Network QoS policies can be applied to network interfaces, CSC network interfaces in a VPRN, pseudowires in VLL and VPLS services, and IES or VPRN spoke interfaces to provide ingress and egress QoS control for the traffic on those objects. Network QoS policies can also be applied to provide aggregate ingress QoS on VPRN and VXLAN services.
The ingress component of a network QoS policy defines the packet classification to internal forwarding class and profile state. The forwarding class and profile state define the Per Hop Behavior (PHB) or the QoS treatment through the router. The mapping defaults to that defined in the default network QoS policy until an explicit policy is defined for the network interface. Packets can also be redirected to an ingress FP queue group.
The egress component of a network QoS policy allows further egress classification to internal forwarding class and profile state. The egress of the network QoS policy also defines the marking based on the forwarding class and the profile state. Packets can also be redirected to an egress port queue group.
Network policy 1 is applied to all network interfaces by default. It cannot be modified or deleted. It defines the default DSCP-to-FC mapping and MPLS EXP-to-FC mapping for the ingress. For the egress, it defines eight forwarding classes and the packet marking criteria.
New (non-default) network policy parameters can be modified. A new network policy must include the definition of at least one queue and specify the default action. Incomplete network policies cannot be applied to network interfaces.
Changes made to a policy are applied immediately to all networks to which the policy is applied. For this reason, when a policy requires several changes, it is recommended to copy the policy to a work area policy-id. This work-in-progress copy can be modified until all the changes are made, then the original policy can be overwritten using the config qos copy command.
FP2-, FP3-, and FP4-based cards store QoS policy match-criteria entries in dedicated memory banks in hardware, also referred to as CAM tables:
To optimize both scale and performance, policy match-criteria entries configured by the operator are compressed by each FP4 line card prior to being installed in hardware.
This compression can result, in an unexpected scenario typically only achieved in a lab environment, in an overload condition where entries for a line card QoS policy on a line card FP are not programmed. This overload condition can occur when applying a QoS policy for the first time on a line card FP or when adding entries to a QoS policy.
Applying a QoS Policy
A policy is installed for the first time on a line card FP if no router interface, service interface, SAP, spoke SDP, mesh SDP or ESM subscriber host was using the policy on this FP.
A policy installed for the first time on a line card FP can lead to a compression failure resulting in an overload condition for this policy on this FP. In this case, none of the entries for the affected QoS match-criteria policy are programmed, and the QoS policy queuing, FC mapping, and FC marking are unaffected.
Adding QoS Match-Criteria Entries
Adding an additional entry to a QoS policy can lead to a compression failure resulting in an overload condition.
In this case, the newly added entry is not programmed on the affected FP. Additional entries added to the same policy after the first overload condition are also not programmed on the affected FP as the system attempts to install all outstanding additions in order.
The CPM QoS management task controls the maximum number of match criteria entries per FP. If the operator attempts to go over the scaling limit, the system will return an interactive error message.
Note: A trap is raised if a policy is in overload, there is no interactive error message.
Removing QoS Match-Criteria Entries
Removing match-criteria entries from a QoS policy is always successful.
Resolving Overload
The overload condition should be resolved by the network operator before adding new entries in the affected policy.
To identify the affected policy, the system logs the overload event providing slot number, FP number, and impacted memory bank. Based on this information, the tools>dump>qos>match-criteria-overload command allows the operator to identify the affected policy and policy entries in the system.
To resolve the overload condition, the network operator can remove the newly added entries from the affected policy or assign a different policy.
The following types of QoS mapping decisions are applicable to the ingress of a network QoS policy:
The default QoS mapping always exists and every received packet will be mapped to this default if no explicitly defined matching entry exists.
The packets for a specified forwarding class can be redirected to an ingress FP queue group.
By default, a tunnel that terminates on the ingress IP interface (the node is the last hop for the tunnel) is evaluated based on the type of tunnel: IP GRE or MPLS LSP. An IP tunneled packet may match a dot1p entry, IP ToS precedence entry, or IP ToS DSCP entry when defined in the applied policy. An MPLS LSP may match a dot1p entry or MPLS EXP entry when defined.
Tunnel termination QoS override only applies to IP routing decisions when the tunnel encapsulation is removed. Non-IP routed packets within a terminating tunnel are ignored by the override and are forwarded as described in Network Ingress.
Any tunnel received on the ingress IP interface that traverses the node (where the node is not the ultimate hop for the tunnel) is not affected by the QoS override mechanism and is forwarded as described in Network Ingress.
Tunnel termination QoS override, provides the ability to ignore the network ingress QoS mapping of a terminated tunnel containing an IP packet that is to be routed to a base router or VPRN destination. This is useful when the mapping for the tunnel QoS marking does not accurately or completely reflect the required QoS handling for the IP routed packet. When the mechanism is enabled on an ingress network IP interface using the ingress ler-use-dscp parameter, the IP interface will ignore the tunnel’s QoS mapping and derive the internal forwarding class and profile based on the precedence or DSCP values within the routed IP header ToS field compared to the network QoS policy defined on the IP interface.
IP match criteria classification is supported in the ingress section of a network QoS policy.
The classification only applies to the outer IPv4 header of non-tunneled traffic. Consequently, the use of an IP criteria statement in a network QoS policy is ignored for received traffic when the network QoS policy is applied on the ingress network IP interface in the following cases:
The only exception is for traffic received on a Draft Rosen tunnel, for which classification on the outer IP header only is supported.
Attempting to apply a network QoS policy containing an IP criteria statement to any object except a network IP interface will result in an error.
The following is an example configuration:
IPv6 match criteria classification is supported in the ingress section of a network QoS policy.
The classification only applies to the outer IPv6 header of non-tunneled traffic; consequently, the use of an ipv6-criteria statement in a network QoS policy is ignored for received traffic when the network QoS policy is applied on the ingress network IP interface in the following cases:
Attempting to apply a network QoS policy containing an IPv6 criteria statement to any object except a network IP interface will result in an error.
The following is an example configuration:
The following types of QoS mapping decisions are applicable to the egress of a network QoS policy:
Default dot1p/DE, DSCP, and EXP packet marking are defined for each forwarding class for in and out of profile packets, together with the remarking capability based on the trusted state of the packet's ingress interface.
The packets of a specified forwarding class can be redirected to an egress port queue group.
The user enables IP precedence or DSCP based egress reclassification by applying the following command in the context of the network QoS policy applied to the egress context of a spoke-SDP.
config>qos>network>egress>prec ip-prec-value [fc fc-name] [profile {exceed | out | in | inplus}]
config>qos>network>egress>dscp dscp-name [fc fc-name] [profile {exceed | out | in | inplus}]
The IP precedence bits used to match against DSCP reclassification rules come from the Type of Service (ToS) field within the IPv4 header or the Traffic Class field from the IPv6 header.
The IP DSCP bits used to match against DSCP reclassification rules come from the Type of Service (ToS) field within the IPv4 header or the Traffic Class field from the IPv6 header.
If the packet does not have an IP header, DSCP or IP-precedence based matching is not performed.
The IP precedence and DSCP based re-classification are supported on a network interface, on a CSC network interface in a VPRN, and on a PW used in an IES or VPRN spoke-interface. The CLI blocks the application of a network QoS policy with the egress re-classification commands to a network IP interface or to a spoke-SDP part of L2 service. Conversely, the CLI does not allow the user to add the egress re-classification commands to a network QoS policy if it is being used by an L2 spoke-SDP.
In addition, the egress re-classification commands only take effect if the redirection of the spoke-SDP or CSC interface to use an egress port queue-group succeeds; for example, the following CLI commands succeed:
config>service>vprn>if>spoke-sdp>egress>qos network-policy-id port-redirect-group queue-group-name instance instance-id
config>service>ies>if>spoke-sdp>egress>qos network-policy-id port-redirect-group queue-group-name instance instance-id
config>service>vprn>nw-if>qos network-policy-id port-redirect-group queue-group-name instance instance-id
When the redirection command fails in CLI, the PW uses the network QoS policy assigned to the network IP interface, however any reclassification in the network QoS policy applied to the network interface will be ignored.
IP match criteria classification is supported in the egress section of a network QoS policy.
The configuration of egress prec/DSCP classification and the configuration of an egress IP criteria entry statement within a network QoS policy are mutually exclusive.
The criteria action statement port redirect group is not supported on the 7750 SR-a4/a8.
Network QoS policies containing egress IP criteria entry statements are only applicable to network interfaces.
Network egress IP match criteria classification is not supported on an HSMDA.
The following is an example configuration:
IPv6 match criteria classification is supported in the egress section of a network QoS policy.
The configuration of egress prec/DSCP classification and the configuration of an egress IPv6 criteria entry statement within a network QoS policy are mutually exclusive.
The criteria action statement port redirect group is not supported on the 7750 SR-a4/a8.
Network QoS policies containing egress IPv6 criteria entry statements are only applicable to network interfaces.
Network egress IPv6 match criteria classification is not supported on an HSMDA.
The following is an example configuration:
Differentiated services code point (DSCP), forwarding class (FC), and IEEE 802.1p values can be specified to be used by protocol packets generated by the node. This enables prioritization or deprioritization of every protocol (as required). The markings effect a change in behavior on ingress when queuing.
DSCP marking for internally generated control and management traffic should be used for the given application. This can be configured per routing instance. For example, OSPF packets can carry a different DSCP marking for the base instance than for a VPRN service. ARP, IS-IS, and PPPoE are not IP protocols, so only 802.1p values can be configured.
The DSCP value can be set per application. When an application is configured to use a specified DSCP value, the 802.1p and MPLS EXP bits will be marked in accordance with the network (default 802.1p value of 7) or access (default 802.1p value of 0) egress policy as it applies to the logical interface that the packet will be egressing.
The configuration of self-generated QoS is supported in the base router, VPRN, and management contexts.
The default values for self-generated traffic on network interfaces are:
The default QoS values for self-generated traffic on network interfaces are listed in Table 19.
Protocol | DSCP |
ANCP | NC1 |
APS | NC1 |
ARP | N/A |
BFD | NC1 |
BGP | NC1 |
BMP | AF41 |
Cflowd | NC1 |
DHCP | NC1, AF41, NC2 |
Diameter | AF41 |
DNS | AF41 |
FTP | AF41 |
gRPC | AF41 |
GTP | NC1, NC2 |
HTTP | AF41 |
ICMP | BE, NC1 |
IGMP | NC1 |
IGMP Reporter | NC1 |
IS-IS | N/A |
L2TP | NC1 |
LDP | NC1 |
LMP | NC1 |
MLD | NC1 |
MSC (Multichassis Support) | NC1 |
MSDP | NC1 |
Mtrace2 | NC1 |
ND (NDIS) | NC1, NC2 |
NTP/SNTP | NC1 |
OpenFlow | NC1 |
OSPF | NC1 |
PCEP | NC1 |
PIM | NC1 |
PPPoE | N/A |
PTP | NC1 |
RADIUS | NC1 |
RIP | NC1 |
RSVP | NC1 |
sFlow | NC1 |
SNMP Gets/Sets | AF41 |
SNMP Traps | AF41 |
SRRP | NC1 |
SSH, SCP, SFTP | AF41 |
Syslog | AF41 |
TACACS+ | AF41 |
Telnet | AF41 |
TFTP | AF41 |
Traceroute | BE |
TWAMP, TWAMP Light | N/A |
VRRP | NC1 |
WSC | NC1 |
XMPP | NC1 |
![]() | Note: ICMP echo requests (type 8) and ICMPv6 echo requests (type 128) initiated from the router will use the DSCP value set by the sgt-qos command. The FC value is NC by default, or the value specified in the ping command parameter fc fc-name. |
![]() | Note: The DSCP values for TWAMP and TWAMP Light test packets are not configured with sgt-qos commands. The DSCP value for TWAMP test packets reflected by the TWAMP server is specified in the TWAMP control process. The DSCP value for TWAMP Light test packets is set by the test configuration. The TWAMP Light reflector uses the arriving TWAMP test packet to determine the return DSCP value. |
![]() | Note: Some applications have multiple DSCP default values depending on the context or service. |
![]() | Note: Configurable values for ANCP, APS, BFD, LMP, MSC, OpenFlow, WSC, and XMPP are not supported. |
*The default forwarding class mapping is used for all DSCP names/values for which there is no explicit forwarding class mapping.
A basic network QoS policy must conform to the following:
Configuring and applying QoS policies other than the default policy is optional. A default network policy of the appropriate type is applied to each router interface.
To create a network QoS policy when operating, define the following:
Use the following CLI syntax to create a network QoS policy:
Use the following CLI syntax to apply network policies to the router access uplink port’s IP interfaces:
The following output displays the configuration for router interface ALA-1-2 with network policy 600 applied to the interface.
The default network policy for IP interfaces is identified as policy-id 1. Default policies cannot be modified or deleted. Table 20 lists default network policy parameters.
Field | Default | ||||
description | Default network QoS policy. | ||||
scope | template | ||||
ingress | |||||
default-action | fc be profile out | ||||
dscp | |||||
be | fc be | profile out | |||
ef | fc ef | profile in | |||
cs1 | fc l2 | profile in | |||
nc1 | fc h1 | profile in | |||
nc2 | fc nc | profile in | |||
af11 | fc af | profile in | |||
af12 | fc af | profile out | |||
af13 | fc af | profile out | |||
af21 | fc l1 | profile in | |||
af22 | fc l1 | profile out | |||
af23 | fc l1 | profile out | |||
af31 | fc l1 | profile in | |||
af32 | fc l1 | profile out | |||
af33 | fc l1 | profile out | |||
af41 | fc h2 | profile in | |||
af42 | fc h2 | profile out | |||
af43 | fc h2 | profile out | |||
lsp-exp | |||||
0 | fc be | profile out | |||
1 | fc l2 | profile in | |||
2 | fc af | profile out | |||
3 | fc af | profile in | |||
4 | fc h2 | profile in | |||
5 | fc ef | profile in | |||
6 | fc h1 | profile in | |||
7 | fc nc | profile in | |||
egress | |||||
remarking | no | ||||
fc af | |||||
dscp-in-profile | af11 | ||||
dscp-out-profile | af12 | ||||
lsp-exp-in-profile | 3 | ||||
lsp-exp-out-profile | 2 | ||||
fc be | |||||
dscp-in-profile | be | ||||
dscp-out-profile | be | ||||
lsp-exp-in-profile | 0 | ||||
lsp-exp-out-profile | 0 | ||||
fc ef | |||||
dscp-in-profile | ef | ||||
dscp-out-profile | ef | ||||
lsp-exp-in-profile | 5 | ||||
lsp-exp-out-profile | 5 | ||||
fc h1 | |||||
dscp-in-profile | nc1 | ||||
dscp-out-profile | nc1 | ||||
lsp-exp-in-profile | 6 | ||||
lsp-exp-out-profile | 6 | ||||
fc h2 | |||||
dscp-in-profile | af41 | ||||
dscp-out-profile | af42 | ||||
lsp-exp-in-profile | 4 | ||||
lsp-exp-out-profile | 4 | ||||
fc l | |||||
dscp-in-profile | af21 | ||||
dscp-out-profile | af22 | ||||
lsp-exp-in-profile | 3 | ||||
lsp-exp-out-profile | 2 | ||||
fc l2 | |||||
dscp-in-profile | cs1 | ||||
dscp-out-profile | cs1 | ||||
lsp-exp-in-profile | 1 | ||||
lsp-exp-out-profile | 1 | ||||
fc nc | |||||
dscp-in-profile | nc2 | ||||
dscp-out-profile | nc2 | ||||
lsp-exp-in-profile | 7 | ||||
lsp-exp-out-profile | 7 |
The following output displays the default configuration:
A network policy is associated by default with router interfaces.
The default policy can be replaced with a non-default policy, but cannot be removed from the configuration. When a non-default policy is removed, the policy association reverts to the appropriate default network policy.
The following output displays a sample configuration.
To delete a network policy, enter the following commands:
An existing network policy can be copied to a new policy ID value or overwrite an existing policy ID. The overwrite option must be specified or an error occurs if the destination policy ID exists.
The following output displays the copied policies:
Existing policies, except the default policies and entries in the CLI, can be changed. The changes are applied immediately to all interfaces where the policy is applied. To prevent configuration errors, use the copy command to make a duplicate of the original policy in a work area, make the edits, then overwrite the original policy.