mirror of
https://github.com/kernelkit/infix.git
synced 2026-07-31 13:03:02 +02:00
Joachim Wiberg
1fb97055ab
The networking guide has grown out of control for quite some time, it is time to split it up into multiple files. This will hopefully also make it a bit more accessible to users. Signed-off-by: Joachim Wiberg <troglobit@gmail.com>
209 lines
6.7 KiB
Markdown
209 lines
6.7 KiB
Markdown
# Ethernet Interfaces
|
|
|
|
This document covers VLAN interfaces, physical Ethernet interfaces,
|
|
and virtual Ethernet (VETH) pairs.
|
|
|
|
|
|
## VLAN Interfaces
|
|
|
|
Creating a VLAN can be done in many ways. This section assumes VLAN
|
|
interfaces created atop another Linux interface. E.g., the VLAN
|
|
interfaces created on top of the Ethernet interface or bridge in the
|
|
picture below.
|
|
|
|
|
|
|
|
A VLAN interface is basically a filtering abstraction. When you run
|
|
`tcpdump` on a VLAN interface you will only see the frames matching the
|
|
VLAN ID of the interface, compared to *all* the VLAN IDs if you run
|
|
`tcpdump` on the lower-layer interface.
|
|
|
|
<pre class="cli"><code>admin@example:/> <b>configure</b>
|
|
admin@example:/config/> <b>edit interface eth0.20</b>
|
|
admin@example:/config/interface/eth0.20/> <b>show</b>
|
|
type vlan;
|
|
vlan {
|
|
tag-type c-vlan;
|
|
id 20;
|
|
lower-layer-if eth0;
|
|
}
|
|
admin@example:/config/interface/eth0.20/> <b>leave</b>
|
|
</code></pre>
|
|
|
|
The example below assumes bridge br0 is already created, see [VLAN
|
|
Filtering Bridge](bridging.md#vlan-filtering-bridge).
|
|
|
|
<pre class="cli"><code>admin@example:/> <b>configure</b>
|
|
admin@example:/config/> <b>edit interface vlan10</b>
|
|
admin@example:/config/interface/vlan10/> <b>set vlan id 10</b>
|
|
admin@example:/config/interface/vlan10/> <b>set vlan lower-layer-if br0</b>
|
|
admin@example:/config/interface/vlan10/> <b>leave</b>
|
|
</code></pre>
|
|
|
|
As conventions, a VLAN interface for VID 20 on top of an Ethernet
|
|
interface *eth0* is named *eth0.20*, and a VLAN interface for VID 10 on
|
|
top of a bridge interface *br0* is named *vlan10*.
|
|
|
|
> [!NOTE]
|
|
> If you name your VLAN interface `foo0.N` or `vlanN`, where `N` is a
|
|
> number, the CLI infers the interface type automatically.
|
|
|
|
|
|
## Physical Ethernet Interfaces
|
|
|
|
### Ethernet Settings and Status
|
|
|
|
Physical Ethernet interfaces provide low-level settings for speed/duplex as
|
|
well as packet status and [statistics](#ethernet-statistics).
|
|
|
|
By default, Ethernet interfaces defaults to auto-negotiating
|
|
speed/duplex modes, advertising all speed and duplex modes available.
|
|
In the example below, the switch would by default auto-negotiate speed
|
|
1 Gbit/s on port eth1 and 100 Mbit/s on port eth4, as those are the
|
|
highest speeds supported by H1 and H2 respectively.
|
|
|
|
|
|
|
|
The speed and duplex status for the links can be listed as shown
|
|
below, assuming the link operational status is 'up'.
|
|
|
|
<pre class="cli"><code>admin@example:/> <b>show interface eth1</b>
|
|
name : eth1
|
|
index : 2
|
|
mtu : 1500
|
|
operational status : up
|
|
auto-negotiation : on
|
|
duplex : full
|
|
speed : 1000
|
|
physical address : 00:53:00:06:11:01
|
|
ipv4 addresses :
|
|
ipv6 addresses :
|
|
in-octets : 75581
|
|
out-octets : 43130
|
|
...
|
|
admin@example:/> <b>show interface eth4</b>
|
|
name : eth4
|
|
index : 5
|
|
mtu : 1500
|
|
operational status : up
|
|
auto-negotiation : on
|
|
duplex : full
|
|
speed : 100
|
|
physical address : 00:53:00:06:11:04
|
|
ipv4 addresses :
|
|
ipv6 addresses :
|
|
in-octets : 75439
|
|
out-octets : 550704
|
|
...
|
|
admin@example:/>
|
|
</code></pre>
|
|
|
|
### Configuring fixed speed and duplex
|
|
|
|
Auto-negotiation of speed/duplex mode is desired in almost all
|
|
use-cases, but it is possible to disable auto-negotiation and specify
|
|
a fixed speed and duplex mode.
|
|
|
|
> [!IMPORTANT]
|
|
> When setting a fixed speed and duplex mode, ensure both sides of the
|
|
> link have matching configuration. If speed does not match, the link
|
|
> will not come up. If duplex mode does not match, the result is
|
|
> reported collisions and/or bad throughput.
|
|
|
|
The example below configures port eth3 to fixed speed 100 Mbit/s
|
|
half-duplex mode.
|
|
|
|
<pre class="cli"><code>admin@example:/> <b>configure</b>
|
|
admin@example:/config/> <b>edit interface eth3 ethernet</b>
|
|
admin@example:/config/interface/eth3/ethernet/> <b>set speed 0.1</b>
|
|
admin@example:/config/interface/eth3/ethernet/> <b>set duplex half</b>
|
|
admin@example:/config/interface/eth3/ethernet/> <b>set auto-negotiation enable false</b>
|
|
admin@example:/config/interface/eth3/ethernet/> <b>show</b>
|
|
auto-negotiation {
|
|
enable false;
|
|
}
|
|
duplex half;
|
|
speed 0.1;
|
|
admin@example:/config/interface/eth3/ethernet/> <b>leave</b>
|
|
admin@example:/>
|
|
</code></pre>
|
|
|
|
Speed metric is in Gbit/s. Auto-negotiation needs to be disabled in
|
|
order for fixed speed/duplex to apply. Only speeds `0.1`(100 Mbit/s)
|
|
and `0.01` (10 Mbit/s) can be specified. 1 Gbit/s and higher speeds
|
|
require auto-negotiation to be enabled.
|
|
|
|
### Ethernet statistics
|
|
|
|
Ethernet packet statistics[^1] can be listed as shown below.
|
|
|
|
<pre class="cli"><code>admin@example:/> <b>show interface eth1</b>
|
|
name : eth1
|
|
index : 2
|
|
mtu : 1500
|
|
operational status : up
|
|
auto-negotiation : on
|
|
duplex : full
|
|
speed : 1000
|
|
physical address : 00:53:00:06:11:0a
|
|
ipv4 addresses :
|
|
ipv6 addresses :
|
|
in-octets : 75581
|
|
out-octets : 43130
|
|
|
|
eth-in-frames : 434
|
|
eth-in-multicast-frames : 296
|
|
eth-in-broadcast-frames : 138
|
|
eth-in-error-fcs-frames : 0
|
|
eth-in-error-oversize-frames : 0
|
|
eth-out-frames : 310
|
|
eth-out-multicast-frames : 310
|
|
eth-out-broadcast-frames : 0
|
|
eth-out-good-octets : 76821
|
|
eth-in-good-octets : 60598
|
|
admin@example:/>
|
|
</code></pre>
|
|
|
|
|
|
## VETH Pairs
|
|
|
|
A Virtual Ethernet (VETH) pair is basically a virtual Ethernet cable. A
|
|
cable can be "plugged in" to a bridge and the other end can be given to
|
|
a [container](container.md), or plugged into another bridge.
|
|
|
|
The latter example is useful if you have multiple bridges in the system
|
|
with different properties (VLAN filtering, IEEE group forwarding, etc.),
|
|
but still want some way of communicating between these domains.
|
|
|
|
<pre class="cli"><code>admin@example:/> <b>configure</b>
|
|
admin@example:/config/> <b>edit interface veth0a</b>
|
|
admin@example:/config/interface/veth0a/> <b>set veth peer veth0b</b>
|
|
admin@example:/config/interface/veth0a/> <b>end</b>
|
|
admin@example:/config/> <b>diff</b>
|
|
interfaces {
|
|
+ interface veth0a {
|
|
+ type veth;
|
|
+ veth {
|
|
+ peer veth0b;
|
|
+ }
|
|
+ }
|
|
+ interface veth0b {
|
|
+ type veth;
|
|
+ veth {
|
|
+ peer veth0a;
|
|
+ }
|
|
+ }
|
|
}
|
|
admin@example:/config/>
|
|
</code></pre>
|
|
|
|
> [!TIP]
|
|
> This is another example of the automatic inference of the interface
|
|
> type from the name. Any name can be used, but then you have to set
|
|
> the interface type to `veth` manually.
|
|
|
|
[^1]: Ethernet counters are described in *ieee802-ethernet-interface.yang*
|
|
and *infix-ethernet-interface.yang*. There is a dedicated document on
|
|
[Ethernet Counters](eth-counters.md) that provide additional details
|
|
on the statistics support.
|