Table Of Contents
Qos - Policing SUPPORT for GRE Tunnels
The Qos - Policing Support for GRE Tunnels feature allows you to set the Differentiated Services Code Point (DSCP) and IP precedence values on Generic Routing Encapsulation (GRE) tunnel packets.
This feature is essential for MPLS carriers to offer QoS on Multicast VPN services. MVPN uses GRE tunnels between PE devices, and multicast packets are placed in GRE tunnels for transmission across the MPLS core network. The Qos - policing SUPPORT for GRE Tunnels feature allows users to configure QoS for the GRE tunnel packets. Once the GRE packets accurately reflect the QoS markings of the underlying multicast packets, they may be queued accordingly as they travel across the core nodes.
History for the Qos - Policing Support for GRE Tunnels Feature
This feature was introduced and implemented on the Cisco 10000 series router.
Finding Support Information for Platforms and Cisco IOS Software Images
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Restrictions for Qos - Policing Support for GRE Tunnels
•Service policies with GRE tunnel header marking actions can only be attached to the ingress interfaces.
•There is no direct means of marking the inner IP header that arrives in a tunnel (aka tunnel decapsulation or tunnel receive).
•The Cisco 10000 Series router supports only one police action.
Information About Qos - Policing Support for GRE Tunnels
Table 1 shows how the various tunnel-specific marking functions interact with one another.
The policing commands are logically applied last and thus have the highest priority. This means that the value associated with the set ip [dscp | precedence] tunnel transmit command, when applied, will always show up in the outer IP header's ToS byte.
The set ip [dscp | precedence] tunnel transmit command value that is specified will supersede the tunnel tos value and any default tunnel action.
The tunnel tos value command overrides any default tunnel marking action.
If the input QoS action uses a dcsp value and the police action specifies a precedence value, only the police action bits will be changed. The bits associated with the input QoS actions' dscp value will be ignored.
How to Configure Qos - Policing Support for GRE Tunnels
To configure Qos - Policing Support for GRE Tunnels, perform the following configuration tasks:
2. configure terminal
3. class-map class-map-name
4. match fr-de
6. policy-map name
7. class map-class
8. police bps conform-action action
The following sections provide references related to Policing Support for GRE Tunnels.
Related Topic Document Title
Quality of Service on GRE Tunnel Interfaces
Tech Note: Quality of Service Options on GRE Tunnel Interfaces at http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a008017405e.shtml
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.