High latency

Question

High latency

*NOTE* Cross posted to http://discussions.apple.com/thread.jspa?threadID=2387809&stqc=true

ISSUE: There is noticeably high latency on the Mini over the airport connection. I am having pings averaging over 100ms just to the Airport base station (first hop). The throughput on the card is not spectacular either, as whenever I do a speedtest over the local network, I get at most 500KBit/sec of throughput. Here is a sample ping report from another machine on the local network to the mini (10.0.1.3 is the mini):

me@jenolen:~$ ping -c 100 10.0.1.3
PING 10.0.1.3 (10.0.1.3) 56(84) bytes of data.
64 bytes from 10.0.1.3: icmp_seq=1 ttl=64 time=120 ms
64 bytes from 10.0.1.3: icmp_seq=2 ttl=64 time=42.0 ms
64 bytes from 10.0.1.3: icmp_seq=3 ttl=64 time=1.21 ms
64 bytes from 10.0.1.3: icmp_seq=4 ttl=64 time=0.985 ms
64 bytes from 10.0.1.3: icmp_seq=5 ttl=64 time=1.23 ms
64 bytes from 10.0.1.3: icmp_seq=6 ttl=64 time=34.1 ms
64 bytes from 10.0.1.3: icmp_seq=7 ttl=64 time=1.24 ms
64 bytes from 10.0.1.3: icmp_seq=8 ttl=64 time=0.916 ms
64 bytes from 10.0.1.3: icmp_seq=9 ttl=64 time=1.59 ms
64 bytes from 10.0.1.3: icmp_seq=10 ttl=64 time=25.1 ms
64 bytes from 10.0.1.3: icmp_seq=11 ttl=64 time=252 ms
64 bytes from 10.0.1.3: icmp_seq=12 ttl=64 time=169 ms
64 bytes from 10.0.1.3: icmp_seq=13 ttl=64 time=90.5 ms
64 bytes from 10.0.1.3: icmp_seq=14 ttl=64 time=9.33 ms
64 bytes from 10.0.1.3: icmp_seq=15 ttl=64 time=1.16 ms
64 bytes from 10.0.1.3: icmp_seq=16 ttl=64 time=1.10 ms
64 bytes from 10.0.1.3: icmp_seq=17 ttl=64 time=69.6 ms
64 bytes from 10.0.1.3: icmp_seq=18 ttl=64 time=298 ms
64 bytes from 10.0.1.3: icmp_seq=19 ttl=64 time=220 ms
64 bytes from 10.0.1.3: icmp_seq=20 ttl=64 time=140 ms
64 bytes from 10.0.1.3: icmp_seq=21 ttl=64 time=61.9 ms
64 bytes from 10.0.1.3: icmp_seq=22 ttl=64 time=1.17 ms
64 bytes from 10.0.1.3: icmp_seq=23 ttl=64 time=1.28 ms
64 bytes from 10.0.1.3: icmp_seq=24 ttl=64 time=1.09 ms
64 bytes from 10.0.1.3: icmp_seq=25 ttl=64 time=47.0 ms
64 bytes from 10.0.1.3: icmp_seq=26 ttl=64 time=275 ms
64 bytes from 10.0.1.3: icmp_seq=27 ttl=64 time=1.14 ms
64 bytes from 10.0.1.3: icmp_seq=28 ttl=64 time=1.21 ms
64 bytes from 10.0.1.3: icmp_seq=29 ttl=64 time=37.1 ms
64 bytes from 10.0.1.3: icmp_seq=30 ttl=64 time=265 ms
64 bytes from 10.0.1.3: icmp_seq=31 ttl=64 time=186 ms
64 bytes from 10.0.1.3: icmp_seq=32 ttl=64 time=98.5 ms
64 bytes from 10.0.1.3: icmp_seq=33 ttl=64 time=27.6 ms
64 bytes from 10.0.1.3: icmp_seq=34 ttl=64 time=1.10 ms
64 bytes from 10.0.1.3: icmp_seq=35 ttl=64 time=1.19 ms
64 bytes from 10.0.1.3: icmp_seq=36 ttl=64 time=1.16 ms
64 bytes from 10.0.1.3: icmp_seq=37 ttl=64 time=13.8 ms
64 bytes from 10.0.1.3: icmp_seq=38 ttl=64 time=241 ms
64 bytes from 10.0.1.3: icmp_seq=39 ttl=64 time=162 ms
64 bytes from 10.0.1.3: icmp_seq=40 ttl=64 time=83.5 ms
64 bytes from 10.0.1.3: icmp_seq=41 ttl=64 time=3.36 ms
64 bytes from 10.0.1.3: icmp_seq=42 ttl=64 time=230 ms
64 bytes from 10.0.1.3: icmp_seq=43 ttl=64 time=150 ms
64 bytes from 10.0.1.3: icmp_seq=44 ttl=64 time=71.3 ms
64 bytes from 10.0.1.3: icmp_seq=45 ttl=64 time=1.18 ms
64 bytes from 10.0.1.3: icmp_seq=46 ttl=64 time=1.21 ms
64 bytes from 10.0.1.3: icmp_seq=47 ttl=64 time=139 ms
64 bytes from 10.0.1.3: icmp_seq=48 ttl=64 time=59.6 ms
64 bytes from 10.0.1.3: icmp_seq=49 ttl=64 time=287 ms
64 bytes from 10.0.1.3: icmp_seq=50 ttl=64 time=205 ms
64 bytes from 10.0.1.3: icmp_seq=51 ttl=64 time=126 ms
64 bytes from 10.0.1.3: icmp_seq=52 ttl=64 time=43.7 ms
64 bytes from 10.0.1.3: icmp_seq=53 ttl=64 time=272 ms
64 bytes from 10.0.1.3: icmp_seq=54 ttl=64 time=193 ms
64 bytes from 10.0.1.3: icmp_seq=55 ttl=64 time=101 ms
64 bytes from 10.0.1.3: icmp_seq=56 ttl=64 time=21.7 ms
64 bytes from 10.0.1.3: icmp_seq=57 ttl=64 time=248 ms
64 bytes from 10.0.1.3: icmp_seq=58 ttl=64 time=167 ms
64 bytes from 10.0.1.3: icmp_seq=59 ttl=64 time=87.6 ms
64 bytes from 10.0.1.3: icmp_seq=60 ttl=64 time=7.15 ms
64 bytes from 10.0.1.3: icmp_seq=61 ttl=64 time=219 ms
64 bytes from 10.0.1.3: icmp_seq=62 ttl=64 time=140 ms
64 bytes from 10.0.1.3: icmp_seq=63 ttl=64 time=61.4 ms
64 bytes from 10.0.1.3: icmp_seq=64 ttl=64 time=289 ms
64 bytes from 10.0.1.3: icmp_seq=65 ttl=64 time=210 ms
64 bytes from 10.0.1.3: icmp_seq=66 ttl=64 time=131 ms
64 bytes from 10.0.1.3: icmp_seq=67 ttl=64 time=51.5 ms
64 bytes from 10.0.1.3: icmp_seq=68 ttl=64 time=279 ms
64 bytes from 10.0.1.3: icmp_seq=69 ttl=64 time=199 ms
64 bytes from 10.0.1.3: icmp_seq=70 ttl=64 time=108 ms
64 bytes from 10.0.1.3: icmp_seq=71 ttl=64 time=29.4 ms
64 bytes from 10.0.1.3: icmp_seq=72 ttl=64 time=256 ms
64 bytes from 10.0.1.3: icmp_seq=73 ttl=64 time=175 ms
64 bytes from 10.0.1.3: icmp_seq=74 ttl=64 time=96.5 ms
64 bytes from 10.0.1.3: icmp_seq=75 ttl=64 time=12.8 ms
64 bytes from 10.0.1.3: icmp_seq=76 ttl=64 time=240 ms
64 bytes from 10.0.1.3: icmp_seq=77 ttl=64 time=160 ms
64 bytes from 10.0.1.3: icmp_seq=78 ttl=64 time=81.4 ms
64 bytes from 10.0.1.3: icmp_seq=79 ttl=64 time=308 ms
64 bytes from 10.0.1.3: icmp_seq=80 ttl=64 time=844 ms
64 bytes from 10.0.1.3: icmp_seq=81 ttl=64 time=1.01 ms
64 bytes from 10.0.1.3: icmp_seq=82 ttl=64 time=67.6 ms
64 bytes from 10.0.1.3: icmp_seq=83 ttl=64 time=294 ms
64 bytes from 10.0.1.3: icmp_seq=84 ttl=64 time=215 ms
64 bytes from 10.0.1.3: icmp_seq=85 ttl=64 time=136 ms
64 bytes from 10.0.1.3: icmp_seq=86 ttl=64 time=55.6 ms
64 bytes from 10.0.1.3: icmp_seq=87 ttl=64 time=276 ms
64 bytes from 10.0.1.3: icmp_seq=88 ttl=64 time=196 ms
64 bytes from 10.0.1.3: icmp_seq=89 ttl=64 time=117 ms
64 bytes from 10.0.1.3: icmp_seq=90 ttl=64 time=37.6 ms
64 bytes from 10.0.1.3: icmp_seq=91 ttl=64 time=255 ms
64 bytes from 10.0.1.3: icmp_seq=92 ttl=64 time=175 ms
64 bytes from 10.0.1.3: icmp_seq=93 ttl=64 time=96.0 ms
64 bytes from 10.0.1.3: icmp_seq=94 ttl=64 time=17.3 ms
64 bytes from 10.0.1.3: icmp_seq=95 ttl=64 time=245 ms
64 bytes from 10.0.1.3: icmp_seq=96 ttl=64 time=166 ms
64 bytes from 10.0.1.3: icmp_seq=97 ttl=64 time=86.7 ms
64 bytes from 10.0.1.3: icmp_seq=98 ttl=64 time=7.21 ms
64 bytes from 10.0.1.3: icmp_seq=99 ttl=64 time=235 ms
64 bytes from 10.0.1.3: icmp_seq=100 ttl=64 time=156 ms

--- 10.0.1.3 ping statistics ---
100 packets transmitted, 100 received, 0% packet loss, time 99187ms
rtt min/avg/max/mdev = 0.916/121.527/844.483/121.995 ms

I get this same level of latency when pinging from hosts A, B, or C on the local network to the mini. The latency is not there when pinging from A to B, B to C, C to A, A to C, B to A and so on. I have switched out base stations... tried an Airport Express G, Airport Express N, Time Capsule, Airport Extreme.... same results every time.

The mini comes preloaded with 10.6.2 which I just received in the mail on Thursday. I've had the problem from minute one, and spent the last 48 hours trying to troubleshoot it. I upgraded to 10.6.3 hoping that would fix it - nope. Formatted and reinstalled from the restore discs, still no loving.

I'm about to my wits end... this thing is brand new!

Ideas?!

Mac OS X (10.6)

Posted on Apr 3, 2010 11:34 PM

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Answer 1

Camelot

Level 9

58,515 points

Apr 3, 2010 11:45 PM in response to G[H]etto|Dalai|Lama

Your problem is one of interference.

If you look closely at those times, you have some very low-latency responses (e.g. sub 1-ms) very close to some awful ones.

This is a classic indication of interference - some other device is interfering with the radio broadcasts. The issue is identifying what that is.

Certain other electronic equipment could be affecting it, as could an enclosure (e.g. if the Mini is housed in an entertainment center, surrounded by your receiver, TV, cable/satellite box, etc., that could have an effect). If this is the case, relocating the Mini might be in order (doesn't necessarily have to move far, depending on what's causing the interference)
It could also be other wireless networks in the area - a common problem in dense population areas. The easiest fix for this one is to switch your base station to use a different channel. Trial an error might be the fastest solution here - use AirPort Admin to try different channels to see if any others work better.

Then, of course, there's always the option of going wired, not wireless. That will eliminate all the above issues but depends, of course, on where your Mini is located in relation to the rest of the network.

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Answer 2

Apr 4, 2010 1:11 AM in response to Camelot

The mini is right beside an iMac running 10.6.2 that has no issues itself. No enclosure or anything of the sort. I believe I've eliminated the possability of interferience as well by switching between 5Ghz and 2.4Ghz, along with b/g modes and n-only. Further, I live in an extremely rural area (the closest stop light is 500 miles away) - not a lot of other access points around.

So here are traceroutes from a third workstation to the mini, then to the imac sitting side by side to eachother on a table, with the access point being at the end of the table as well:

MINI:
localhost.localdomain:~ me$ ping -c 50 10.0.1.3
PING 10.0.1.3 (10.0.1.3): 56 data bytes
64 bytes from 10.0.1.3: icmp_seq=0 ttl=64 time=210.261 ms
64 bytes from 10.0.1.3: icmp_seq=1 ttl=64 time=130.636 ms
64 bytes from 10.0.1.3: icmp_seq=2 ttl=64 time=52.576 ms
64 bytes from 10.0.1.3: icmp_seq=3 ttl=64 time=280.856 ms
64 bytes from 10.0.1.3: icmp_seq=4 ttl=64 time=201.894 ms
64 bytes from 10.0.1.3: icmp_seq=5 ttl=64 time=123.429 ms
64 bytes from 10.0.1.3: icmp_seq=6 ttl=64 time=352.723 ms
64 bytes from 10.0.1.3: icmp_seq=7 ttl=64 time=273.613 ms
64 bytes from 10.0.1.3: icmp_seq=8 ttl=64 time=195.109 ms
64 bytes from 10.0.1.3: icmp_seq=9 ttl=64 time=116.747 ms
64 bytes from 10.0.1.3: icmp_seq=10 ttl=64 time=345.460 ms
64 bytes from 10.0.1.3: icmp_seq=11 ttl=64 time=267.560 ms
64 bytes from 10.0.1.3: icmp_seq=12 ttl=64 time=121.473 ms
64 bytes from 10.0.1.3: icmp_seq=13 ttl=64 time=109.943 ms
64 bytes from 10.0.1.3: icmp_seq=14 ttl=64 time=338.785 ms
64 bytes from 10.0.1.3: icmp_seq=15 ttl=64 time=260.251 ms
64 bytes from 10.0.1.3: icmp_seq=16 ttl=64 time=181.917 ms
64 bytes from 10.0.1.3: icmp_seq=17 ttl=64 time=1.297 ms
64 bytes from 10.0.1.3: icmp_seq=18 ttl=64 time=332.127 ms
64 bytes from 10.0.1.3: icmp_seq=19 ttl=64 time=253.654 ms
64 bytes from 10.0.1.3: icmp_seq=20 ttl=64 time=175.123 ms
64 bytes from 10.0.1.3: icmp_seq=21 ttl=64 time=404.011 ms
64 bytes from 10.0.1.3: icmp_seq=22 ttl=64 time=325.554 ms
64 bytes from 10.0.1.3: icmp_seq=23 ttl=64 time=247.059 ms
64 bytes from 10.0.1.3: icmp_seq=24 ttl=64 time=169.485 ms
64 bytes from 10.0.1.3: icmp_seq=25 ttl=64 time=397.388 ms
64 bytes from 10.0.1.3: icmp_seq=26 ttl=64 time=318.981 ms
64 bytes from 10.0.1.3: icmp_seq=27 ttl=64 time=240.439 ms
64 bytes from 10.0.1.3: icmp_seq=28 ttl=64 time=161.232 ms
64 bytes from 10.0.1.3: icmp_seq=29 ttl=64 time=390.598 ms
64 bytes from 10.0.1.3: icmp_seq=30 ttl=64 time=311.583 ms
64 bytes from 10.0.1.3: icmp_seq=31 ttl=64 time=233.764 ms
64 bytes from 10.0.1.3: icmp_seq=32 ttl=64 time=155.376 ms
64 bytes from 10.0.1.3: icmp_seq=33 ttl=64 time=384.183 ms
64 bytes from 10.0.1.3: icmp_seq=34 ttl=64 time=305.631 ms
64 bytes from 10.0.1.3: icmp_seq=35 ttl=64 time=227.490 ms
64 bytes from 10.0.1.3: icmp_seq=36 ttl=64 time=148.694 ms
64 bytes from 10.0.1.3: icmp_seq=37 ttl=64 time=377.475 ms
64 bytes from 10.0.1.3: icmp_seq=38 ttl=64 time=299.344 ms
64 bytes from 10.0.1.3: icmp_seq=39 ttl=64 time=220.613 ms
64 bytes from 10.0.1.3: icmp_seq=40 ttl=64 time=142.660 ms
64 bytes from 10.0.1.3: icmp_seq=41 ttl=64 time=370.940 ms
64 bytes from 10.0.1.3: icmp_seq=42 ttl=64 time=292.395 ms
64 bytes from 10.0.1.3: icmp_seq=43 ttl=64 time=213.940 ms
64 bytes from 10.0.1.3: icmp_seq=44 ttl=64 time=135.432 ms
64 bytes from 10.0.1.3: icmp_seq=45 ttl=64 time=364.219 ms
64 bytes from 10.0.1.3: icmp_seq=46 ttl=64 time=285.770 ms
64 bytes from 10.0.1.3: icmp_seq=47 ttl=64 time=207.316 ms
64 bytes from 10.0.1.3: icmp_seq=48 ttl=64 time=128.817 ms
64 bytes from 10.0.1.3: icmp_seq=49 ttl=64 time=358.180 ms

--- 10.0.1.3 ping statistics ---
50 packets transmitted, 50 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 1.297/242.880/404.011/97.499 ms

pinging the imac:

localhost.localdomain:~ me$ ping -c 50 10.0.1.10
PING 10.0.1.10 (10.0.1.10) 56(84) bytes of data.
64 bytes from 10.0.1.10: icmp_seq=1 ttl=64 time=1.08 ms
64 bytes from 10.0.1.10: icmp_seq=2 ttl=64 time=1.14 ms
64 bytes from 10.0.1.10: icmp_seq=3 ttl=64 time=1.78 ms
64 bytes from 10.0.1.10: icmp_seq=4 ttl=64 time=1.10 ms
64 bytes from 10.0.1.10: icmp_seq=5 ttl=64 time=1.22 ms
64 bytes from 10.0.1.10: icmp_seq=6 ttl=64 time=1.06 ms
64 bytes from 10.0.1.10: icmp_seq=7 ttl=64 time=2.55 ms
64 bytes from 10.0.1.10: icmp_seq=8 ttl=64 time=1.19 ms
64 bytes from 10.0.1.10: icmp_seq=9 ttl=64 time=1.39 ms
64 bytes from 10.0.1.10: icmp_seq=10 ttl=64 time=1.09 ms
64 bytes from 10.0.1.10: icmp_seq=11 ttl=64 time=1.36 ms
64 bytes from 10.0.1.10: icmp_seq=12 ttl=64 time=1.07 ms
64 bytes from 10.0.1.10: icmp_seq=13 ttl=64 time=1.32 ms
64 bytes from 10.0.1.10: icmp_seq=14 ttl=64 time=4.23 ms
64 bytes from 10.0.1.10: icmp_seq=15 ttl=64 time=2.09 ms
64 bytes from 10.0.1.10: icmp_seq=16 ttl=64 time=1.05 ms
64 bytes from 10.0.1.10: icmp_seq=17 ttl=64 time=1.02 ms
64 bytes from 10.0.1.10: icmp_seq=18 ttl=64 time=1.21 ms
64 bytes from 10.0.1.10: icmp_seq=19 ttl=64 time=1.05 ms
64 bytes from 10.0.1.10: icmp_seq=20 ttl=64 time=1.05 ms
64 bytes from 10.0.1.10: icmp_seq=21 ttl=64 time=2.00 ms
64 bytes from 10.0.1.10: icmp_seq=22 ttl=64 time=1.05 ms
64 bytes from 10.0.1.10: icmp_seq=23 ttl=64 time=1.06 ms
64 bytes from 10.0.1.10: icmp_seq=24 ttl=64 time=1.10 ms
64 bytes from 10.0.1.10: icmp_seq=25 ttl=64 time=2.08 ms
64 bytes from 10.0.1.10: icmp_seq=26 ttl=64 time=3.13 ms
64 bytes from 10.0.1.10: icmp_seq=27 ttl=64 time=1.07 ms
64 bytes from 10.0.1.10: icmp_seq=28 ttl=64 time=1.16 ms
64 bytes from 10.0.1.10: icmp_seq=29 ttl=64 time=1.57 ms
64 bytes from 10.0.1.10: icmp_seq=30 ttl=64 time=1.22 ms
64 bytes from 10.0.1.10: icmp_seq=31 ttl=64 time=1.08 ms
64 bytes from 10.0.1.10: icmp_seq=32 ttl=64 time=1.07 ms
64 bytes from 10.0.1.10: icmp_seq=33 ttl=64 time=1.14 ms
64 bytes from 10.0.1.10: icmp_seq=34 ttl=64 time=4.99 ms
64 bytes from 10.0.1.10: icmp_seq=35 ttl=64 time=1.39 ms
64 bytes from 10.0.1.10: icmp_seq=36 ttl=64 time=1.52 ms
64 bytes from 10.0.1.10: icmp_seq=37 ttl=64 time=1.08 ms
64 bytes from 10.0.1.10: icmp_seq=38 ttl=64 time=1.08 ms
64 bytes from 10.0.1.10: icmp_seq=39 ttl=64 time=1.08 ms
64 bytes from 10.0.1.10: icmp_seq=40 ttl=64 time=1.85 ms
64 bytes from 10.0.1.10: icmp_seq=41 ttl=64 time=1.25 ms
64 bytes from 10.0.1.10: icmp_seq=42 ttl=64 time=2.39 ms
64 bytes from 10.0.1.10: icmp_seq=43 ttl=64 time=1.57 ms
64 bytes from 10.0.1.10: icmp_seq=44 ttl=64 time=1.25 ms
64 bytes from 10.0.1.10: icmp_seq=45 ttl=64 time=2.58 ms
64 bytes from 10.0.1.10: icmp_seq=46 ttl=64 time=1.62 ms
64 bytes from 10.0.1.10: icmp_seq=47 ttl=64 time=1.07 ms
64 bytes from 10.0.1.10: icmp_seq=48 ttl=64 time=1.09 ms
64 bytes from 10.0.1.10: icmp_seq=49 ttl=64 time=1.09 ms
64 bytes from 10.0.1.10: icmp_seq=50 ttl=64 time=1.81 ms

--- 10.0.1.10 ping statistics ---
50 packets transmitted, 50 received, 0% packet loss, time 49101ms
rtt min/avg/max/mdev = 1.024/1.533/4.990/0.793 ms

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Answer 3

Dogcow-Moof

Level 8

36,833 points

Apr 4, 2010 8:03 AM in response to G[H]etto|Dalai|Lama

As stated, it's interference.

The more devices you have, the worse latency may be due to the way collisions are handled in 802.11.

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Answer 4

oxcart

Level 1

94 points

Apr 4, 2010 9:02 AM in response to Dogcow-Moof

Yes, probably, my cordless phone base stating, screws up airport connection and vice versa if they are too close.

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Answer 5

Dogcow-Moof

Level 8

36,833 points

Apr 4, 2010 9:07 AM in response to oxcart

As can microwave ovens, which share the same 2.4 GHz frequency band as Wi-Fi.

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Answer 6

Apr 4, 2010 9:12 AM in response to Dogcow-Moof

No microwave ovens or cordless phones, and I'm seeing the same results regardless of if I use 2.4Ghz or put it in N-only mode and switch to 5Ghz.

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Answer 7

Boece

Level 5

6,264 points

Apr 4, 2010 3:18 PM in response to G[H]etto|Dalai|Lama

It could be some of your own computer or wifi router equipment that is interfering.

As I stated in the other thread, the Mini is the wifi weak-sister of the Apple line-up, IMHO, and a TimeCapsule-N set to use full spectrum, can use up a lot of wifi channels in both the 2.4 and 5 frequencies.

I would try a test with the minimum of equipment turned on, to see if you can isolate which piece is blowing the Mini out of the competition.

I'd also recommend not setting the Mini on a router, or vice-versa.

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