[ale] PPP Perfromance

[Dow Hurst]

you can try it out by setting all interface on your LAN on both sides of 
the tunnel to 1500 while the tunnel interfaces are set up by the vtun 
docs.  Then pass a large file of ~1Gb measuring avg throughput.  Repeat 
with internal LAN interfaces set at 1412 or 1452.  I don't know the most 
appropriate value but going to the books on TCP/IP packets and seeing 
what the max packet load for an Ethernet packet, a PPP packet 
encapsulated in an Ethernet packet, and a Ethernet packet encapsulated 
in a PPP packet encapsulated in an Ethernet packet would be.  (You get 
the drift! :-) )

I think it would be an interesting experiment especially if the Internet 
bandwidth wasn't too small to see your differences.  Probably a test bed 
of two firewalls running your tunnel with single machines behind each 
firewall would be more definitive.  I understand that no one probably 
has the time or resources to set this up.  Experimenting with MTU on the 
LAN at home is probably good enough to get a rough idea.  1412 was a 
value I had read at one point.
Dow


Christopher Fowler wrote:

>Now you guys have me thinking :)
>
>I have a vtun connection that use ppp.  This connection allows me to connect
>to a rmote location and ping all the machines there.  It basically 
>joins two networks.  To get top perfomance from it should I 
>modify mtu settings on any machine on my and the remote network?
>
>Thanks,
>Chris
>
>
>On Sat, Nov 01, 2003 at 07:20:54AM -0500, Geoffrey wrote:
>  
>
>>Holmquist, Thomas W. wrote:
>>    
>>
>>>How would one set the MRU and MTU on a Linux box running PPPoE?
>>>      
>>>
>>From the 'how-to-connect.txt file at roaring penguin:
>>
>>'If you want to manually configure the LAN hosts, here's how:
>>
>>In Linux, use: "ifconfig eth0 mtu 1452".  For best results, put this
>>in an /etc/rc.d/rc.local script.'
>>
>>So it appears that you do it the same way you would any other ethernet 
>>connection.
>>
>>http://www.roaringpenguin.com/products/rp-pppoe/how-to-connect.txt
>>
>>-- 
>>Until later, Geoffrey	esoteric at 3times25.net
>>
>>Building secure systems inspite of Microsoft
>>
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>>    
>>
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>  
>

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Dow Hurst                  Office: 770-499-3428            *
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