Qos Bandwidth remaining percent command

[k.hariharan1]

Hi,

I want to udersatand exactly what is the use of bandwidth remaining percent command ,

1. The bandwidth remaining percent command takes a percentage of the available bandwidth not from the total reservable bandwidth (100% of the interface). But the bandwidth percent command takes a percentage of the total reserveable bandwidth.

2. Although the bandwidth guarantees provided by the bandwidth and priority commands have been described with words like "reserved" and "bandwidth to be set aside", neither command implements a true reservation. In other words, if a traffic class is not using its configured bandwidth, any unused bandwidth is shared among the other classes.     what about the bandwidth remaining percentage , whether it can utilize the bandwidth of other classes during non conjestion.

For example , if i configure Bandwidth remaining percentage as follows, during non-conjestion time whether the class SAP can able to utilize the bandwidth configured for the other class if there is no bandwidth utilized by other classes.

Class-map voice

match protocol rtp

class-map web

match protocol http

class-map SAP

match access group 101

Policy-map ROOT

class voice

priorty 35%

class web

bandwidth percent 25%

class SAP

bandwidth remaing percent 15%

Interface fa0/0

service-policy output ROOT

Regards,

Hariharan k

[Adrian Lazar · Accepted solution]

Hi Hariharan,

The single difference between  "bandwidth percent" and "bandwidth remaining percent" is that the first  one takes a percent of the total interface bandwidth (by default 75% of  the interface bandwidth is available for reservations) and the second,  takes a percent of the interface bandwidth minus all the reservations done up to that point = remaining interface bandwidth.

Regarding the behavior when no congestion occurs this is the same like with "bandwidth percent" or "priority" commands thus the class configured with "bandwitdh remaining percent" can have all the bandwidth it needs if there is free bandwidth available.If you want to limit a class at all times to a certain amount of bandwidth you must do shaping or policing for that particular class.

Regards,

Adrian

[cadet alain · Accepted solution]

Hi,

1. The bandwidth remaining percent command takes a percentage of the available bandwidth not from the total reservable bandwidth (100% of the interface). But the bandwidth percent command takes a percentage of the total reserveable bandwidth.

the total reservable bandwidth is by default 75% of interface bandwidth and  not 100% like you said but it can be modified with

the max-reserved bandwidth interface command.

2. Although the bandwidth guarantees provided by the bandwidth and 
priority commands have been described with words like "reserved" and 
"bandwidth to be set aside", neither command implements a true 
reservation. In other words, if a traffic class is not using its 
configured bandwidth, any unused bandwidth is shared among the other 
classes.     what about the bandwidth remaining percentage , whether it can utilize the bandwidth of other classes during non conjestion.

these minimum bandwiths are only used when there is congestion and wheter it is configured in percent or remaining percent or bits doesn't change

the way it works.

Regards.

Alain.

[k.hariharan1]

Thanks for your reply.

Regards,

Hariharan k