Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Ask HN: Why isn't VoIP better?

news.ycombinator.com

Post reply on HN
Print view View original

121–130 of 141 posts

Re: Ask HN: Why isn't VoIP better?

#121

Post by detaro »

Bombthecat wrote: post #120
richbhanover wrote: post #52

I'm surprised that no one has mentioned bufferbloat yet. In most home routers, people can see seconds of delay when there's significant other traffic on the link. (And remember, "other traffic" can be ordinary web browsing, where pages average 2 mbytes these days...) The latency (and jitter) caused by bufferbloat has been a solved problem for almost five years: fq_codel, and the newer cake qdisc's are are in the Linu…

Not in Germany, kernels and routers need! To be locked by law. I accidentally updated without know. Now I'm locked...

citation needed. If that were true, quite a few router models available would be illegal, so it probably isn't.

(TP-link started locking down at least some models, in response to FCC rules, and some manufacturers don't allow you to downgrade, but there is no legal requirement to do so and often ways around it. Other manufacturers like Linksys openly advertise their routers for use with OpenWRT)

Re: Ask HN: Why isn't VoIP better?

#122

Post by drcongo »

Your first paragraph could have been written by me so it was nice to discover I'm not alone. However, I find FaceTime audio calls to be of such higher quality than regular phone lines or most other VOIP services that it is my go-to for calls where I need to be able to concentrate. The only other service I've found to be comparable is Slack's calls.

Re: Ask HN: Why isn't VoIP better?

#124

Post by richbhanover »

ra1n85 wrote: post #66
richbhanover wrote: post #52

I'm surprised that no one has mentioned bufferbloat yet. In most home routers, people can see seconds of delay when there's significant other traffic on the link. (And remember, "other traffic" can be ordinary web browsing, where pages average 2 mbytes these days...) The latency (and jitter) caused by bufferbloat has been a solved problem for almost five years: fq_codel, and the newer cake qdisc's are are in the Linu…

Bufferbloat is a side affect of congestion or microbursts, and not the primary cause of poor voice calls. Either packets get dropped (shallow buffer) or queued (enough buffer), and in both cases the quality of the call will suffer. Mitigation: Don't congest. If you need to, mark VOIP traffic with a DSCP value that has queues that are serviced prior to all others (e.g., EF, DSCP46).

Yes, Don't Congest. But you can spend your life marking various kinds of traffic (many apps already do mark it, as someone down-thread mentioned), and pray that your router (and remote equipment) handles the markings properly.

Or just use SQM with Cake qdisc. It actually looks at the "sojourn time" for packets in various streams/flows of data and offers backpressure for sessions that are generating queues of data: all the other flows "go right through" without a lot of other settings.

Re: Ask HN: Why isn't VoIP better?

#125

Post by lobster_johnson »

colanderman wrote: post #117
lobster_johnson wrote: post #104

Earlier quoted context omitted.

Anyone know if Mikrotik's RouterOS suffers from this?

Bufferbloat is typically a disease of your ISP (which throttles traffic), not of your router. A Mikrotik in its default configuration, like most other routers, will do nothing to address – nor exacerbate – bufferbloat caused by ISP throttling. However, it is fairly simple to address ISP bufferbloat using RouterOS's "simple queues". In the most basic configuration, just add a simple queue targeting your WAN interface,…

Awesome, thanks!

Re: Ask HN: Why isn't VoIP better?

#126

Post by richbhanover »

colanderman wrote: post #117
lobster_johnson wrote: post #104

Earlier quoted context omitted.

Anyone know if Mikrotik's RouterOS suffers from this?

Bufferbloat is typically a disease of your ISP (which throttles traffic), not of your router. A Mikrotik in its default configuration, like most other routers, will do nothing to address – nor exacerbate – bufferbloat caused by ISP throttling. However, it is fairly simple to address ISP bufferbloat using RouterOS's "simple queues". In the most basic configuration, just add a simple queue targeting your WAN interface,…

Not so - Bufferbloat can occur everywhere there's a bottleneck link.

Your home router's link to the ISP is likely to be one, and most don't have any mitigation, and suffer from high latency. (And various ISP's equipment has bufferbloat for data coming toward your home.)

Some sites suggest that you knock your bandwidth down to 70% of the link speed to "leave some headroom" for other packets. That's fine if you want to give away 30% of your capacity.

SQM (implemented through fq_codel or cake qdisc's) takes off a few percentage points from the rated link speed, and achieves great results with minimal setup and configuration. Check out https://www.bufferbloat.net/projects/bloat/wiki/What_to_do_a... for more info.

Re: Ask HN: Why isn't VoIP better?

#127

Post by colanderman »

richbhanover wrote: post #126
colanderman wrote: post #117

Earlier quoted context omitted.

Bufferbloat is typically a disease of your ISP (which throttles traffic), not of your router. A Mikrotik in its default configuration, like most other routers, will do nothing to address – nor exacerbate – bufferbloat caused by ISP throttling. However, it is fairly simple to address ISP bufferbloat using RouterOS's "simple queues". In the most basic configuration, just add a simple queue targeting your WAN interface,…

Not so - Bufferbloat can occur everywhere there's a bottleneck link. Your home router's link to the ISP is likely to be one, and most don't have any mitigation, and suffer from high latency. (And various ISP's equipment has bufferbloat for data coming toward your home.) Some sites suggest that you knock your bandwidth down to 70% of the link speed to "leave some headroom" for other packets. That's fine if you want to…

That is… exactly what I said? Bufferbloat occurs where there's congestion. That's generally on the ISP's router, since they're the ones throttling your connection to 10 Mbps or whatever.

Yes, if you have a gigabit fiber connection and your home router can only handle 50 Mbps, you can get bufferbloat on your home router. But most people aren't in that scenario.

SQM is great, but not available on RouterOS, which is what the GP was asking about.

Re: Ask HN: Why isn't VoIP better?

#128

Post by richbhanover »

saurik wrote: post #106
AstralStorm wrote: post #76

Earlier quoted context omitted.

Applications do it already, but edge routers are adept at ignoring these flags or applying them only to their own service. So that you use it and not competition. Net neutrality would be the antidote.

If those flags provide better quality of service, why am I not applying them to all of my traffic? Any attempt to "know" if my use is legitimate would undermine network neutrality.

Sure, you could make yourself crazy trying to prioritize all the traffic with varying kinds of flags.

Or you could just let an algorithm (SQM - fq_codel or cake) automatically determine which flows are sending more than their fair share of traffic into the bottleneck link, and offer backpressure to slow those applications down, so other applications work well.

re: net neutrality. That applies to whether my ISP (or any provider upstream in the Internet) should prioritize packets/data from various sources toward (or from) me. The answer should be, No. My contract with my ISP is that I get X mbps of data. The contract doesn't say the ISP will provide higher priority or data rate for service Y over service Z...

SQM has no effect on net neutrality: I'm simply configuring my own router to prioritize the data that I'm requesting (or sending). My ISP should handle them in a totally neutral way...

Re: Ask HN: Why isn't VoIP better?

#129

Post by richbhanover »

colanderman wrote: post #127
richbhanover wrote: post #126

Earlier quoted context omitted.

Not so - Bufferbloat can occur everywhere there's a bottleneck link. Your home router's link to the ISP is likely to be one, and most don't have any mitigation, and suffer from high latency. (And various ISP's equipment has bufferbloat for data coming toward your home.) Some sites suggest that you knock your bandwidth down to 70% of the link speed to "leave some headroom" for other packets. That's fine if you want to…

That is… exactly what I said? Bufferbloat occurs where there's congestion. That's generally on the ISP's router, since they're the ones throttling your connection to 10 Mbps or whatever. Yes, if you have a gigabit fiber connection and your home router can only handle 50 Mbps, you can get bufferbloat on your home router. But most people aren't in that scenario. SQM is great, but not available on RouterOS, which is wha…

Yes, but it can occur on both ends of the bottleneck. Your ISP's equipment has a bottleneck link toward your home, and can have bloated buffers on that side. But if your router doesn't handle the uplink well, it'll be bloated as well.

Fortunately, SQM is available (from LEDE) for many MikroTik routers, so there may be a way out for the GP.

Re: Ask HN: Why isn't VoIP better?

#130

Post by Bombthecat »

detaro wrote: post #121
Bombthecat wrote: post #120

Earlier quoted context omitted.

Not in Germany, kernels and routers need! To be locked by law. I accidentally updated without know. Now I'm locked...

citation needed. If that were true, quite a few router models available would be illegal, so it probably isn't. (TP-link started locking down at least some models, in response to FCC rules, and some manufacturers don't allow you to downgrade, but there is no legal requirement to do so and often ways around it. Other manufacturers like Linksys openly advertise their routers for use with OpenWRT)

Oh boy, direct down vote instead of looking on your own or asking...

http://eur-lex.europa.eu/legal-content/EN/TXT/HTML/?uri=CELE...

http://www.tp-link.de/download/Archer-C7_V2.html#Firmware 1.For Archer C7(EU)V2. 2.The EU firmware was specialized for CE certification and can't be downgraded to other version, please click here for choosing your region and selecting the most suitable firmware version to upgrade. 3.Old firmware's configuration file can be imported into this new firmware; 4.Your device's configuration will be lost after upgrading, which means you need to configure your device again

All routers are doing the same. EU law.

Post reply on HN