Alcatel Switch Configuration

An Alcatel-Lucent OmniSwitch does the same job as a Cisco switch, but its operating system, AOS, does not think the same way. The commands differ, and above all the configuration handling rests on a mechanism absent from IOS: two distinct boot directories, whose understanding conditions everything else.

This article starts from that peculiarity, then walks through the usual operations in the order you meet them: reading and saving, starting over, addressing and segmenting, stacking and monitoring.

A CLI that does not think like IOS

Three differences stand out within the first minutes.

No nested modes. Where IOS requires enable then configure terminal then interface, AOS accepts every command from a single prompt. There is no (config-if)# to get lost in.
Case-insensitive commands. show vlan, Show VLAN and SHOW VLAN are strictly equivalent. The examples in this article use lowercase by convention.
Saving happens in two stages, which is the subject of the next section.

For anyone coming from Cisco, this table gives the most useful equivalences:

Goal	Cisco IOS	Alcatel AOS
Show the configuration	`show running-config`	`show configuration snapshot`
Save	`write memory`	`write memory` then `copy working certified`
Create a VLAN	`vlan 10` then `name TEST`	`vlan 10 name TEST`
Delete a VLAN	`no vlan 10`	`no vlan 10`
Address an interface	`interface vlan 10` then `ip address`	`ip interface ... vlan 10`
List IP interfaces	`show ip interface brief`	`show ip interface`
Reboot	`reload`	`reload from working`

NoteAOS 6 and AOS 8

Several commands were renamed between the two major AOS generations, notably the reload ones: reload working in AOS 6 becomes reload from working in AOS 8. When in doubt, ? at the end of a line lists the forms accepted by the device in front of you, just like on IOS.

Reading and saving the configuration

Showing the active configuration

show configuration snapshot

The command produces an image of the active configuration, directly reusable as a configuration file. A feature keyword narrows it to one area, for example show configuration snapshot vlan.

Understanding the two directories

This is the structuring peculiarity of AOS. The switch keeps two sets of boot files in flash memory.

Directory	Content	Role
`/flash/working`	the work-in-progress configuration	receives your saved changes
`/flash/certified`	the reference configuration	safety net, known to work

ExplanationWhy two directories rather than one

On IOS, saving overwrites the startup configuration: if it holds a mistake that cuts your access off, only physical console access is left. AOS keeps an untouched certified version, which the switch can reboot onto automatically. A remote change therefore becomes reversible without travelling on site.

Saving in two stages

Write the active configuration into working
Terminal
write memory
The active configuration is saved into /flash/working/boot.cfg. The certified directory stays untouched: on a reboot onto certified, your change would be lost.
Check the synchronisation state
Terminal
show running-directory
The output states which directory the switch booted from and whether working and certified are synchronised. This is the command that answers “will my configuration survive a reboot”.
Certify once the configuration is validated
Terminal
copy working certified
This step copies working into certified and pins the new configuration as the reference. Only run it after confirming everything works, connectivity included.
TipThe chassis and stack case
On a chassis with two management modules or on a stack, the write memory flash-synchro command writes the configuration and propagates it to every element. Without that synchronisation, a failover onto the secondary module would bring back a stale configuration.

ImportantNever certify straight away

Chaining write memory and copy working certified without testing amounts to removing the safety net at the exact moment it becomes useful. Deliberately leave certified behind as long as the change is unproven: that is the whole point of the mechanism.

Starting over from a blank configuration

Resetting a switch recovered from another site means deleting both boot files, since the certified one would otherwise act as a fallback.

Delete both configuration files

rm /flash/working/boot.cfg
rm /flash/certified/boot.cfg

Move onto the working directory
Terminal
cd working
Reboot with no rollback timer
Terminal
reload working no rollback-timeout
Confirm with y. The switch reboots onto an empty directory and comes back with its factory configuration.
ExplanationWhat the rollback timeout does
By default, a reboot onto working arms a countdown. If you do not certify the configuration before it expires, the switch automatically comes back on certified. This is a protection against the configuration that cuts your access off: it repairs itself. no rollback-timeout disarms that mechanism, which is legitimate here since an empty configuration is precisely what we want, but dangerous in any other remote context.

Danger

These commands wipe the whole configuration, with no intermediate confirmation and no way back. Export an image with show configuration snapshot before starting if the current content holds the slightest value.

Addressing and segmenting

Creating and deleting a VLAN

vlan 10 name TEST

Creates VLAN 10 and names it TEST, in one command where IOS needs two.

no vlan 10

Deletes VLAN 10.

Viewing VLAN assignment on ports

show vlan port

This is the equivalent of Cisco’s show vlan brief: the command to run first when two machines cannot see each other.

Addressing an interface

ip interface <name> address <ip> mask <mask> vlan <vlan_num>

show ip interface

ExplanationAn IP interface is named, not numbered

On AOS, an IP interface carries a free-form name you choose, and attaches to a VLAN through the vlan parameter. Cisco reasons the other way round, with a virtual interface whose number is the VLAN’s (interface vlan 10). Pick a meaningful name, such as vlan10-admin: that is what will show up in every diagnostic output.

Stacking and monitoring

Renumbering a stack element

stack set slot 1 saved-slot 2

1 is the current slot number, 2 the one you want to give it. The change takes effect on the next reboot.

show stack topology

Shows the order of the elements and the state of the stacking cables.

TipWhy renumber

The slot number determines port naming, 1/1/1 for the first port of the first element. Replacing a failed device without reusing its number shifts the whole naming scheme, and makes both the documentation and the patch panel labels wrong.

Creating a user

user User1 password Test read-only all

Creates the User1 account with read-only access across every command family. read-write all grants full powers instead.

Warning

That example password obviously has no place anywhere but a lab. On a real device, apply your organisation’s password policy and delete the default admin account, or change its password before going live.

Configuring SNMP

snmp security no security

DangerThis setting disables all SNMP protection

no security accepts SNMP requests with no authentication and no encryption. Anyone able to reach the switch can then read its configuration and, depending on the rights granted, write to it. This setting is only justifiable in a closed lab, to make an old monitoring tool work.

In production, use SNMPv3 with authentication and encryption, and restrict access to your monitoring server’s addresses only.

These commands cover bringing an OmniSwitch into service and running it day to day. The two-directory mechanism remains the only real surprise for anyone coming from IOS: once understood, it turns every remote change into a reversible operation.