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CISC-RT-000760 - The Cisco PE router must be configured to enforce a Quality-of-Service (QoS) policy to provide preferred treatment for mission-critical applications - QoS policy in accordance with the QoS DODIN Technical Profile.

Information

Different applications have unique requirements and toleration levels for delay, jitter, bandwidth, packet loss, and availability. To manage the multitude of applications and services, a network requires a QoS framework to differentiate traffic and provide a method to manage network congestion. The Differentiated Services Model (DiffServ) is based on per-hop behavior by categorizing traffic into different classes and enabling each node to enforce a forwarding treatment to each packet as dictated by a policy.

Packet markings such as IP Precedence and its successor, Differentiated Services Code Points (DSCP), were defined along with specific per-hop behaviors for key traffic types to enable a scalable QoS solution. DiffServ QoS categorizes network traffic, prioritizes it according to its relative importance, and provides priority treatment based on the classification. It is imperative that end-to-end QoS is implemented within the IP core network to provide preferred treatment for mission-critical applications.

NOTE: Nessus has provided the target output to assist in reviewing the benchmark to ensure target compliance.

Solution

Configure to enforce a QoS policy to provide preferred treatment for mission-critical applications.

Step 1: Configure class-maps to match on DSCP values as shown in the configuration example below.

RP/0/0/CPU0:R2(config-cmap)#class-map match-all C2_VOICE
RP/0/0/CPU0:R2(config-cmap)#match dscp 47
RP/0/0/CPU0:R2(config-cmap)#class-map match-all VOICE
RP/0/0/CPU0:R2(config-cmap)#match dscp ef
RP/0/0/CPU0:R2(config-cmap)#class-map match-all VIDEO
RP/0/0/CPU0:R2(config-cmap)#match dscp af41
RP/0/0/CPU0:R2(config-cmap)#class-map match-all CONTROL_PLANE
RP/0/0/CPU0:R2(config-cmap)#match dscp cs6
RP/0/0/CPU0:R2(config-cmap)#class-map match-all PREFERRED_DATA
RP/0/0/CPU0:R2(config-cmap)#match dscp af33
RP/0/0/CPU0:R2(config-cmap)#exit

Step 2: Configure a policy map to be applied to the core-layer-facing interface that reserves the bandwidth for each traffic type as shown in the example below.

RP/0/0/CPU0:R2(config-pmap)#policy-map QOS_POLICY
RP/0/0/CPU0:R2(config-pmap)#class C2_VOICE
RP/0/0/CPU0:R2(config-pmap-c)#bandwidth percent 10
RP/0/0/CPU0:R2(config-pmap-c)#class VOICE
RP/0/0/CPU0:R2(config-pmap-c)#bandwidth percent 15
RP/0/0/CPU0:R2(config-pmap-c)#class VIDEO
RP/0/0/CPU0:R2(config-pmap-c)#bandwidth percent 25
RP/0/0/CPU0:R2(config-pmap-c)#class CONTROL_PLANE
RP/0/0/CPU0:R2(config-pmap-c)#bandwidth percent 10
RP/0/0/CPU0:R2(config-pmap-c)#class PREFERRED_DATA
RP/0/0/CPU0:R2(config-pmap-c)#bandwidth percent 25
RP/0/0/CPU0:R2(config-pmap-c)#class class-default
RP/0/0/CPU0:R2(config-pmap-c)#bandwidth percent 15
RP/0/0/CPU0:R2(config-pmap-c)#exit

Step 3: Apply the output service policy to the core-layer-facing interface as shown in the configuration example below.

RP/0/0/CPU0:R2(config)#int g0/0/0/1
RP/0/0/CPU0:R2(config-if)#service-policy output QOS_POLICY
RP/0/0/CPU0:R2(config-if)#exit
RP/0/0/CPU0:R2(config)#int g0/0/0/2
RP/0/0/CPU0:R2(config-if)#service-policy output QOS_POLICY
RP/0/0/CPU0:R2(config-if)#end

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_IOS-XR_Router_Y24M07_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5(2), CAT|III, CCI|CCI-001095, Rule-ID|SV-216804r917439_rule, STIG-ID|CISC-RT-000760, STIG-Legacy|SV-105953, STIG-Legacy|V-96815, Vuln-ID|V-216804

Plugin: Cisco

Control ID: f41b8bf3e3168f5bb6d0c3e118eb9afda7ba677c0f98238eb989af8b543f975a