Hi Dan,
please see inline:
On 05/10/17 13:05 , Dan Romascanu wrote:
Reviewer: Dan Romascanu
Review result: Ready with Issues
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Document: draft-ietf-ospf-segment-routing-extensions-19
Reviewer: Dan Romascanu
Review Date: 2017-10-05
IETF LC End Date: 2017-10-13
IESG Telechat date: Not scheduled for a telechat
Summary:
A useful and well-written document. It requires previous reading and
understanding of OSPF, SPRING and other routing work. It is Ready for
publication. I found some unclear minor issues. I recommend to address them
before approval and publication.
Major issues:
Minor issues:
1. I am wondering why, at this stage of progress of the document, the type
values are still 'TBD, suggested value x'. Is there any other document defining
this?
good point, fixed it.
2. Section 3.1 - are there other algorithms planned to be added in the future?
If yes, do we need a registry? If no, what is this field an octet?
yes, we know about this. The question is where do we want to put this
registry - draft-ietf-spring-segment-routing defines Prefix-SID
Algorithms 3.1.1. Both IGP SR drafts defines the same algorithms. This
looks redundant. We need to keep it either in
draft-ietf-spring-segment-routing and define a registry there and remove
the definitions from IGP SR drafts and simply point to them to
draft-ietf-spring-segment-routing. An alternative is to remove the
section 3.1.1 from teh draft-ietf-spring-segment-routing and keep the SR
Algorithm definition in IGP SR drafts and define the registry in one of
them.
I need to talk to authors of draft-ietf-spring-segment-routing to
resolve this.
3. It would be useful to mention that the Length fields are expressed in
Octets. Also please clarify if padding is applied or not.
I fixed those cases where the "octets" was missing in the Length
specification.
For the padding, all OSPF TLVs are always padded to 4-octet alignment. I
don't believe we need to specify that here again.
4. Section 3.3:
'The originating router MUST NOT advertise overlapping ranges.'
How are conflicts resolved at receiver?
SRLB sub-TLV is not used by routers running ISIS. The advertisement is
only there for the benefit of external entities such as controllers so
they can determine what labels are available for assignment. We do not
define controllers behavior in our drafts.
5. I like Section 9 - Implementation Status - which I found rather useful. Is
there any chance to keep a trimmed down version of it, with synthetic
information on the lines of 'at the time the document was discussed a survey
was run, it showed that there were x implementation, y were implementing the
full specification, z were included in released production software ....'
I'm not sure, typically such section is removed prior to publication. I
have no problem keeping it if that is allowed.
6. Section 10 - beyond recommending the counting and logging of the mal-formed
TLVs and sub-TLVs, should not supplementary security recommendations be made?
for example - throttling mechanisms to preempt DoS attacks.
added following statement:
"Logging of malformed TLVs and Sub-TLVs should be rate-limited to
prevent a Denial of Service (DoS) attack (distributed or otherwise) from
overloading the OSPF control plane. "
thanks,
Peter
Nits/editorial comments:
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