Ask Slashdot: What Is an Acceptable Broadband Latency?

holmedog writes "A simple question with a lot of answers (I hope). I recently had issues with my DSL broadband at home, and after a month of no resolution, I was told 300ms latency (to their test servers) was the acceptable range for Centurylink 10.0Mbps. This got a shocked reaction out of me to say the least. I would think anything over 125ms to be in the unacceptable range. So, I have come to you to ask: What do you consider to be acceptable broadband latency and why?"

Comments

Latency

[Anonymous Coward]

I used to work for AT&T Uverse and over 200ms was enough to get a tech onsite to look at the problem.

Re:Latency

[Anonymous Coward]

Your comment assumes that all the devices and media between locations were functioning properly. Latency can also be caused by bad wiring, bad modem, etc. Hell, even line noise can cause it because the line noise forces re-transmits.

Re:Latency

[gknoy]

No, but if you point out that the latency between everything up to your street is low, and you have massive latency over the last two hops, it helps show them that something isn't normal.

Re:Latency

[rogueippacket]

More often than not, latency is caused by congestion and not number of hops. Hops do introduce latency, but few modern applications need to go very far. So, whether the customer intentionally (bit-torrent) or unintentionally (malware) introduced this congestion is the first thing a tech will check for - usually by disconnecting the local network and running a speed-test directly from a laptop. The latency could also be caused by a local wireless network which is saturated, underpowered, or experiencing interference. So if the wireline speed-test passes, a wireless speed-test is likely to happen next with the tech standing right beside the modem.
In the much more unlikely scenario that the latency is being introduced by the network itself, the technician will usually escalate the problem and check both the street-side cabinet (DSLAM in this case), and customer profile at the B-RAS deep inside the provider network. It is not uncommon to see a low-speed DSL profile applied to a poor quality local loop, or for the wrong Layer 3 profile to be applied by provisioning error on the B-RAS itself. Both scenarios would result in poor performance for the user, leading to congestion and therefore, latency.

Re:Latency

[mikael_j]

Yeah, I used to do tech support and anything over 100 ms or so for the first hop outside the ISP's network was likely to be escalated to a 3rd line tech if we couldn't solve it.

Hell, right now I'm getting approximately 100-120 ms pings against random machines in the US northeast and around 190-200 ms for the west coast and I'm in northern Sweden...

Re:Latency

[crafty.munchkin]

You may think it's too specific however it's highly relevant information and should've been in the summary... if it's the third hop, there's nothing you can do at your place to fix it, and most of the above comments are redundant. This issue needs to be escalated within their networks team... *sigh*

Re:Latency

[Forty Two Tenfold]

Actually, you're wrong. It won't.

Yes it will:

PING slashdot.org (216.34.181.45) 56(84) bytes of data.
64 bytes from slashdot.org (216.34.181.45): icmp_seq=1 ttl=239 time=144 ms
64 bytes from slashdot.org (216.34.181.45): icmp_seq=2 ttl=239 time=140 ms
64 bytes from slashdot.org (216.34.181.45): icmp_seq=3 ttl=239 time=139 ms

Now go read about TTL and apologize.

Re:300 Acceptable?

[AvitarX]

I consider anything past 80ms to be slow for my cable connection (to 8.8.8.8).

I just tested 19,17,18,18

I previous test had a 60 something thrown in. This is via a boring home VPN router, shared connection, but under a dozen, and all light users.

13 hops to 8.8.8.8 from here.

33,34,33,63 to /.

300 is what I get on hotel wifi, or my cellphone (to be fair, on my cell phone it goes up to 1000), as can hotel wifi become unusable, I swear most hotels must have 300+ rooms sharing a T1 line.

Re:300 Acceptable?

[DamonHD]

Generally 1ms or less.

Pinging one of my servers in co-lo on the other side of London and traversing my moderate-speed (~4Mbps/1Mbps) ASDL only takes just over 14ms round-trip.

Pinging my server in the US gives ~110ms.

Singapore: ~270ms.

Sydney, Australia: ~310ms.

So I can get right round the globe and back in about 300ms, *starting* the trip over ADSL.

Rgds

Damon

Rgds

Damon