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   systemd.netdev    ( 5 )

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[BRIDGE] SECTION OPTIONS

The [Bridge] section only applies for netdevs of kind "bridge", and accepts the following keys:

HelloTimeSec= HelloTimeSec specifies the number of seconds between two hello packets sent out by the root bridge and the designated bridges. Hello packets are used to communicate information about the topology throughout the entire bridged local area network.

MaxAgeSec= MaxAgeSec specifies the number of seconds of maximum message age. If the last seen (received) hello packet is more than this number of seconds old, the bridge in question will start the takeover procedure in attempt to become the Root Bridge itself.

ForwardDelaySec= ForwardDelaySec specifies the number of seconds spent in each of the Listening and Learning states before the Forwarding state is entered.

AgeingTimeSec= This specifies the number of seconds a MAC Address will be kept in the forwarding database after having a packet received from this MAC Address.

Priority= The priority of the bridge. An integer between 0 and 65535. A lower value means higher priority. The bridge having the lowest priority will be elected as root bridge.

GroupForwardMask= A 16-bit bitmask represented as an integer which allows forwarding of link local frames with 802.1D reserved addresses (01:80:C2:00:00:0X). A logical AND is performed between the specified bitmask and the exponentiation of 2^X, the lower nibble of the last octet of the MAC address. For example, a value of 8 would allow forwarding of frames addressed to 01:80:C2:00:00:03 (802.1X PAE).

DefaultPVID= This specifies the default port VLAN ID of a newly attached bridge port. Set this to an integer in the range 1...4094 or "none" to disable the PVID.

MulticastQuerier= Takes a boolean. This setting controls the IFLA_BR_MCAST_QUERIER option in the kernel. If enabled, the kernel will send general ICMP queries from a zero source address. This feature should allow faster convergence on startup, but it causes some multicast-aware switches to misbehave and disrupt forwarding of multicast packets. When unset, the kernel's default will be used.

MulticastSnooping= Takes a boolean. This setting controls the IFLA_BR_MCAST_SNOOPING option in the kernel. If enabled, IGMP snooping monitors the Internet Group Management Protocol (IGMP) traffic between hosts and multicast routers. When unset, the kernel's default will be used.

VLANFiltering= Takes a boolean. This setting controls the IFLA_BR_VLAN_FILTERING option in the kernel. If enabled, the bridge will be started in VLAN-filtering mode. When unset, the kernel's default will be used.

VLANProtocol= Allows setting the protocol used for VLAN filtering. Takes 802.1q or, 802.1ad, and defaults to unset and kernel's default is used.

STP= Takes a boolean. This enables the bridge's Spanning Tree Protocol (STP). When unset, the kernel's default will be used.

MulticastIGMPVersion= Allows changing bridge's multicast Internet Group Management Protocol (IGMP) version. Takes an integer 2 or 3. When unset, the kernel's default will be used.