07-12-2019 02:41 PM
LHi all,
The ACI endpoint learning white paper describes an issue with a stale endpoint when a server is deployed on a border node
The white paper states "This behavior is observed only when a packet to L3Out is sourced from a first-generation leaf switch."
What is different on 2nd generation leaf switches that solves this problem?
Thanks!
Solved! Go to Solution.
07-13-2019 05:36 PM - edited 07-13-2019 05:44 PM
Hi Bram,
It is due to GEN1 switches setting the DL (don' learn) bit in the iVXLAN header. The DL bit informs a remote leaf that it should not do dataplane learning for the particular frame.
Consider the following:
Leaf 101 - Compute Leaf
Leaf 103 - Compute Leaf
Leaf 105 - Border Leaf (BL)
GEN2 switches do not have this issue. Disabling remote EP learning fix:
Also, in 3.2 we introduced a new feature called EP Announce which should prevent stale endpoint issues (I have yet to see a stale EP issue since this). Basically when the bounce timer expires, leaf sends EP announce delete message which will trigger an XR delete on any leaf still pointing to the old leaf.
Hope this helps.
07-13-2019 05:36 PM - edited 07-13-2019 05:44 PM
Hi Bram,
It is due to GEN1 switches setting the DL (don' learn) bit in the iVXLAN header. The DL bit informs a remote leaf that it should not do dataplane learning for the particular frame.
Consider the following:
Leaf 101 - Compute Leaf
Leaf 103 - Compute Leaf
Leaf 105 - Border Leaf (BL)
GEN2 switches do not have this issue. Disabling remote EP learning fix:
Also, in 3.2 we introduced a new feature called EP Announce which should prevent stale endpoint issues (I have yet to see a stale EP issue since this). Basically when the bounce timer expires, leaf sends EP announce delete message which will trigger an XR delete on any leaf still pointing to the old leaf.
Hope this helps.
07-13-2019 11:58 PM - edited 07-14-2019 12:09 AM
Thanks Michael for the detailed explanation!
Does this mean that when traffic is send from a Gen2 leaf to a L3out on a boarder leaf, that the border leaf does learn the remote endpoint?
07-14-2019 09:30 AM
Correct it doesn't set the DL bit. Highly recommend to upgrade to 3.2 or higher though. Fixes almost all stale EP issues with EP announce feature.
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