The connection speed isn't matching what the router claims.
The connection speed isn't matching what the router claims.
Iperf displays outcomes without considering the Ethernet + TCP/IP delay that belongs to each packet. More headers mean less actual data sent per packet, yet it still reflects the real line speed—bits of 1s and 0s moving from point A to B via a switch. To observe genuine throughput, use a dedicated traffic generator with FPGAs that sends authentic packets, rather than relying on Iperf which may lag at higher speeds. For details, visit https://sourceforge.net/p/iperf/mailman/.../19147882/.
The above is exactly what expected. The header don't mean anything to the end user it's network overhead only packets carry information for the user, So you lose some tiny meaningful bandwidth because the packets needs to carry with them extra information in order to reach their destination, that why its 9.35 Gbps and not 10 exactly. Same applies to the Modem to ISP scenario + we have the loss of the wires depending on how far we are from the provider.
This is exactly what I'm trying to point out, but I'll do it again in case you missed it: THE ISP IS SUPPOSED TO TAKE THAT INTO ACCOUNT WHEN TELLING YOU THE SPEED YOU'RE GOING TO GET. I'm not an idiot. I'm not some stupid guy who's never noticed that theoretical network speeds are almost never met. I never argued that the network speed is always at it's theoretical maximum. I argued that the network speed should be as advertised. If they tell you you've got a 75mbit connection, then your connection is supposed to operate at that rate, or maybe something just below it. Meaning that, when your modem negotiates the speed to 64mbit, you're not getting even close to the speed agreed on, therefore not getting what you pay for. You can argue due to overhead etc. it's 57mbit instead of 64, but then the 64mbit is still not the right number to begin with. The OP got 57mbit instead of the 75 the ISP states, which is way too low to be acceptable. That's nothing at all like 9.4gbit on a 10GE LAN, it's far, far further off. So yeah, not at all tiny, more like 24% of your entire network speed in this case. Therefore I'd contact the ISP and ask them what's going on.
Initially, I wanted to remind you that with VDSL you typically experience about a 10% reduction in speed compared to the line rate in real-world performance. The protocol adds significant overheads from DSL itself and additional layers like PPP or TCP/IP, which affect the actual data you receive. Next, have you considered restarting your router? VDSL generally requires a minimum signal-to-noise ratio of around 6dB downstream. Your current level is 8.7dB, indicating something may have disrupted the connection and slowed it down. This could simply mean another VDSL user has turned off their modem, allowing clearer communication for you. Such situations are common, as VDSL connects based on the line’s capacity at the moment your router starts up. Regarding your 75Mbit payment, I’m not certain you received that speed. VDSL is usually marketed as an “up to” service, meaning it can’t reliably guarantee 75Mbit due to factors like line condition and distance. In your situation, it’s clear you should be achieving a faster connection than before. However, in most cases, there’s limited control over this issue. Your lines are both set for 80Mbit by the ISP, but actual speeds vary widely depending on quality and interference from neighboring connections. I used to get consistent 80Mbit, but as more neighbors got VDSL and caused interference, my speed dropped.
Thanks for information my friend. So just a minute ago, ISP called me and said "I see that in the past you got max 71 Mbps so means your infrastructure supports that, not 78. But I also see that you're getting 60 Mbps so I send a ground unit to check your ports. I will keep you informed." Btw I tried rebooting, resetting, replacing my router but nothing changed. And of course I meant UP TO 75 Mbps because you know, that's their marketing strategy. So they say my infrastructure supports 71 Mbps, but I can see that it supports 78, so that's a lie. And yes, I should definitely get higher. And thanks for helping me confirm that my router isn't the main issue. So I want to ask something. I'm currently using from wall, a combination of cable-splitter-cable-splitter-cable because my cable doesn't reach my router because I should keep my router close to my PC. Will buying a long one piece phone cable affect my speed, and is it worth it? And my current router is supports 150 Mbps max. Will upgrading it help?
Absolutely, it's always within the allowed limits. That clarifies any concerns about speed differences with neighbors—things like wiring issues or distance from exchange or cab can affect performance. My connection supports up to 24 Meg, and being near an exchange keeps sync speeds around 14,000-16,000, while throughput rarely exceeds 12 Meg. I've been thinking about upgrading for years but didn't act. It's fine; I manage streaming smoothly at 1080p, just one stream at a time.
The page indicates a maximum downstream speed of 78,624 kbit/s and an upstream rate of 32,295 kbit/s, which equals approximately 32.3 Mbps. The downstream line speed is 64.8 Mbps upstream, with an 8.2 Mbps drop-off. This suggests the DSL router evaluates the quality of the connection between itself and the device, aiming for optimal performance in terms of latency, packet loss, and stability. It appears to synchronize at a lower rate rather than higher, similar to wireless setups where throughput fluctuates based on distance and network load. Unlike fiber or Ethernet, which maintain consistent speeds without degradation, DSL’s performance depends on factors like distance, concurrent usage, and line configuration. You may experience around 90-95% success with a DSL connection, which is reasonable given typical conditions. If the advertised speed seems too low compared to expectations, consider negotiating a more suitable plan or switching to a different provider offering clearer guarantees. Wireless connections usually provide higher and more stable speeds, though they might add some delay.
I mentioned the main Ethernet device is in my apartment, three floors down. They claimed it could handle up to 75 Mbps, and even admitted they weren’t delivering the full speed. I never exceeded 71 Mbps, which was still acceptable. My internet speed supports 78 Mbps, but they only provide 64 Mbps. At least that reaches my router. They say there’s an internal issue with the building and can’t fix it. The cabling inside the building has been fine for about two and a half years, but after upgrading to 75 Mbps, it seemed to deteriorate within a week. I was using around 70 Mbps for the first week without problems. Then suddenly my connection slowed down unexpectedly. That’s what bothers me. I don’t understand why they’re doing this—it feels unfair, like when you ask for more and get less while charging more. It’s similar to how coffee shops with larger cups seem to disappoint customers. It’s frustrating for both parties.
The connection you have to the box relies on the existing setup, which currently limits speeds to 67Mbit. While the building’s box supports up to 80Mbit, it only provides 67Mbit through one line and 56Mbit via another. The infrastructure may not be optimized for higher speeds, possibly due to cable quality or nearby interference from other DSL connections. It seems the decision to use DSL rather than faster fiber or CAT6 was likely aimed at reducing costs. The wiring performance was acceptable when you had a lower data requirement, as it didn’t need to handle higher frequencies. You should also check if the line has multiple outlets and whether it shares the same telephone service—shared lines can affect both DSL and phone calls.