11-23-2007 12:48 AM - edited 03-03-2019 07:39 PM
Hi all,
What's different between CBWFQ and DSCP. If use Sup32 in 7604, it seems CBWFQ not
support and DSCP is the only choice. Any sample configuration on it ?
Thx!
11-23-2007 02:37 AM
Hi,
CBWFQ and DSCP are different concepts. CBWFQ is a queing tool that reserves bandwidth for defined queues. DSCP is a 6-bit-field in the IP header carried end-to-end with default conditions/configurations. DSCP marks packets for the future actions on queues.
Also you can set DSCP values anytime with a route-map(CB marking) when CEF is enabled.
For instance, you can use DSCP values while configuring CBWFQ like below;
Router(config)# class-map class-xx
Router(config-cmap)# match ip dscp 30
Router(config-cmap)# exit
Router(config)# class-map class-yy
Router(config-cmap)# match ip dscp 10
Router(config-cmap)# exit
Router(config)# policy-map policy-zz
Router(config-pmap)# class class-xx
Router(config-pmap-c)# bandwidth percent 30%
Router(config-pmap-c)# exit
Router(config-pmap)# exit
Router(config)# class class-yy
Router(config-pmap-c)# bandwidth 20000
Router(config-pmap-c)# exit
Router(config)# interface xa/b
Router(config-if)# service-policy output policy-zz
Router(config-if)# exit
11-23-2007 03:38 AM
Hi,
- DSCP (Differentiated Service Code Point) is a field in the IP packet header used for packet classification and marking, so each application (voice, video, mission-critical, transactional, best-effort, â¦) is given a DSCP value (marked) according to which it is classified.
- CBWFQ (Class-Based Weighted Fair Queuing) is an advanced software queuing mechanism based on WFQ with the support of user-defined traffic classes, CBWFQ classification is performed using the Cisco MQC (Modular QoS CLI) and applied only to output queue.
CBWFQ is used to classify data and the combination with a strict priority queue form LLQ (Low-Latency Queuing) which allow to optimally handle voice traffic and data traffic.
- Take a look at the enclosed pictures which I hope will give you an idea about those concepts.
Here is an example of MQC where different type of traffic (voice, http, streaming video and ftp) are classified by classes (CBWFQ for data + strict-priority for voice=LLQ), marked and given special treatment according to their DSCP marking.
****
class-map match-all sip-voice-policy
match protocol rtp
set ip dscp ef
class-map match-all http-policy
match protocol http
set ip dscp af11
class-map match-all rtspplayer-policy
match ip dscp default
set protocol rtsp
class-map match-all ftp-policy
match protocol ftp
set ip dscp af21
policy-map mypolicy
class sip-voice-policy
set ip dscp ef
priority 500
class ftp-policy
set ip dscp af21
bandwidth 150
random-detect dscp-based
class http-policy
set ip dscp af11
bandwidth 100
random-detect dscp-based
class rtspplayer-policy
set ip dscp default
bandwidth 50
queue-limit 50
interface Serial0/0
service-policy output mypolicy
****
- For more details about MQC: http://www.cisco.com/en/US/products/sw/iosswrel/ps5014/products_feature_guide_chapter09186a008008813a.html
- I know that both 7600 Optical Service Module (doesn't seem to be supported on sup32) and FlexWAN module (supported on sup32) with MSFC and PFC support CBWFQ.
- Qos on FlexWAN:
I hope this will help!
Abdel
11-23-2007 03:43 AM
11-23-2007 03:57 AM
Excellent diagram
It talks about complete queuing and Qos
11-25-2007 02:20 AM
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