Here is my RTG-DIR Early Review of draft-ietf-lsr-ip-flexalgo-06.

Regards
Matthew

Summary
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The document is generally well written. Thank you. I have a few comments/nits as listed below.

Major Comments: 
It is not clear to me how, in the IPv6 case, you can distinguish between flex-algo for IPv6 and SRv6. For example, you could advertise an IPv6 prefix for both SRv6 and "native" IPv6 with different flex-algos. How do you decide which to use?

Minor Comments:
Figure 4: The formatting of the figure looks like it is missing some characters and the field after 'algorithm' is blank. My reading of this is that the Pfx Length starts on Bit 0 of the 32-bit aligned block, but I think what you mean is that Pfx Length comes immediately after the Algorithm field, so it is not 32-bit aligned with e.g. the Flags field. Please can you look at how this is presented and clarify.

Nits:
- The definite and indefinite articles (e.g. the, a, etc) are missing in places. Please go through and add these as it would make the draft much more readable.
- Section 7 Title: "Calculating of IP...". This should probably be "Calculation of IP...".
- Section 8, 3rd Paragraph: "calculated using such Flex-Algorithm" should be "calculated using this Flex-Algorithm".
- Section 9, 1st paragraph. I suggest breaking/rewording the second sentence as follows: "The original specification was for SR and SRv6. This specification adds IP as another data-plane...".
- While we are on the topic of data planes, SRv6 is often thought of as "Segment Routing with an IPv6 Data Plane" to many people. Maybe it would be worth talking about a 'native' IP data plane in this draft?
- Section 9: Last paragraph. "..same time and, and as such, ...". Delete the first 'and'.