Prefix Lists; Route Maps; Match Criteria; C H A P T E R 16 Configuring Route Policy Manager - Cisco Nexus 7000 Series Configuration Manual

Information About Route Policy Manager
S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m .

Prefix Lists

You can use prefix lists to permit or deny an address or range of addresses. Filtering by a prefix list
involves matching the prefixes of routes or packets with the prefixes listed in the prefix list. An implicit
deny is assumed if a given prefix does not match any entries in a prefix list.
You can configure multiple entries in a prefix list and permit or deny the prefixes that match the entry.
Each entry has an associated sequence number that you can configure. If you do not configure a sequence
number, Cisco NX-OS assigns a sequence number automatically. Cisco NX-OS evaluates prefix lists
starting with the lowest sequence number. Cisco NX-OS processes the first successful match for a given
prefix. Once a match occurs, Cisco NX-OS processes the permit or deny statement and does not evaluate
the rest of the prefix list.
Note An empty prefix list permits all routes.

Route Maps

You can use route maps for route redistribution or policy-based routing. Route map entries consist of a
list of match and set criteria. The match criteria specify match conditions for incoming routes or packets,
and the set criteria specify the action taken if the match criteria are met.
You can configure multiple entries in the same route map. These entries contain the same route map
name and are differentiated by a sequence number.
You create a route map with one or more route map entries arranged by the sequence number under a
unique route map name. The route map entry has the following parameters:
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By default, a route map processes routes or IP packets in a linear fashion, that is, starting from the lowest
sequence number. You can configure the route map to process in a different order using the continue
statement, which allows you to determine which route map entry to process next.

Match Criteria

You can use a variety of criteria to match a route or IP packet in a route map. Some criteria, such as BGP
community lists, are applicable only to a specific routing protocol, while other criteria, such as the IP
source or the destination address, can be used for any route or IP packet.
When Cisco NX-OS processes a route or packet through a route map, it compares the route or packet to
each of the match statements configured. If the route or packet matches the configured criteria, Cisco
NX-OS processes it based on the permit or deny configuration for that match entry in the route map and
any set criteria configured.
The match categories and parameters are as follows:
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Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
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Sequence number
Permission—permit or deny
Match criteria
Set changes
IP access lists—(For policy-based routing only). Match based on source or destination IP address,
protocol, or QoS parameters.
Chapter 16 Configuring Route Policy Manager
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