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Carrier Ethernet, a PTN Transport Technology

Carrier Ethernet

A little slice of history: The Ethernet definition includes the PHYsical Layer 1 (10Baset-T, 10Mbps/ twisted pair) and Layer 2 of Data Link with MAC with control (Media Access Control). This was designed for short distance LAN with bridge and switch. The request to accommodate different group of users in the same LAN created the interest to tag and drive these communications of groups. In 1999, the IEEE had defined the VLAN 802.1Q that makes easy identified access and switch to dedicated resources. This was also the year the Spanning Tree Protocol had been defined as IEEE 802.1D to support the connection of two networks with Bridge. But many issues were created because of the organization of traffic in each network. Generally, to connect two distant networks, we were using one router at each external connection over Leased Line (LL) E1/T1… or serial. This isolates both networks and the eventual Telco/Carrier provides the leased line. Public Carrier or internal IT organization have started to propose Ethernet connection between sites. But they must be out of each LAN organization and prove the stability of Ethernet pipe as LL.

In 2006 came the definition of the Provider Bridges IEEE 802.1ad, or Q-in-Q, the dual/triple VLAN tagging or S-VLAN which allows the multipoint transport between sites of the customer traffic and their C-VLANs. This makes it easy to share many S-VLAN is the same large pipe if we apply OAM. Instead of multiplying the fibers with protection, local Carriers or multisite enterprises or a group of activities in MAN area as Town Technical Services can deploy a secured Carrier Ethernet GE/10GE network and provide the transport of services from many actors/customers and manage their QoS in MAN area. For Carriers, this solution has rapidly replaced the LL with aggregation router, at less cost and higher bandwidth optimization. But this transport is limited to the MAN without long distance solutions and the number of service is limited to 4096.

In 2008 the IEEE validated the Provider Backbone Bridge 802.1ah or Mac-in-Mac, for unlimited Ethernet network of transportation, but it is designed for TELCO and thus not in Loop Telecom’s target.

MEF and CE 1.0/2.0/3.0:  In 2001 the Metro Ethernet Forum MEF was created with the mission to structure the Ethernet transport WAN with the service based on Port or virtual port or C/S-VLAN and to develop the tools to manage the bandwidth as OAM. 2006 MEF CE 1.0 and then 2012 CE 2.0 have been published, and defined:

  • Each user access is UNI, each link between 2 or more UNI is a Point-to-Point or Multipoint Ethernet Virtual Connection EVC Based services
  • Per-EVC QoS, Policing and Shaping for Service Isolation and Traffic Engineering
  • The Ethernet service interconnection E-Line, E-LAN, E-Tree, E-Access

In 2019 CE3.0 includes all and adds the Operator Virtual Connection (OVC) Service to interconnect multiple operators of transport by ENNI and many other definitions including the SDN and NVF solutions of integration.

Loop Telecom proposes a range of NID (Network Interface Device, previously named Ethernet Demarcation Devices), the IP6608/IP6618 and the Aggregation, 10GE Backbone, NIDs Concentrator G7820, G7860A and PTN10G that support CE 2.0 services.

VLAN features:  The Loop Telecom NIDs support full VLAN features to create EVC as Q-in-Q (C-VLAN, s-VLAN), MAC or Protocol-based or IP subnet-based VLAN and MRP, Voice VLAN and Auto VoIP. To optimize the transport, the NIDs provides the Layer 3 VLAN translation, VLAN Trunking and for their administration supports multiple VLAN Registration MVRP and GVRP.

Protection:  Based on port and EVC the NIDs and Concentrators support RSTP, MSTP, Link Aggregation but also the ITU-T ERPS with Ring and Subring. This gives the possibility to deploy no-single-point-of-failure mandatory in many infrastructures such as Railway.

QoS:  This is a key point of warranty for the private or carrier transport network relating to each customer. With 8 hardware priority queues the NIDs build the QoS Per-EVC, then per subscriber. The Traffic Engineering Engine provides Strict Priority and Weighted Round-Robin Scheduling, with fixed rates for service as TDM-PseudoWire transport and Rate limiting per EVC.

OAM Operation, Administration and Maintenance:  The OAM gives the possibility to managed stable transport. Thanks to Link Layer Discovery Protocol (LLDP), Connection Fault Management (CFM), access Ethernet First Mile (EFM) and ITU-T Y.1731 and Y.1564 Performance and Service Activation Test the operator of transport network can manage at End points and Intermediate points by the NIDs and Concentrators.

The OAM is used for mixed infrastructures as Carrier Ethernet at the EDGE and MPLS-TP in the core and give command of the protection.

Time and Frequency Synchronization: NIDs and Concentrators transport and distribute the Synchronization along the Network and to UNI for industrial applications, TDM PseudoWire transport or 3G, LTE and 5G Node-B/BTS. The frequency synchronization is given by SyncE GE/10GE with SSM message of quality. The Phase or Timing synchronization is given by the PTP 1588v2 protocol that support Peer-to-Peer or End-to-End Transparent Clock with ns accuracy for industrial automation, and Boundary Clock, slave with Multiple Timing Domains for multiple clients per site.

The OAM gives the possibility to managed stable transport thanks to Link Layer Discovery Protocol (LLDP), Connection Fault Management.

Secure Access:  NIDs include a high level of security at UNI and NNI ports. Based on single or multiple IEEE 802.1X with VLAN and QoS assignment per authentication, they support Radius and TACACS+ servers with 15 users’ levels. Port authentication can be MAC-Based or multiple ACLs role of Filtering, Policing and Ports Copy and IP MAC Binding. Switching Guard can be set for loop, role and BPDU.

Carrier Ethernet NIDs and Concentrator Router/MPLS-TP:  Loop Telecom proposes the integrated solution with full Carrier Ethernet or a mix of infrastructure with Layer 3 router to provide VRRP for redundant server access or long-distance infrastructure with MPLS-TP in the Core.

All ranges of equipment are supported by our EMS iNET that help in deployment and monitoring.