Limit an Application's Total Bandwidth
Instructions to limit bandwidth allocation for applications
that tend to swell to consume more than their fair share of bandwidth
For example, contain file transfers to 15 percent of WAN capacity. Or
contain music downloads to 2 percent of capacity. Or contain Microsoft
Exchange to 40 percent of capacity. Or contain medical digital images
to 25 percent of capacity. Or, for service providers, contain one bandwidth
customer to the contracted amount.
- The fact that traffic requires a bandwidth limit does not imply anything
about its importance or lack thereof. It says only that it tends to
consume bandwidth to the extent that others' performance is impacted.
- This procedure does not ensure that an individual session will stay
within limits (use a rate policy for that), only that the aggregate
of all sessions stays within limits.
a traffic class (in Sky or Advanced UI) to identify and isolate the traffic you want to
contain, if one does not already exist.
For example, if you want to cap file transfers, then you probably
don't need to do anything because the presence of FTP traffic automatically
prompts PacketWise to create FTP classes. But if you want to limit
file transfers from a certain server, then you'd need to create a
child FTP class that classifies FTP traffic for this server (for example,
a class called Inbound/FTP/ServerName).
For more information, see Traffic Tree Overview (Advanced UI, Blue Coat Sky) and Traffic
- Decide the maximum amount of your WAN capacity you are willing to
devote to your traffic class for each direction. Remember that if the
bandwidth is unused, PacketWise automatically loans it to other traffic
in need, so it's never wasted.
Decide the minimum amount of your WAN capacity that your traffic
requires, even during times of peak congestion. It is not uncommon
to decide on a minimum of zero (0 Kbps) for traffic that is to be
contained or limited. Minimums that are greater than zero are typically
used to protect traffic.
Both these sizes will be used to define a partition to contain your
traffic. For help in determining appropriate sizes, see Sizing
a Static Partition.
a partition to contain the total of all traffic in your traffic
class. Make the partition burstable, and use the minimum and maximum
from previous steps for the partition's field values. Remember to
create partitions for your traffic on both your Inbound and Outbound