BGP Routing Policies - BGP Communities - Filtering NLRIs Using Special COMMUNITY Values

7 important questions on BGP Routing Policies - BGP Communities - Filtering NLRIs Using Special COMMUNITY Values

What are the COMMUNITY Values Used especially for NLRI Filtering?

NO_EXPORT FFFF:FF01
NO_ADVERT FFFF:FF02
LOCAL_AS/NO_EXPORT_SUBCONFED(RFC 1997) FFFF:FF03
Report

What does the COMMUNITY Value NO_EXPORT mean and what is the value?

-FFFF:FF01
-Do not advertise outside this AS
-Can be advertised to other confederation autonomous systems

AS 1 could advertise eBGP route into AS 2 only
AS2 will only advertise route inside AS 2
Report

What does the COMMUNITY Value NO_ADVERT mean and what is the value?

-FFFF:FF02
-Do not advertise to any iBGP peer

Router 1 can advertise a route to Router 2
Router 2 will not advertise to any other router
Report

What does the COMMUNITY Value LOCAL_AS mean and what is the value?

-FFFF:FF03
-Do  not advertise outside the local confederation sub-AS
Report

When can the COMMUNITY LOCAL_AS be used?

To prevent an sub-AS to be a transit sub-AS (confederations)
Report

When can the COMMUNITY NO_ADVERT be used?

allows a router to advertise a prefix to a peer, with the intent that the peer will not advertised the route
Report

What is the command to check the routes with NO_EXPORT/NO_ADVERT/LOCAL_AS

show ip bgp community no-export
show ip bgp community no-advertise
show ip bgp community local-as
Report

The question on the page originate from the summary of the following study material:

  • A unique study and practice tool
  • Never study anything twice again
  • Get the grades you hope for
  • 100% sure, 100% understanding
Remember faster, study better. Scientifically proven.
Trustpilot Logo
  • Higher grades + faster learning
  • Never study anything twice
  • 100% sure, 100% understanding
Discover Study Smart