Here are some QoS examples configured on a Cisco Catalyst 3550:
\n<\/p>\n
1. mls qos
\n### enables qos globally#######<\/p>\n
2. mls qos cos-map 0 8 16 26 34 46 48 56
\n### maps cos values to dscp values properly######<\/p>\n
3. For IP phones ports, apply the following commands<\/p>\n
int range fa 0\/1 , fa 0\/2
\n#### ip phone ports<\/p>\n
flowcontrol receive off ***** important command********
\nflowcontrol send off *********important command*******<\/p>\n
4. Mapping voice bearer traffic in priority queue<\/p>\n
int fa0\/1<\/p>\n
wrr-queue cos-map 4 5
\npriority-queue out
\n### if asked to put Voice bearer in priority queue<\/p>\n
5. Mapping voice signalling traffic in queue 3<\/p>\n
wrr-queue cos-map 3 3<\/p>\n
6. Port configuration<\/p>\n
interface fa0\/1<\/p>\n
mls qos trust cos
\n#### trusts packet cos
\nmls qos trust device cisco-phone
\n#### trusts cos only if a phone is attached<\/p>\n
switchport priority extend cos 0<\/p>\n
### zeros out PC cos values.<\/p>\n
7. If asked to modify bandwidth and buffer settings for each queue (only then do the following)<\/p>\n
For fastE ports:<\/p>\n
mls qos min-reserve 5 170
\nmls qos min-reserve 6 130
\nmls qos min-reserve 7 51
\nmls qos min-reserve 8 34
\n#### defines min-reserve levels (upto 8 levels may be defined, default buffer size is 100 for all levels)####<\/p>\n
int range fa 0 \/1, fa 0\/2<\/p>\n
wrr-queue bandwidth 20 20 60 1
\n### priority queue doesnt need wrr bandwidth allocation
\nwrr-queue min-reserve 1 5
\nwrr-queue min-reserve 2 6
\nwrr-queue min-reserve 3 7
\nwrr-queue min-reserve 4 8
\n### maps min-reserve levels to queues#####<\/p>\n
For GigE ports:<\/p>\n
int range gi 0\/1 , gi 0\/2
\nwrr-queue queue-limit 60 20 20 1
\n#### defines more buffer space for low priority queue ####
\nwrr-queue bandwidth 20 20 60 1<\/p>\n
8. DSCP maps (optional)<\/p>\n
For gig ports there is a dscp map that maps dscp values to thresholds.
\nEach queue has two thresholds, and by default all dscp values are mapped to threshold 1.
\nIf asked to set voice traffic (may be video) to threshold 2, use command.<\/p>\n
wrr-queue dscp-map 2 26 34 46 (this is higher threshold in the queue)<\/p>\n
9. Tail Drop or WRED (optional)<\/p>\n
For gig ports default drop mechanism is tail drop. Here is how you may modify these thresholds:<\/p>\n
wrr-queue threshold 1 80 100
\nwrr-queue threshold 2 80 100
\nwrr-queue threshold 3 80 100<\/p>\n
### no need to define drop thresholds for queue 4 if its priority queue<\/p>\n
To enable WRED and specify thresholds, use following commands:<\/p>\n
wrr-queue random-detect max-threshold 1 80 100
\nwrr-queue random-detect max-threshold 2 80 100
\nwrr-queue random-detect max-threshold 3 80 100<\/p>\n
### WRED and tail drop are mutually exclusive<\/p>\n
10. Classification using ACLs.<\/p>\n
To classify based on subnet, define standard or extended acl’s.<\/p>\n
access-list 101 permit ip any any dscp 24<\/p>\n
class-map test
\nmatch access-group 101<\/p>\n
11 .Defining Policer and Remarking traffic
\nmls qos map policed-dscp-map 26 46 to 0
\n#### remarks voice control and bearer traffic to dscp 0. (Defined in policer)<\/p>\n
mls qos aggregate-policer TestPolicer 256000 8000 exceed-action policed-dscp-transmit
\n#### defines an aggregate policer with a rate of 256kbps, burst of 8000 bits and remarks dscp for voice and bearer traffic based on above policed-dscp map
\nclass-map match-all Voice
\nmatch ip dscp af31 ef<\/p>\n
policy-map Voice
\nclass Voice
\ntrust dscp
\npolice aggregate TestPolicer
\n#### applies aggregate policer to the class.
\nYou cannot define same policer across multiple policy-maps.<\/p>\n
int range fa 0\/1 , fa0\/2
\nservice policy input Voice<\/p>\n
Example configs:<\/p>\n
1. To define a class-map that remarks traffic:
\n\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014
\nclass-map match-all VoiceControl
\nmatch ip dscp af31
\nclass-map match-all VoiceBearer
\nmatch ip dscp ef<\/p>\n
policy-map Voice
\nclass VoiceControl
\ntrust dscp
\nset ip dscp 40
\nclass VoiceBearer
\ntrust dscp
\nset ip dscp 24
\nint range fa 0\/1 , fa0\/2
\nservice policy input Voice<\/p>\n
2 . To perform per-vlan, per-port classification, marking, policing. (may be required on gateway ports which may be a trunk port)
\n\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014
\nclass-map match-all Voice
\nmatch ip dscp af31 ef<\/p>\n
class-map match-all VoiceVLAN
\nmatch vlan 100 \u2014\u2014\u2014\u2014\u2013 defines which vlan you want to match
\nmatch class-map Voice \u2014\u2014- defines all traffic on voice vlan with dscp af31 or ef.
\npolicy-map Voice
\nclass VoiceVLAN
\ntrust dscp
\npolice aggregate TestPolicer<\/p>\n
#### applies aggregate policer to vlan 100
\nYou cannot define same policer across multiple policy-maps.<\/p>\n
int range fa 0\/3
\nDecription Gateway port
\nservice policy input Voice<\/p>\n
3. To perform individual policing on each class:
\n\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014\u2014-<\/p>\n
mls qos map policed-dscp-map 26 46 to 0<\/p>\n
class-map match-all Voice
\nmatch ip dscp af31 ef<\/p>\n
policy-map Voice
\nclass Voice
\ntrust dscp
\npolice 256000 8000 exceed-action policed-dscp-transmit
\n####This is a individual policer<\/p>\n
int range fa 0\/1 , fa0\/2
\nservice policy input Voice<\/p>\n
Source:
\nCCIE Voice Notes at:
\nhttp:\/\/cciev.wordpress.com\/2006\/05\/25\/qos-templates-for-3550\/<\/p>\n","protected":false},"excerpt":{"rendered":"
Here are some QoS examples configured on a Cisco Catalyst 3550:<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[83,76],"tags":[21],"_links":{"self":[{"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/515"}],"collection":[{"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=515"}],"version-history":[{"count":4,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/515\/revisions"}],"predecessor-version":[{"id":535,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/515\/revisions\/535"}],"wp:attachment":[{"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=515"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=515"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/darenmatthews.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=515"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}