUs, which supports 64K subscribers each. Is it correct? So, is it possible to associate 128K BNG subscribers in this MOD?

In this project, we are estimating that each subscriber will use approximately 1.5Mbps of link consumption. So, 128K subscribers demand a throughput of 192Gbps.

Can I use this amount of subscribers with MOD-400-SE and have the throughput required to connect to the backplane?

100% of subscribers' traffic will be forwarded to the VSM modules, to do CGNAT. We will use four VSM modules, because each module supports only 60Gbps of throughput.

Another question, I want to ask in this post about QoS policies.

I understand that it is advisable to use MPAs with 10GE interfaces, because QoS is applied on physical interfaces. But, do I also need to know if anyone has had any experience using QoS policies on 40GE or 100GE interfaces.

Is there an official Cisco document that indicates best practices for using QoS on 10GE interfaces?

Thank you,

Caio Szekely

25 Replies 25


Regarding to the number of BNG subscribers, is there any scale impact giving IPv6 address in PPPoE sessions?


Caio Szekely


do you mean IPv6 only sessions or dualstack sessions (IPv4+IPv6)?

Only IPv6

there is no scale limit to the number of addresses, basically we provide a prefix to the subscriber for it to hand out to its clients based on that larger network assignment. there is no rule as to how large that should be, but the facto seems to be /48's.



if you are asking about IPv6 session scale then you can check out this chart.

Hi I'm having a question about the MOD 160 2 MPA 8/10 with a RSP 440-SE and 64K or 128K



there is a part of your question missing. 

I have a question that I would like help with.
So while a subset of bundle is controlled by rsp, it is still programmed in LC.
Then a MOD-160 with 2 MPA 8/10 gigas the limit subset 64k sessions per LC.

yes, with classic XR the limit is 64k sessions per LC.


You have to pay some attention to how you distribute the bundle members. If a single bundle has members on all four NPs, we have to replicate the subsriber interfaces on all NPs, meaning you get 32k per LC.


Hope this helps,


@xthuijs wrote:


For the QOS, you can apply that to the subscriber, vlan and hpy interface, the media doesn't matter. The only thing you need to be aware of that the tpyhoon NPU has 32k shapers (another reason for the 32k cap per npu there), and these 32k are seggregated in 4 chunks of 8k. the chunk is assigned to a subinterface level. this means that in order to reach 32k subs, you need 4 subinterfaces of 8k each to reach that number of subs.


Where to read about dividing into 4 chunks ? How are these chunks assigned on subif?

Level 1
Level 1

I have a issue with interface policy rate limiting on Asr9k . I would be grateful if anyone share information and opinions on the subject.

Line card: A9K-MOD400-SE

MPA : A9K-MPA-20x10G