Subject: WG ACTION: ACCEPT [LL37] Aggressive Time-outs

From: Erik Guttman <[email-masked]>
Date: Mon, 05 Jan 2004 20:26:48 +0100

Accept the changes - as modified by discussion.

===
1)

section 2.3, from

time values specified above result in a delay of 8-10 seconds before

to

time values specified above result in a delay of 5-8 seconds before

=============

2)

section 2.2.1, from

    When ready to begin probing, the host should then wait for a random
    time interval selected uniformly in the range PROBE_MIN to PROBE_MAX
    seconds, and should then send three probe packets, spaced randomly,
    PROBE_MIN to PROBE_MAX seconds apart.

to

    When ready to begin probing, the host should then wait for a random
    time interval selected uniformly in the range PROBE_MIN to PROBE_MAX
    seconds, and should then send NUM_PROBES probe packets, spaced
    randomly, PROBE_MIN to PROBE_MAX seconds apart.

section 9, from

9.  Constants

    The following timing constants are used in this protocol.

    PROBE_MIN    1 second
    PROBE_MAX    2 seconds

to

9.  Constants

    The following defaults are used in this protocol.  In the future,
    a protocol specification may be issued which recommends different
    values for these constants for use in particular contexts.

    PROBE_MIN    1 second
    PROBE_MAX    2 seconds
    NUM_PROBES   3

=============

3)

Replace section 2.3,

2.3.  Shorter timeouts

    The time values specified above are intended for use on technologies
    such as IEEE 802, where switches that implement Spanning Tree
    [802.1d] often silently discard all packets for several seconds. The
    time values specified above result in a delay of 8-10 seconds before
    a chosen IP address may be used.  For a desktop machine on an IEEE
    802 LAN, this may not be a great problem, but for other types of
    device, particularly portable hand-held wireless devices, a ten-
    second delay before networking services becomes available may not be
    acceptable.  For this reason, shorter time values may be used on
    network technologies that allow the device to determine when the link
    has become active and can be reasonably trusted to deliver packets
    reliably.  On these network technologies the recommended time values
    are: The host should first wait for a random time interval selected
    uniformly in the range 0-200 milliseconds, and then send four probe
    packets, waiting 200 milliseconds after each probe, making a total
    delay of 800-1000 milliseconds before a chosen IPv4 address may be
    used.

    Should future versions of the IEEE 802 Spanning Tree Protocol be
    enhanced to inform clients when the link is ready to begin forwarding
    packets, then the shorter time values may be used on these networks
    too.

with

2.3.  Shorter timeouts

    Network technologies may emerge for which shorter delays are
    appropriate than those required by this document. A subsequent IETF
    publication may be produced providing guidelines for different timer
    settings for PROBE_MIN and PROBE_MAX on those technologies.

===

Please see: http://www.merit.edu/mail.archives/zeroconf/msg00001.html
And: http://www.drizzle.org/~aboba/ZEROCONF/ll37.html

Regards,

Erik