xref: /freebsd-src/share/man/man4/edsc.4 (revision 97759ccc715c4b365432c16d763c50eecfcb1100)

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.Dd March 25, 2007
.Dt EDSC 4
.Os
.Sh NAME
.Nm edsc
.Nd Ethernet discard network interface
.Sh SYNOPSIS
.Cd "device edsc"
.Sh DESCRIPTION
The
.Nm
interface is a software discard mechanism which may be
used for performance analysis and software testing.
It imitates an Ethernet device, which
allows for its use in conjunction with such drivers as
.Xr if_bridge 4
and
.Xr vlan 4 .
.Pp
As with other network interfaces, an
.Nm
interface must have network addresses assigned for each address family
with which it is to be used.
These addresses may be set or changed with the
.Dv SIOCSIFADDR
.Xr ioctl 2
or
.Xr ifconfig 8
utility.
.Pp
Each
.Nm
interface is created at runtime using interface cloning.
This is most easily done with the
.Xr ifconfig 8
.Cm create
command or using the
.Va cloned_interfaces
variable in
.Xr rc.conf 5 .
.Sh SEE ALSO
.Xr ioctl 2 ,
.Xr arp 4 ,
.Xr if_bridge 4 ,
.Xr inet 4 ,
.Xr intro 4 ,
.Xr vlan 4 ,
.Xr rc.conf 5 ,
.Xr arp 8 ,
.Xr ifconfig 8
.Sh HISTORY
The
.Nm
device was derived from the
.Xr disc 4
device and first appeared in
.Fx 6.3 .
This manpage was adapted from
.Xr disc 4 .
.Sh CAVEATS
Since outgoing packets are just discarded by
.Nm ,
ARP requests stay unreplied.
Consequently, an IP packet cannot be sent via
.Nm
until a static
.Xr arp 4
entry is created for its next hop using
.Xr arp 8 .
.Pp
Initially an
.Nm
interface has a zero link level address.
It can be changed with
.Xr ifconfig 8
.Cm lladdr
if needed.