Subject: WG ACTION: continued 1 week discussion [LL53] Forward references requested

From: Erik Guttman <[email-masked]>
Date: Tue, 25 May 2004 17:54:30 +0200 (CEST)

LL53:

Several suggestions and comments had to be merged.  Please respond by
June 2 if there are any comments on this proposed resolution.  If no
comments are received, I will assume the change will be accepted as
stated, below.

--------------------------------------------

I received 3 direct emails supporting the suggested change of section 3.1
below and Bernard agreed.

Those who responded supported the additional text for the constants,
suggested by Stuart.

Since LL69 was rejected, and there was no support for the additional text
that Stuart suggested, most of the text added was dropped in the below
proposed resolution.

Please note that I left the text "Future standards documents..." which
I think is excellent.  It captures the thread which Mika and others
championed.

--------------------------------------------

Section 9, From:

   The following timing constants are used in this protocol; they are
   not intended to be user configurable.

   PROBE_MIN              1 second
   PROBE_MAX              2 seconds
   ANNOUNCE_INTERVAL      2 seconds
   PROBE_N                2
   ANNOUNCE_N             2
   NUM_PROBES             3
   MAX_COLLISIONS        10
   WATCH_WAIT            10 seconds
   RATE_LIMIT_INTERVAL   60 seconds

To:

   The following timing constants are used in this protocol; they are
   not intended to be user configurable.

   START_WAIT           1 second   (initial random delay)
   PROBE_MIN            1 second   (minimum delay till repeated probe)
   PROBE_MAX            2 seconds  (maximum delay till repeated probe)
   PROBE_NUM            3          (number of probe packets)
   PROBE_INTERVAL       1 second   (time between probe packets)
   ANNOUNCE_NUM         2          (number of announcement packets)
   ANNOUNCE_INTERVAL    2 seconds  (time between announcement packets)
   RATE_LIMIT_NUM      10          (max collisions before rate limiting)
   RATE_LIMIT_INTERVAL 60 seconds  (delay between successive attempts)
   DEFEND_INTERVAL     10 seconds  (minimum time between defensive ARPs)

   Future standards documents, extending IPv4 Link-Local Addressing to
   media types other than those covered in this document, may specify
   different values for these constants.

And:

Sec. 3.1 from

    Link-layer technologies that support ARP but operate at rates below 1
    Mbps or latencies above one second may need to specify different
    values for the following parameters described in Sections 2.2, 2.3
    and 2.4:

    (a) the number of, and interval between, ARP probes,
    (b) the number of, and interval between, ARP announcements,
    (c) the maximum rate at which address claiming may be attempted, and
    (d) the time interval between conflicting ARPs below which a host
        MUST reconfigure instead of attempting to defend its address.

to

    Link-layer technologies that support ARP but operate at rates below 1
    Mbps or latencies above one second may need to specify different
    values for the following parameters.

    (a) the number of, and interval between, ARP probes
        See NUM_PROBES, PROBE_MIN, PROBE_MAX defined in section 2.2.1

    (b) the number of, and interval between, ARP announcements,
        See ANNOUNCE_N and ANNOUNCE_INTERVAL defined in section 2.4

    (c) the maximum rate at which address claiming may be attempted
        See RATE_LIMIT_INTERVAL and MAX_COLLISIONS defined in section 2.2.1

    (d) the time interval between conflicting ARPs below which a host
        MUST reconfigure instead of attempting to defend its address
        See WATCH_WAIT defined in section 2.5

Erik Guttman
ZEROCONF WG Chair

---

From: "Philip Nye" <[email-masked]>
Date: Wed, 26 May 2004 11:12:04 +0100

Erik,

1. WATCH_WAIT seems to have disappeared in the proposed change to section 9. It should not have done.

2. You have got your knickers in a twist over PROBE_INTERVAL and DEFEND_INTERVAL. Alex Elder proposed using PROBE_INTERVAL in a comment on LL61. This has been accepted in your resolution to LL61 but you have changed the name to DEFEND_INTERVAL. Now in the proposed parameter text for LL53 you have both but with wildly different values!

3. PROBE_INTERVAL is not "time between probe packets". It is "wait time after last probe packet" and I can find nothing in the discussion that defines DEFEND_INTERVAL as "minimum time between defensive ARPs".

3. We now have 5 parameters for the probing process and there is clearly confusion over their meaning. I would like to see clearer naming: NUM_PROBES, PRE_PROBE_MAX, INTER_PROBE_MIN, INTER_PROBE_MAX, POST_PROBE_WAIT.

4. The new text of 3.1(a) should name all 5 of the probing parameters thus:

    (a) the number and timing of ARP probes
        See NUM_PROBES, PRE_PROBE_MAX, INTER_PROBE_MIN, INTER_PROBE_MAX,
        POST_PROBE_WAIT defined in section 2.2.1

regards,
Philip