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Mode
Global Config
8.3 CLI Commands: Differentiated Services
This chapter contains the CLI commands used for the QOS Differentiated Services (DiffServ) package.
The user configures DiffServ in several stages by specifying:
1. Class
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creating and deleting classes
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defining match criteria for a class. Note: The only way to remove an individual match criterion
from an existing class definition is to delete the class and re-create it.
2. Policy
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creating and deleting policies
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associating
classes with a policy
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defining policy statements for a policy/class combination
3. Service
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adding and removing a policy to/from a directional (i.e., inbound, outbound) interface
Packets are filtered and processed based on defined criteria. The filtering criteria are defined by a class.
The processing is defined by a policy's attributes. Policy attributes may be defined on a per-class
instance basis, and it is these attributes that are applied when a match occurs.
Packet processing begins by testing the match criteria for a packet. A policy is applied to a packet when a
class match within that policy is found.
Note that the type of class - all, any, or acl - has a bearing on the validity of match criteria specified when
defining the class. A class type of 'any' processes its match rules in an ordered sequence; additional rules
specified for such a class simply extend this list. A class type of 'acl' obtains its rule list by interpreting
each ACL rule definition at the time the Diffserv class is created. Differences arise when specifying match
criteria for a class type 'all', since only one value for each non-excluded match field is allowed within a
class definition. If a field is already specified for a class, all subsequent attempts to specify the same field
fail, including the cases where a field can be specified multiple ways through alternative formats. The
exception to this is when the 'exclude' option is specified, in which case this restriction does not apply to
the excluded fields.
The following class restrictions are imposed by the DiffServ design:
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nested class support limited to:
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'any'
within
'any'
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'all'
within
'all'
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no nested 'not' conditions
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no nested 'acl' class types
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each class contains at most one referenced class
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hierarchical service policies not supported in a class definition
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access list matched by reference only, and must be sole criterion in a class