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New Member

LLQ, CBWFQ Question

Hello people I have this big confusion on mind.

My question is LLQ reserves strictly Bandwidth when a class is applied to a policy.

Example if I have a 512 Kbps link to some place

and doing this at router config:

policy-class Victor

class VOIP

Priority 300

interface serial 0/0

service-police output Victor

Will reserve 300 Kbps from my 512 Kbps. So all the traffic that is not matched in the class VOIP will have only to deal with 200 kbps even if there is no congestion on the link???

I know that CBWFQ apply the reserved bandwitdh when a congestion occur.

Please read the Above from the New BCRAN Book.

It is also important to remember that regardless of the queuing method that is employed, in most

cases, it never actually functions unless the egress interface is busy. If an interface is not stressed,

and there is no outbound packet congestion, then the queuing strategy is not applied (LLQ is the

exception to this rule). It you want the queuing policy to work at all times, you must adjust the

outbound hardware buffers to make it appear that the interface is always busy.

2 REPLIES
New Member

Re: LLQ, CBWFQ Question

QoS only kick in when you experience the congestion. Without congestion, you have all bandwidth for all application, there is no restriction.

/Beng

New Member

Re: LLQ, CBWFQ Question

Beng, then the book is wrong ?

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