Re: suppress-map vs advertise-map

 Hi Modi,
I think this may help..
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094826.shtml
Impact of the Use of suppress-map with Other Configuration Commands

The *aggregate-address* command includes other configuration commands, such
as *suppress-map*. In order to understand the impact of the use of all the
configuration commands in combination, note that *aggregate-address* only
inherits the attributes from the more-specific routes when you use the *
as-set* configuration command. Examples of the attributes that *
aggregate-address* can inherit include *no-export* and *no-advertise*.

   -

   When you use the *suppress-map* configuration command along with the *
   summary-only* configuration command, the *summary-only* configuration
   command does not have any effect. With use of the
*suppress-map*configuration command, the more-specific routes that the
   *suppress-map* suppresses are not advertised. However, the routes that
   the *suppress-map* does not cover are advertised in addition to the
   aggregated route. Therefore, the notes in this section apply to the use of
   *suppress-map* either with or without the *summary-only* configuration
   command.
   -

   When you use *as-set* with *suppress-map*, although the suppressed routes
   are not advertised, the aggregated route inherits the attributes of all the
   suppressed routes. But you can override the inherited attributes with the
   use of other configuration commands, such as *attribute-map*. The Change
   the Attributes of the Aggregate
Route<http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094826.shtml#changingtheattributesoftheaggregateroute>section
describes the use of
   *attribute-map*.
   -

   When you use the *as-set* and *suppress-map* configuration commands with
   *advertise-map*, the aggregate forms. The aggregate inherits the
   attributes only out of the routes that are selected in the *advertise-map
   *, irrespective of whether *suppress-map* suppresses the route. See the Use
   advertise-map to Aggregate a Subset of Specific
Routes<http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094826.shtml#usingadvertisemaptoaggregateasubsetofspecificroutes>section.
   -

   When you use *advertise-map* and *attribute-map* along with *as-set* and
   other configuration commands, the *attribute-map* overrides the
   attributes that are chosen in the *advertise-map*.

In general, when you use *advertise-map*, only the
*advertise-map*influences the aggregate. In the absence of
*advertise-map*, the aggregate inherits the attributes of the more-specific
routes, both suppressed and unsuppressed. In both the cases, you can use the
*attribute-map* configuration command to override the chosen attributes.

HTH

-Kaushal

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Received on Tue Jun 30 2009 - 15:53:05 ART