Dell PowerConnect J-8216 Software Guide for JUNOS version 10.3 - Page 3137

Chapter 120: MPLS-Overview CCC interface on the same switch to use IEEE2. All the CCC interfaces on the switch must use the same DSCP classifier and the same type of IEEE 802.1p classifier. • You cannot configure one CCC interface as DSCP and another CCC interface as IP precedence, because these classifier types overlap. • You can configure one CCC interface as DSCP and another CCC interface as IEEE 802.1p. • You can configure one CCC interface as both DSCP and IEEE 802.1p. If you configure a CCC interface with both these classifiers, the DSCP classifier is used for routing Layer 3 packets and the IEEE 802.1p classifier is used for routing Layer 2 packets. NOTE: You can define multiple types of DSCP, IP precedence, and IEEE 802.1p on the switch and use the different classifier types for the non-CCC interfaces on the switch. Using CoS Classifiers with IP over MPLS When you are configuring CoS for IP over MPLS, the customer-edge interface uses the CoS configuration that has been set up for the switch as the default. You do not have to bind a classifier to the customer-edge interface in this case. There are no restrictions regarding using multiple types of DSCP, IP precedence, and IEEE 802.1p on the same switch. • You can modify the CoS classifier for a particular interface, but it is not required. • You can configure one interface as DSCP1 and another as DSCP2 and another and IP precedence, and so forth. Default Classifiers and Default Rewrite Rules The default classifiers support only two forwarding classes, best-effort and network-control, and use only two queues, 0 and 7. However, J-EX Series switches support up to sixteen forwarding classes and eight queues. To use the additional forwarding classes and queues, create a custom classifier. To modify the code point and loss priority for a specific forwarding class, configure a rewrite rule on the switch. The default rewrite rule for EXP is enabled in the default configuration. However, the default rewrite rules for the other classifiers are not enabled in the default configuration. You can display the default classifier mappings and default rewrite mappings by entering the show class-of-service command on the switch. EXP Rewrite Rules When traffic passes from the customer-edge interface to an MPLS interface, the DSCP, IP precedence, or IEEE 802.1p CoS classifier is translated into the EXP bits within the MPLS header. You cannot disable the default EXP rewrite rule, but you can configure your own custom EXP classifier and a custom EXP rewrite rule. You cannot bind the EXP classifier to individual MPLS interfaces; the switch applies it globally to all the MPLS-enabled interfaces on the switch. 3065