Slow client speeds behind Asus-WRT(Merlin Build)-flashed N66U

[deniaron]

Greetings to everyone,

Since a week I've replaced my home server (BSD-based) with the N66U since my home server was not doing anything more than being an idle router..

However, since the swap I've noticed several things which completely frazzle me.

• I've installed transmission through optware (thanks for the guide, it worked nicely), but the daemon is unable to peek above 4 MB/s..
• As a matter of fact: All clients behind the N66U seem to not be able to take full advantage of my ISP and all are stuck at ~4 MB/s (usually 2-3, but sometimes it peeks at 4) during download. (So this might be related to point 1 my brain figured..)
• The silly thing is, doing a speedtest results in a proper 59.8 Mbit/sec (where 60 Mbit is my max, so brilliant!), so something seems to go right there as well. However, all other sites, even the ones I know are fast, all get stuck at 4 MB/s. (FTP / HTTP, it does not matter.) It feels like some QoS system is pushing me down, while it is not active as far as the interface can tell me.
• My N66U is attached to a 2 TB HDD via USB 2.0 (although dmesg keeps claiming stuff like usb 1-1.1) and the overall performance is just poor. I have cat6 + gigabit interfaces and still I'm getting an overall connection of around 10 MB/sec.
• Finally: Yes, there are some "slow" devices on my network (like the raspberry pi and a smart tv) so I can imagine some kind of switch / router decided against going gigabit, but still: Isn't hardware advanced enough to determine this based on a connection? (My clients are all connected through a Cisco gigabit switch and "used to have" good connection speeds in the old setup.. I could try connecting one client directly to the LAN ports of the N66U..)

Now I'm not expecting miracles, but I'm just very frazzled and just too unfamiliar with this "get the most out of your router"-thing to be able to understand what the problems are.

So to all you guru's out there: What do you think that might be a problem causing the slow client speeds?

Obviously, I'll post any logs/settings that you guy want, but I'm just about clueless to where to look for it now. I expect it's something very simple like "have you tried enabling <X>?", but if someone could assist I'd be forever grateful.

Update 01/03/2013: I just noticed that my game system (another client) suddenly starts to download Steam games (of all platforms!) at 7 MB/s. Yet torrents are still stuck at 4 MB/s and HTTP transfers speeds also wont go above 4 MB/s. Just to add to the confusion I guess..

 

[Hothersale]

As was explained to me, 10-12 MB/sec is about the best throughput you are going to get with a connected hard drive. It's a limitation of the router itself.

I'd be THRILLED if my torrents got up to 4 MB/s! I don't usually get more than about 1.5 MB/s.

 

[nubyOz]

Hi,

Just to clarify you seem to mix Mb and MB.
getting 4MB(ytes)/s is about 40Mb(its) so in the right ballpark considering overheads.

Cheers

 

[deniaron]

Hi there,

With all respect, not trying to provoke a war here .

I tend to disagree. I've been (hopefully) paying good attention on where to write MB (byte..) and Mbit (the obvious counterpart).

In a nutshell: My previous setup (home server with FreeBSD) gave me me a nice throughput of around 7 MB/s (torrents!) and for a 60 Mbit/s line the theoretical max is 7.5 MB/s if you could eliminate all overheads, which you cant..

You are claiming that 4 MB/s -> 32 Mbit/s is about right provided the overheads. That means I have approx. 28 Mbit/s overhead on my 60 Mbit/s line or, in other words, the RT-N66U "consumes" 46% of my bandwidth as overhead? I find that rather hard to believe.

However, given the fact that only *TP (HTTP/FTP) based downloads for clients and torrents seem to be capped, there seems to be some kind of "limit" I'm reaching. The torrent daemon on the N66U seems to draw out nearly 95% of the CPU while running at 4.5 MB/s, so it mist just be plain game over here.

The *TP based downloads perhaps also need some additional work since they need to be filtered (in comparison to being shot through one specific port), but I'm completely unfamiliar on this territory to make any kind of assumption. Maybe it was just bad luck..

Anyhow, thanks for your input. The investigation continues!

Kind regards,

Deni

 

[KevTech]

In a nutshell: My previous setup (home server with FreeBSD) gave me me a nice throughput of around 7 MB/s (torrents!) and for a 60 Mbit/s line the theoretical max is 7.5 MB/s if you could eliminate all overheads, which you cant..

You are claiming that 4 MB/s -> 32 Mbit/s is about right provided the overheads. That means I have approx. 28 Mbit/s overhead on my 60 Mbit/s line or, in other words, the RT-N66U "consumes" 46% of my bandwidth as overhead? I find that rather hard to believe.

Seems you are comparing a modern setup (server) that most likely had a higher end CPU/more ram to a router which has the CPU/RAM of a desktop used maybe 10 or more years ago.

 

[deniaron]

Seems you are comparing a modern setup (server) that most likely had a higher end CPU/more ram to a router which has the CPU/RAM of a desktop used maybe 10 or more years ago.

You are absolutely correct. However, my question originally was: Is this to be expected? These routers sure came a long way and looking at the consumption vs the "power" of the N66U. (It truly is quite a beast.)

But still, could I expect more given these numbers?

Or should I just accept the way they are. (It's not like I'm really struggling or it's annoying, but still I have the feeling more could be gained.)

 

[got_milk]

7MB/s should be more than achievable with the RT-N66U (the SmallNetBuilder review measured WAN to LAN throughput at 732Mbps!), but it is asking quite a lot of the RT-N66U to perform all the routing functions it needs to, run Transmission, download a torrent and save it to the external drive. It's not shocking you're capping out at 4MB/s on the downloads.

However, if you're capping out at 4MB/s on downloads from computers connected to the router, that indicates a different problem that does need troubleshooting and a fix.

 

[deniaron]

Thank you for your response gotmilk. (And the rest of you obviously as well!)

I was already settling into the idea that the router was "pushed to its limits" and let's be reasonable 4 MB/s is not bad for general usage. So I'll leave that part for what it is. (Just a reminder: I'm most definately not complaining, just wondering! )

As for the second part: I do have the feeling something is off. Therefor I've started the original post to ask if someone has experience discovering what exactly is going wrong.

A quick summary of the symptoms:

- A normal file download using my browser maxes out at 3 MB/s "at most". (Usually 2-2.5 MB/s)
- A FTP transfer conducted by Total Commander (my app of choice) from a trusted server (and thus high speed guaranteed) caps out at 3 MB/s.
- Torrents downloaded by my client caps out 3 MB/s..

It vaguely feels like something is intentionally capping it.

 

[got_milk]

Is this over a wired connection or wireless?

Do you have QoS enabled? If so, are the values for bandwidth correct?

 

[RMerlin]

One thing to keep in mind is that the router's 600 MHz CPU is roughly equivalent to an old Pentium II CPU in terms of speed. Anything that is CPU bound will quickly hit a wall with the router. Torrents are pretty bad, because they have to handle a lot of simultaneous connection attempts, there is disk I/O involved, file hash calculations, etc...

From what I gathered so far, it seems that the USB implementation Broadcom uses is quite weak. I did some raw disk throughput benchmarks (that means running a benchmark tool on the router, and directly accessing the disk, bypassing the filesystem), and the USB performance was capped at 24 MB/s. That explains why SMB performance pretty much caps at around 13-15 MB/s once you add the Samba CPU overhead, filesystem overhead, etc...

 

[deniaron]

Is this over a wired connection or wireless?

Do you have QoS enabled? If so, are the values for bandwidth correct?

No, QoS is disabled. That was the first thing I thought it might have been. However, I have never even enabled QoS, so any "lingering settings" should not be there. (Since it was never activated..)

For the sake of testing I'm using wired connections. The setup I'm testing with is:

Cable Modem --> N66U --> Switch* --> Desktop system (i7, 16Gb ram, etc.)
*(Cisco 8-port gigabit switch, always worked in previous setup)

Also, since my last post I've tried downloading on the desktop system with torrents being disabled. It should not matter afaik and luckily for me: it didnt. Even with transmission disabled a direct FTP download caps at 3 MB/s.

 

[RMerlin]

No, QoS is disabled. That was the first thing I thought it might have been. However, I have never even enabled QoS, so any "lingering settings" should not be there. (Since it was never activated..)

For the sake of testing I'm using wired connections. The setup I'm testing with is:

Cable Modem --> N66U --> Switch* --> Desktop system (i7, 16Gb ram, etc.)
*(Cisco 8-port gigabit switch, always worked in previous setup)

Also, since my last post I've tried downloading on the desktop system with torrents being disabled. It should not matter afaik and luckily for me: it didnt. Even with transmission disabled a direct FTP download caps at 3 MB/s.

Try bypassing the switch to rule out any issue specific to it.

 

[deniaron]

Update

I know it's been a long long time since my last post, but just to create a proper ending for this thread:

I've eliminated the router all together, and performance improved marginally little. (It went from 59.6 Kbit/sec to 59.9 Kbit/sec.) So the router is not draining performance, I was just too focussed on having everything running on the router which probably would have maxed the router out.

However... (there is always a but)
Both the poor performance on torrent department and slow USB connection made me decide to go back to my home server. The initial idea of cost reduction on the electric bill has proven to be very little: e.g. in comparison to my low-energy server home server I was saving about 5 dollars / month in energy. For me personally, that was not worth the sacrifice in speed on my network.

After reinstalling my home server I've regained 7.3 MB/sec downloads on the server and having a proper 75 MB/s samba connection instead of the 7-8 MB/sec which the RT-N66U gave me.

The RT-N66U is now switched to AP mode and is working brilliantly. The switch was effortless. (It still is an amazing device and I've switched back to it during server maintenance with ease..)

So thank you all for helping out and all the best to you!

 

[Jcconnell]

I found this thread while searching for an answer to my speed issues. I'm only getting about 300 -400 kbps down on the Transmission client installed on the router. Its downloading to the internal MicroSD.

I'm trying to determine if these speeds should be expected for the MicroSD and if so, would it speed up if I attached an external HDD. Else, what could my issue be?

 

[CoolDuckie]

You are absolutely correct. However, my question originally was: Is this to be expected? These routers sure came a long way and looking at the consumption vs the "power" of the N66U. (It truly is quite a beast.)

But still, could I expect more given these numbers?

Or should I just accept the way they are. (It's not like I'm really struggling or it's annoying, but still I have the feeling more could be gained.)

You should expect more. I have a fiber-optical connection to the Internet. My N66U connects to this via a 100 megabit Ethernet connection. I get an effective bittorrent download speed of about 6.5 MB/sec over 5 ghz wireless AND over Ethernet if I use my Synology NAS bittorrent client.

CD

 

[guz26]

Hi,

im thinking about to buy this router just for torrents, i have a 10mb internet connection, i can download files using a 1mb/s

i was considering in build a home server, but in Brazil the problem is the price of energy

sometimes i download files with 80gb, i will have some problems?


what is the maximum size of the HDD pluged in this router?

I know it's been a long long time since my last post, but just to create a proper ending for this thread:

I've eliminated the router all together, and performance improved marginally little. (It went from 59.6 Kbit/sec to 59.9 Kbit/sec.) So the router is not draining performance, I was just too focussed on having everything running on the router which probably would have maxed the router out.

However... (there is always a but)
Both the poor performance on torrent department and slow USB connection made me decide to go back to my home server. The initial idea of cost reduction on the electric bill has proven to be very little: e.g. in comparison to my low-energy server home server I was saving about 5 dollars / month in energy. For me personally, that was not worth the sacrifice in speed on my network.

After reinstalling my home server I've regained 7.3 MB/sec downloads on the server and having a proper 75 MB/s samba connection instead of the 7-8 MB/sec which the RT-N66U gave me.

The RT-N66U is now switched to AP mode and is working brilliantly. The switch was effortless. (It still is an amazing device and I've switched back to it during server maintenance with ease..)

So thank you all for helping out and all the best to you!