Suive
From: tom petch <[email protected]>
Sent: 22 December 2024 17:24
From: Acee Lindem <[email protected]>
Sent: 20 December 2024 18:26
This email begins a 2 week WG Last Call for the following draft: "Prefix Flag
Extension for OSPFv2 and OSPFv3" - draft-ietf-lsr-ospf-prefix-extended-flags-03
Please review the document and indicate your support or objections by January
11th, 2025. The extra week is to allow for the holidays.
<tp>
First impression - needs tidying up
'there are not many undefined bits'
How many? please work it out for me allowing for I-D work in progress and the
like.
Perhaps, 'At the time of writing, there are ...' better still, identify the
bits
/flield/ field /
'that are undefined as shown in Table 1.'
well, no; undefined does not figure in Table 1 (but it should IMHO)
If no flags are defined is it valid to send the Sub-TLV?
'An implementation that
does not understand or support the Prefix Attribute Flags Sub-TLV
MUST ignore the TLV.'
which is fine if that behaviour is already in place. What is the expected
behaviour for Sub-TLV that is not recognised? where is it defined?
And 'ignore the TLV' or 'ignore the Sub-TLV'?
<tp2>
'capabilities,by
There is a character in there after the comma but it does not seem to be
behaving the way I expect a space to
| TBD | U | [I-D.ietf-lsr-igp-ureach-prefix-announce] |
** should be Normative IMHO
' This document creates the variable length Prefix Attribute Flags Sub-
TLVs for OSPFv2 and OSPFv3 respectively. '
Not really - it just creates the one for both so 'respectively ' confuses me
' It MUST be a multiple of 4 octets.'
and if not? ignore the excess? ignore the sub-TLV? what if the TLV appears
twice, once valid and once invalid because someone realised they had made a
mistake but did not clean up properly?
Ditto for OSPFv3.
'Currently, no bits are defined in this document.
Unassigned bits MUST be set to zero on transmission and MUST be
ignored on receipt.'
What is the difference between 'defined' and '(un)assigned'?
3,
'Flags that an implementation is
not supporting MUST be set to zero on transmission'
And if no flags are supported, is the Sub-TLV omitted or sent with zeros?
'it currently supports or understands, '
What is the difference between supports and understands? 'understands' seems
redundant
'as if they are set to 0'
'it MUST act as if
the bits beyond the length were not set.'
Is there a difference between not set and set to zero? I do not see one
More generally, if a future implementation supports e.g five flags but the
transmitting implemenation only supports three, can the receiver tell? I think
not which means that the zero state of a flag must cause no action, no change.
Seems quite a burden, a pitfall that others may fall into in future.
Tom Petch
Thanks,
Acee
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