[spring] solicit feedback on draft-dunbar-sr-sdwan-over-hybrid-networks-02 proposing SD-WAN source node using UDP port to indicate to SR ingress node how to map to appropriate Binding SID

[Linda Dunbar <[e-mail]>]

https://datatracker.ietf.org/doc/draft-dunbar-sr-sdwan-over-hybrid-networks/ describes a method for end-to-end (E2E) SD-WAN paths (most likely encrypted) to traverse specific list of network segments, some of which are SR enabled and others may be IP networks that do not support SR, to achieve the desired optimal E2E quality. 
In another word, one or both SD-WAN end points are NOT directly attached to SR PE nodes. 

Under many circumstances the SR's Binding SID can't be exposed to the SD-WAN source node (e.g. if the SD-WAN source node belongs to a different administrator than the one who manage/own the SR domain). 

The draft propose a method for SR Controller to expose a "Key" to the SD-WAN source node. The SR Ingress node will map the "Key" carried by the SD-WAN traffic/flows to their designated Binding SID. 
The "Key" can be carried by GRE key field, or be encoded as UDP Source Port used by SD-WAN source node to differentiate flows. 

We understand that UDP source port is usually used for Entropy purpose. 

We want to hear feedback, flaws or allergic reaction to our proposed method for some deployment scenarios like: 
  1) only one or two 3rd party hops are between SD-WAN end points and PE and those hops may not even use Entropy (like LTE links); or 
  2) Grouping Applications by UDP ports may enforce same application traverse through same route, which is acceptable by many deployment scenarios).

Thank you very much. 

Linda Dunbar