Contention

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networkn

Networkn
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#236321 28-May-2018 18:54

Hi.

So a customers ISP and I are having a little disagreement about the customers speed and what should be expected.

Customer is in Albany and ISP whom I won't name right now has assigned us an "account manager" who has been at us about the contended plans and that is why we are not getting our expected speeds.

Customer is on a 100/100mbps plan and has never been able to get above 85mbps, not day, night weekend etc. ISP are stating it's contention despite the results being within 5Mbps of this speed but never over it.

Requested a plan change to 200Mbps which the process was disaster and new speed tests show.... 85Mbps. They are stating it's contention and insisting to get better I need to move to a higher plan with lower contention.

We have tried different modems etc, doesn't make any difference.

I don't' believe it's contention at all.

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#2024132 28-May-2018 19:03

Sounds like not enough capacity on the ISP but how are they testing as well?

John

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#2024186 28-May-2018 19:31

Just to be clear, it's gigabit Ethernet all the way right?

tdgeek

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#2024189 28-May-2018 19:35

A Ferrari with a 2 barrel carb.

Sounddude

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#2024192 28-May-2018 19:39

sounds very much like the customer has a 100mbit port on their network.

Jase2985

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#2024203 28-May-2018 19:58

not suing something like an hg630 as the router?

networkn

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#2024428 29-May-2018 09:12

Sounddude:

sounds very much like the customer has a 100mbit port on their network.

ONT to Sonicwall TZ400 is Gigabit, Switch is Gigabit and Server testing from is Gigabit.

Previously it was connected via a Cisco intermediary RSP supplied device, but pretty sure that was Gigabit.

freitasm

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#2024436 29-May-2018 09:25

And cables are cat5E or cat6, not cat5 only?

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networkn

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#2024444 29-May-2018 09:37

CAT5E. Negotiating at 1Gbps.

BarTender

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#2024447 29-May-2018 09:42

And are you sure it's not because there isn't a shaper in place at the ISP??

What happens if you do a UDP speedtest, and are you seeing a lot of packet loss / re-transmits.

networkn

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#2024748 29-May-2018 13:03

Do you have a UDP test you recommend?

I am unsure if there is traffic shaping occuring, they are now investigating more closely.

I presume it's pretty much correct that if the issue was contention, that they would be experiencing fluctuation rather than set speeds, and that sometimes they could get very close to line speed?

There is also some discussion that perhaps the "exchange" they are connected to, is overloaded and there isn't capacity for them to go beyond 85Mbps, but that seems relatively unlikely, even in a fairly highly utilized area.

Linux

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#2024751 29-May-2018 13:07

@ChorusNZ network does not have congestion in it's network

John

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#2024754 29-May-2018 13:09

Here's the Chorus whitepaper on their "congestion free network".

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#2024821 29-May-2018 14:00

Is the firewall running IPS? That could have a performance penalty.

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#2024836 29-May-2018 14:17

I'm putting money on either a 100M interface or 100M policer somewhere in the solution. It's not contention/congestion.

CHeers - N

Please note all comments are from my own brain and don't necessarily represent the position or opinions of my employer, previous employers, colleagues, friends or pets.

BarTender

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#2024840 29-May-2018 14:20

Using iPerf:

Server side: iperf -s -u -i 1

(-s run as server, -u run over udp, -i update every 1 second)

Client side: iperf -c x.x.x.x -u -i 1 -l 1000 -t 10 -b 1000000

(-c run as client to x.x.x.x IP, -u run over udp, -i update every 1 second, -l send 1000 byte packets, -t send for 10 seconds, -b send 1000000 bytes per second aka 1Mbit/s)

Then play with the -l packet size to see if you are having MTU issues when you get over 1450 / 1500 bytes. And increase the -b to 10000000 (10Mbit) or 100000000 etc.

Also make sure you are collecting stats on both ends as you will see packet loss on the server end if it is being lost in transit not on the client side.

Similar tricks can be done using iPerf3 but iPerf3 is better for TCP tests, iPerf2 or iPerf 3.4 or higher (which isn't included in most distributions so you need to compile it yourself from source).

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