Subject: [lisp] Suresh Krishnan's Discuss on draft-ietf-lisp-lcaf-16: (with DISCUSS and COMMENT)

From: "Suresh Krishnan" <[email-masked]>
Date: Tue, 11 Oct 2016 18:19:25 -0700

Suresh Krishnan has entered the following ballot position for
draft-ietf-lisp-lcaf-16: Discuss

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DISCUSS:
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The way that the length field is specified in this document is
inconsistent, extremely confusing and sometimes wrong. 

e.g. In Section ASCII Names in the Mapping Database 

Length value n:  length in bytes AFI=17 field and the null-terminated
ASCII string (the last byte of 0 is included).

but the field mentions 2+n. Only one of these can be correct

Similarly in Section 4.9.  Replication List Entries for Multicast
Forwarding

   Length value n:  length in bytes of fields that follow.

but the field mentions 4+n. Again one of these can be correct.

Similar error in Section 5.2 (Generic Database Mapping Lookups)

* Section 4.10.4.  Using Recursive LISP Canonical Address Encodings

The "IP TOS, IPv6 QQS or Flow Label" field is underspecified and cannot
be implemented in an interoperable manner. There are multiple ways to
encode the 8 bit values (the IP TOS and the IPv6 Traffic Class) into the
24 bit field. Similarly, there are at least two obvious ways to encode
the 20 bit flow label into this field.

Also the "IPv6 QoS" needs to be renamed to "IPv6 Traffic Class"

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COMMENT:
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* Can you please clarify why Rsvd2 is reserved for future use but this
document already ends up specifying it under "Segmentation"

* I think the reference for AFI is not correct. Shouldn't it be
http://www.iana.org/assignments/address-family-numbers/address-family-numbers.xhtml?
The current reference leads to a generic IANA page.

* Section 4.8:

Is the explanation for the AFI correct? The source dest lookups don't
seem to be multicast addresses.

"When a specific AFI has its own encoding of a multicast address, this
field must be either
      a group address or a broadcast address."