I'm sponsoring this self-review case for Erik Nordmark.
-Artem
Template Version: @(#)sac_nextcase 1.70 03/30/10 SMI
This information is Copyright (c) 2010, Oracle and/or its affiliates. All rights
reserved.
1. Introduction
1.1. Project/Component Working Name:
Different MTU for unicast and multicast
1.2. Name of Document Author/Supplier:
Author: Erik Nordmark
1.3 Date of This Document:
13 August, 2010
4. Technical Description
Consolidation private interfaces for datalinks with different
Max packet size for unicast and multicast
-----------------------------------------
This case relates to CR 6836162 "Interface to report different
multicast and unicast MTUs from network stack"
With IP over InfiniBand connected-mode (IPoIB-CM) we have a
datalink which can send very large unicast packets (currently
limited to 64kbyte) but where broadcast and multicast have
a much smaller limit (typically around 2kbyte).
This doesn't fit with how IP currently views datalinks, since IP
(and other datalink users) only sees one MTU number.
The effect is that IP multicast and broadcast packets that exceed 2k
are dropped.
The remediation is to introduce a set of consolidation private
interfaces that make it possible for IPoIB-CM to pass a separate
multicast (and broadcast) MTU size up to IP, so that IP can do the
right thing. Those interfaces are consolidation private since they
are only needed for IPoIB-CM. Should in the future there be
additional datalink types with the same properties we will consider
elevating these interfaces.
Requested release binding is patch, even though we plan to introduce
these in a minor release.
_________________________________________________________________________
| Interfaces Added by This Case |
|_______________________________|_______________________|_______________|
|Interface | Classification | Comments |
|_______________________________|_______________________|_______________|
| DL_NOTE_SDU_SIZE2 | Consolidation Private | <sys/dlpi.h> |
| mac_register_t added field | Consolidation Private |<sys/mac_provider.h>|
| mac_sdu_get2() function | Consolidation Private | <sys/mac.h> |
| mac_maxsdu_update2() function | Consolidation Private | <sys/mac.h> |
|_______________________________|_______________________|_______________|
6. Resources and Schedule
6.4. Steering Committee requested information
6.4.1. Consolidation C-team Name:
ON
6.5. ARC review type: Automatic
6.6. ARC Exposure: open
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