DI 624 revC- severe wireless latency after consistent throughput

Hi,

I've purchased a DI 624 revC while searching for a replacement router
for my Netgear WGR614 v1. I've noticed though that after about 6-7
hours of consistent use, the DLink router starts becoming sluggish over
the wireless connection. The wireless client would initially see pings
fluctuate between 20-70ms. And after about 10minutes after that it
would hit 200ms-400ms consistently. This tended to happen more quickly
when there was consistent throughput on the router (eg. online games,
BitTorrent, other P2P apps). Actually more specifically BitTorrent and
P2P apps sped up the process more quickly causing this problem to
surface in a matter of an hour or so.

I did read up on problems where the router would reboot when using
BitTorrent. I haven't encountered that problem however. I'm using the
latest firmware which claims to have fixed the problem. My setup:

DI-624
(Firmware v2.70)
WEP enabled

WMP54G
(Driver version 3.0.3.0)

Other than this problem and some WPA problems, the router is blazing
fast. Does anyone have any ideas what might be causing this?

Thanks.
K

On 26 Sep 2005 13:53:52 -0700, (E-Mail Removed) wrote:

>Hi,
>
>I've purchased a DI 624 revC while searching for a replacement router
>for my Netgear WGR614 v1. I've noticed though that after about 6-7
>hours of consistent use, the DLink router starts becoming sluggish over
>the wireless connection. The wireless client would initially see pings
>fluctuate between 20-70ms. And after about 10minutes after that it
>would hit 200ms-400ms consistently. This tended to happen more quickly
>when there was consistent throughput on the router (eg. online games,
>BitTorrent, other P2P apps). Actually more specifically BitTorrent and
>P2P apps sped up the process more quickly causing this problem to
>surface in a matter of an hour or so.
>
>I did read up on problems where the router would reboot when using
>BitTorrent. I haven't encountered that problem however. I'm using the
>latest firmware which claims to have fixed the problem. My setup:
>
>DI-624
>(Firmware v2.70)
>WEP enabled
>
>WMP54G
>(Driver version 3.0.3.0)
>
>Other than this problem and some WPA problems, the router is blazing
>fast. Does anyone have any ideas what might be causing this?
>
>Thanks.
>K

Latency going from 20-70ms to 200-400ms under heavy use is NOT a
problem, it's just how things are on a router that does not employ
QoS. Specifically, you must ensure that your upstream is not saturated
to the point where it is lagging ACK responses. The combined internet
usage of all your applications on all the computers hooked to the
router should not exceed ~75% of your upstream at any time. This is
kind of hard to do manually if you are consuming bandwidth agressively
on more than one comp.

A better replacement to your router might have been this one:
http://games.dlink.com/products/?pid=370
even though it implements QoS only on a limited basis.

(E-Mail Removed) wrote:
>I've noticed though that after about 6-7
>hours of consistent use, the DLink router starts becoming sluggish over
>the wireless connection.

>I did read up on problems where the router would reboot when using
>BitTorrent.

I had every low-end router I tried fall over with heavy use on Verizon
FIOS (30M/2M) with the exception of the supplied DI-624, which is
running a specific firmware (2.43DDM) which apparently avoids this
problem. You used to be able to download this from the Verizon FIOS
support site, but now it requires IE6, ActiveX controls, and all sorts
of ugly stuff.

Oh, wait, someone found a more direct pointer:

http://www2.verizon.net/micro/dlink/Default.asp?

The latency I measured was from the wireless client to the router. When
we measured this latency the only program that was running was World of
Warcraft. I can guarantee that World of Warcraft did not saturate an
802.11g connection. That is a problem. We're very careful of watching
our upstream. I'm aware of latency introduced by this and I'm fairly
certain that this isn't it.

Thanks though.

Interesting. Thanks. I may give that a go. No other router seems to be
working. Unfortunately my aged WGR614v1 is running better than the
rest. It just lacks some of the newer security features. :/

On 26 Sep 2005 17:10:30 -0700, (E-Mail Removed) wrote:

>The latency I measured was from the wireless client to the router.

That can't be correct. Wireless latency between the client and the
router should be about 1-3msec. At a 54Mbit/sec connection, ping
usually shows zero latency when I ping the router. You were getting
20-70msec which is what I would expect if you were pinging something
on the internet over a partially congested broadband connection.
Could you describe how you got latency numbers?

>When
>we measured this latency the only program that was running was World of
>Warcraft. I can guarantee that World of Warcraft did not saturate an
>802.11g connection. That is a problem. We're very careful of watching
>our upstream. I'm aware of latency introduced by this and I'm fairly
>certain that this isn't it.

Playing games for 6 or 7 hours? Slacker. I wished I had time for
that.

How much of your upstream are you normally using? Most of the games
I've seen send data in bursts during which they saturate the outgoing
bandwidth. You don't see that because the traffic statistics are
averages. However, if you tried to ping something on the internet
while there bursty traffic, you would see very wide variations in ping
times.

Any chance that Windoze Update, NAV update, MS Anti-Spyware, etc were
doing updates when you were testing after 6-7 hours?

My guess(tm) is that you may have found a bug or problem in the
DI-624. However, if reproducing the problem requires 6 hours of
traffic, it's going to be difficult to identify. If possible, borrow
a different brand or model router and try it instead. If it also does
the same thing, then there's something wrong with how your testing,
with your assumptions, or with your client computers. That doesn't
solve the problem, but at least it narrows down the potential
culprits.



--
Jeff Liebermann (E-Mail Removed)
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558

> Could you describe how you got latency numbers?

The latency measurements were from pinging the router from the wireless
client (ping 192.168.0.1). Pretty simple test. Of course pinging
external sites had higher latency but the brunt of the latency was
between the router and the wireless client. My wired client was pinging
<1ms the entire way. Resetting the router was the only option to
restart this process and the wireless client would then ping between
1ms-3ms, which is what I would expect.

> How much of your upstream are you normally using?

I have a 800Kbit upstream on my DSL modem. On average we're only using
about 20KB/s up. I like to keep a good buffer zone as I tend to host a
website on that connection as well. The reason why I'm quite confident
that it's not us choking the upstream is that if the upstream was
choked, my wired client would have the same problem. Moreover, the
wireless client wouldn't be experiencing lag to the router alone.
54Mbit is quite a bit larger than an 800Kbit connection. It would take
a lot to saturate that.

For the more intensive games like FPS games, the burst data rate
typically won't ever exceed 10KB/s per client unless the server is
configured to accept higher data rates. I've run a UT server before and
typical usage is 6-8KB/s for a smooth gameplay feel. Of course you can
ramp this up if you'd like but it's harder to notice the differences.
In any case, I doubt the games we're playing are eating up that much
bandwidth. I played the same game with two wired clients and the
bandwidth did not saturate.

> Any chance that Windoze Update, NAV update, MS Anti-Spyware, etc were
> doing updates when you were testing after 6-7 hours?

All of the auto update features are disabled on my computer. I hate
being interrupted by those features. Although I should check with my
roommate's computer. I'm pretty sure he does the same, but I'll verify.
I still can't quite come up with a reason as to why that would cause
high latency between the wireless client and router though.
Specifically if the DSL modem is the bandwidth chokepoint and not the
wireless connection.

> However, if reproducing the problem requires 6 hours of
> traffic, it's going to be difficult to identify.

Actually I can speed up the process by running a P2P app. Typically
BitTorrent can get this reproduced in under an hour. I've seen many
posts about people's DI624 routers being reset after consistent
throughput, but I haven't seen that actually happen to me. It's just
the wireless client that gets this insane latency to the router that
kills me. I've tried 2 DI624 routers from different stores and tried
nearly all permutations of settings (I really wanted to get it working
:P It's so damned fast.).

I have tried different brands as well. Linksys is one. Those had its
own assortment of problems (packet loss). Currently I'm back to my
WGR614v1 Netgear router which has been surprisingly the most reliable
wireless G router I've used. It has none of these problems. Well it
does get the latency problem but only after 2months of use. I'm pretty
sure it's something to do with DNS caching on the router as enabling
the DNS relay on the router speeds up that process as well. But I can
specify the DNS servers directly through the connection and I don't
have to bother resetting the router for a couple months.

On 27 Sep 2005 14:20:33 -0700, (E-Mail Removed) wrote:

>> Could you describe how you got latency numbers?
>
>The latency measurements were from pinging the router from the wireless
>client (ping 192.168.0.1). Pretty simple test. Of course pinging
>external sites had higher latency but the brunt of the latency was
>between the router and the wireless client. My wired client was pinging
><1ms the entire way. Resetting the router was the only option to
>restart this process and the wireless client would then ping between
>1ms-3ms, which is what I would expect.

1-3msec is normal. If it creeps up to 20-70msec, then there's
something seriously wrong. Unfortunately, I don't know exactly what.

>> How much of your upstream are you normally using?
>
>I have a 800Kbit upstream on my DSL modem. On average we're only using
>about 20KB/s up.

Bits and bytes? b=bits, B=Bytes. 20KB/sec is 160Kbits/sec. However,
that's sufficient headroom out of 800Kbit/sec to not impact the
latency very much. That's not the problem.


>Moreover, the
>wireless client wouldn't be experiencing lag to the router alone.
>54Mbit is quite a bit larger than an 800Kbit connection. It would take
>a lot to saturate that.

54Mbits/sec is the wireless connection speed, not the thruput. At
best, you'll get about 25Mbits/sec thruput with a 54Mbit/sec
connection. That's still way more than 800Kbits/sec, so again, that's
not the problem.

>In any case, I doubt the games we're playing are eating up that much
>bandwidth. I played the same game with two wired clients and the
>bandwidth did not saturate.

Well, the traffic is not going through the router section of the
DI-624 when you're playing just locally. If a local wireless client
to client game works as expected, then it's not the wireless part of
the puzzle. That leaves the DI-624 router section.

>All of the auto update features are disabled on my computer.

So much for that idea.

>> However, if reproducing the problem requires 6 hours of
>> traffic, it's going to be difficult to identify.

>Actually I can speed up the process by running a P2P app. Typically
>BitTorrent can get this reproduced in under an hour.

What's unique about BitTorrent is that it opens up as many parallel
streams as it can to move its traffic. My guess(tm) is that the
DI-624 can only handle about 32 streams before it complains.
BitTorrent might be trying to open more. If you're running it
"unchoked", it can easily open more, especially on a high bandwidth
connection. There are some clues here:
http://groups.yahoo.com/group/the_gdf/message/21143
but I won't pretent to understand all the BitTorrent unique buzzwords.
If there's a setting to reduce the number streams, connections, users,
or such, you might want to try it. My guess(tm) is that your game
might also be trying to do the same thing.

>I've seen many
>posts about people's DI624 routers being reset after consistent
>throughput, but I haven't seen that actually happen to me. It's just
>the wireless client that gets this insane latency to the router that
>kills me. I've tried 2 DI624 routers from different stores and tried
>nearly all permutations of settings (I really wanted to get it working
>:P It's so damned fast.).
>
>I have tried different brands as well. Linksys is one. Those had its
>own assortment of problems (packet loss). Currently I'm back to my
>WGR614v1 Netgear router which has been surprisingly the most reliable
>wireless G router I've used. It has none of these problems. Well it
>does get the latency problem but only after 2months of use.

Have you tried a different client computah or wireless device? If
juggling all those wireless routers doesn't yield an improvement, then
it's possible that the problem is being caused by the client, not the
router. I guess you could test the client with a different setup, but
sitting at Starbucks for 6-7 hours playing games may not be a great
idea.

>I'm pretty
>sure it's something to do with DNS caching on the router as enabling
>the DNS relay on the router speeds up that process as well. But I can
>specify the DNS servers directly through the connection and I don't
>have to bother resetting the router for a couple months.

Well, that's really odd because DNS timeouts are usually around 30-45
seconds and not in milliseconds. Windoze clients also cache DNS
lookups for about 24 hours for a successful lookup and 5 minutes for a
failed lookup:
http://vlaurie.com/computers2/Articles/dnscache.htm
If that has an effect, I'm lost. I don't have a clue why the DNS
cache would affect ping latency, especially since you're pinging by IP
address which does not require a DNS lookup.

Weird...


--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice Skype: JeffLiebermann
# http://www.LearnByDestroying.com AE6KS
# http://802.11junk.com
# (E-Mail Removed)
# (E-Mail Removed)

On Tue, 27 Sep 2005 22:38:24 GMT, Jeff Liebermann
<(E-Mail Removed)> wrote:

>>I'm pretty
>>sure it's something to do with DNS caching on the router as enabling
>>the DNS relay on the router speeds up that process as well. But I can
>>specify the DNS servers directly through the connection and I don't
>>have to bother resetting the router for a couple months.
>
>Well, that's really odd because DNS timeouts are usually around 30-45
>seconds and not in milliseconds. Windoze clients also cache DNS
>lookups for about 24 hours for a successful lookup and 5 minutes for a
>failed lookup:
> http://vlaurie.com/computers2/Articles/dnscache.htm
>If that has an effect, I'm lost. I don't have a clue why the DNS
>cache would affect ping latency, especially since you're pinging by IP
>address which does not require a DNS lookup.

Ooops. I forgot that some versions of ping *DO* run a DNS lookup for
every last lousy ping packet. For ping by IP address, it does a
reverse DNS lookup. I know SCO Unix OSR5 and the BIND derived
utilities do that. If the DNS lookup from the cache in the DI-624 is
delayed, so will the ping results. If the system is really screwed
and DNS has to go to the root domain servers to walk down the tree to
the authoritative servers each time, then it would easily take the
70msecs you've observed. However, methinks that's unlikely.

I'm not sure if Windoze ping also does a DNS/RDNS lookup, but I can
sniff the traffic and see for my myself, later. So, maybe there
really is a connection between DNS and slothish pings. However, I
doubt that would affect game traffic that does not require more than
an ocassional DNS lookup.

--
# Jeff Liebermann 150 Felker St #D Santa Cruz CA 95060
# 831.336.2558 voice Skype: JeffLiebermann
# http://www.LearnByDestroying.com AE6KS
# http://802.11junk.com
# (E-Mail Removed)
# (E-Mail Removed)

>What's unique about BitTorrent is that it opens up as many parallel
>streams as it can to move its traffic. My guess(tm) is that the
>DI-624 can only handle about 32 streams before it complains.
>BitTorrent might be trying to open more. If you're running it
>"unchoked", it can easily open more, especially on a high bandwidth
>connection. There are some clues here:
> http://groups.yahoo.com/group/the_gdf/message/21143
>but I won't pretent to understand all the BitTorrent unique buzzwords.
>If there's a setting to reduce the number streams, connections, users,
>or such, you might want to try it. My guess(tm) is that your game
>might also be trying to do the same thing.

That might be it. It's worth a shot at this point. I'll check to see if
I can control the number of streams. One thing that is odd though is
that once the router acts up, it does so for a long time regardless of
activity between the wireless client and router. After a day or so (I
didn't time it exactly, but it eventually went down after we just
stopped using the connection), it went back to normal until another
game or P2P client was run. This time though it would immediately jump
back to high latency instead of waiting 1 hr for BitTorrent or 6-7hrs
for games.

>but sitting at Starbucks for 6-7 hours playing games may not be a great
>idea.

I disagree. :P

>Well, that's really odd because DNS timeouts are usually around 30-45
>seconds and not in milliseconds. Windoze clients also cache DNS
>lookups for about 24 hours for a successful lookup and 5 minutes for a
>failed lookup:
> http://vlaurie.com/computers2/Articles/dnscache.htm
>If that has an effect, I'm lost. I don't have a clue why the DNS
>cache would affect ping latency, especially since you're pinging by IP
>address which does not require a DNS lookup.

I wouldn't be surprised if it was just a firmware problem. It was
Netgear's first attempt at a wireless G router. They've switched chips
so many times under this product. I'm tempted to try out a later
version of the same router as it does seem to be the most stable thus
far. I just want to clarify one thing. The DNS problem is a separate
issue with my Netgear WGR614v1 router. Not the DI 624.

Essentially (as you've seen my other post as well), I've tried out the
following routers:

DI 624
WRT54GS v2
WRT54GC v1
WGR614 v1

Each one has had its own problems:

DI 624 - wireless latency between wireless client and router after
consistent throughput
WRT54GS v2 - wireless packet loss
WRT54GC v1 - severe wireless packet loss
WGR614 v1 - wireless latency between wireless client and router after 2
months of use.

The WGR614 v1 (Netgear) has been the most reliable and it is the one
that I believe suffers some problem with the DNS relay. I haven't had a
whole lot of luck with wireless G routers thus far. We'll see if I can
resolve this. It's a real bummer that everything I try has a problem in
one form or another.

Thanks again for the help.