Qos Recommendation

QOS Parameters :----

Total Bandwidth consumption for different Traffic on a particular interface can be Capped to a particular limit .e.g Video Traffic has to be capped with 40% of the available bandwidth on an interface. To specify max. percentage of total bandwidth that a forwarding class can use , configure a transmit rate.

[edit class-of-service]
Schedulers   {
  sched-assure {
      transmit-rate percent 40;

This configuration sets the maximum transmission rate for assured forwarding class to 40% of the available bandwidth on interface.If the total throughput of the link is 1.5Mbps
At most this class will consume 600kbps.

This will help in case where High Priority & Strict Priority are consuming most of the available bandwidth in the Network.This is really helpful in preventing a single application or traffic flow from interface’s entire set of resources.

The second most important resource to cap on an interface is Buffer Size. Buffer refers to available memory on an interface card before they are sent downstream. After Router performs the next-hop lookup , it sends the packets to the interface where they are served on the basis of relative priority of the Queue they belong to. While the Queue is serviced
Packets being sent for transmission are stored up in Buffers. During periods of congestion
When buffers begin to fill new packets being sent on interface can be dropped because there is no place to store them.

However the larger the Buffer Size greater is the delay that is why it is recommended to
put “Strict High Priority” traffic on least “Buffer Size” & all the other Traffic can be on
a bit deeper Buffers.

In the periods of congestion when “Rate of Queuing” exceeds the “Rate of Transmission” these Buffers begin to full .“Drop Profiles” can be configured to cater with the congestion of different
Queue Buffers.

Tail drop profile is a congestion management mechanism that allows switch to drop arriving packets when queue...