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    Overview of BA Classifier Types

    The idea behind class of service (CoS) is that packets are not treated identically by the routers on the network. In order to selectively apply service classes to specific packets, the packets of interest must be classified in some fashion.

    The simplest way to classify a packet is to use behavior aggregate classification. The DSCP, DSCP IPv6, or IP precedence bits of the IP header convey the behavior aggregate class information. The information might also be found in the MPLS EXP bits, IEEE 802.1ad, or IEEE 802.1p CoS bits.

    You can configure the following classifier types:

    • DSCP, DSCP IPv6, or IP precedence—IP packet classification (Layer 3 headers)
    • MPLS EXP—MPLS packet classification (Layer 2 headers)
    • IEEE 802.1p—Packet classification (Layer 2 headers)
    • IEEE 802.1ad—Packet classification for IEEE 802.1ad formats (including DEI bit)

    If you apply an IEEE 802.1 classifier to a logical interface, this classifier takes precedence and is not compatible with any other classifier type. On Juniper Networks MX Series Ethernet Services Routers using IEEE 802.1ad frame formats, you can apply classification on the basis of the IEEE 802.1p bits (three bits in either the inner virtual LAN (VLAN) tag or the outer VLAN tag) and the drop eligible indicator (DEI) bit. On routers with IQ2 PICs using IEEE 802.1ad frame format, you can apply classification based on the IEEE 802.1p bits and the DEI bit. Classifiers for IP (DSCP or IP precedence) and MPLS (EXP) can coexist on a logical interface if the hardware requirements are met. (See Applying Behavior Aggregate Classifiers to Logical Interfaces.)

    The Enhanced Queuing DPC (EQ DPC) does not support BA classification for packets received from a Layer 3 routing interface or a virtual routing and forwarding (VRF) interface and routed to an integrated routing and bridging interface (IRB) to reach the remote end of a pseudowire connection. The EQ DPC also does not support BA classification for Layer 2 frames received from a Virtual Private LAN Service (VPLS) pseudowire connection from a remote site and routed to a Layer 3 routing interface through an IRB interface.

    Modified: 2017-03-23