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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.

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.

R5(config-cmap)#class-map match-all C2_VOICE
R5(config-cmap)#match ip dscp 47
R5(config-cmap)#class-map match-all VOICE
R5(config-cmap)#match ip dscp ef
R5(config-cmap)#class-map match-all VIDEO
R5(config-cmap)#match ip dscp af41
R5(config-cmap)#class-map match-all CONTROL_PLANE
R5(config-cmap)#match ip dscp cs6
R5(config)#class-map match-all PREFERRED_DATA
R5(config-cmap)#match ip dscp af33
R5(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.

R5(config)#policy-map QOS_POLICY
R5(config-pmap-c)#class C2_VOICE
R5(config-pmap-c)#priority percent 10
R5(config-pmap-c)#class VOICE
R5(config-pmap-c)#priority percent 15
R5(config-pmap-c)#class VIDEO
R5(config-pmap-c)#bandwidth percent 25
R5(config-pmap)#class CONTROL_PLANE
R5(config-pmap-c)#priority percent 10
R5(config-pmap-c)#class PREFERRED_DATA
R5(config-pmap-c)#bandwidth percent 25
R5(config-pmap-c)#class class-default
R5(config-pmap-c)#bandwidth percent 15
R5(config-pmap-c)#exit
R5(config-pmap)#exit

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

R5(config)#int g1/1
R5(config-if)#service-policy output QOS_POLICY
R5(config-if)#exit
R5(config)#int g1/2
R5(config-if)#service-policy output QOS_POLICY
R5(config-if)#end

See Also

https://dl.dod.cyber.mil/wp-content/uploads/stigs/zip/U_Cisco_IOS_Router_Y26M01_STIG.zip

Item Details

Category: SYSTEM AND COMMUNICATIONS PROTECTION

References: 800-53|SC-5(2), CAT|III, CCI|CCI-001095, Rule-ID|SV-216619r917417_rule, STIG-ID|CISC-RT-000760, STIG-Legacy|SV-105777, STIG-Legacy|V-96639, Vuln-ID|V-216619

Plugin: Cisco

Control ID: 33f61918cf3dc584ac700bebe6a5e423078920b1b62b1beac725d3c23f048102