in that case you don't need ack-filter, just the dual-dsthost/dual-srchost
as for the overhead i use docsis because i have cable.
that user is doing 'ethernet' for overhead.
not sure what is the correct overhead to use for fiber
sounds like ethernet is a valid choice for fiber.
found this online:
SQM: Link Layer Adaptation Tab
The purpose of Link Layer Adaptation is to give the shaper more knowledge about the actual size of the packets so it can calculate how long packets will take to send. When the upstream ISP technology adds overhead to the packet, we should try to account for it. This primarily makes a big difference for traffic using small packets, like VOIP or gaming traffic. If a packet is only 150 bytes and say 44 bytes are added to it, then the packet is 29% larger than expected and so the shaper will be under-estimating the bandwidth used if it doesn't know about this overhead.
Getting this value exactly right is less important than getting it close, and over-estimating by a few bytes is generally better at keeping bufferbloat down than underestimating. With this in mind, to get started, set the Link Layer Adaptation options based on your connection to the Internet. The general rule for selecting the Link Layer Adaption is:
- Choose ATM: select for e.g. ADSL1, ADSL2, ADSL2+ and set the Per-packet Overhead to 44 bytes if you use any kind of DSL/ADSL connection to the Internet other than a modern VDSL high speed connection (20+Mbps). In other words if you have your internet service through a copper telephone line at around 1 or 2Mbps.
- Choose Ethernet with overhead: select for e.g. VDSL2 and set the Per-packet Overhead to 34 if you know you have a VDSL2 connection (this is sometimes called Fiber to the Cabinet, for example in the UK). VDSL connections operate at 20-100Mbps over higher quality copper lines. If you are sure that PPPoE is not in use, you can reduce this to 26.
- If you have a cable modem, with a coaxial cable connector, you can try 22 bytes, or see the Ethernet with Overhead details below.
- Choose Ethernet with overhead if you have an actual Fiber to the Premises or metro-Ethernet connection and set the Per-Packet Overhead to 44 bytes. This can be reduced somewhat for example if you know you are not using VLAN tags, but will usually work well.
- Choose none (default) if you have some reason to not include overhead. All the other parameters will be ignored.
If you are not sure what kind of link you have, first try using Ethernet with Overhead and set 44 bytes. Then run the Quick Test for Bufferbloat. If the results are good, you’re done. If you get your internet through an old-style copper wired phone line and your speeds are less than a couple of megabits, you have ATM so see above for the ATM entry. If you have a slow connection such as less than 2Mbps in either direction and/or you regularly use several VOIP calls at once while gaming etc (so that more than 10 to 20% of your bandwidth is small packets) then it can be worth it to tune the overhead more carefully, see below for extra details.
An important exception to the above rules is when the bandwidth limit is set by the ISP's traffic shaper, not by the equipment that talks to the physical line. Let's consider an example. The ISP sells a 15 Mbit/s package and enforces this limit, but lets the ADSL modem connect at whatever speed is appropriate for the line. And the modem “thinks” (as confirmed in its web interface) that 18 Mbps is appropriate. In this case, the ATM Link Layer Adaptation is likely inappropriate, because the ISP's shaper is the only relevant speed limiter, and it does not work at the ATM level. In fact, it is more likely to work at the IP level, which means that
none is the appropriate setting.