From: Scott Morris (smorris@ipexpert.com)
Date: Sun May 04 2008 - 22:32:01 ART
The idea of this is that in a non-congested scenario, the packets still get
priority in terms of the scheduling routine and in terms of bypassing
fragmentation. In a congested scenario, a policer also kicks in to make
sure no traffic above the guaranteed rate occurs.
HTH,
Scott Morris, CCIE4 (R&S/ISP-Dial/Security/Service Provider) #4713, JNCIE-M
#153, JNCIS-ER, CISSP, et al.
CCSI/JNCI-M/JNCI-ER
VP - Technical Training - IPexpert, Inc.
IPexpert Sr. Technical Instructor
Telephone: +1.810.326.1444
Fax: +1.810.454.0130
http://www.ipexpert.com
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of C
Chan
Sent: Sunday, May 04, 2008 8:01 PM
To: Cisco certification
Subject: LLQ traffic behavior if no congestion
Hi Expert,
Can anyone explain how to de-queue traffic assigned to LLQ if there is *no
congestion*? Normally, LLQ traffic use expedited queue to de-queue during
congestion. From Doc CD, the VOIP traffic is allowed to exceed 256kbps if no
congestion. But, will these traffic continue to use expedited queue to
de-queue? Or, it just performs de-queue with normal CBWFQ queues (eg HTTP,
SMTP) per round-robin basis according to allocated bandwidth ratio. If it
is true, low latency of exceed traffic is not guaranteed.
Where I can find cisco doc to discuss the detail of LLQ operation during *
non-congestion*?
*Quote from DocCD*
When the device is not congested, the priority class traffic is allowed to
exceed its allocated bandwidth.
When the device is congested, the priority class traffic above the allocated
bandwidth is discarded.
*Example*
interface BW: 1536k
!
policy-map FR_QOS
class VOIP
priority 256
class HTTP
bandwidth 512
class SMTP
bandwidth 256
!
Regards,
CH
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