Juniper Destination Based CoS Configuration

cosjuniperqos

I'm trying to do destination based CoS on Juniper MX basing on destination ASN.
I've tried config below.

set policy-options as-path BGP-PATH-TO-MARK-COS "65512 .*

set policy-options policy-statement MARK-POLICY-1 term term-1 to as-path BGP-PATH-TO-MARK-COS
set policy-options policy-statement MARK-POLICY-1 term term-1 then forwarding-class network-control
set routing-options forwarding-table export MARK-POLICY-1

set class-of-service interfaces ge-7/2/2 unit 0 rewrite-rules inet-precedence default

I expect traffic to AS65512 destinations to be marked as network-control, however tcpdump shows 0x0 tos filed.
Looks like term-1 condition is right, since if I change 'then forwarding-class network-control' to 'then reject' traffic towards AS65512 is indeed rejected.

Let's ignore for a moment 'network-control' it's here only to see that marking is indeed happens (which is not the case).

What could be wrong with my config?

Best Answer

Packet classification occurs when the packet enters the router. You're trying to apply it on the forwarding table. That's not supported.

The Juniper documentation shows the packet flow in the router:

Packet flow in MX Routers

So try to apply the policy on the input interface like so:

set interfaces ge-x/x/x.x family inet policer input MARK-POLICY-1

Another way to update a packet in the forwarding-table is to use the classification-override feature:

Overriding the Input Classification

set class-of-service forwarding-policy class POLICY-1 classification-override forwarding-class network-control
set policy-options policy-statement MARK-POLICY-1 term term-1 to as-path BGP-PATH-TO-MARK-COS
set policy-options policy-statement MARK-POLICY-1 term term-1 then class POLICY-1
set policy-options policy-statement MARK-POLICY-1 term term-2 then accept
set routing-options forwarding-table export MARK-POLICY-1

Related Solutions

Are CoS and QoS ever interchangeable

QoS is an umbrella term which covers the use of features such as policing, shaping, traffic classification, and advanced queuing mechanisms.

CoS is a form of QoS limited to layer-2 Ethernet and it uses 3-bits (8 values) of the 802.1Q tag to differentiate your traffic. Therefore no trunking, no CoS.

DSCP is the most commonly acted upon value at layer-3 and it is found in 6-bits (64 values) of the IP header. Typically only 14 of the values are used and are referred to using the notations of best effort, expedited forwarding (EF), and assured forwarding (AF). AF values are in the form AFxy, where x is 1-4 and refers to the precedence and y is 1-3 and refers to the drop probability.

Telco vendors (such as AT&T specifically) use the term CoS to define the bandwidth allocation classes that they support in their MPLS offerings. Basically they turned CoS into a marketing term. Typically a Telco uses DSCP to know which of their CoS classes your traffic is supposed to be a part of.

Another important point for configuring these features is that in a Cisco switch or router you need to use a command such as 'mls qos trust dscp' or 'mls qos trust cos' or else the device will reset the QoS marking to zero. There are some exceptions based on model, configuration, and IOS version but this has been true for everything within the last few years in my experience. This configuration is required because the device needs to know which marking you want it to act upon since it cannot use both. I like using DSCP. I haven't found a solid reason to use CoS over it but I'm sure someone has one.

Cisco QoS – What is the 5 Level QoS Model (with Config Example)?

Cisco has something they call Cisco Validated Designs (CVD). These are network designs from different perspectives like QoS, high availability, WAN etc that Cisco recommends and have tested.

For QoS they have 3 different designs with 4, 8 or 12 classes which can be seen in the picture below.

Cisco QoS classes

Starting with the 4 class model:

! This section defines the 4-Class class-maps 
! (three are explicitly defined and one is default)
Router(config)# class-map match-any REALTIME
Router(config-cmap)# match dscp ef
 ! Matches VoIP
Router(config-cmap)# match dscp cs5
 ! Matches Broadcast Video
Router(config-cmap)# match dscp cs4
 ! Matches Realtime-Interactive

Router(config)# class-map match-any CONTROL
Router(config-cmap)# match dscp cs6
 ! Matches Network-Control
Router(config-cmap)# match dscp cs3
 ! Matches Signaling (control-plane traffic for voice/video infrastructure)
Router(config-cmap)# match dscp cs2
 ! Matches Network Management

Router(config)# class-map match-any CRITICAL-DATA
Router(config-cmap)# match dscp af41 af42 af43
 ! Matches Multimedia Conferencing on AF4 
Router(config-cmap)# match dscp af31 af32 af33
 ! Matches Multimedia Streaming on AF3
Router(config-cmap)# match dscp af21 af22 af23
 ! Matches Transactional Data on AF2
Router(config-cmap)# match dscp af11 af12 af13
 ! Matches Bulk Data on AF1


! This section defines the 4-Class Policy-Map
Router(config)# policy-map WAN-EDGE-4-CLASS
Router(config-pmap)# class REALTIME
Router(config-pmap-c)# priority percent 33
 ! Provisions 33% LLQ for REALTIME class
Router(config-pmap-c)# class CONTROL
Router(config-pmap-c)#  bandwidth percent 7
 ! Provisions 7% CBWFQ for CONTROL class
Router(config-pmap-c)# class CRITICAL-DATA
Router(config-pmap-c)#  bandwidth percent 35
 ! Provisions 35% CBWFQ for CRITICAL-DATA class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on CRITICAL-DATA class
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on CRITICAL-DATA class
Router(config-pmap-c)#   random-detect dscp af11 50 64
 ! Tunes WRED min and max drop-thresholds for AF11/10 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af12 45 64
 ! Tunes WRED min and max drop-thresholds for AF12/12 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af13 40 64
 ! Tunes WRED min and max drop-thresholds for AF13/14 to 40 and 64 packets
Router(config-pmap-c)#   random-detect dscp af21 50 64
 ! Tunes WRED min and max drop-thresholds for AF21/18 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af22 45 64
 ! Tunes WRED min and max drop-thresholds for AF22/20 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af23 40 64
 ! Tunes WRED min and max drop-thresholds for AF23/22 to 40 and 64 packets
Router(config-pmap-c)#   random-detect dscp af31 50 64
 ! Tunes WRED min and max drop-thresholds for AF31/26 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af32 45 64
 ! Tunes WRED min and max drop-thresholds for AF32/28 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af33 40 64
 ! Tunes WRED min and max drop-thresholds for AF33/30 to 40 and 64 packets
Router(config-pmap-c)#   random-detect dscp af41 50 64
 ! Tunes WRED min and max drop-thresholds for AF41/34 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af42 45 64
 ! Tunes WRED min and max drop-thresholds for AF42/36 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af43 40 64
 ! Tunes WRED min and max drop-thresholds for AF43/38 to 40 and 64 packets
Router(config-pmap-c)# class class-default
Router(config-pmap-c)#  bandwidth percent 25
 ! Provisions 25% CBWFQ for default (Best-Effort) class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on default (Best-Effort) class
Router(config-pmap-c)#  queue-limit 128 packets
 ! Expands queue-limit to 128 packets
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on default (Best-Effort) class
Router(config-pmap-c)#   random-detect dscp default 100 128
 ! Tunes WRED min and max drop-thresholds for DF/0 to 100 and 128 packets
Router(config-pmap-c)#   random-detect dscp cs1 60 100
 ! Tunes WRED min and max drop-thresholds for CS1/8 to 60 and 100 packets

As you can see it matches on different DSCP values. DSCP EF is generally used for VoIP. This means that your packets should already have been marked as early as possible in your network. The bandwidth values are entered in percent which means that the policy can applied on different speed interfaces and still provide good values compared to entering them in kbit/s. On very high speed interfaces like 10 Gbit it could be a lot to use 7% for control traffic though since that would be 700 Mbit/s.

Both the data and the class-default uses fair-queue which is a way of queueing packets based on DSCP and packet size to provide fair queueing even for small packet flows. To be able to use this you need an image supporting Hierarchical Queing Framework (HQF) which is 12.4(20)T or newer.

Weighted Random Early Detection (WRED) is also applied to take care of issues like TCP synchronization where TCP flows will speed up and back off at the same time.

Then you have the 8 class model.

! This section defines the 8-Class class-maps 
! (seven are explicitly defined and one is default)
Router(config)# class-map match-all VOICE
Router(config-cmap)# match dscp ef
 ! Matches VoIP

Router(config)# class-map match-any INTERACTIVE-VIDEO
Router(config-cmap)# match dscp cs5
 ! Matches Broadcast Video
Router(config-cmap)# match dscp cs4
 ! Matches Realtime-Interactive
Router(config)# class-map match-any NETWORK-CONTROL
Router(config-cmap)# match dscp cs6
 ! Matches Network Control
Router(config-cmap)# match dscp cs2
 ! Matches Network Management

Router(config)# class-map match-all SIGNALING
Router(config-cmap)# match dscp cs3
 ! Matches Signaling

Router(config)# class-map match-all MULTIMEDIA-STREAMING
Router(config-cmap)# match dscp af31 af32 af33
 ! Matches Multimedia-Streaming on AF3

Router(config)# class-map match-any CRITICAL-DATA
Router(config-cmap)# match dscp af41 af42 af43
 ! Matches Multimedia-Conferencing on AF4
Router(config-cmap)# match dscp af21 af22 af23
 ! Matches Transactional-Data on AF2
Router(config-cmap)# match dscp af11 af12 af13
 ! Matches Bulk-Data on AF1

Router(config)# class-map match-all SCAVENGER
Router(config-cmap)# match dscp cs1
 ! Matches Scavenger


! This section configures the 8-class policy-map
Router(config)# policy-map WAN-EDGE-8-CLASS
Router(config-pmap)# class VOICE
Router(config-pmap-c)#  priority percent 10
 ! Provisions 10% LLQ for VOICE class (dual LLQ-policy)
Router(config-pmap-c)# class INTERACTIVE-VIDEO
Router(config-pmap-c)#  priority percent 23
 ! Provisions 23% LLQ for INTERACTIVE-VIDEO class (dual-LLQ policy)
Router(config-pmap-c)# class NETWORK-CONTROL
Router(config-pmap-c)#  bandwidth percent 5
 ! Provisions 5% CBWFQ for NETWORK-CONTROL class
Router(config-pmap-c)# class SIGNALING
Router(config-pmap-c)#  bandwidth percent 2
 ! Provisions 2% CBWFQ for SIGNALING class
Router(config-pmap-c)# class MULTIMEDIA-STREAMING
Router(config-pmap-c)#  bandwidth percent 10
 ! Provisions 10% CBWFQ for MULTIMEDIA-STREAMING class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on MULTIMEDIA-STREAMING class
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on MULTIMEDIA-STREAMING class
Router(config-pmap-c)#   random-detect dscp af31 50 64
 ! Tunes WRED min and max drop-thresholds for AF31/26 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af32 45 64
 ! Tunes WRED min and max drop-thresholds for AF32/28 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af33 40 64
 ! Tunes WRED min and max drop-thresholds for AF33/30 to 40 and 64 packets
Router(config-pmap-c)# class CRITICAL-DATA
Router(config-pmap-c)#  bandwidth percent 24
 ! Provisions 24% CBWFQ for CRITICAL-DATA class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on CRITICAL-DATA class
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on CRITICAL-DATA class


Router(config-pmap-c)#   random-detect dscp af11 50 64
 ! Tunes WRED min and max drop-thresholds for AF11/10 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af12 45 64
 ! Tunes WRED min and max drop-thresholds for AF12/12 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af13 40 64
 ! Tunes WRED min and max drop-thresholds for AF13/14 to 40 and 64 packets
Router(config-pmap-c)#   random-detect dscp af21 50 64
 ! Tunes WRED min and max drop-thresholds for AF21/18 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af22 45 64
 ! Tunes WRED min and max drop-thresholds for AF22/20 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af23 40 64
 ! Tunes WRED min and max drop-thresholds for AF23/22 to 40 and 64 packets
Router(config-pmap-c)#   random-detect dscp af41 50 64
 ! Tunes WRED min and max drop-thresholds for AF41/34 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af42 45 64
 ! Tunes WRED min and max drop-thresholds for AF42/36 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af43 40 64
 ! Tunes WRED min and max drop-thresholds for AF43/38 to 40 and 64 packets
Router(config-pmap-c)# class SCAVENGER
Router(config-pmap-c)#  bandwidth percent 1
 ! Constrains Scavenger class to 1% CBWFQ
Router(config-pmap-c)# class class-default
Router(config-pmap-c)#  bandwidth percent 25
 ! Provisions 25% CBWFQ for default (Best-Effort) class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on default (Best-Effort) class
Router(config-pmap-c)#  queue-limit 128 packets
 ! Expands queue-limit to 128 packets
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on default (Best-Effort) class
Router(config-pmap-c)#   random-detect dscp default 100 128
 ! Tunes WRED min and max drop-thresholds for DF/0 to 100 and 128 packets

This policy is more granular for the realtime applications like video, streaming and signaling for these protocols.

Finally this is the 12 class model.

! This section configures the class-maps
! (eleven class maps are explicitly defined and one is default)
Router(config)# class-map match-all VOICE
Router(config-cmap)# match dscp ef
 ! Matches VoIP

Router(config)# class-map match-all BROADCAST-VIDEO
Router(config-cmap)# match dscp cs5
 ! Matches Broadcast Video

Router(config)# class-map match-all REALTIME-INTERACTIVE
Router(config-cmap)#  match dscp cs4
 ! Matches Realtime-Interactive

Router(config)# class-map match-all NETWORK-CONTROL
Router(config-cmap)# match dscp cs6
 ! Matches Network Control

Router(config)# class-map match-all SIGNALING
Router(config-cmap)# match dscp cs3
 ! Matches Signaling

Router(config)# class-map match-all NETWORK-MANAGEMENT
Router(config-cmap)# match dscp cs2
 ! Matches Network Management

Router(config)# class-map match-any MULTIMEDIA-CONFERENCING
Router(config-cmap)# match dscp af41
Router(config-cmap)# match dscp af42
Router(config-cmap)# match dscp af43
 ! Matches Multimedia-Conferencing
 ! One match statement per Drop Precedence increases visibility

Router(config)# class-map match-any MULTIMEDIA-STREAMING
Router(config-cmap)# match dscp af31
Router(config-cmap)# match dscp af32
Router(config-cmap)# match dscp af33
 ! Matches Multimedia-Streaming
 ! One match statement per Drop Precedence increases visibility

Router(config)# class-map match-any TRANSACTIONAL-DATA
Router(config-cmap)# match dscp af21
Router(config-cmap)# match dscp af22
Router(config-cmap)# match dscp af23
 ! Matches Transactional-Data
 ! One match statement per Drop Precedence increases visibility

Router(config)# class-map match-any BULK-DATA
Router(config-cmap)# match dscp af11
Router(config-cmap)# match dscp af12
Router(config-cmap)# match dscp af13
 ! Matches Bulk-Data
 ! One match statement per Drop Precedence increases visibility

Router(config)# class-map match-all SCAVENGER
Router(config-cmap)# match dscp cs1
 ! Matches Scavenger


! This section configures the 12-Class policy-map
Router(config)# policy-map WAN-EDGE-12-CLASS
Router(config-pmap)# class VOICE
Router(config-pmap-c)#  priority percent 10
 ! Provisions 10% LLQ to VOICE class (multi-LLQ policy)
Router(config-pmap-c)# class BROADCAST-VIDEO
Router(config-pmap-c)#  priority percent 10
 ! Provisions 10% LLQ to BROADCAST-VIDEO class (multi-LLQ policy)
Router(config-pmap-c)# class REALTIME-INTERACTIVE
Router(config-pmap-c)#  priority percent 13
! Provisions 13% LLQ to REALTIME-INTERACTIVE class (multi-LLQ policy)
Router(config-pmap-c)# class NETWORK-CONTROL
Router(config-pmap-c)#  bandwidth percent 2
 ! Provisions 2% CBWFQ to NETWORK-CONTROL class
Router(config-pmap-c)# class SIGNALING
Router(config-pmap-c)#  bandwidth percent 2
 ! Provisions 2% CBWFQ to SIGNALING class
Router(config-pmap-c)# class NETWORK-MANAGEMENT
Router(config-pmap-c)#  bandwidth percent 3
 ! Provisions 3% CBWFQ to NETWORK-MANAGEMENT class
Router(config-pmap-c)# class MULTIMEDIA-CONFERENCING
Router(config-pmap-c)#  bandwidth percent 10
 ! Provisions 10% CBWFQ to MULTIMEDIA-CONFERENCING class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on MULTIMEDIA-CONFERENCING class
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on MULTIMEDIA-CONFERENCING class
Router(config-pmap-c)#   random-detect dscp af41 50 64
 ! Tunes WRED min and max drop-thresholds for AF41/34 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af42 45 64
 ! Tunes WRED min and max drop-thresholds for AF42/36 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af43 40 64
 ! Tunes WRED min and max drop-thresholds for AF43/38 to 40 and 64 packets
Router(config-pmap-c)# class MULTIMEDIA-STREAMING
Router(config-pmap-c)#  bandwidth percent 10
 ! Provisions 10% CBWFQ to MULTIMEDIA-STREAMING class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on MULTIMEDIA-STREAMING class
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on MULTIMEDIA-STREAMING class
Router(config-pmap-c)#   random-detect dscp af31 50 64
 ! Tunes WRED min and max drop-thresholds for AF31/26 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af32 45 64
 ! Tunes WRED min and max drop-thresholds for AF32/28 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af33 40 64
 ! Tunes WRED min and max drop-thresholds for AF33/30 to 40 and 64 packets
Router(config-pmap-c)# class TRANSACTIONAL-DATA
Router(config-pmap-c)#  bandwidth percent 10
 ! Provisions 10% CBWFQ to TRANSACTIONAL-DATA class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on TRANSACTIONAL-DATA class
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on TRANSACTIONAL-DATA class
Router(config-pmap-c)#   random-detect dscp af21 50 64
 ! Tunes WRED min and max drop-thresholds for AF21/18 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af22 45 64
 ! Tunes WRED min and max drop-thresholds for AF22/20 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af23 40 64
 ! Tunes WRED min and max drop-thresholds for AF23/22 to 40 and 64 packets
Router(config-pmap-c)# class BULK-DATA
Router(config-pmap-c)#  bandwidth percent 4
 ! Provisions 4% CBWFQ to BULK-DATA class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on BULK-DATA class
Router(config-pmap-c)#   random-detect dscp-based
! Enables DSCP-based WRED on BULK-DATA class
Router(config-pmap-c)#   random-detect dscp af11 50 64
 ! Tunes WRED min and max drop-thresholds for AF11/10 to 50 and 64 packets
Router(config-pmap-c)#   random-detect dscp af12 45 64
 ! Tunes WRED min and max drop-thresholds for AF12/12 to 45 and 64 packets
Router(config-pmap-c)#   random-detect dscp af13 40 64
 ! Tunes WRED min and max drop-thresholds for AF13/14 to 40 and 64 packets
Router(config-pmap-c)# class SCAVENGER
Router(config-pmap-c)#  bandwidth percent 1
 ! Constrains Scavenger to 1% CBWFQ
Router(config-pmap-c)# class class-default
Router(config-pmap-c)#  bandwidth percent 25
 ! Provisions 25% CBWFQ for default (Best-Effort) class
Router(config-pmap-c)#  fair-queue
 ! Enables fair-queuing pre-sorter on default (Best-Effort) class
Router(config-pmap-c)#  queue-limit 128 packets
 ! Expands queue-limit to 128 packets
Router(config-pmap-c)#   random-detect dscp-based
 ! Enables DSCP-based WRED on default (Best-Effort) class
Router(config-pmap-c)#   random-detect dscp default 100 128
 ! Tunes WRED min and max drop-thresholds for DF/0 to 100 and 128 packets

This policy has even more classes for interactive traffic and also more classes for different types of data and a management class.

Finally you have to apply the policy to an interface like this.

int gix/x service-policy output WAN-EDGE-12-CLASS

Here is a link to WAN QoS CVD.

Best Answer

Related Solutions

Are CoS and QoS ever interchangeable

Cisco QoS – What is the 5 Level QoS Model (with Config Example)?

Related Topic