Is my connection problems due to "UP BROADCAST RUNNING MULTICAST"?
 

Hi all.

I have kubuntu 9.10 on my laptop. My question is regarding the wireless connection.

I have a wireless modem (NOT a router) that I connect to.

When I startup kubuntu and choose my (wireless) network to connect to through the network manager, I get an unstable and sluggish download speed.

It is a good speed for a few seconds (sometimes even longer) but then it hits rock bottom (really no download at all) for many seconds. Then it goes up again for a few seconds, just to go back to zero again, and so on. This keeps repeating forever.

A screenshot of system monitor's network diagrams would really show mountains intervened by flat valleys.

I took note of relevant parts of ifconfig's and iwconfig's outputs.

Then I do

ifconfig wlan0 down
ifconfig wlan0 up

after that I choose my wireless network to connect to through the network manager again.

Now I have excellent and stable download speed. No problems at all (unless the speed can even be better than what I observe but I doubt this).

Now, remember I said I took note of ifconfig's and iwconfig's outputs? Well I produce their outputs again and the only difference I can observe is that ifconfig says "UP BROADCAST RUNNING MULTICAST" for wlan0 instead of "UP BROADCAST MULTICAST" as it said for the same interface before I did ifconfig down and up.

QUESTION 1: Is the broacast-thingie what's causing my troubles? What is it anyway?

If I restart kubuntu then I have the same problem going on again.

QUESTION 2: How can I fix this permanently?

Thx!

//PureRumble

/proc/net/wireless

#man iwconfig

you can tweak many things : freq, bit rate ...

Hi,

How about sharing the outputs?

Does no good for a description since there is possible omissions or misdiagnosis.

The modem your are using is a broadband or DSL with a wireless device?
:hattip:

Hi! Thx for helping out!

It is a DSL wireless modem, and like I said before it is not a router.

Now I'll give some output!

Recall that the problem (sluggish download speed) goes away after I have done ifconfig wlan0 down followed by ifconfig wlan0 up (I obtain a stable download speed). I wanna know why so I can make the change permanent!

So here is the output of ifconfig & iwconfig before I do ifconfig wlan0 down & up:

output of ifconfig:
output of iwconfig:
And here is the output of ifconfig & iwconfig after that I've done ifconfig wlan0 down & up.

output of ifconfig:
output of iwconfig:
Does this tell you guys why the problem all of a sudden goes away? Do you need me to share anymore output?

Thx for reading!

//PureRumble

Bump + an update.

I don't think this is related to security settings, since I changed the protocol from WEP to WPA PSK and the problem still remains.

So I just wanna know why doing ifconfig wlan0 down+up solves this problem.

Anyone?

When i do:- ifconfig

It reports the same thing as you. I don't think its a problem.

Use

sudo dhclient eth0

then internet will work.

Once you use other modes to use internet (like wireless, usb tethering) and get to ethernet, you may get this problem. I had same problem and it was solved using above command.

Thanks,
PT

I can see no significant differences in the output from ifconfig/ifwonfig before and after you took the interface down and back up. If anything, the reported link quality was better before the interface reset.

Disabling and re-enabling the interface will cause entries in the routing table to be removed and re-inserted. In your case, it will also cause some background daemon to renew the DHCP lease and thereby re-insert the default gateway entry.

Could you post the output from route -n before and after you reset the wlan0 interface?