BT SHDS - Short Haul Data Services
The SHDS product replaced the legacy BT LES (LAN Extension Service) and is now the primary product to create dedicated private metro fibre circuits. There are restrictions on the distance between your locations to qualify for SHDS circuits, the range is typically 25km radial distance.
The product also supports extended range which, with 1Gbps circuits, will push to 35km. SHDS bandwidth supports 100Mbps and 1Gbps with the option to implement a secondary diverse circuit to avoid any single point of failure. The secondary short haul capability does increase the commercials of your overall solution but when uptime is necessary, there is no better technical solution.
The SLA (Service Level Agreement) offers 99.997% for RA01 (Resilient Access Option 1) which uses a single BT PoP (Point of Presence) and 99.998% RA02 with diverse NTEs and PoPs. BT Short Haul is often used by Government or Financial organisations due to the benefit of security. The services are delivered with CESG to Impact level 2.2.4 which offers assurance to those organisations with a need to implement connectivity to this level of privacy.
How much do BT SHDS circuits cost?
- BT SHDS is priced anywhere from £300 to £1000 per month depending on distance to the local PoP and bandwidth.
SHDS is normally more competitive when compared to national Ethernet, VPLS or MPLS circuits. In order to check pricing via BT Partner Sales, send us your postcodes and we’ll send you the results.
BT VLL - Virtual Leased Lines
Where your sites fall outside of the 35km distance limitation of SHDS, your next option to create point to point or multipoint Virtual Ethernet leased lines (VLL). The VLL is essentially emulating a dedicated short haul circuit by leveraging the capability of the BT MPLS network.
While emulation does essentially provide Global or UK Ethernet reach across UK, Europe, Asia Pac and North America, the circuits do not offer the same security level when compared to SHDS and neither do they provide the same latency figures. With this said, in terms of security and latency, Ethernet VLL circuits are comparable to layer 3 MPLS VPN and therefore deemed to be a secure technology for the majority of clients. VLL is also known as E-Line which provides point to point and multipoint topology with E-LAN (known as VPLS for the most part) offering any to any connectivity between LANs across your business sites.
A further benefit of VLL services is the capability to connect smaller sites to FTTC (Fibre to the Cabinet) and FTTP (Fibre to the Premises). Where voice or delay sensitive applications are to be provisioned, QoS (Quality of Service) is available to provide a consistent level of service as follows:
- Default – in contract / discard eligible
- Multi-CoS - choice of 5 classes
BT Optical - Wavelength supporting 10Gbps
Lastly, BT Optical services provide wavelength services of 2.5Gbps and 10Gbps with multiples of each to offer significant bandwidth. With support for a wide range of interfaces including Ethernet, ESCON and Fibre Channel, Optical Connect is a great way to interconnect data centres or campus sites that need to serve large data transfer.
While Cisco is the main hardware supplier for SHDS and VLL services, BT optical connectivity is available with Cisco, Ciena and ADVA. The configuration options are different vs the previous point to point services discussed within this article. With optical bearer notes, either a chain is formed where a maximum of 25 bearer nodes are linked together or a ring service option where 16 bearer nodes and be linked together as one logical entity. The wavelengths can be ordered between and two nodes on the ring technology. Topology for Optical Connect:
Point to Point - A to B
Ring - A to B to C to A
Chain - A to B to C to D
Conclusion, which point to point service is best for your business?
If your business is looking at connecting two locations within 35km, we would always recommend SDHS as your first product to consider. However, any organisation looking to add multiple locations may be better suited to VPLS Ethernet services which not only provides layer 2 connectivity but also the opportunity to add managed services if required. In most cases, and even with the advent of Internet SD WAN, networks are a hybrid of services that draw from the product which makes the most sense per business case. SHDS offers almost wire speed latency with excellent throughput and security accreditations.
The complete privacy of dedicated fibre will always be the default option for metro customers within particular sectors. Layer 2 VLL and VPLS achieve network topologies to interconnect data centres within different geographic locations. The average latency of VPLS (based on MPLS) is around 20ms round trip in the UK which is somewhat higher than SHDS but more than capable of supporting almost all applications other than the most latency sensitive trading data. VPLS is configurable with all topologies supported from any to any, point to multipoint and point to point. Where wavelength or high bandwidth is required, Optical is the only route forward. In many cases, Optical services are used for backup data transfer services or for traffic aggregation, i.e. an ISP taking customer traffic into a hosting facility.
BT Ethernet Connect “E-Line” and E-LAN have been certified by the Metro Ethernet Forum to MEF 9 & 14.