Live data from Hacker News

Ask HN: Why isn't VoIP better?

news.ycombinator.com

101–110 of 141 posts

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

#102

Skype used to be fantastic when you could establish a point-to-point call. Today, I think everything gets routed through Microsoft so they can provide access to law enforcement. Some days it's good, often it's pretty bad.

I believe FaceTime is still point-to-point.

I've heard good things about WeChat and it's support for low-bandwitdth networks but haven't worked up the courage to try it out.

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

#103

Old fashioned PSTN lines would secure the full bandwidth needed end-to-end when the original call was established (which was really in efficient from a data utilization perspective). With VoIP you are: 1. Beholden to the bandwidth/latency issues of the crappiest link in your end-to-end path. 2. Intentional use of poorer quality codecs (by your ISP and/or VoIP software to reduce aggregate bandwidth use). Ironically th…

> 2. Intentional use of poorer quality codecs (by your ISP and/or VoIP software to reduce aggregate bandwidth use). Ironically this can be inverted, there are codecs that sound much better than PSTN calls (but use more bandwidth).

I mean, people use G.729 for example because, yes, it is more efficient than G.711. But ultimately, if you want to communicate with the PSTN those are your only two choices and it's easier to just say "G.729 for everything" instead of wasting processing time on the server re-encoding everything that goes off the network.

You want better codecs? Bitch at the phone companies who have drug their feet on implementing G.722 while more and more IP phones and mobile devices continue to add support for wideband audio.

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

#104

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…

Anyone know if Mikrotik's RouterOS suffers from this?

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

#105
post #60
post #33

Earlier quoted context omitted.

VOIP is considerably better than PSTN if configured correctly. There's no comparison. Your sysadmins don't understand VOIP.

just want to point out: vast knowledge of telephony/VOIP is not something every sysadmin should be expected to know. If you don't have telephony expertise on staff I hesitate to suggest someone build out a VOIP infrastructure on their own. It can be extremely time consuming to learn and it is definitely painful to troubleshoot.

Eh, I'd argue this varies a lot. In some cases you are more likely to run into issues setting up multiple SIP clients behind a NAT trying to connect to a server out on the public internet than you are to install your own PBX on-premises.

Grandstream, Yealink, etc. all provide pretty easy to administer Asterisk-based PBX appliances that can be paired with a SIP trunk of your choice (shout out to Flowroute here, they're great).

If you're feeling more adventurous sipXecs from sipfoundry is pretty easy to configure relative to the additional complexity it brings over the more simplified alternatives. I went from having 0 real world experience with SIP to managing a small installation for my aunts shop as well as one at home in a couple days.

For proprietary offerings there's of course Skype for Business, etc. and I would argue they aren't terribly hard to configure or maintain either.

Most of the work is just in network configuration once you have multiple sites and you need to ensure QOS going over your MPLS or whatever to ensure your voice packets take priority - that can be more difficult but that's something a competent network admin can help you with.

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

#106
post #66

Earlier quoted context omitted.

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).

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.

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

#107
post #91
post #85

Ive seen some enterprise level voip providers in the UK not only provide clients with VOIP systems either on site or a cloud PBX, but also a dedicated leased ADSL line. Usually 2mbps both up / down (They say this is good for about 20 concurrent users). They also connect the the line directly to their voip server, so it dosnt have to make multiple hops. Never tried one in practice though. We run our voip over our main…

Is that ADSL? If it's 2 up/2 down, is that not SDSL?

While A in ADSL stands for Asymmetrical, it is primarily name of the used DMT-based technology, S(H)DSL is completely different thing (in fact it is related to 1000-Base-T, but with significantly smaller symbol rate) that does not work across non-dedicated lines (and usually needs carefully selected pairs to work reliably).

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

#108
post #107
post #91

Earlier quoted context omitted.

Is that ADSL? If it's 2 up/2 down, is that not SDSL?

While A in ADSL stands for Asymmetrical, it is primarily name of the used DMT-based technology, S(H)DSL is completely different thing (in fact it is related to 1000-Base-T, but with significantly smaller symbol rate) that does not work across non-dedicated lines (and usually needs carefully selected pairs to work reliably).

That's counter-intuitive! TIL, thanks!

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

#109
8kHz pcm ulaw or alaw isn't exactly stellar, and high bandwidth Skype or sip is much much better really.

Maybe you are conditioned to like the can-effect, your friends have really shitty headsets, or there is something wrong with the available bandwidth...

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

#110

Skype used to be fantastic when you could establish a point-to-point call. Today, I think everything gets routed through Microsoft so they can provide access to law enforcement. Some days it's good, often it's pretty bad.

Probably rather because the p2p algorithm was not included when they bought Skype, they only licences it...
Post reply on HN