Robert Wilton has entered the following ballot position for draft-ietf-ospf-te-link-attr-reuse-15: No Objection
When responding, please keep the subject line intact and reply to all email addresses included in the To and CC lines. (Feel free to cut this introductory paragraph, however.) Please refer to https://www.ietf.org/iesg/statement/discuss-criteria.html for more information about IESG DISCUSS and COMMENT positions. The document, along with other ballot positions, can be found here: https://datatracker.ietf.org/doc/draft-ietf-ospf-te-link-attr-reuse/ ---------------------------------------------------------------------- COMMENT: ---------------------------------------------------------------------- Discuss cleared. Thank you for addressing my comments. Two possible nits in section 5: If the same attribute is advertised in more than single ASLA sub-TLVs with the application listed in the Application Bit Masks, the application SHOULD use the first instance of advertisement and ignore any subsequent advertisements of that attribute. Propose changing "single" to "one". If link attributes are advertised associated with zero length Application Identifier Bit Masks for both standard applications and user defined applications, then any Standard Application and/or any User Defined Application is permitted to use that set of link attributes. Propose changing "associated with" to "with associated" or just "with" Thanks, Rob Previous discuss comments: I found parts of this document hard to understand, but I'm not familiar with the specifics of the protocols. This discuss is in the vein of "I think that folks might struggle to implement this correctly/consistently". In particular I had some questions/concerns about section 5 which, if clarified, would probably help this document. In Section 5: The ASLA sub-TLV is an optional sub-TLV and can appear multiple times in the OSPFv2 Extended Link TLV and OSPFv3 Router-Link TLV. The ASLA sub-TLV MUST be used for advertisement of the link attributes listed at the end on this section if these are advertised inside OSPFv2 Extended Link TLV and OSPFv3 Router-Link TLV. It has the following format: I think that it would be useful to clarify when/why the ASLA sub-TLV can be included multiple times. I.e. when different applications want to control different link attributes. Standard Application Identifier Bits are defined/sent starting with Bit 0. Undefined bits which are transmitted MUST be transmitted as 0 and MUST be ignored on receipt. Bits that are not transmitted MUST be treated as if they are set to 0 on receipt. Bits that are not supported by an implementation MUST be ignored on receipt. It was not clear to me what it means if the SABM (or UDABM) fields are entirely empty. This paragraph states that they are treated as if they are 0, but sections 8 and 11 imply that if the field is omitted then it acts as if all applications are allowed. Section 12.2 implies that if the field is omitted then it is as if all applications are allowed unless there there is another ASLA with the given application bit set, in which case it is treated as being a 0 again. I think that this document would be helped if the specific behaviour was defined in section 5, retaining the justification/clarification in the subsequent sections. It is also not entirely clear to me exactly how the bits are encoded on the wire. My assumption is that if bit 0 is set, then this would sent the highest bit of the first byte. E.g. 0x80? Is that correct? If not, then I think that the document needs more text, if so, then an example of the encoding may still aid readability. User Defined Application Identifier Bits have no relationship to Standard Application Identifier Bits and are not managed by IANA or any other standards body. It is recommended that bits are used starting with Bit 0 so as to minimize the number of octets required to advertise all UDAs. Doesn't this need more constraints to ensure easy interop (i.e. bits default to 0). Otherwise, it would seem that anyone is allowed to put any value in this field that they like that could harm interop, or otherwise it might be tricky to compare a 4 byte UDABM to an 8 byte UDABM? This document defines the initial set of link attributes that MUST use the ASLA sub-TLV if advertised in the OSPFv2 Extended Link TLV or in the OSPFv3 Router-Link TLV. Documents which define new link attributes MUST state whether the new attributes support application specific values and as such MUST be advertised in an ASLA sub-TLV. The link attributes that MUST be advertised in ASLA sub-TLVs are: I think that I get what this means, but I find the last two sentences slightly jarring given than the ASLA TLV is optional. Perhaps predicate both of these constraints with "(if supproted)". E.g., something like, Documents which define new link attributes MUST state whether the new attributes support application specific values and as such MUST be advertised in an ASLA sub-TLV (if supported). The link attributes that MUST be advertised in ASLA sub-TLVs (if supported) are: _______________________________________________ Lsr mailing list Lsr@ietf.org https://www.ietf.org/mailman/listinfo/lsr
