Bandwidth requirement and Network design

[MrBeginner]

Hi,

I would like to ask about bandwidth calculation .I am confuse somebody said that we need to add ipsec overhead when we calculate the bandwidth requirement.Let say if our application is require 1G bandwidth ,do i need to add to calculate IPSec overhead.Some body told me we need to add 10% bandwidth for IPSec.is it true?

If our application use upload 1 G and download 1 G concurrently,do i need to apply 2 G  ISP link ?

Please see the below diagram let me know your advice which one the best practice in industry  ? Which one we get good performance ?

1.Routing in Server (diagram 1 )

2.Router in L3 switch ( diagram 2)

[Rob Ingram · Accepted solution]

Hi,
Yes there will be additional overhead when encryption is used,10% at a minimum. Depending what algorithms are used (ESP-AES or ESP-GCM) will increase/decrease the IPSec overhead, as would what mode (tunnel or transport) is used.

Don't expect to get 1Gb throughput if you are using encryption.

HTH

[Marvin Rhoads]

Is this a homework question?