Subject: [dhcwg] Review of draft-ietf-dhc-dynamic-shared-v4allocation-02

From: Tom Taylor <[email-masked]>
Date: Thu, 30 Oct 2014 19:19:25 -0400

Hi. Thought I'd respond to the call for review.

Tom Taylor

Summary:

Major issues:

Minor issues:

1) There seems to be an inconsistency between Section 5 and 7 and 
Section 6 on the other:

Sec. 5 and 7: The client MAY insert an
        OPTION_V4_PORTPARAMS with a non-zero value in the PSID-Len field
        to indicate a preferred size for the restricted port set to the
        DHCP 4o6 Server.

Sec. 6, third bullet:
     o  The address requested in the 'Requested IP Address' option along
       with the PSID in the OPTION_V4_PORTPARAMS, if the requested pair
       of address and PSID is valid and not already allocated

So which is it, PSID value or (much trickier to manage) PSID length? In 
the latter case, I can see garbage collection issues, as the PSID space 
gets fragmented by repeated client attachments and detachments from the 
network.

2) The operator configures a reserved set of ports. The advice on PSID 
assignment to exclude these ports at the end of Section 8 has a SHOULD 
NOT. Under what circumstances would the server violate its configured 
policy?

Editorial and nits:

1) Abstract, first sentence of second paragraph:

OLD

    Due to the nature of IP addresses sharing, some limitations to their
    applicability are necessary.

NEW

    Due to the nature of IP address sharing, some limitations to its
    applicability are necessary.  ^^                             ^^^

In English, "address" is sort of a kludged noun-turned-adjective 
modifying "sharing" and "IP address sharing" is a singular subject.

2) Section 2, RFC 2119 reference is duplicated.

3) Section 6, end of second last paragraph: s/messages/message/.

4) Section 7.1, first bullet, rewrite in active voice:

OLD

    o  Only port-aware protocols or ICMP implementing [RFC5508] MUST be
       used.
  (Doesn't quite say what you want.)

NEW

    o  The client MUST use only port-aware protocols or ICMP 
implementing [RFC5508].

5) Section 8, fourth bullet below Figure 1, s/valid/the value/

6) Section 8, final paragraph, for accuracy and consistency with 
previous text. The SHOULD NOT as opposed to MUST NOT is questioned above 
as a minor issue.

OLD

  In order to exclude the system ports ([RFC6335]) or ports saved by
    ISPs, the former port-sets that contain well-known ports SHOULD NOT
    be assigned.

NEW

Some PSIDs may include ports within ranges excluded by the operator 
(e.g., the well-known ports 0-1023). These SHOULD NOT be assigned to any 
client.