Maximum Latency for ISPs? 127
fluor2 asks: "My ISP is providing me 8mbit ADSL, and my speed is in fact 8mbit (downstream). However, we all know that there is no relation between transfer rate and latency, eg, a high transfer rate and high latency will kill your FPS games. A packet that travels through the sky and up to a satellite is bound to give high latency. Using pathping, I discovered that my ISP provides me with a latency of 22ms before my sent packets are sent out of my ISP's backbone (6 hops). I have a friend that also tried the same, and he got only 10ms before he was out of his ISP's network. I know 22ms is decent, but I still think that it's far too high if one uses IP-phones and similar. What kind of latency can we accept for a normal 8mbit ADSL connection, and isn't it about time that we get more focus on this subject?"
"Normal" 8Mb? (Score:5, Interesting)
PS, latency is 24-24ms on an unladen connection (Score:2)
Re:PS, latency is 24-24ms on an unladen connection (Score:1, Funny)
Re:PS, latency is 24-26ms on an unladen connection (Score:2)
BTW, I can't understand why anyone would bother modding down the AC who replied to the parent. Surely you can find better places to spend mod points? And if not, give him a +1 Funny or explain what you have against Python misquotes.
Re:"Normal" 8Mb? (Score:1)
Eight megabits!!! Why does anyone need eight megabits?
Re:"Normal" 8Mb? (Score:1)
Re:"Normal" 8Mb? (Score:1)
Re:"Normal" 8Mb? (Score:1)
Re:"Normal" 8Mb? (Score:1)
Re:"Normal" 8Mb? (Score:1)
Re:"Normal" 8Mb? (Score:1)
Not that I need more than 600K, but it's nice to know that it's available if you want it!
Re:"Normal" 8Mb? (Score:2, Funny)
I'm sure that Bill Gates appreciates your comment. =)
Re:"Normal" 8Mb? (Score:1)
What I should have said was 'Not that I need more than 600K _at the moment_' as I'm sure I'll need more later!
Re:"Normal" 8Mb? (Score:3, Funny)
It makes downloading m... surfing the web much, much faster. Seriously, though, it's not the 8Mb/s download rate that's important to me so much as the 640Kb/s upload rate. If you're doing P2... I mean, running a personal FTP server (with no copyright violating content, no sirree!), you NEED that upload rate.
Well... (Score:5, Funny)
Since you're one of the first folks to try out this new tech, I think you need to tell US what to expect.
How much do you pay for that thing anyways? Just to play games?
Holy shit. I have trouble putting food on the table and you're worried about your high latency times for an 8mbps connection?
Re:Well... (Score:2)
If he's paying some crazy sum of money he expects to get what he pays for, right?
If I'm on dail-up I expect a slow connection. If I'm on a DSL 512kb I expect a 512kb connection. If I pay an arm, a leg, and sold my soul to the devil I expect a speedy connection with low latency.
Re:Well... (Score:2, Funny)
Re:Well... (Score:2)
Comment removed (Score:5, Informative)
Re:CAP or DMT? (Score:2, Informative)
Re:CAP or DMT? (Score:4, Informative)
It's my belief this is a myth.
VoIP itself cares little about one-way delay, but cares a whole lot about jitter. If I can provide you with a one-way link that has extremely high one-way delay, but I have routers on each end of the link to ensure voice gets queued and transmitted before any other data in the queue, the service will be acceptable. The only piece that may be unreasonable to users is the delay itself; the ITU standard is 150ms of one-way delay (300ms, as you mention, would be a correct "round trip" time assuming delay in each direction was the same).
High delay can lead to users talking over one another; we're not use to this when we call granny down the street. But for remote locations or international calls, they are use to extremely high delays and so taking their call across an extremely high-delay path (such as satellite, as you mention) results in no net difference for the end-user. Yes, VoIP endpoints will add some of their own delays, but these will be fairly insignificant if you're talking about a 500ms one-way delay budget.
I have a collegue with a customer who has 100+ sites about Alaska, in VERY rural areas. All their voice calls go across an satellite-transported IP network. Sure, _you_ might have a little trouble getting use to it at first, but the regular users are use to high delays on their calls (much like your cell phone, as you pointed out). In the grand scheme of things, I would argue that as long as the packets arrive jitter-free (meaning there are not huge inter-frame gaps, which would mean there is nothing for the far end codec to decode and play out) the quality of the call itself will be acceptable.
In the end, though, I think we both agree -- I just don't know that I've ever run in to an environment where delay was the cause of "poor voice quality". Loss and jitter will typically be the root cause for why codec isn't producing the quality you'd expect. Delay is just, well, delay.
Re:CAP or DMT? (Score:2)
The most important concern that that the latency remain fairly constant. If you have a consistant 300ms latency, the call will be great. If, however, the latency fluctuates between 100ms and 400ms, that's where call quality can rapidly go down the tubes.
Consistant latency is the most important factor for streaming traffic.
Re:CAP or DMT? (Score:1)
Dude, you have POWER! If you thought IP over carrier pigeons were more scalable, would they switch to that?
That's good.. (Score:3, Interesting)
I don't see whats wrong with what you are getting, maybe you are whining just a little bit too much about what you are getting.
Heck, I'd like 8mbps down on my ADSL. I'm stuck with 1.53mbps/640kbps.
Oh well. There is nothing wrong with what you get..
Re:That's good.. (Score:4, Funny)
From your computer to your MODEM??? How many miles of cable are you going through to the modem that sits by your computer??
Re:That's good.. (Score:2)
Oh, to be so lucky to have 1.53/640. I can't even get *cable TV* where I live. I do the happy dance when I'm able to connect at 40K on dial-up.
(insert "and I was *grateful*" speech here)
Someone's always got it worse off than you.
Re:That's good.. (Score:2)
We used to get DSL through the local phone company. 100-110ms was not that uncommon during the day. (I kid you not!)
Interestingly, it takes 3ms to get to the modem. Actually that's not that bad considering about 50ft of cable between this computer and the router/modem in the basement.
That's a major non sequitur! (Score:1, Offtopic)
Er, what in the BSD licence prevents you from profiting from your own code later?
What in the GPL prevents you from profiting from your own code later? Just the other contributors. You can only profit from your own pieces of code, which in a big project are going to be pretty close to useless by themselves. And that's totally fair.
I also reckon that it's totally fair, fine and dandy if you choos
Re:That's good.. (Score:2)
who cares (well, besides you)
Spoiled (Score:3, Insightful)
isn't it about time that we get more focus on this subject?
About time, sure. If I could get anything other than no-server cable, I'd be sure to jump on your bandwagon.
Can we focus on getting decent broadband to everyone first, and THEN start worrying about 12 ms of ping time? Good god, man.
Re:Spoiled (Score:2, Insightful)
Spot on. I have family who have almost never used the net and say hey wow you get that in your computer, how do ya do that, can I? (Streaming video and radio). Then you explain that they live in the UK and thus their exhange is not enabled yet (for ADSL) and even if it was you are probably too far from it to get broadband(512K/s up 256K/s down). All they really want is 128k/s upstream always on! Oh what is ti that I hear "thats that", not "oh we should do something about this," so give a thought to thouse
Re:Spoiled (Score:2)
You'll get it when you get it. It takes approximately one hour to convince yourself that your pre-broadband days were just a distant memory. We're working hard to make sure that one hour after you get broadband that you are still happy.
But seriously, the pingpath app linked above runs on some weird OS that I don't use. Does anybody know what the equivalent Linux functionality is?
Re:Spoiled (Score:1)
Re:Spoiled (Score:1)
What is MTR?
mtr combines the functionality of the 'traceroute' and 'ping' programs in a single network diagnostic tool.
As mtr starts, it investigates the network connection between the host mtr runs on and a user-specified destination host. After it determines the address of each network hop between the machines, it sends a sequence ICMP ECHO requests to each one to determine the quality of the link to each machine. As it does this, it prints running statistics about each machi
Re:Spoiled (Score:2)
Look it actually matters for gaming. In fact upstream matters more than downstream if you are playing quake3. (upstream traffic is about 1.5 times more than downstream).
If you dont play games, the current development of broadband connectivity is going to help you. Nobody is really considering what games needs, just 'more downstream, more downstream'.
Gaming needs better upstream & very very low l
Re:Spoiled (Score:2, Informative)
If that fails, get yourself an ISP with their head screwed on (i.e. not a big one) and have a chat with them about it. They can ask BT to supply it on an if-it-works-it-work
Boohoo.. (Score:5, Funny)
Alright, yeah. I'm jealous.
Re:Boohoo.. (Score:2, Funny)
22ms is too long??? (Score:1)
I liked the speed, frequently between 2 and 3 mbps. But, I complained about the lag. My ISP didn't get a complaint phonecall until my GATEWAY became at least 150ms away (instead of the normal 75ms), let alone the internet...
I found that average internet ping time was 600ms. this was a problem. I was used to a fast cable provider which could offer internet ping times in the 150-250ms range. (and gateway pings in the 20-40ms)
So please, stop compl
22ms? (Score:5, Funny)
200ms is *nothing* (Score:3, Funny)
Re:22ms? (Score:2)
I remember being accused of cheating because I had a 3DFX card.
Re:22ms? (Score:2)
Re:22ms? (Score:1)
You LPB! Us real HPB were 300ms and up!
Re:22ms? (Score:1)
Re:22ms? (Score:1)
Why I remember playing Land Of Devistation on my 1200 baud modem. I would get less then 1 FPS! Killing mutant valley girls and avoiding land mines took real skill! And we were HAPPY, dangnabbit! You consarnit whippersnappers and your fancy shmancy 3D games makes my blood boil. Why if I had my electric sword, I show you ALL what REAL gaming is like!
Cable pings better than DSL (Score:4, Informative)
On my cable modem (adelphia) I get 10-12ms for the first 8 or so hops as they are all on the adelphia servers, after that I can get as low as 20ms or even 18ms for more local stuff (I get about 23 to www.yahoo.com). I live in San Diego and this type of service is only about $35/month. On my DSL (Pacbell) I used to get 15-20ms to the first hop even, whereas i get 9-11ms now.
Re:Cable pings better than DSL (Score:2)
And, of course, latencies change diurnally, i.e., over time, due to the changing traffic patterns throughout the day and week. Traffic levels through major ISP's will be higher during the day because of people surfing porn^H^H^H^H the web at work, but they may be higher for cable modem/DSL users during the evening, wh
Re:Cable pings better than DSL (Score:3, Informative)
Re:Cable pings better than DSL (Score:2)
Um... Wow?
I also have cablemodem through Adelphia, and get FAR higher ping times...
To just my segment gateway, I get 11ms. To the very first non-Adelphia node, I get 75ms. To a machine on COX's cablemodem network, I get as high as 120ms (speaking of which, back when I had COX myself, which used @home at the time, I got similar latencies).
So I don't think
ISP's (Score:5, Informative)
I was on the fitjistsu on the 768/128, about a 33ms ping to the seattle bbnplanet backbone, I moved down the street, and they put in the new higherspeed network. 1500/384 and 10ms to the bbnplanet backbone.
USwest back in Spokane was about 15ms on a 768/768 cisco modem.
While I find Verizon and other telcos to be better bandwidth and ping, smaller mom and pop ISP's tend to oversell. Speakeasy was would be choice if the telco is oversold, and earthlink if ISDN is your only choice. Thou small ISP's do re-sell ISDN cheaper, and ping is good enough for multiplayer games, 20ms+. (Remember its different for each user and location!)
I'd check out dslreports [dslreports.com] and ask other people in your area. And networks change from city to city, cable/dsl/isdn/frame all depend on the routers and hop count. Plus if your ISP is a peering partner with local ISP's, they connect all major ISPs locally, thats a plus. Sometimes you notice crazy routing, like Seattle to California and back to go across town to an ISP without a local peering agreement.
Also, you call your ISP, and ask them to do a traceroute from their network to a gameserver and email it to you. I've asked this from hosting services, and who they having peering agreements with. Some will even give you a network diagram or have them posted on the site, like Verio. (Who while expensive, does seem to have good peering agreements.)
Re:ISP's (Score:3, Informative)
The actual difference between the two is the Fijitsu is frame-relay based and the Westell is ATM.
Why VoIP an issue? (Score:4, Insightful)
count yourself lucky (Score:4, Informative)
Re:count yourself lucky (Score:2)
Re:count yourself lucky (Score:1)
Just checked your DSL offerings, and something only roughly equivalent with no mention of static IP's is $10 more than what I pay today, and that's before all the myriad fees get tacked on.
Hmph... (Score:2)
Re:Hmph... (Score:2)
Why do some people always assume the worst in others?
Re:Hmph... (Score:1)
Non satelite Gamer plans (Score:1)
Latency and Throughput (Score:5, Informative)
The maximum possible throughput of a TCP connection is one "window" of data per round-trip time. The "window" size is essentially the amount of unacknowledged (ACK'ec) data that can be outstanding. This is often called the bandwidth-delay product, I think.
What you need to take away from this is that even if you had infinite bandwidth between you and your peer, the throughput of a single TCP connection is upper-bounded by the delay product. For example, if your window size is 32KBytes (I'm going to use 32,000 to make the numbers prettier) and the round-trip time is 100ms, then you can transmit (or receive) at most 32KB * 10 = 320KB per second. To go faster, you have to either increase the window size (which consumes more memory) or decrease the round-trip time (which is sometimes impossible, since the speed of light is a constant, or so my physicist friends claim).
A couple other points.
You're probably not capable of noticing the difference between 10ms and 20ms in terms of response time for interactive applications, including online gaming. if it were 10ms vs 100ms or 200ms, then yes, but 10ms is less than one refresh interval on your monitor, so you really can't "see" the difference.
As far as VoIP (IP telephony) and other multimedia network applications are concerned, again, you must consider the end-to-end latency (one-way delay) and/or the round-trip time, not the latency between you and some arbitrary router at your ISP.
The phone companies spec their systems (or so I've heard) such that the *round trip* latency for a domestic call is always less than or equal to 100ms. We're talking POTS here, not cell service, which experiences higher latencies.
I work on VoIP software; in an IP call (both ends are IP clients), it's very hard to keep the *one way* latency below about 100ms, if you're lucky, even if both clients are on a LAN. This is because you have to have various buffer and jitter compensation delays so that the sound quality is acceptible under somewhat adverse network conditions. In a typical call across the internet, 200ms one-way latency, IMHO, would be considered quite good.
So your 20ms intra-ISP latency (vs. the 10ms that your friend reports) is in the noise.
Oh, I should also mention, for completeness, that packet loss (or even reordering, which is more common that you may realize) can *really* hurt both TCP and VoIP (which usually uses UDP) performance/quality. This gets into some messier technical issues... basically, though, if your DSL isn't lossy, and you're getting 20ms intra-ISP latencies, you're doing as well or better than most of us.
Your friends who are running on 56k modems, who eat 200ms just to get their packets to the ISP's router on the other side of the PSTN are really going to be hurting
Re:Latency and Throughput (Score:3, Insightful)
For gaming, though you often have human race conditions. The frame is drawn, the two players see each other for the first time and hit the "fire" button. Whoever gets the message to the server first kills the other. Taking a
Re:Latency and Throughput (Score:2)
time of the cause, not the time of the arrival of the packet
reporting the cause (within the limits of the jitter of the
clock synchronization protocol, at least).
Re:Latency and Throughput (Score:3, Insightful)
A better method is what halflife does -- Check clients ping, check what they saw $ping ago, then process. The downside (for us LPBs, but upside for dialups) is I can run past a hallway, see an enemy a the other end, and keep running. then in ~400ms, I'm dragged back to the hallway because according to the server, they shot me.
Re:Latency and Throughput (Score:1)
Funny, I always thought it was called the window size.
Or increase the MTU (bigger packets), which may not be a big problem if you're on DSL (short hop) connected to a fiber link (low error rate), set MTU discovery off, and clear the DF bit.
Re:Latency and Throughput (Score:2)
Increasing the MTU will not necessarily improve throughput.
If anything, a lower MTU could conceivably improve TCP throughput, since smaller packets get to the far end more quickly and would thus be acknoledged sooner, and much less total bandwidth is wasted on retransmissions of the (smaller) lost packets.
Imagine a worst
Re:Latency and Throughput (Score:2)
Re:Latency and Throughput (Score:2)
Actually, in most digital communication systems, this is untrue, not just TCP/IP. Also on a hardware level, there is a trade off between latency and bandwidth - e.g. in microprocessor pipelines, bus interfaces. If it were possible to reduce latency and maintain the same bandwidth, they would do it.
Re:Latency and Throughput -- TCP Window Scaling (Score:1)
Yes, latency and throughput are related, but
The point about TCP windows is likely bogus for this application. Most modern TCP implementations include the window scaling option, which will allow scaling to quite high data transfer rates. At these low data rates (a few megabits, or even lower for games) the windows are unlikely to cramp your style (by limiting bandwidth) One usually wants bigger windows for high volume transfers (say > 10 Mbytes/second) that you would see on a LAN.
Re:Latency and Throughput (Score:1)
It Depends (Score:3, Insightful)
ADSL vs. SDSL (Score:5, Informative)
Some of those ISP's that offer ADSL have started to offer SDSL or VDSL. VDSL is currently very expensive in my area and only people within a short distcance from a telephone central can get it. SDSL is more flexible when it comes to max distace. Most people on SDSL get lower ping.
When I got my new connection I could either choose between 1024/512 ADSL at $85 or 1024/1024 at $140.
A bit expensive, but I get my own permanent IP, no pay per GB thing, can have my own servers etc.
And I can't complain at the latency, since many of the other users on the ISP are offices and bussiness whom almost only use their computers at office hours I get very low latency. Approx. 15 ms. to many CS-servers and the same to a backbone.
So I'm happy, but I still gaze at the connection of a friend of mine. He just got a VDSL 12500/6250 at $227. Officially, According to their User Agreement he cant't resell but the ISP is not that strict on it so he allready has 10+ customers... ;-)
Re:ADSL vs. SDSL (Score:2)
If you don't mind my asking, where does your friend live (in general -- country and city), and what kind of hurdles did he have to jump through to get it?
Yes, I'm jealous too.
Re:ADSL vs. SDSL (Score:2)
Sorry for late reply.
He lives in Norway and his new ISP is Firstmile. (www.firstmile.no). Its a new ISP, a subsidiary of ZyXEL Comunnications. Unfortunately, they only deliver in limited parts of Norway.
Products and pricing at the bottom of this [firstmile.no] page. Prices in NOK, so you have to divide with 7 to get $.
No special hurdles, but he had to terminate his old ISP-agreement and pay them 3-months extra because of a 2 year agreement setup.
Not much of an issue really (Score:2)
No its not about time we get focused here, when ISPs were over 500ms it was an issue. Below 50ms theres no issue at all unless you just WANT to have lower latency for the sake of it. And then counting hops and demarcating the bounds of your ISP gets you nowhere. If Sym
Latency to where? (Score:5, Interesting)
If you're going to measure how long it takes for your packets to get somewhere, make sure you also measure where your packets are getting to.
DSL and Latency is a recurrent issue. (Score:1)
The added latency in dsl setups can also add to irritation when web surfing as well.
Re:DSL and Latency is a recurrent issue. (Score:2)
22 ms latency for voip? (Score:1)
leaving the ISP is not the issue (Score:2)
than your friend's ISP. What matters is not the latency
to the AS boundary, but the average latency to your
peers. Also, 8MB up with a 128k down is not going to
get much better ping time than 512k up with a 128k
down: The 128k down segment is going to dominate
your ping time (which is bidirectional).
Yes, latency sucks. It's sucking more and more as
ISPs optimize devices for b/w at the expense of latency,
although the customer base would benefit more from
decrease
What about *nix? (Score:1)
It would be nice to have a way to do it because pathping seems as useful a utility for network admin as nmap, etherape, and ethereal.
Free equivalent (Score:3, Informative)
Believe me, there isn't anything you can do on a network in Windows that you can't do better in Linux.
22 ms is pretty good (Score:2)
If you have a service level agreement, it usually specifies 100ms as maximum round trip time within the ISPs network. I guess they pick this rather high number as it usually is fast enough and sho
8mb dsl latency (Score:2, Informative)
Dsl speeds won't affect latency too much. I know it's not supposed to, but it does.
A 1184/160 dsl will ping around 15ms to its gateway
A 1728/384 dsl will ping around 11ms to its gateway
A 3488/800 dsl will ping around 7ms to its gateway
I have a feeling its more related to the upstream speeds than the downstream. An 8MB dsl has an 800 upstream maximum so the pings will most likely be the same as a 3MB dsl. Isp's can have different upstream spe
router equipment (Score:2, Informative)
The other thing is, that you shold really only be interested in end-to-end RTT, not the individual hops. For example, if there's cisco 4xxx series switches with SUP-3's out there, your icmp/traceroute IP packets gets processed in the processor card, not on the interface, causing an 10ms more l
22ms? ouch. (Score:2)
For games, it's ~50ms for anything on the west coast, and ~10-30ms for anything on speakeasy's network.
Residential better than commercial (Score:2)
This is a very expensive ADSL line that we have going here... I would think
MCI's latency. (Score:2, Funny)
I heard some MCI execs were hoping for a latency of 5 years + good behavior.
Trade? (Score:3, Funny)
Pathping in 'nix (Score:2)
Re:Pathping in 'nix (Score:4, Informative)
my speakeasy numbers (Score:2)
Packets Pings
Hostname %Loss Rcv Snt Last Best Avg Worst
1. myhost 0% 9 9 0 0 0 2
2. sfo1.dsl.speakeasy.net 0% 9 9 14 13 14 15
3. border5.g3-4.speakeasy-29.sfo.pnap. 0% 9 9 14 13 18 46
4. core4.ge2-0-bbnet2.sfo.pnap.net 0% 9 9 15 14 51 207
5. so-1-3-0.0.ar4.sfo1.gblx.net 0% 9 9 17 14 21 62
6. pos1-1.core1.SanFrancisco1.Level3.n 0% 9 9 14 14 16 18
7. so-4-0-0.mp2.SanFrancisco1.Level3.n
VoIP can tolerate latency IF the echo is cancelled (Score:1)
Oh here, let me change the speed of light for you, (Score:1)
Boy have a I got bridge to sell you! ( and some terrific coastline property too!)
No matter how fast you can download data, all the signaling involved has to obey the laws of physics.
Expecting to get less than 20ms of latency getting from your pc to your ISP's connection to the NET is extremely unrealistic (the average T1 introduces 20ms of latency) just because of the number of signal + data processing devic
what do you need ? (Score:2)
We use the term "bandwidth delay product" rather than "bandwidth" as this refects the combination of speed and latency.
local fast, xcountry slow (Score:1)
1 my.gateway (216.xxx.xxx.xxx) 0.690 ms 19.335 ms 0.404 ms
2 some.machine.at.savvis.net (216.xxx.xxx.xxx) 1.929 ms 1.903
ms 2.108 ms
3 500.POS2-1.GW4.ATL3.alter.net (157.130.81.41) 2.266 ms 2.175 ms 2.007 ms
4 147.at-1-0-0.XL3.ATL1.ALTER.NET (152.63.81.50) 2.449 ms 2.797 ms 2.680 ms 5 0.so-7-0-0.XL3.ATL5.ALTER.NET (152.63.85.190) 3.104 ms 3.372 ms 3.207 ms
6 193.ATM6-0.BR1.ATL5.ALTER.NET (152.63.80.113) 3.139
22ms is not good enough for voice chat ???? (Score:2)
The main culprit in VoIP latency is really jitter. That's basically packets that arrive out of order or don't get there and need to be resent. If you've got a lot of jitter it drives up the latency to compensate (the codec needs time to reassemble them in the right order). It's better often just to drop missed packets
Jitter i
PING Is *NOT* Accurate - Please Read! (Score:1)
It's not.
PING was intended for reachability checking, and as a secondary feature, response time.
The ICMP part of most IP stacks often has the lowest priority to receive CPU time in a lot of IP stack implementations. When you PING, the return packet back to you is at the mercy of the resources of the system writing, generating, a
Re:Man, talk about spoiled (Score:1)
Re:w00t?! (Score:1)