> For the complete documentation index, see [llms.txt](https://jncia-workbook.gitbook.io/workbook/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jncia-workbook.gitbook.io/workbook/junos-switching/1-basic-switching.md).
# 1) Basic Switching
### Pre-Work
Load the config called **lab1.cfg** using the **load\_config\_on\_nodes.py** script.
```
python3 load_config_on_nodes.py --lab_dir switched-lan --config_filename lab1.cfg
```
### Lab
Configure SW2 and SW3 as follows:
* Configure two VLANs:
* VLAN 100, name PROD
* VLAN 200, name DEV
* The link between the switches, `ge-0/0/1`, should be a trunk port carrying both VLANs
* On both switches, `ge-0/0/2` should be assigned to VLAN 100, and `ge-0/0/3` should be assigned to VLAN 200
The simulated hosts host1-host3 should be able to ping each other within VLAN 100, as well as host2-host4 within VLAN 200.
```
admin@HOST-RTR> ping 10.0.100.103 routing-instance host1 count 2
PING 10.0.100.103 (10.0.100.103): 56 data bytes
64 bytes from 10.0.100.103: icmp_seq=0 ttl=64 time=3.174 ms
64 bytes from 10.0.100.103: icmp_seq=1 ttl=64 time=3.893 ms
admin@HOST-RTR> ping 2001:db8:100::103 routing-instance host1 count 2
PING6(56=40+8+8 bytes) 2001:db8:100::101 --> 2001:db8:100::103
16 bytes from 2001:db8:100::103, icmp_seq=0 hlim=64 time=3.065 ms
16 bytes from 2001:db8:100::103, icmp_seq=1 hlim=64 time=3.519 ms
admin@HOST-RTR> ping 10.0.200.104 routing-instance host2 count 2
PING 10.0.200.104 (10.0.200.104): 56 data bytes
64 bytes from 10.0.200.104: icmp_seq=0 ttl=64 time=9.837 ms
64 bytes from 10.0.200.104: icmp_seq=1 ttl=64 time=4.354 ms
admin@HOST-RTR> ping 2001:db8:200::104 routing-instance host2 count 2
PING6(56=40+8+8 bytes) 2001:db8:200::102 --> 2001:db8:200::104
16 bytes from 2001:db8:200::104, icmp_seq=0 hlim=64 time=263.428 ms
16 bytes from 2001:db8:200::104, icmp_seq=1 hlim=64 time=3.766 ms
```
### Answer
Expand to reveal
Configuration for both switches is the same:
```
set vlans PROD vlan-id 100
set vlans DEV vlan-id 200
set interfaces ge-0/0/1.0 family ethernet-switching interface-mode trunk
set interfaces ge-0/0/1.0 family ethernet-switching vlan members [ PROD DEV ]
set interfaces ge-0/0/2.0 family ethernet-switching interface-mode access
set interfaces ge-0/0/2.0 family ethernet-switching vlan members PROD
set interfaces ge-0/0/3.0 family ethernet-switching interface-mode access
set interfaces ge-0/0/3.0 family ethernet-switching vlan members DEV
```
### Explanation
Expand to reveal
We create VLANs using `set vlans vlan-id `
\
We assign access port using:
```
set interfaces ge-0/0/2.0 family ethernet-switching interface-mode access
set interfaces ge-0/0/2.0 family ethernet-switching vlan members
```
\
By default, a port with `family ethernet-switching` is an access port, so technically speaking we don't need this line:
```
set interfaces ge-0/0/2.0 family ethernet-switching interface-mode access
```
\
Another method for configuring access ports is assigning the interface under the VLAN config hierarchy, instead of directly under the interface config.
```
set vlans PROD interface ge-0/0/2.0
```
\
By default, all trunk ports carry no VLANs. We can use `members all`, or the more safe option, specifying each individual VLAN. Remember that in Junos, a list of values goes inside square braces with no comma separation.
```
set interfaces ge-0/0/1.0 family ethernet-switching vlan members [ PROD DEV ]
```
\
Use `native-vlan-id` if you want to define the untagged VLAN on the trunk.
```
set interfaces ge-0/0/1.0 family ethernet-switching native-vlan-id
```
* This does not appear to be available on vJunos-switch.
\
We can use `show vlans` to verify. The `*` next to an interface means the interface is up.
```
admin@SW2> show vlans
Routing instance VLAN name Tag Interfaces
default-switch DEV 200
ge-0/0/1.0*
ge-0/0/3.0*
default-switch PROD 100
ge-0/0/1.0*
ge-0/0/2.0*
default-switch default 1
```
\
Above, notice that `ge-0/0/1` is seen in both VLANs because it is a trunk port with both VLANs as members.
\
We can also use `show ethernet-switching interface` which more clearly provides separation between access and trunk ports.
```
admin@SW3> show ethernet-switching interface
Logical Interface flags (DL - disable learning, AD - packet action drop,
LH - MAC limit hit, DN - interface down,
MMAS - Mac-move action shutdown, AS - Autostate-exclude enabled,
SCTL - shutdown by Storm-control, SL - Secure Learning,
MI - MAC+IP limit hit, LP - Loop Protect Down,
MLAS - Mac limit action shutdown, CISO - Shutdown due to core isolation,
EMS - Shutdown due to evpn maintenance)
Routing Logical Vlan TAG MAC MAC+IP STP Logical Tagging
Instance interface members limit limit state interface flags
default-switch ge-0/0/1.0 524287 8192 tagged
default-switch DEV 200 65535 1024 Forwarding tagged
default-switch PROD 100 65535 1024 Forwarding tagged
default-switch ge-0/0/2.0 524287 8192 untagged
default-switch PROD 100 65535 1024 Forwarding untagged
default-switch ge-0/0/3.0 524287 8192 untagged
default-switch DEV 200 65535 1024 Forwarding untagged
```
\
We can use `show ethernet-switch` table to see the MAC table.
```
admin@SW3> show ethernet-switching table
MAC flags (S - static MAC, D - dynamic MAC, L - locally learned, P - Persistent static, C - Control MAC
SE - statistics enabled, NM - non configured MAC, R - remote PE MAC, O - ovsdb MAC
GBP - group based policy, B - Blocked MAC)
Ethernet switching table : 4 entries, 4 learned
Routing instance : default-switch
Vlan MAC MAC Age GBP Logical NH MAC RTR
name address flags Tag interface Index property ID
DEV aa:c1:ab:2d:bf:36 D - ge-0/0/1.0 0 0
DEV aa:c1:ab:d8:57:57 D - ge-0/0/3.0 0 0
PROD aa:c1:ab:51:b4:6d D - ge-0/0/1.0 0 0
PROD aa:c1:ab:d5:d9:3a D - ge-0/0/2.0 0 0
```
### Further Reading