kernel/Documentation/networking/bonding.rst, branch 0x221E-v0.0.1-v6.19

bonding: support aggregator selection based on port priority

2025-09-09T08:56:02Z

Add a new ad_select policy 'port_priority' that uses the per-port actor priority values (set via ad_actor_port_prio) to determine aggregator selection. This allows administrators to influence which ports are preferred for aggregation by assigning different priority values, providing more flexible load balancing control in LACP configurations. Signed-off-by: Hangbin Liu Link: https://patch.msgid.link/20250902064501.360822-3-liuhangbin@gmail.com Signed-off-by: Paolo Abeni

bonding: add support for per-port LACP actor priority

2025-09-09T08:56:02Z

Introduce a new netlink attribute 'actor_port_prio' to allow setting the LACP actor port priority on a per-slave basis. This extends the existing bonding infrastructure to support more granular control over LACP negotiations. The priority value is embedded in LACPDU packets and will be used by subsequent patches to influence aggregator selection policies. Signed-off-by: Hangbin Liu Link: https://patch.msgid.link/20250902064501.360822-2-liuhangbin@gmail.com Signed-off-by: Paolo Abeni

bonding: Remove support for use_carrier

2025-09-02T21:01:54Z

Remove the implementation of use_carrier, the link monitoring method that utilizes ethtool or ioctl to determine the link state of an interface in a bond. Bonding will always behaves as if use_carrier=1, which relies on netif_carrier_ok() to determine the link state of interfaces. To avoid acquiring RTNL many times per second, bonding inspects link state under RCU, but not under RTNL. However, ethtool implementations in drivers may sleep, and therefore this strategy is unsuitable for use with calls into driver ethtool functions. The use_carrier option was introduced in 2003, to provide backwards compatibility for network device drivers that did not support the then-new netif_carrier_ok/on/off system. Device drivers are now expected to support netif_carrier_*, and the use_carrier backwards compatibility logic is no longer necessary. The option itself remains, but when queried always returns 1, and may only be set to 1. Link: https://lore.kernel.org/000000000000eb54bf061cfd666a@google.com Link: https://lore.kernel.org/20240718122017.d2e33aaac43a.I10ab9c9ded97163aef4e4de10985cd8f7de60d28@changeid Signed-off-by: Jay Vosburgh Reported-by: syzbot+b8c48ea38ca27d150063@syzkaller.appspotmail.com Acked-by: Stanislav Fomichev Link: https://patch.msgid.link/2029487.1756512517@famine Signed-off-by: Jakub Kicinski

net: bonding: send peer notify when failure recovery

2025-07-08T08:59:42Z

In LACP mode with broadcast_neighbor enabled, after LACP protocol recovery, the port can transmit packets. However, if the bond port doesn't send gratuitous ARP/ND packets to the switch, the switch won't return packets through the current interface. This causes traffic imbalance. To resolve this issue, when LACP protocol recovers, send ARP/ND packets if broadcast_neighbor is enabled. Cc: Jay Vosburgh Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Simon Horman Cc: Jonathan Corbet Cc: Andrew Lunn Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Nikolay Aleksandrov Signed-off-by: Tonghao Zhang Signed-off-by: Zengbing Tu Reviewed-by: Nikolay Aleksandrov Link: https://patch.msgid.link/3993652dc093fffa9504ce1c2448fb9dea31d2d2.1751031306.git.tonghao@bamaicloud.com Signed-off-by: Paolo Abeni

net: bonding: add broadcast_neighbor option for 802.3ad

2025-07-08T08:59:41Z

Stacking technology is a type of technology used to expand ports on Ethernet switches. It is widely used as a common access method in large-scale Internet data center architectures. Years of practice have proved that stacking technology has advantages and disadvantages in high-reliability network architecture scenarios. For instance, in stacking networking arch, conventional switch system upgrades require multiple stacked devices to restart at the same time. Therefore, it is inevitable that the business will be interrupted for a while. It is for this reason that "no-stacking" in data centers has become a trend. Additionally, when the stacking link connecting the switches fails or is abnormal, the stack will split. Although it is not common, it still happens in actual operation. The problem is that after the split, it is equivalent to two switches with the same configuration appearing in the network, causing network configuration conflicts and ultimately interrupting the services carried by the stacking system. To improve network stability, "non-stacking" solutions have been increasingly adopted, particularly by public cloud providers and tech companies like Alibaba, Tencent, and Didi. "non-stacking" is a method of mimicing switch stacking that convinces a LACP peer, bonding in this case, connected to a set of "non-stacked" switches that all of its ports are connected to a single switch (i.e., LACP aggregator), as if those switches were stacked. This enables the LACP peer's ports to aggregate together, and requires (a) special switch configuration, described in the linked article, and (b) modifications to the bonding 802.3ad (LACP) mode to send all ARP/ND packets across all ports of the active aggregator. Note that, with multiple aggregators, the current broadcast mode logic will send only packets to the selected aggregator(s). +-----------+ +-----------+ | switch1 | | switch2 | +-----------+ +-----------+ ^ ^ | | +-----------------+ | bond4 lacp | +-----------------+ | | | NIC1 | NIC2 +-----------------+ | server | +-----------------+ - https://www.ruijie.com/fr-fr/support/tech-gallery/de-stack-data-center-network-architecture/ Cc: Jay Vosburgh Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: Simon Horman Cc: Jonathan Corbet Cc: Andrew Lunn Cc: Steven Rostedt Cc: Masami Hiramatsu Cc: Mathieu Desnoyers Cc: Nikolay Aleksandrov Signed-off-by: Tonghao Zhang Signed-off-by: Zengbing Tu Link: https://patch.msgid.link/84d0a044514157bb856a10b6d03a1028c4883561.1751031306.git.tonghao@bamaicloud.com Signed-off-by: Paolo Abeni

docs: net: bonding: fix typos

2024-12-19T01:27:35Z

The bonding documentation had several "insure" which is not properly used in the context. Suggest to change to "ensure" to improve readability. Signed-off-by: shunlizhou Link: https://patch.msgid.link/20241216135447.57681-1-shunlizhou@aliyun.com Signed-off-by: Jakub Kicinski

Documentation: bonding: add XDP support explanation

2024-10-28T23:09:42Z

Add document about which modes have native XDP support. Reviewed-by: Nikolay Aleksandrov Signed-off-by: Hangbin Liu Reviewed-by: Toke Høiland-Jørgensen Link: https://patch.msgid.link/20241021031211.814-3-liuhangbin@gmail.com Signed-off-by: Jakub Kicinski

bonding: Add independent control state machine

2024-02-06T12:17:54Z

Add support for the independent control state machine per IEEE 802.1AX-2008 5.4.15 in addition to the existing implementation of the coupled control state machine. Introduces two new states, AD_MUX_COLLECTING and AD_MUX_DISTRIBUTING in the LACP MUX state machine for separated handling of an initial Collecting state before the Collecting and Distributing state. This enables a port to be in a state where it can receive incoming packets while not still distributing. This is useful for reducing packet loss when a port begins distributing before its partner is able to collect. Added new functions such as bond_set_slave_tx_disabled_flags and bond_set_slave_rx_enabled_flags to precisely manage the port's collecting and distributing states. Previously, there was no dedicated method to disable TX while keeping RX enabled, which this patch addresses. Note that the regular flow process in the kernel's bonding driver remains unaffected by this patch. The extension requires explicit opt-in by the user (in order to ensure no disruptions for existing setups) via netlink support using the new bonding parameter coupled_control. The default value for coupled_control is set to 1 so as to preserve existing behaviour. Signed-off-by: Aahil Awatramani Reviewed-by: Hangbin Liu Link: https://lore.kernel.org/r/20240202175858.1573852-1-aahila@google.com Signed-off-by: Paolo Abeni

Documentation: Fix typos

2023-08-18T17:29:03Z

Fix typos in Documentation. Signed-off-by: Bjorn Helgaas Link: https://lore.kernel.org/r/20230814212822.193684-4-helgaas@kernel.org Signed-off-by: Jonathan Corbet

Documentation: bonding: fix the doc of peer_notif_delay

2023-05-10T08:27:20Z

Bonding only supports setting peer_notif_delay with miimon set. Fixes: 0307d589c4d6 ("bonding: add documentation for peer_notif_delay") Signed-off-by: Hangbin Liu Signed-off-by: David S. Miller