I need a clarification for bandwidth management

[R Manjunatha]

How to calculate bandwidth for 100 users in IT infrastructures. 

[balaji.bandi]

Its hard to calculate that way. depends on what they use application and services. some time i seen even single user 1GB bandwidth not good enough, so its hard to say here.

in other way, when you mentioned bandwidth for Internet ? or Intranet ?

[R Manjunatha]

Yes, its bandwidth for the Internet

This is one of the interview questions and I told clearly based on the application & service 

[balaji.bandi]

It all depends on how you manage the network, sometimes 10MB works for all 100users, and some 5 users consume 1GB also.

[Georg Pauwen]

Hello,

typically, you would deploy a quality of service strategy that would guarantee each user a certain amount of bandwidth, and if that bandwidth is unused, it would be available to the other others. The example below specifies a parent-child shaper, in which each class gets 1MB of bandwidth, guaranteed, and if that bandwidth is not used, it is available for all other users. The total bandwidth of 100MB is shaped in the parent default class.

policy-map CHILD_SHAPER
class CLASS_1
priority 1024
class CLASS_2
priority 1024
class class-default
fair-queue
!
policy-map PARENT_SHAPER
class class-default
shape average 10240000
service-policy CHILD_SHAPER

[Joseph W. Doherty]

As the other posters have already noted, it can be a bit difficult, but there are lots of methods that may help in such a calculation.  As an alternative, network equipment vendors and ISPs might also guide you in this area, using their tried and true question (in Latin) quid potes praestare?  ; )