Internet slowless

Posted on 2014-02-21
Last Modified: 2014-03-07
I am having a network latency with our internet circuit.  If I connect my laptop directly to the Comcast modem, I get 100MB but if I connect my laptop behind the Sonicwall TZ 205, I get only about 30MBs.  The WAN and LAN are set to auto , which detects at 1GB.

The cpu and memory is very low, at about less than 5MB and we monitor the traffic going through the internet and see at most about 3-4MB to the internet.

I dont' see any other issues with the Sonicwall (check the logs, errors and other diagnostics tool) .  I am just curious what would cause this network latency when we should be getting about 100MB (instead of 30MB).

thanks much,
Question by:LateNaite
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LVL 95

Expert Comment

by:John Hurst
ID: 39878491
I had a Cisco RV042 that gave me about 1/3 of the available speed through it. No issues when my computer was direct connected.

The only solution for me was to go to a Cisco RV042G with 4 times the available internal NAT throughput. Now my speed is back to full.

See if you can find the specs for your Sonicwall, in particular the internal NAT speed. You can try upgrading the firmware to see if that might work.

However, likely you will need a faster router.
LVL 26

Expert Comment

by:Fred Marshall
ID: 39878520
Just to be clear, latency and throughput are two different things.
Latency is delay in units of seconds (or microseconds...)
Throughput is *utilized* or *realized* bandwidth measured in Hz or, for networks, usually Mbps.

In general, the two are separate and distinct.
But you may have low realized bandwidth AND high latency at the same time for the same reasons (e.g. low router cpu instructions per second or high demand for cpu instructions per second).

It's certainly possible to have high latency and high bandwidth.  It just means there's a big delay along with the high bandwidth.
LVL 11

Accepted Solution

Miftaul earned 500 total points
ID: 39878578
Sonicwalls are not good at Auto setting. Please set your interfaces to 1gb or 100mbps which is actual.

Also check the actual mtu with a ping -f -l and set the value to the wan interface. It may be that packets are being fragmented due to incorrect mtu.

Also temporarily disable security services and see if that improves bandwith.
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LVL 57

Expert Comment

ID: 39879897
First, big "B" means bytes and little "b" means bits.

Based on the TZ 205 doc if you have enable full DPI (deep packet inspection) the best you can get is 40 Mbps, which sound close to what you are getting.

Author Comment

ID: 39895604
Ok, disabling DPI did help for a day and then it worked after that.  Why would it go back to normal?

LVL 57

Expert Comment

ID: 39895793
I'm a little confused.  I get that you disabled DPI and that helped with performance.

But I' not sure what you mean by "Why would it go back to normal?"

Are you saying that after one day of better performance that it went back to "slow" (30 Mbps) without you doing anything?

If so I would check to see if DPI may have re-enabled its self "magically."
LVL 26

Expert Comment

by:Fred Marshall
ID: 39896058
A router would "go back to normal" if you didn't save the changes you made.  That's for your protection.  Various manufacturers have various rules for doing this.

Author Closing Comment

ID: 39913504
Disabling IPS, Antivirus and other securit services on the non-wan helped.
LVL 57

Expert Comment

ID: 39913996
I'm not complaining, but I am confused (I get confused often).

You stated that disabling IPS/DPI helped, but the answer you accepted had nothing to do with IPS/DPI.

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