Fabric Path / Multidestination topology tree

[andy!doesnt!like!uucp]

Hello Gents

Can somebody explain or help with ref on how Fabric Path multidestination tree converges in case of ISL failures?

F.e. lets assume from picture below that ISL between S100 and S10 has failed. If immidiately after the link failure S200 cannot be notified that S100 is no longer available via Tree 1, S200 may decide to use Tree 1 for frame forwarding, and frame will be dropped on S10. Thus there must be mechanism to almost immediately notify S200 (and probably all the othe leafs) to completely switch to tree 2.

                  

[Jerry Ye]

What traffic are you referring? Multidestination tree are used for multicast, broadcast and unknown unicast.

In terms of how FP rebuilt the tree (not switch from tree 1 to tree 2), the underlying control protocol ISIS will do the recalcuation when links or switches failed.

HTH,

jerry

[andy!doesnt!like!uucp]

While Q also addresses broadcast and unknown unicast, generally it refers to multicast (assume multicast sender is located on S200). Ok, as I understand U both topologies Tree1 and Tree2 are also rebuilt during IS-IS convergence?

Thank U

[Jerry Ye]

That is correct.

Regards,

jerry