The Cisco PE router must be configured to enforce a Quality-of-Service (QoS) policy to provide preferred treatment for mission-critical applications.

Overview

Finding ID	Version	Rule ID	IA Controls	Severity
V-216804	CISC-RT-000760	SV-216804r917439_rule		Low

Description
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.

Description

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.

STIG	Date
Cisco IOS XR Router RTR Security Technical Implementation Guide	2024-06-06

Details

Check Text ( C-18036r917437_chk )
Review the router configuration and verify that a QoS policy has been configured to provide preferred treatment for mission-critical applications. Step 1: Verify that the class-maps are configured to match on DSCP values as shown in the configuration example below. class-map match-all VIDEO match dscp af41 end-class-map ! class-map match-all VOICE match dscp ef end-class-map ! class-map match-all C2_VOICE match dscp 47 end-class-map ! class-map match-all CONTROL_PLANE match dscp cs6 end-class-map ! class-map match-all PREFERRED_DATA match dscp af33 end-class-map ! Step 2: Verify that the policy map reserves the bandwidth for each traffic type as shown in the following example: policy-map QOS_POLICY class C2_VOICE bandwidth percent 10 ! class VOICE bandwidth percent 15 ! class VIDEO bandwidth percent 25 ! class CONTROL_PLANE bandwidth percent 10 ! class PREFERRED_DATA bandwidth percent 25 ! class class-default bandwidth percent 15 ! end-policy-map ! Step 3: Verify that an output service policy is bound to all interface as shown in the configuration example below. interface GigabitEthernet0/0/0/1 service-policy output QOS_POLICY ipv4 address x.1.24.2 255.255.255.252 ! interface GigabitEthernet0/0/0/2 service-policy output QOS_POLICY ipv4 address x.1.24.5 255.255.255.252 Note: Enclaves must mark or re-mark their traffic to be consistent with the DODIN backbone admission criteria to gain the appropriate level of service. A general DiffServ principle is to mark or trust traffic as close to the source as administratively and technically possible. However, certain traffic types might need to be re-marked before handoff to the DODIN backbone to gain admission to the correct class. If such re-marking is required, it is recommended that the re-marking be performed at the CE egress edge. If the router is not configured to enforce a QoS policy in accordance with the QoS DODIN Technical Profile, this is a finding.

Check Text ( C-18036r917437_chk )

Review the router configuration and verify that a QoS policy has been configured to provide preferred treatment for mission-critical applications.

Step 1: Verify that the class-maps are configured to match on DSCP values as shown in the configuration example below.

class-map match-all VIDEO
match dscp af41
end-class-map
!
class-map match-all VOICE
match dscp ef
end-class-map
!
class-map match-all C2_VOICE
match dscp 47
end-class-map
!
class-map match-all CONTROL_PLANE
match dscp cs6
end-class-map
!
class-map match-all PREFERRED_DATA
match dscp af33
end-class-map
!

Step 2: Verify that the policy map reserves the bandwidth for each traffic type as shown in the following example:

policy-map QOS_POLICY
class C2_VOICE
bandwidth percent 10
!
class VOICE
bandwidth percent 15
!
class VIDEO
bandwidth percent 25
!
class CONTROL_PLANE
bandwidth percent 10
!
class PREFERRED_DATA
bandwidth percent 25
!
class class-default
bandwidth percent 15
!
end-policy-map
!

Step 3: Verify that an output service policy is bound to all interface as shown in the configuration example below.

interface GigabitEthernet0/0/0/1
service-policy output QOS_POLICY
ipv4 address x.1.24.2 255.255.255.252
!
interface GigabitEthernet0/0/0/2
service-policy output QOS_POLICY
ipv4 address x.1.24.5 255.255.255.252

Note: Enclaves must mark or re-mark their traffic to be consistent with the DODIN backbone admission criteria to gain the appropriate level of service. A general DiffServ principle is to mark or trust traffic as close to the source as administratively and technically possible. However, certain traffic types might need to be re-marked before handoff to the DODIN backbone to gain admission to the correct class. If such re-marking is required, it is recommended that the re-marking be performed at the CE egress edge.

If the router is not configured to enforce a QoS policy in accordance with the QoS DODIN Technical Profile, this is a finding.

Fix Text (F-18034r917438_fix)
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

Fix Text (F-18034r917438_fix)

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