QOs detoriation with increase in bandwidth utilisation

Question

we are the MPLS service provider providing MPLS services in India.we notice that Voice quality detoriates as soon as the bandwdith utilisation of the customer links increase more than 60% of link bandwdith particularly with FTP. we have implemented QOS properly. i am told that qos is ineffective if bandwdith utilisation increases more than 60% of link bandwdith. customer should be adviced to increase the bandwdith. Is it true? please help

Answer 1

Hi
AFAIK if u configure strict priority to your voice traffic (i.e.,LLQ for your voice)it shuldnt affect your voice traffic at all regardless to your bandwidth utilsation since it reserves a particular amount of B/W for your voip traffic which again can be configured manually.
The same you can do under your policy map configurations,hope you are having LLQ in place for your voice otherwise would suggest to look onto that and try out the same.
And when theres no congestion thts your h/w queue is ample enough to serve your traffic the software queues will be bypassed (which are manually configured) and if theres some congestion then your S/W queues kicksin.
so in a ideal customer network with voip and other traffic i would go with llq for voip and cbwfq for other traffic based on the traffic patterns using the DSCP,IP Prec values..
to be more precise you can go for LFI also to slice your packets so that your voip packets dont get backlogged..
regds