[c-nsp] round-trip differences towards google

[tkacprzynski at SpencerStuart.com]

This relates to google, does anyone know how they do their global DNS resolution? I am having few issues resolving to the closest google datacenter webserver (i.e. Sydney users resolved to US servers [verified by traceroute])?

Thanks



-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Brian Turnbow
Sent: Wednesday, July 08, 2009 7:55 AM
To: Rens; cisco-nsp at puck.nether.net
Subject: Re: [c-nsp] round-trip differences towards google

 
As google is not a single server but a cloud of clusters of servers you are getting routed by a "load balancer" of some sort. 
In a nutshell this is what happens, the IP address 209.85.227.103 is a virtual address that gets sent to various real servers.
As the source address changes the load balancer sends to the request to different real servers. 
It is actually much more complicated, if you search for google infrastructure or google network architecture you can find much more detail. 
The video about how google uses containers in their data center is very interesting. 


Regards

Brian

  


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net [mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Rens
Sent: mercoledì 8 luglio 2009 11.39
To: cisco-nsp at puck.nether.net
Subject: [c-nsp] round-trip differences towards google

Hi all,

 

I'm having some difficulties understand some round-trip difference on the
same router just by changing the source interface:

 

Pings are done towards a resolved IP of www.google.be

 

ping 209.85.227.103 repeat 50

 

Type escape sequence to abort.

Sending 50, 100-byte ICMP Echos to 209.85.227.103, timeout is 2 seconds:

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Success rate is 100 percent (50/50), round-trip min/avg/max = 8/9/12 ms

 

ping 209.85.227.103 repeat 50 source AT3/0.102

 

Type escape sequence to abort.

Sending 50, 100-byte ICMP Echos to 209.85.227.103, timeout is 2 seconds:

Packet sent with a source address of xxx

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Success rate is 100 percent (50/50), round-trip min/avg/max = 8/9/12 ms

 

ping 209.85.227.103 repeat 50 source AT3/0.134

 

Type escape sequence to abort.

Sending 50, 100-byte ICMP Echos to 209.85.227.103, timeout is 2 seconds:

Packet sent with a source address of xxx 

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Success rate is 100 percent (50/50), round-trip min/avg/max = 80/83/88 ms

 

ping 209.85.227.103 repeat 50 source lo0 

 

Type escape sequence to abort.

Sending 50, 100-byte ICMP Echos to 209.85.227.103, timeout is 2 seconds:

Packet sent with a source address of xxx 

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Success rate is 100 percent (50/50), round-trip min/avg/max = 80/83/88 ms

 

Is this google magic depending on my source IP address?

 

Regards,

 

Rens

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