24 - 07 - 2024

VLAN translaction on Alcatel

In this article I would like to descirbe  the Alcatel VLAN Translation service by using ethernet-services feature. The service allows to translate VLAN 802.1 taggs as for this example from 1000 to 100, in the way similar to the NAT. It could be use to provide the L2 connectivity for networks that have diffrent VLAN numbering. 

This article is based on the Alcatel Command Reference, and all quotes marked by (2) or (1) came from it, this is not written by me just referring to the Alcatel guides.

SW_TRANSLATE - Alcatel 9702, this device is providing VLAN Translation.

W_OLD_NETWORK - The old switch that has not capability of 802.1ad. Also this switch has an old VLAN (100) that exists on the SW_NEW_NETWORK for other services(needs to be translated).

SW_NEW_NETWORK - The new network device that needs to have L2 connection to SW_SOURCE using diffrent VLAN numbering(1000).

# Prepare VLAN stacking 

-> ethernet-service svlan 1000

(2)"Vlan Stacking provides a mechanism to tunnel customer VLANs (CVLAN) through a service provider network using one or more service provider VLANs(SVALN) by way of 802.1Q double-tagging or VLAN translation.

# Trunk NEW_NETWORK VLAN to the port connected to SW_NEW_NETWORK

-> ethernet-service svlan 1000 nni 3/5

(1) "Network Network Interface (NNI) - is a port that resides on either a PE Bridge (an ethernet switch that resides on the edge of the service provider network) or a Transit Bridge (an ethernet switch that resides inside the service provider network). Traffic ingressing on a network port is considered SVLAN traffic and is switched to a customer-facing port or to another network port."

# Define new SAP profile with method of translation

-> ethernet-service sap-vlan_profile "sap-vlan_1000" cvlan-tag translate

(1) "A SAP profile contains traffic engineering attributes for specifying bandwidth sharing, rate limiting, CVLAN translation or double-tagging, and priority bit mapping. A default profile is automatically associated with a SAP at the taime the SAP is created".

# Assign the NEW_NETWORK VLAN to previously created service

-> ethernet-service service-name "1000_TO_100" svlan 1000

(1) "A service name is associated with an SVLAN to identify the customer traffic that the SVLAN will carry through the provider network"

# Create new service SAP with VLAN assigned to it

-> ethernet-service sap 1000 service-name "1000_TO_100"

(1) "Once the VLAN Stacking service is created, the name is used to configure and display all components associated with that service. The service name provides a single point of reference for a specific VLAN Stacking configuration.

# Assign SAP profile to the SAP

-> ethernet-service sap 1000 sap-vlan_profile "sap-vlan_1000"

(1) "After a profile is created, it is then necessary to associate the profile with a VLAN Stacking SAP.

# Assign SAP profile to the SAP

-> ethernet-service sap 1000 sap-vlan_profile "sap-vlan_1000"

(1) "After a profile is created, it is then necessary to associate the profile with a VLAN Stacking SAP.

At this point we have configured the VLAN Translaction service, but know it should be assigned to the OLD_NETWORK interface/VLAN.
We can do this for Access port and Trunk port.

## To use with Trunk port toward

-> ethernet-service sap 1000 uni 3/3
-> ethernet-service sap 1000 cvlan 100

## To use with Access port

ethernet-service sap 1000 uni 3/10
ethernet-service sap 1000 cvlan untagged

The solution at time of creating(AOS 6 / July 2010) the configuration had some issues:
*  The ports are shown as vstkQtag   
*  STP issues, the port went in Learning/Listening state, depends on STP type. This was caused by not sending the BPDUs on the ports toward SW_TRANSLATION