PPPoE subscriber's bandwidth dropping after a period of time - NE40E-M2K-B

Hi guys,

Some of our customers is reporting that after a while the bandwidth of his subscribers drops to a much lower rate than the one that was assigned. For example, a subscriber with 155Mb/s of assigned bandwidth drops to 22Mb/s. Currently the bandwidth is being informed by radius:

ACL&QoS:

  Inbound qos configuration     : User-CAR

  Inbound cir                   : 155000(kbps)(Radius)

  Inbound pir                   : 155000(kbps)(Radius)

  Inbound cbs                   : 12109375(bytes)(Radius)

  Inbound pbs                   : 12109375(bytes)(Radius)

  Outbound qos configuration    : User-queue

  Outbound cir                  : 155000(kbps)(Radius)

  Outbound pir                  : 155000(kbps)(Radius)

  Link bandwidth auto adapt     : Disable

  UpPriority                    : Unchangeable

  DownPriority                  : Unchangeable

They tested this in many ways. The last test was based on configuring 4 Mikrotik routerboard's to do a bandwidth test to a Mikrotik CCR inside the network.

The topology for the test was the following:

[CPE: Mikrotik Routerboard] --------- [HUAWEI Switch] ------------ [NE40] ----------- [Huawei Switch] ----------- [Mikrotik CCR]

                        <-------------------------------         Traffic flow (Download)         --------------------------------------------------<

It's weird because just after connecting throught PPPoE, the bandwidth is fully avaiable, but after a while the problem happens.

Do you guys have any suggestions?