Olivier Langlois's blog - Last comments

In response to: A new page in my career

Argh ... I tried to contact you (via your personal email address) in your STW role on 12th May regarding aacPlus streaming problems ... no reply back then ... I guess you were busy handing over.
Would still be grateful if you could get in touch.

In response to: Logitech Quickcam Fusion

Have the same problem with software. After using official software XP becomes unstable.

Now, trying fix this not welcome problem

In response to: TCP RST flag subtleties

Thank you, you are right, the router with IOS Firewall is doing NAT/PAT on the single IP address of the outside T1 interface. So the Google servers will see all users with the same IP address and different TCP port numbers. I will take a look at this some more.

In response to: TCP RST flag subtleties

Hi John,

it seems to be different. In the scenario I am describing, the client TCP/IP stack do receive the server reply. It is the application that do not sees it because a RST is immediately following the reply and is received by the TCP/IP stack before the application has the chance to read the reply from the stack.

This is not the problem that you have because if it was, you would see the reply precedes the RST segment with Wireshark.

In your situation, if you were asking me my opinion, I would suspect your router to be a NAT device and gmail server must have an internal limit that makes it refuse a single IP address to initiate more than a certain number of connections to protect itself against spammers.

I see some avenues to solve the problem:

1. If possible, configure your router to have more than 1 public IP address on the external NIC and make the router NAT module load balance the connections among the available public IP addresses.

2. Here is what my DNS server returns me for gmail.com:

Non-authoritative answer:
Name: gmail.com
Address: 72.14.204.17
Name: gmail.com
Address: 72.14.204.18
Name: gmail.com
Address: 72.14.204.19
Name: gmail.com
Address: 72.14.204.83

You could tweek your DNS server to let it do the load balance for your users.

Please report back here if this has helped you to fix the problem.

In response to: TCP RST flag subtleties

I think I am experiencing the problem you are referring to in this blog.

I should preface my comment by stating that I am not a software programmer, I am a network hardware person who sells, install and maintains Cisco network switches, routers and firewalls for small and medium businesses.

I am troubleshooting an intermittent problem for a client who has about 100 users on gmail. They experiencing intermittent periods where one or more users cannot access their gmail. All other internet traffic (web, etc.)is ok. Resetting the Cisco3825 router firewall on the T1 line clears the problem. I did not believe that this was really a router problem. All sessions are terminated when the router restarts which is probably why it clears.

I have some Wireshark captures from when users are experiencing problems. What I am seeing is an immediate TCP RST coming back from the Google gmail server after the successfull TCP 3 way session initiation for HTTPS. There are no HTTP codes coming back from the server. This repeats over and over.

In response to: What is the C++ SFINAE principle ?

Michal,

To be honest, I had an intellectual understanding of the example I was giving but I have
never bothered to compile it to see if it works until today.

I have tried to compile it with gcc 3.4.4 and I get the same error message. I will try to
find an answer and post it if possible.

Thank you for the comment.

In response to: What is the C++ SFINAE principle ?

Hallo Olivier.
Thank You for Your example.

So far I am trying to understand how it works.

Unfortunatelly I have problem with preliminary step: it does not compile on my linux box (g++ (GCC) 4.3.0 20080428 (Red Hat 4.3.0-8)).

I get the following error:
p41.cpp:12: error: expected primary-expression before ">" token

Line 12 in my program is the following:

enum { Yes = sizeof(IsClassT...::test....(0)) == 1 };

(sorry for modifications in line above, but I couldn't put template parameter T in Your page, because they have a format of tag).

have You got idea why doesn't it compile?

best regards
Michal

In response to: CLOSE_WAIT vs TIME_WAIT

Funny that you asked why in a TIME WAIT state, the time out period is not 2*MSL. Actually, if you look at the diagram of TCP finite state machine (12 states), the Timeout is indicated to be 2MSL (towards the bottom, right next to TIME WAIT state). (In my case, the state digram is in the back inside cover of Inside TCP/IP book by K Siyan).

In response to: UNIX Network Programming: Networking APIs: Sockets and XTI; Volume 1, Second edition

How is the sock variable initialized? It must be a variable returned from the socket() function.

In response to: UNIX Network Programming: Networking APIs: Sockets and XTI; Volume 1, Second edition

hi prasanna i am having a problem with connect function...
i dont know why...
i m giving u the code here..plz help me...

if ((conn=connect(sock,(struct sockaddr *)&server_addr,sizeof(struct sockaddr)))<0)
{
printf("error entered");
getchar();
perror("Connect");
exit(1);
}

the problem is i am having an error like...socket operation on non-socket...
can u help me out...the server program is okay...)

In response to: XML Schema - The W3C's Object-Oriented Descriptions for XML

This is a great book for learning the XSD standard.

Couple this with a good XML Schema Editor like Liquid XML Studio, and you'll learn the basics of the standard in no time.

The split code/diagram view provides the feedback required to quickly learn the effects on the XSD code as the documents structure changes.

In response to: AAC ADTS header buffer fullness field

Great information, thanks! Good to know I probably won't break decoders by setting it to all ones.

In response to: CLOSE_WAIT vs TIME_WAIT

when does TCP connection goes into FIN_WAIT on LINUX. what it is waiting for.on linux it is not able to detect that the peer is longer (if we disable LAN Connection ) where as on windows it immediatly detect what the difference is can anybody help.

In response to: CLOSE_WAIT vs TIME_WAIT

Nice write up. I was confusing CLOSE_WAIT with FIN_WAIT_2 but it seems clear that close wait is, as you put is "waiting for close."
Take care.
-R

In response to: Rock Band on Nintendo Wii?

Hi there, in case you own Rock Band you may wanna unlock all the songs.

http://www.danielpoon.com/lifehacking/2008/07/04/wii-rock-band-unlock-all-songs/

In response to: AAC versus MP3

Velvet,

As far as I know (and I am starting to know AAC very well), there is no protection related to DRM included in AAC. It is just another method for compressing audio which happens to do a better job than MP3 for the same bitrate.

In response to: AAC versus MP3

I am not quite deep in this subject, but in my opinion one of the main reasons why AAC has appeared is DRM.

PS:
I found your review on Amazon.ca and then I got your site. I need to say, you have made a great job by sorting and reviewing all these books. Thank you! Now your site is added to my bookmarks!

In response to: Logitech Quickcam Fusion

The Logitech QuickCam Fusion's design looks sleek, slightly blurry video and pixilated image but has a good built microphone. I thought the software package was good but did had some minor issues with yahoo integration.

In response to: Cross console online gaming

I couldn't agree more with you, Olivier. In our Gamer Connect blog we were having the same discussion. In fact I even linked to your post from one of the comments: http://gamerconnect.blogspot.com/2008/03/gamerconnect-xbox-360-online-events.html

In response to: Rock Band on Nintendo Wii?

Hi Daniel,

Except for what I describe in the original post, I have no other insights yet.

Stay tuned.