Mobile Backhaul 3G and 4G-LTE

Metrofibre networxTM is building a certified Metro Ethernet Forum (MEF) Carrier Class, fibre optic Open Access infrastructure, based on MEF9 and MEF14 that will provide managed broadband, bandwidth over the “Last Mile” connecting Service and Application Providers to their customers, including Mobile Backhaul.

The Metrofibre networx infrastructure is fibre optic based and the Managed Bandwidth Services comply with the MEF (Metro Ethernet Forum) Carrier Ethernet recommendations.

Mobile Backhaul: With the introduction of 3G/4G-LTE technologies and smart-phones supporting higher bandwidth and faster download rates, the increase in data traffic and the number of mobile subscribers has dynamically changed usage patterns and variation in type of traffic transported across todays cellular mobile network.  

Subsequently, this has fueled a demand for higher backhaul network capacity, intelligence and critical requirements to migrate mobile backhaul to Carrier Ethernet technologies that can support quality of service (QoS), User traffic prioritization and Class of Service (CoS) to separate traffic streams, lower packet loss and Performance Monitoring.

Mobile Backhaul over Carrier Ethernet has the advantage of being cost effective, easy to use and managed, while supporting various services and maintaining performance requirements.

Metrofibre networx Mobile Services: Metrofibre networx Carrier Ethernet highly manageable VPN-based Backhaul Services (E-Line, emulated LAN [E-LAN] and E-Tree services) can provide either unicast (Point-to-Point) or multicast (Point-to-Multipoint) services at Layer 2 or Layer 3, between the Radio Access Network Base Station (RAN-BS) and the Radio Access Network-Network Controller (RAN-NC).     

How do we do it? Depending on the network’s design, Metrofibre networx backhaul Tagged (Q-in-Q) or/and Untagged frames between the RAN-BS and RAN-NC.

Frames coming in from the cell tower are tagged with both location and service information. The location tag is stripped from the frames at the cell site device. The frames are then sent with only the service tags that are recognized all through the network into the Mobile Core.

  • Frames coming in from the cell tower that are only tagged with the location VLAN information. The service tags are added at the cell site.
  • Frames coming from the cell site untagged. The appropriate location and service VLAN tags are added at the RAN-BC with the location VLAN tag information based on the port that the untagged frames were received.  

Location VLAN tag is information based on the site from where they originated and is present all through the backhaul network and packets are handed off into the mobile core with the tag information.  

A service VLAN tag identifies the service that is being provided on the particular VLAN. Each service can be offered on a separate VLAN or all the services can be bundled into a single pipe that uses one VLAN for all services versus VLAN per service. The traffic in the backhaul can thus be separated either based on services or location.

Performance Assurance

For best traffic performance assurance guarantees, we track and measure the performance of traffic transiting across the entire Metrofibre  Backhaul Network, from RAN-BS interface (NID) to RAN-NC (NID) interface, with our Network Performance Management system that collects, monitors and measures end-to-end service performance for each Class of Service (CoS) priority.

Class of Service (CoS)

Each of the traffic types/ applications; voice, video, network signaling management, and best-effort data can be assigned to a Class of Service and prioritized through the network accordingly type of CoS guarantees.

Class of Service (CoS) Mapped

CoS Traffic Class CoS Service Class Diffserv Traffic Class Wired Packet Switched Network Typical Applications
Background Low (non real-time traffic) Best Effort (BE) Wired / Mobile IP data / Email
Interactive Low (non real-time traffic) Assured Forwarding (AF12) TCP-based services - HTTP / Telnet
Streaming Medium (real-time traffic) Assured Forwarding (AF11) UDP / RTP - Streaming Video
Conversational High (real-time traffic) Expedited Forwarding (EF) Voice - VoIP / Video conferencing

Backhaul Service Definitions 

Point-to-Point (E-Line)

  • Similar to leased lines
  • Requires traffic separation per RAN BS at RAN NC
  • Private and virtual private line EPL & EVPL
  • Diagram shows a EVPL

Point-to-Multipoint (E-LAN)

  • Similar to leased lines
  • Requires traffic separation per RAN BS at RAN NC
  • The specification cover private and virtual private line
  • Diagram shows a EVPL

Routed Multipoint (E-Tree)

  • Similar behavior as leased lines
  • Supports simpler RAN BS and RAN NC solutions
  • Multiplexing could be used for increased traffic separation
  • The specification cover private and virtual private routed multipoint  services Diagram shows a EVP-Tree

3G/4G LTE Small Cell Backhaul over Access fibre


  • The reasons for deploying Small Cells are becoming increasingly compelling for operators – they are often the best way to increase network capacity and bolster network coverage
  • Deployment of Small Cells into high traffic areas can give as much as a 600% increase in total cell capacity


  • Backhaul presents a number of challenges to mobile operators and is perhaps the most complex and usually the most expensive part of a Small Cell  deployment
  • Small Cells will substantially increase the number of physical sites, and the cost of backhaul can make or break the business case


  • Backhaul Small Cells over a “Open Access” highly-managed, high-speed Carrier Ethernet fibre network.