zram: use __bio_add_page for adding single page to bio
[linux-block.git] / net / hsr / Kconfig
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ec8f24b7 1# SPDX-License-Identifier: GPL-2.0-only
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2#
3# IEC 62439-3 High-availability Seamless Redundancy
4#
5
6config HSR
8f4c0e01 7 tristate "High-availability Seamless Redundancy (HSR & PRP)"
a7f7f624 8 help
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9 This enables IEC 62439 defined High-availability Seamless
10 Redundancy (HSR) and Parallel Redundancy Protocol (PRP).
11
f421436a 12 If you say Y here, then your Linux box will be able to act as a
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13 DANH ("Doubly attached node implementing HSR") or DANP ("Doubly
14 attached node implementing PRP"). For this to work, your Linux box
15 needs (at least) two physical Ethernet interfaces.
16
17 For DANH, it must be connected as a node in a ring network together
18 with other HSR capable nodes. All Ethernet frames sent over the HSR
19 device will be sent in both directions on the ring (over both slave
20 ports), giving a redundant, instant fail-over network. Each HSR node
21 in the ring acts like a bridge for HSR frames, but filters frames
22 that have been forwarded earlier.
f421436a 23
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24 For DANP, it must be connected as a node connecting to two
25 separate networks over the two slave interfaces. Like HSR, Ethernet
26 frames sent over the PRP device will be sent to both networks giving
27 a redundant, instant fail-over network. Unlike HSR, PRP networks
28 can have Singly Attached Nodes (SAN) such as PC, printer, bridges
29 etc and will be able to communicate with DANP nodes.
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30
31 This code is a "best effort" to comply with the HSR standard as
ee1c2797 32 described in IEC 62439-3:2010 (HSRv0) and IEC 62439-3:2012 (HSRv1),
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33 and PRP standard described in IEC 62439-4:2012 (PRP), but no
34 compliancy tests have been made. Use iproute2 to select the protocol
35 you would like to use.
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36
37 You need to perform any and all necessary tests yourself before
38 relying on this code in a safety critical system!
39
40 If unsure, say N.