[Sidrops] Comments on draft-ietf-sidrops-8210bis-01

["Borchert, Oliver (Fed)" <[e-mail]>]

Hi Randy and Rob,

Reading section “5.12 ASPA PDU” in draft-ietf-sidrops-8210bis-01 (8210-bis01), it mentions the possibility of zero provider ASs.


   ...An ASPA PDU represents one single customer AS

   and zero or more provider ASs for a particular Address Family.

   ...
   The Provider AS Count is the number of Provider Autonomous System
   Number(s) at the end of the PDU, and may be zero or more.
   ...

   The Provider AS Count is the number of 32-bit Provider Autonomous
   System Numbers in the PDU.  There may be none.


   There are zero or more 32-bit Provider Autonomous System Number

   fields; see [I-D.ietf-sidrops-aspa-profile<https://tools.ietf.org/html/draft-ietf-sidrops-8210bis-01#ref-I-D.ietf-sidrops-aspa-profile>].

I noticed though that the ASCII ART of the PDU specifies the field “Provider Autonomous System Number(s)” correctly as 1..N which means the field “Provider AS Count” cannot be zero.

  |                                           |
   +-------------------------------------------+
   |                                           |
   |   Provider Autonomous System Number(s)    |
   |                                           |
   ~-------------------------------------------~
The ASPA Profile (draft-ietf-sidrops-aspa-profile-XX) which is referred to in the text specifies 1..N provider ASs

      ASProviderAttestation ::= SEQUENCE {
           version [0] ASPAVersion DEFAULT v0,
           AFI  AddressFamilyIdentifier,
           customerASID  ASID,
           providerASSET  SEQUENCE (SIZE(1..MAX)) OF ASID }

I believe the wording in 8210-bis01 is still based upon the initial draft-ietf-sidrops-aspa-profile-00. Though since version 01, the draft was updated to require 1..N providers and 8210-bis01 needs to be updated (see below) to reflect these changes.

The proposed modification could be:

Change: /zero or more/one or more/

   ...An ASPA PDU represents one single customer AS

   and one or more provider ASs for a particular Address Family.

   ...


Change: /may be zero/must be one/
   The Provider AS Count is the number of Provider Autonomous System
   Number(s) at the end of the PDU, and must be one or more.
   ...

Change: /may be none/must be one or more/

   The Provider AS Count is the number of 32-bit Provider Autonomous
   System Numbers in the PDU.  There must be one or more.

Change: /zero or more/one or more/

   There are one or more 32-bit Provider Autonomous System Number

   fields; see [I-D.ietf-sidrops-aspa-profile<https://tools.ietf.org/html/draft-ietf-sidrops-8210bis-01#ref-I-D.ietf-sidrops-aspa-profile>].


In Addition I noticed Section 5.1 does not contain any of the new Fields and the “Flags” field does not contain any information on the new “AFI” bit used for ASPA. There are bits and pieces in 5.12 but a more detailed explanation in 5.1 would be great.


Thanks,
Oliver

-----------------------------------------------
Oliver Borchert, Computer Scientist
National Institute of Standards and Technology
(Office) +1.301.975.4856
(GVoice) +1.240.668.4117