Copyright (c) 2019 David Gwynne <dlg@openbsd.org>
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.Dd $Mdocdate: August 20 2019 $ .Dt TPMR 4 .Os .Sh NAME .Nm tpmr .Nd IEEE 802.1Q Two-Port MAC Relay interface .Sh SYNOPSIS .Cd "pseudo-device tpmr" .Sh DESCRIPTION The .Nm driver implements an 802.1Q (originally 802.1aj) Two-Port MAC Relay (TPMR). A TPMR is a simplified Ethernet bridge that provides a subset of the functionality as found in .Xr bridge 4 . A TPMR has exactly two members, and unconditionally relays Ethernet packets between the them.
p .Nm interfaces can be created at runtime using the c ifconfig tpmr Ns Ar N Ic create command or by setting up a .Xr hostname.if 5 configuration file for .Xr netstart 8 . The interface itself can be configured with .Xr ifconfig 8 ; see its manual page for more information.
p
.Nm
interfaces may be configured with
.Xr ifconfig 8
and
.Xr netstart 8
using the following options:
l -tag -width Ds t Cm add Ar child-iface Add
.Ar child-iface
as a member.
t Cm del Ar child-iface Remove the member
.Ar child-iface .
t Cm link0 Disable the filtering of Ethernet frames destined for the TPMR
component reserved addresses, as specified by IEEE 802.1Q.
t Cm -link0 Enable the filtering of Ethernet frames destined for the TPMR
component reserved addresses, as specified by IEEE 802.1Q.
This is the default.
t Cm link1 Disable the filtering of IPv4 and IPv6 packets with
.Xr pf 4 .
t Cm -link1 Enable the filtering of IPv4 and IPv6 packets with
.Xr pf 4 .
Packets will appear to enter or leave the member port interfaces.
This is the default.
.El
document the ioctls?
p Other forms of Ethernet bridging are available using the .Xr bridge 4 driver. Other forms of aggregation of Ethernet interfaces are available using the .Xr aggr 4 and .Xr trunk 4 drivers. .Sh EXAMPLES .Nm can be used to cross-connect Ethernet devices that support different physical media. For example, a device that supports a 100baseTX half-duplex connection can be connected to a switch with 1000baseSX optical ports by using .Nm with a pair of physical network interfaces, each of which supports the required media types. If .Xr fxp 4 is used to connect to the 100baseTX device, and .Xr em 4 is used to connect to the 1000baseSX switch, the following configuration can be used: d -literal # ifconfig tpmr0 create # ifconfig tpmr0 add fxp0 add em0 # ifconfig fxp0 up # ifconfig em0 up # ifconfig tpmr0 up .Ed
p Multiple TPMRs can be chained to transport Ethernet traffic for a pair of devices over another network. Given two physically separate Ethernet switches, TPMRs can be used as follows to provide a point-to-point Ethernet link between them. .Nm with the .Cm link0 flag set allows the use of the Link Aggregation Control Protocol (LACP) or Spanning Tree Protocol (STP) by the switches to detect communication failures or connectivity loops respectively, which is not possible using .Xr bridge 4 as it filters those protocols.
p If Host A connected to Router B has the external IP address 192.0.2.10 on em0, Host D connected to Router C has the external IP address 198.51.100.14 on em0, and both hosts have em1 connected to the switches, the following configuration can be used to connect the switches together. .Xr etherip 4 is used to transport the Ethernet packets over the IP network. d -literal Switch X ---- Host A ---------- tunnel ----------- Host D ---- Switch E \e / \e / +---- Router B ---- Router C ----+ .Ed
p Create the .Nm and .Xr etherip 4 interfaces: d -literal -offset indent # ifconfig etherip0 create # ifconfig tpmr0 create link0 .Ed
p Configure the etherip interface: d -literal -offset indent (on Host A) # ifconfig etherip0 tunnel 192.0.2.10 198.51.100.14 up (on Host D) # ifconfig etherip0 tunnel 198.51.100.14 192.0.2.10 up .Ed
p Add the etherip interface and physical interface to the TPMR: d -literal -offset indent # ifconfig tpmr0 add em1 add etherip0 up .Ed
p
An equivalent setup using MPLS pseudowires instead of IP as the
transport can be built using
.Xr mpw 4
interfaces.
.Sh SEE ALSO
.Xr aggr 4 ,
.Xr bridge 4 ,
.Xr pf 4 ,
.Xr trunk 4 ,
.Xr hostname.if 5 ,
.Xr ifconfig 8 ,
.Xr netstart 8
.Sh STANDARDS
.Rs
.%T IEEE 802.1Q
.Re
.Rs
.%T IEEE 802.1aj
.Re
.Sh HISTORY
The
.Nm
driver first appeared in
.Ox 6.6 .