[Roll] route preference using an “administrative distance”

"Pascal Thubert (pthubert)" <pthubert@cisco.com> Thu, 23 May 2019 06:32 UTC

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From: "Pascal Thubert (pthubert)" <pthubert@cisco.com>
To: Routing Over Low power and Lossy networks <roll@ietf.org>
Thread-Topic: route preference using an “administrative distance”
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Date: Thu, 23 May 2019 06:32:16 +0000
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Subject: [Roll] route preference using an “administrative distance”
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Dear all

The general idea in PDAO is that a projected route has precedence over a same route obtained from the distributed instance but the “administrative distance” involved in that process is not really specified. We could also use text to indicate that longest match wins against “administrative distance”.

My question is: should we indicate the “administrative distance” in the PDAO or keep it all implicit? Implicit saves space but implies that all P Routes have the same “administrative distance”, which is better than all distributed instances. Maybe we’re losing an important capability by not signaling the “administrative distance”.

Note that a same “administrative distance” could be placed in the DIO configuration in order to set the precedence between routes obtained from several instances, and projected routes.

My suggestion is to write a small draft on that. What do you think?

Pascal