WAN Bandwidth Provisioning

[ashish.sehgal1]

How do we decide about the bandwidth required for a new link.

One site has 100 users (Data), no Voice, no Video

Another site has 100 users (Data, Voice, Video)

My knowledge and understanding for Voice & Video users)

• 60-65% concurrent users.
• Voice - 16 kbps
• Video - 64 Kbps
• Data - Application specific (FTP-More bw, SMTP-less bw, Database-More bw)

please help me better understand, Bandwidth Provisioning.

Thanks,

[Philip D'Ath]

I guess start with the most important traffic to you and go from there.

I don't believe for a second that your voice on the wire will only be 16 Kb/s.  Perhaps the raw codec is 16Kb/s.  Lets say it is 24Kb/s on the wire.  If is is going over GRE and/or IPSec then allow even more.

Now how many concurrent calls do you want to allow for?  If it was 60, then you need to allocated 60*24Kb/s for this class, or 1.44Mb/s.

Repeat for concurrent video streams,

Data can have what is left over.  You can also create a "scavenger" class for traffic to throw away more aggressively under congestive load.

[ashish.sehgal1]

is there any formula or way to provision bw requirement for the site having 100 users?

[Philip D'Ath]

You have to understand the applications the users are using.

Write down a list, and how much each one needs for bandwidth.  Multiply it by the number of users, and then apply a percentage based no the concurrency.

In my experience, it often comes down to what a company is prepared to spend, rather than strictly what they need,