Exam 350-501 topic 1 question 266 discussion

First line, its has be match-any (either IPv4 or IPv6) not match-all(both IPv4 and IPv6), so exclude option B and C. set ip dscp = IPv4 set dscp = IPv4 + v6 Check the last policy so has to be option D.

Answer: D match-any set dscp default !!(for iPv6)

D is correct 1. match any 2. set ip dscp = IPv4 set dscp = IPv4 + v6

between B and D match all vs match any --- So D wins. it was not catching my eye for a long time :)

In my view it should be 2 options with match-all. we got to match all of the the requirements so include option A and D and exclude option B and C.

3/4 For clarity Option D class-map match-any SELF_TRAFFIC match access-group name SELF_V4 match access-group name SELF_V6 class-map match-all V4_ TRAFFIC match protocol ip class-map match-all V6_TRAFFIC match protocol ipv6 class-map match-all QG_4 match qos-group 4 class-map match-all QG_6 match qos-group 6 ! policy-map LAN-INPUT class V4_TRAFFIC set qos-group 4 class V6_TRAFFIC set qos-group 6 ! policy-map WAN-OUTPUT class SELF_TRAFFIC set dscp cs3 class QG_4 set ip dscp cs1 class QG_6 set dscp default

3/4 For clarity Option C class-map match-all SELF_TRAFFIC match access-group name SELF_V4 match access-group name SELF_V6 class-map match-all V4_ TRAFFIC match protocol ip class-map match-all V6_TRAFFIC match protocol ipv6 class-map match-all QG_4 match qos-group 4 class-map match-all QG_6 match qos-group 6 ! policy-map LAN-INPUT class V4_TRAFFIC set qos-group 4 class V6_TRAFFIC set qos-group 6 ! policy-map WAN-OUTPUT class SELF_TRAFFIC set ip dscp cs3 class QG_4 set ip dscp cs1 class QG_6 set ip dscp default

2/4 For clarity class-map match-all SELF_TRAFFIC match access-group name SELF_V4 match access-group name SELF_V6 class-map match-all V4_ TRAFFIC match protocol ip class-map match-all V6_TRAFFIC match protocol ipv6 class-map match-all QG_4 match qos-group 4 class-map match-all QG_6 match qos-group 6 ! policy-map LAN-INPUT class V4_TRAFFIC set qos-group 4 class V6_TRAFFIC set qos-group 6 ! policy-map WAN-OUTPUT class SELF_TRAFFIC set dscp cs3 class QG_4 set ip dscp cs1 class QG_6 set dscp default

1/4 For clarity Option A class-map match-any SELF_TRAFFIC match access-group name SELF_V4 match access-group name SELF_V6 class-map match-all V4_ TRAFFIC match protocol ip class-map match-all V6_TRAFFIC match protocol ipv6 class-map match-all QG_4 match qos-group 4 class-map match-all QG_6 match qos-group 6 ! policy-map LAN-INPUT class V4_TRAFFIC set qos-group 4 class V6_TRAFFIC set qos-group 6 ! policy-map WAN-OUTPUT class SELF_TRAFFIC set ip dscp cs3 class QG_4 set ip dscp cs1 class QG_6 set ip dscp default

set dscp—Sets DSCP in IP(v4) and IPv6 packets. https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9400/software/release/16-6/configuration_guide/qos/b_166_qos_9400_cg/b_166_qos_9400_cg_chapter_01.html#concept_ww3_gcb_p1b

https://www.cisco.com/c/en/us/td/docs/ios-xml/ios/qos_classn/configuration/xe-16/qos-classn-xe-16-book/ip6-qos-mqc-pkt-cls-xe.html#GUID-78C6AF15-3CD6-4CF4-B4D3-FF755E05C62F To match on IPv6 packets only, use the match dscp command without the ip keyword preceded by the match protocol command.