IOS-XR has duplicate update suppression logic for EBGP sessions,
not for IBGP sessions.
If you are using EBGP and seeing a fault in the duplicate update
suppression logic in IOS-XR, please let me know configs and details
of the experiment.
IOS-XR has duplicate update suppression logic for EBGP sessions
as, i believe, do most all implementations, to protect best path
Does this feature hinder incoming duplicates from triggering best path selection or does it stop the export of duplicates?
This feature suppresses outgoing duplicates. Another feature ignores incoming duplicates from any BGP session.
The simple configuration below allows communities to be forwarded
(send-community-ebgp), but are cleaned at egress (using route-policy and
In the experiment, the router receives announcements with altering
community attributes only, from the internal peer. After the filter is
applied, the router sends duplicates to the external peer.
Also, In a slightly different setup, the router sends duplicates due to
changes in the next-hop only.