Early Review of draft-ietf-rtgwg-srv6-egress-protection-09
review-ietf-rtgwg-srv6-egress-protection-09-opsdir-early-hares-2023-08-08-00

This is an OPS-DIR review of draft-ietf-rtgwg-srv6-egress-protection-09.
This review should be taken as an early review just as other reviews.

Status: Serious Issues + editorial issues
Why: The text describes mechanisms, ISIS sub-TLVs, OSPF sub-TLVs, and security
issues. Each of these sections has problems that need to be fixed before WG LC.

What should the authors do:
I'll happily work with the authors to correct the text. The text in version 09
does not provide a clear way for interoperable implementations. I will also
review -12 to check if these issues have been resolved.

Mechanisms:
The mechanisms provide steps that are unclear and are not easily aligned with
the example. The mechanism section contains the following: - description of
figure 1 - step 1: a normal path set-up (PEA) - step 2: a backup pat set-up
(PEB)
    step 2a: PEB announcement to PEA with PEB
    step 2b: PEA processes the announcement and sends forwarding behavior to PEB
    step 2c: PEB processes forwarding based on Mirror SID into table
    step 2d: processing of anycast that links PEA/PEB to compute LFA with SIDs
- step 3: Steps in fail-over in failure scenario
   step 3a: failure detected via BFD
   step 3b: send IPv6 packet with an encapsulated packet (H.Encaps) at PL1
   step 3c: decapsulate IPv6 packet with End.M (a variant of End.DT6)
- step 4: Handle processing and forwarding a PEB

If these are the correct steps, then the example in section 3.2.
If these are not the correct steps, you confirm the reading is difficult.

Extensions to IS-IS.
The following fields need to be given a range.
Section 4.1
For figure 3 description, please correct the following:
a) length: Please give a valid range.
b) Flags: Normally a reserved value has a default setting (all zeros?) for
transmit,
       and ignore upon reception.
c) SRv6 Endpoint Function: Please give valid range.
d) SID: 16 octets (please give valid ranges.  For example, is SID 0 valid?)

for Figure 4, please valid ranges for length field.

Section 4.2
For figure 5, please correct the following:
length: Please give the valid range.
flags: Normally a reserved value has a default setting (all zeros?) for
transmit,
       and ignore upon reception.
SRv6 Endpoint Function: Please give valid range.
SID: 16 octets (please give valid ranges.  For example, is SID 0 v

The Security Considerations section should provide reasons why this mechanism
to provide re-routing does not provide a potential threat.  It may work in a
walled garden, but it is not clear there are "no extra security issues."