we think that some SM’s suffers from PPPoE disconnections when saturation occours.
In the PMP 450 GUI, in the QoS tab, there’s the voice “PPPoE Control Message Priority” with Normal and High.
We discover that this option prevent the PPPoE disconnections if SM’s traffic saturation occours.
There’s an equivalent option in the ePMP world?
Subscriber Module Priority in the QoS section and PPPoE Intermediate Agent in the network section of the AP.
there is no equivalent to the pppoe control message priority in the epmp line.
things you can do to increase pppoe tunnel stability with no specific order or requirement since I do not know how your network is designed:
- use larger MTU on the provider side of the network, a provider MTU of 1500 will cause PPPoE sessions to randomly drop, minimum for PPPoE is 1536 to pass 1500byte packets on PPPoe.
- use MSS clamping on your SMs. set this to 8bytes smaller than your max client MTU so if passing 1500byte client packets, set to 1492. This will keep all packets smaller than max to provide headroom and ensure that the packets are not fragmented while passing over the provider network.
- use longer pppoe session timeouts on your pppoe server.
- add capacity where peak traffic is using more than 80% of the available bandwidth. So if your backhaul link is getting saturated then you need more capacity, if your AP is getting saturated then split the sector and spread the clients between another AP.
- move to a LAC/LNS setup. This moves the control point closer to the AP to reduce issues with control message timeouts
- move to a routed design without PPPoE and make use of the EAP-TTLS control structure to accommodate the control needs.