8.1 Ethernet OAM
LTE140 “Ethernet OAM” (RL20, RL15TD)
Ethernet OAM (Operation, Administration, Maintenance) features support management of Ethernet (L2) networks in terms of Fault Management (FM), Performance Management (PM) and Configuration
Management (CM). This is beneficial for detection and localizing faults, examining and reporting network status, monitoring network performance, and provisioning and configuring parameters. Ethernet OAM functions and protocols are standardized as follows:
• Link Layer OAM (IEEE 802.3ah)
• Ethernet Service OAM (IEEE 802.1ag / ITU-T Y.1731), a.k.a. “Service Layer OAM” Due to different objectives, these protocols complement each other.
Link Layer OAM (IEEE 802.3ah) operates at a single link and is mainly targeting as "Ethernet in the first
mile" application. Flexi Multiradio BTS supports the following functions:
• OAM Discovery: Identify peer device and its OAM capabilities (with active mode support)
• Remote Failure Indication: Mechanism to provide failure information to the peer. Includes Link Fault, Dying Gasp, Critical Events
• Remote Loopback: allows to check the quality of the link for diagnosis and troubleshooting (w/ active mode support).
• Link Monitoring: Event notifications, including diagnosis information (threshold alarms)
Service Layer OAM (IEEE 802.1ag / ITU-T Y.1731) covers Ethernet end-to-end- and network segment-
connectivity as well as service guarantees. Flexi Multiradio BTS supports the following functions:
• Ethernet Continuity Check: Reports loss of continuity between two MEP’s (Maintenance Endpoints), within a MEG (Maintenance Entity Group) or unintended connectivity
• Ethernet Alarm Indication Signal: indicates alarms to next nodes and suppresses alarms to NMS if indicated alarms occurs on lower levels
• Ethernet Remote Defect Indication: Used by a MEP to communicate to its peer MEP that a defect condition has been encountered.
• Loopback: behavior in Ethernet similar to "Ping" on L3 (with optional troubleshooting extensions)
8.2 Transport Plug’n’Play (SON)
Self-Organizing / Self-Optimizing Networks (SON) principles are essential to decrease operator OPEX. This chapter recapitulates transport related items.
8.2.1 Auto-Connection
LTE154 “SON LTE BTS Auto Connectivity” (RL10, RL15TD)
Flexi Multiradio BTS is delivered from the factory with an initial basic SW to perform the basic boot process, the auto-connectivity agent SW for the establishment of a connection to the IP backhaul network and the self-configuration agent SW. Auto Connection supports fast integration of new or re- located base stations by an automated process based on DHCP [RFC2131], [RFC2132].
The following steps have to be performed beforehand: 1. Site plan preparation
Transport planning data related to the new Flexi Multiradio BTS have to be prepared. This is not needed for the auto-connection phase itself, but for the unambiguous Flexi Multiradio BTS detection in the subsequent auto-configuration step.
2. DHCP server preparation:
DHCP servers have to be preconfigured with suitable options and Flexi Multiradio BTS specific data (vendor specific attributes):
• IP address of the Identity Management System (IDM) respectively another 3rd party PKI Certificate Server providing a CMPv2 interface
• IP address of the Security Gateway protecting the responsible O&M system (NetAct)
• IP address of the management peer of the responsible O&M system
• optionally an IP address of a dedicated LDAP server for Certificate Management
Auto-Connection comprises the following functions. 1. Establishment of IP connectivity
The Flexi Multiradio BTS transport sub-module is automatically configured to enable the following steps:
• L1/L2 auto negotiation
• IP Address Assignment
In order to retrieve all information necessary for the IP connection establishment between Flexi Multiradio BTS and NetAct the Flexi Multiradio BTS acts as DHCP client. DHCP requests are submitted first untagged. If not successful, the whole VLAN ID range is scanned (VLAN probing). The DHCP server assigns an IP address, netmask and the IP address of the default gateway to the Flexi Multiradio BTS and delivers in addition further information as vendor specific attributes as listed above.
If the address of a PKI Certificate Server has been delivered in the previous step, Flexi Multiradio BTS retrieves a new certificate from the operator’s CA using the CMPv2 protocol.
3. Connection to the Security Gateway (optional)
If the address of a Security Gateway has been delivered in step 1, Flexi Multiradio BTS establishes a connection to the gateway and sets up Security Associations for the M-plane.
4. (Secure) O&M plane connection
Flexi Multiradio BTS starts the (secure) M-plane connection to the NetAct framework. In addition to the previously established IPsec tunnel to the SEG, security may be extended further to the O&M application using TLS (optional).
8.2.2 Auto-configuration
LTE720 “SON LTE BTS Auto Configuration” (RL10, RL15TD)
Based upon successful Auto-connection, the Flexi Multiradio BTS configuration plan file (RAML2.1 format) will be downloaded which also contains all transport related parameters. This configuration will be operationally available after an automatically performed reset of the base station.
To derive IP connectivity information of neighbor sites the following procedure is applied:
• During the auto-configuration process each Flexi Multiradio BTS registers itself with its eNB global ID and given IP configuration at NetAct.
• NetAct uses the eNB Global ID to access the related configuration plan file of the newly registered BTS
• NetAct searches for given pre-planned neighbor configurations (respectively for their eNB global IDs)
• NetAct checks if the listed neighbor sites are already registered. For all sites in operation NetAct queries the database for the assigned IP configurations.
• NetAct stores the found IP configurations into the neighbor cell configuration area within the configuration plan file of the newly registered Flexi Multiradio BTS.
• The updated configuration plan file is now ready to be downloaded automatically as part of the auto-configuration process.
The operator is able to start the neighbor site scan and configuration plan file update also manually on demand for a single Flexi Multiradio BTS or a list of BTS’s.
9. FLEXI TRANSPORT SUB-MODULES FOR LTE