Re: [OSPF] WG Adoption Poll for "Using Operator-defined TLVs for Agile Service Deployment"

Les,

In-line [Uma]:

--
Uma C.

-----Original Message-----
From: OSPF [mailto:ospf-bounces@ietf.org] On Behalf Of Les Ginsberg (ginsberg)
Sent: Wednesday, March 16, 2016 9:41 PM
To: Acee Lindem (acee); OSPF WG List
Subject: Re: [OSPF] WG Adoption Poll for "Using Operator-defined TLVs for Agile Service Deployment"

My opinion of the draft has not changed.
It is defining a way to utilize OSPF to send application information - which is not something the protocol should be used to do.
Further, it leaves definition of the new codepoints and formats of the information advertised completely unspecified - the latest draft revision states:

" The meaning of the operator-defined sub-TLV is totally opaque to OSPF
   and is defined by the network local policy and is controlled via
   configuration.  "

How interoperability is achieved is not addressed at all.

[Uma]: The whole point of the draft is,  not to define the format for the sub-TLVs so that it can be used  as per the sub-tlv type as set by the operator (for example service attribute/Label).  Sub-TLV has set of attribute length and attribute value in NBO.

IS-IS has taken a much more stringent approach to a similar request. 	

[Uma]: .. and hence unfortunately I see no body saw using it- in fact including you. For example https://tools.ietf.org/html/draft-ietf-isis-sbfd-discriminator-02 could have used GENAPP but rather resorted to Router capabilities (Remember IETF90 discussion around this).

RFC 6823 (GENAPP) requires that information sent in the generic container TLV MUST be based on a public specification - and that an application specific ID for the application using this mechanism be assigned by IANA. This addresses the interoperability issue.
GENAPP further specifies that such information SHOULD be advertised by a separate instance of the routing protocol (as specified in RFC 6822(MI)) so as to minimize the impact of the application information flooding on the performance of the routing protocol.

[Uma]: As I indicated earlier [I-D.ietf-ospf-transport-instance] can be definitely used if the information related to application need to be used there. If it is used for supporting routing one can use this TLV.

Without addressing both of these issues I cannot support the draft.

   Les

> -----Original Message-----
> From: OSPF [mailto:ospf-bounces@ietf.org] On Behalf Of Acee Lindem
> (acee)
> Sent: Wednesday, March 16, 2016 7:09 PM
> To: OSPF WG List
> Subject: [OSPF] WG Adoption Poll for "Using Operator-defined TLVs for 
> Agile Service Deployment"
> 
> We’ve discussed this draft a number of times. In my opinion, it seems 
> like a useful mechanism if one envisions a generalized API between 
> OSPF and user and third-party applications to convey 
> application-specific information learned from other OSPF routers. In 
> many respects, this has already been envisioned for OSPF Node Tags. 
> Please indicate your opinion on this draft before March 31st, 2016.
> 
> Thanks,
> Acee
> 
> _______________________________________________
> OSPF mailing list
> OSPF@ietf.org
> https://www.ietf.org/mailman/listinfo/ospf
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