OpenWrt Forum Archive

Topic: Is this bitrate too slow?

The content of this topic has been archived on 2 Apr 2018. There are no obvious gaps in this topic, but there may still be some posts missing at the end.

Hi,
I bought a new TP-Link TL-WR841ND v.8.1 today and installed OpenWrt (http://downloads.openwrt.org/attitude_a … actory.bin) on it. What I'm wondering now is, if something is wrong because the router is declared as providing 300Mbps but on LuCI I see:

Generic 802.11bgn Wireless Controller (radio0)
Channel: 9 (2.452 GHz) | Bitrate: 25.2 Mbit/s

And for the clients the rx rates shown are 55-65 Mbit/s and tx rates are about 25-30 Mbit/s.

My WLAN-config is:

config wifi-device 'radio0'
    option type 'mac80211'
    option macaddr XYZ
    option hwmode '11ng'
    list ht_capab 'LDPC'
    list ht_capab 'SHORT-GI-20'
    list ht_capab 'SHORT-GI-40'
    list ht_capab 'TX-STBC'
    list ht_capab 'RX-STBC1'
    list ht_capab 'DSSS_CCK-40'
    option txpower '20'
    option country 'US'
    option channel '9'
    option htmode 'HT40-'
    option noscan '1'

config wifi-iface
    option device 'radio0'
    option network 'lan'
    option mode 'ap'
    option encryption 'psk2'
    option key XYZ
    option ssid XYZ

Shouldn't the bitrate be much higher?

push

It only goes as fast as it needs, within the limit of the environment and client adapters.  If the device is 2.4 only the likelihood of breaking 150 in real world conditions is very limited.

300 is the theoretical maximum speed.
Depending on your broadband provider, the numbers you see are fairly reasonable.
As a comparison, what were you getting with the original firmware?
What does speedtest.net tell you?

You're never going to see 300 Mbps from any 802.11n router out there on a single, 20-MHz channel. These days the "Nxxx" claims are based on the double-wide channels, multiple client streams, and/or two bands supported by 802.11n. Further, the modulation rates reported by the link are not going to be the usable throughput of the link.

Here is some more information on the various modulation rates: http://en.wikipedia.org/wiki/IEEE_802.1 … Data_rates

(Last edited by jeffster on 11 Apr 2013, 17:07)

You'll notice that the OP *is* trying to use double wide channels as he has the following entries in his wifi config:

option htmode 'HT40-'
option noscan '1'

The Bitrate: 25.2 Mbit/s and client tx / rx rates are consistent with what I see on my v8.0 TL-WR841ND with the same firmware. I am also disappointed with this throughput and strongly suspect the double-wide channels are not working. The HT40- or HT40+ options make no measurable difference compared to a single channel wide configuration.

My broadband gives upto 60 Mb/s down 6 Mb/s up and using another router I can see upto 130 Mbits/s throughput on the clients.

I will point out that using noscan is dumb since you can programmatically plug your ears, but it won't stop the interference from those other devices.

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