What:		/sys/class/net/<iface>/name_assign_type
  Date:		July 2014
  KernelVersion:	3.17
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the name assignment type. Possible values are:
  		1: enumerated by the kernel, possibly in an unpredictable way
  		2: predictably named by the kernel
  		3: named by userspace
  		4: renamed
  
  What:		/sys/class/net/<iface>/addr_assign_type
  Date:		July 2010
  KernelVersion:	3.2
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the address assignment type. Possible values are:
  		0: permanent address
  		1: randomly generated
  		2: stolen from another device
  		3: set using dev_set_mac_address
  
  What:		/sys/class/net/<iface>/addr_len
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the hardware address size in bytes.
  		Values vary based on the lower-level protocol used by the
  		interface (Ethernet, FDDI, ATM, IEEE 802.15.4...). See
  		include/uapi/linux/if_*.h for actual values.
  
  What:		/sys/class/net/<iface>/address
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Hardware address currently assigned to this interface.
  		Format is a string, e.g: 00:11:22:33:44:55 for an Ethernet MAC
  		address.
  
  What:		/sys/class/net/<bridge iface>/bridge/group_fwd_mask
  Date:		January 2012
  KernelVersion:	3.2
  Contact:	netdev@vger.kernel.org
  Description:
  		Bitmask to allow forwarding of link local frames with address
  		01-80-C2-00-00-0X on a bridge device. Only values that set bits
  		not matching BR_GROUPFWD_RESTRICTED in net/bridge/br_private.h
  		allowed.
  		Default value 0 does not forward any link local frames.
  
  		Restricted bits:
  		0: 01-80-C2-00-00-00 Bridge Group Address used for STP
  		1: 01-80-C2-00-00-01 (MAC Control) 802.3 used for MAC PAUSE
  		2: 01-80-C2-00-00-02 (Link Aggregation) 802.3ad
  
  		Any values not setting these bits can be used. Take special
  		care when forwarding control frames e.g. 802.1X-PAE or LLDP.
  
  What:		/sys/class/net/<iface>/broadcast
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Hardware broadcast address for this interface. Format is a
  		string, e.g: ff:ff:ff:ff:ff:ff for an Ethernet broadcast MAC
  		address.
  
  What:		/sys/class/net/<iface>/carrier
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the current physical link state of the interface.
  		Posssible values are:
  		0: physical link is down
  		1: physical link is up
  
  		Note: some special devices, e.g: bonding and team drivers will
  		allow this attribute to be written to force a link state for
  		operating correctly and designating another fallback interface.
  
  What:		/sys/class/net/<iface>/dev_id
  Date:		April 2008
  KernelVersion:	2.6.26
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the device unique identifier. Format is an hexadecimal
  		value. This is used to disambiguate interfaces which might be
  		stacked (e.g: VLAN interfaces) but still have the same MAC
  		address as their parent device.
  
  What:		/sys/class/net/<iface>/dormant
  Date:		March 2006
  KernelVersion:	2.6.17
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates whether the interface is in dormant state. Possible
  		values are:
  		0: interface is not dormant
  		1: interface is dormant
  
  		This attribute can be used by supplicant software to signal that
  		the device is not usable unless some supplicant-based
  		authentication is performed (e.g: 802.1x). 'link_mode' attribute
  		will also reflect the dormant state.
  
  What:		/sys/clas/net/<iface>/duplex
  Date:		October 2009
  KernelVersion:	2.6.33
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface latest or current duplex value. Possible
  		values are:
  		half: half duplex
  		full: full duplex
  
  		Note: This attribute is only valid for interfaces that implement
  		the ethtool get_settings method (mostly Ethernet).
  
  What:		/sys/class/net/<iface>/flags
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface flags as a bitmask in hexadecimal. See
  		include/uapi/linux/if.h for a list of all possible values and
  		the flags semantics.
  
  What:		/sys/class/net/<iface>/ifalias
  Date:		September 2008
  KernelVersion:	2.6.28
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates/stores an interface alias name as a string. This can
  		be used for system management purposes.
  
  What:		/sys/class/net/<iface>/ifindex
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the system-wide interface unique index identifier as a
  		decimal number. This attribute is used for mapping an interface
  		identifier to an interface name. It is used throughout the
  		networking stack for specifying the interface specific
  		requests/events.
  
  What:		/sys/class/net/<iface>/iflink
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the system-wide interface unique index identifier a
  		the interface is linked to. Format is decimal. This attribute is
  		used to resolve interfaces chaining, linking and stacking.
  		Physical interfaces have the same 'ifindex' and 'iflink' values.
  
  What:		/sys/class/net/<iface>/link_mode
  Date:		March 2006
  KernelVersion:	2.6.17
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface link mode, as a decimal number. This
  		attribute should be used in conjunction with 'dormant' attribute
  		to determine the interface usability. Possible values:
  		0: default link mode
  		1: dormant link mode
  
  What:		/sys/class/net/<iface>/mtu
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface currently configured MTU value, in
  		bytes, and in decimal format. Specific values depends on the
  		lower-level interface protocol used. Ethernet devices will show
  		a 'mtu' attribute value of 1500 unless changed.
  
  What:		/sys/class/net/<iface>/netdev_group
  Date:		January 2011
  KernelVersion:	2.6.39
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface network device group, as a decimal
  		integer. Default value is 0 which corresponds to the initial
  		network devices group. The group can be changed to affect
  		routing decisions (see: net/ipv4/fib_rules and
  		net/ipv6/fib6_rules.c).
  
  What:		/sys/class/net/<iface>/operstate
  Date:		March 2006
  KernelVersion:	2.6.17
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface RFC2863 operational state as a string.
  		Possible values are:
  		"unknown", "notpresent", "down", "lowerlayerdown", "testing",
  		"dormant", "up".
  
  What:		/sys/class/net/<iface>/phys_port_id
  Date:		July 2013
  KernelVersion:	3.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface unique physical port identifier within
  		the NIC, as a string.
  
  What:		/sys/class/net/<iface>/phys_port_name
  Date:		March 2015
  KernelVersion:	4.0
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface physical port name within the NIC,
  		as a string.
  
  What:		/sys/class/net/<iface>/speed
  Date:		October 2009
  KernelVersion:	2.6.33
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface latest or current speed value. Value is
  		an integer representing the link speed in Mbits/sec.
  
  		Note: this attribute is only valid for interfaces that implement
  		the ethtool get_settings method (mostly Ethernet ).
  
  What:		/sys/class/net/<iface>/tx_queue_len
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface transmit queue len in number of packets,
  		as an integer value. Value depend on the type of interface,
  		Ethernet network adapters have a default value of 1000 unless
  		configured otherwise
  
  What:		/sys/class/net/<iface>/type
  Date:		April 2005
  KernelVersion:	2.6.12
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the interface protocol type as a decimal value. See
  		include/uapi/linux/if_arp.h for all possible values.
  
  What:		/sys/class/net/<iface>/phys_switch_id
  Date:		November 2014
  KernelVersion:	3.19
  Contact:	netdev@vger.kernel.org
  Description:
  		Indicates the unique physical switch identifier of a switch this
  		port belongs to, as a string.
  
  What:		/sys/class/net/<iface>/phydev
  Date:		May 2017
  KernelVersion:	4.13
  Contact:	netdev@vger.kernel.org
  Description:
  		Symbolic link to the PHY device this network device is attached
  		to.