Nortel Networks 5530, 5520, 5510 manual Policies, Default Policy Drop Action

Filters and QoS Configuration for ERS 5500
Technical Configuration Guide	v2.0	NN48500-559

		Max = 11
4	7	Min = 100
		Max = 111
8	15	Min = 1000
		Max = 1111
80	95	Min = 10100000
		Max = 10111111

3.4Policies

•Packets received on an interface are matched against all policies associated with that interface. Hence, all policies are applied to the packet.

•Policy precedence – the precedence attribute is used to specify the evaluation order of policies that apply to the same interfaces. Policies with higher precedence (i.e., a larger value) are applied before those with lower precedence (i.e., a smaller value). Precedence values must be unique for all policies being applied to the same interface role.

•If one policy associated with the specific interface only specifies a value updating the DSCP value while another policy associated with that same interface only specifies a value for updating the 802.1p user priority value, both of these actions occur.

•If two policies on the specified interface request that the DSCP be updated but specify different values - the value from the policy with the higher precedence will be used.

•Referenced component conflicts - action or meter criteria can be specified through individual classifier blocks. When a policy references a classifier block and members of the referenced block identify their own action or meter criteria, action and meter data must not be specified by the policy.

•The actions applied to packets include those actions defined from user-defined policies and those actions defined from system default policies. The user-defined actions always carry a higher precedence than the system default actions. This means that, if user- defined policies do not specify actions that overlap with the actions associated with system default policies (for example, the DSCP and 802.1p update actions installed on untrusted interfaces), the lowest precedence, default policy actions will be included in the set of actions to be applied to the identified traffic.

•The following table displays the ERS 5500 default policy action with corresponding drop actions. The drop action specifies whether a packet should be dropped, not dropped, or deferred. A drop action of deferred-Pass specifies that a traffic flow decision will be deferred to other installed policies.

Table 3: Default Policy Drop Action

ID	Name	Drop	Update DSCP	User Priority	Drop
					Precedence
1	Drop_Traffic	drop	Ignore	Ignore	highDropPrec
2	Standard_Service	Don’t Drop	0x00	Priority 0	highDropPrec
3	Bronze_Service	Don’t Drop	0x0a	Priority 2	lowDropPrec
4	Silver_Service	Don’t Drop	0x12	Priority 3	lowDropPrec
5	Gold_Service	Don’t Drop	0x1a	Priority 4	lowDropPrec
6	Platinum_Service	Don’t Drop	0x22	Priority 5	lowDropPrec
7	Premium_Service	Don’t Drop	0x2e	Priority 6	lowDropPrec
8	Network_Service	Don’t Drop	0x30	Priority 7	lowDropPrec
9	Null_Service	Don’t Drop	ignore	ignore	lowDropPrec

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