Configuring CoS Rules on Services PICs
This topic describes how to configure CoS rules on Services PICs.
Each CoS rule consists of a set of terms, similar to those in a firewall filter configuration. A term consists of the following:
fromstatement—Specifies the match conditions and applications that are included and excluded.thenstatement—Specifies the actions and action modifiers to be performed by the router software.
If you omit the from term, the router accepts all
traffic and the default protocol handlers take effect:
User Datagram Protocol (UDP), Transmission Control Protocol (TCP), and Internet Control Message Protocol (ICMP) create a bidirectional flow with a predicted reverse flow.
IP creates a unidirectional flow.
In addition, each rule must include a match-direction statement that specifies the direction in which the rule match is
applied. To configure where the match is applied, include the match-direction statement at the [edit services cos rule rule-name] hierarchy level:
match-direction (input | output | input-output);
If you configure match-direction input-output, bidirectional
rule creation is allowed.
The match direction is used with respect to the traffic flow through the Services PIC. When a packet is sent to the Services PIC, direction information is carried along with it.
On interface service sets, packet direction is determined by whether a packet is entering or leaving the interface on which the service set is applied.
With a next-hop service set, packet direction is determined
by the interface used to route the packet to the Services PIC. If
the inside interface is used to route the packet, the packet direction
is input. If the outside interface is used to direct the
packet to the Services PIC, the packet direction is output. For more information on inside and outside interfaces, see Configuring Service Sets to be Applied to Services
Interfaces.
On the Services PIC, a flow lookup is performed. If no flow is found, rule processing is performed. All rules in the service set are considered. During rule processing, the packet direction is compared against rule directions. Only rules with direction information that matches the packet direction are considered.
You can use either the source address or the destination address as a match condition, in the same way that you would configure a firewall filter; for more information, see the Routing Policies, Firewall Filters, and Traffic Policers User Guide.
You can also include application protocol definitions that you
have configured at the [edit applications] hierarchy level;
for more information, see the Junos OS Services Interfaces Library for Routing Devices.
To apply one or more specific application protocol definitions, include the
applicationsstatement at the[edit services cos rule rule-name term term-name from]hierarchy level.To apply one or more sets of application protocol definitions you have defined, include the
application-setsstatement at the[edit services cos rule rule-name term term-name from]hierarchy level.Note:If you include a statement that specifies application protocols, the router derives port and protocol information from the corresponding configuration at the
[edit applications]hierarchy level; you cannot specify these properties as match conditions.
The following sections describe how to configure CoS rules in more detail:
Configuring Match Conditions in a CoS Rule
This topic describes how to configure the match conditions for CoS rules.
Before you begin, make sure you have completed the following tasks:
Configure the application protocol definitions at the
[edit applications]hierarchy level; for more information, see theapplicationand Junos OS Services Interfaces Library for Routing Devices.Configure a destination prefix list by including the
prefix-liststatement at the[edit policy-options]hierarchy level.Configure a source prefix list by including the
prefix-liststatement at the[edit policy-options]hierarchy level.
To configure the match conditions for a CoS rule:
Configuring Actions in a CoS Rule
The principal CoS actions are:
dscp—Marks the packet with the specified DiffServ code point (DSCP) value or alias.forwarding-class—Assigns the packet to the specified forwarding class.
This section describes how to configure these CoS actions and includes the following topics:
Configuring Application Profiles
You can optionally define one or more application profiles for inclusion in CoS actions.
The application-profile statement includes two main
components and three traffic types: ftp with the data traffic type and sip with the video and voice traffic types. You can set the appropriate dscp and forwarding-class values for each component within
the application profile.
The ftp and sip statements are not
supported on Juniper Network MX Series 5G Universal Routing Platforms.
You can apply the application profile to a CoS configuration
by including it at the [edit services cos rule rule-name term term-name then] hierarchy level.
To configure an application profile for inclusion in CoS actions:
Configuring Reflexive and Reverse CoS Actions
It is important to understand that CoS services are unidirectional. It might be necessary to specify different treatments for flows in opposite directions.
Regardless of whether a packet matches the input, output, or input-output direction, flows in both directions are created. The difference is that a forward, reverse, or forward-and-reverse CoS action is associated with each flow. You should bear in mind that the flow in the opposite direction might end up having a CoS action associated with it, which you have not specifically configured.
To control the direction in which service is applied, separate
from the direction in which the rule match is applied, you can configure
the reflexive or reverse statement at the [edit services cos rule rule-name term term-name then] hierarchy level.
These two actions are mutually exclusive. If nothing is specified, data flows inherit the CoS behavior of the forward control flow.
reflexivecauses the equivalent reverse CoS action to be applied to flows in the opposite direction.reverseallows you to define the CoS behavior for flows in the reverse direction.
To control the direction in which a service is applied: