A-End (A-Loc)
A-End (also referred to as A-Loc or Point A) is a telecom industry term that designates the starting point or terminal of a data transmission link, leased line, or network service. It is contrasted with B-End (or B-Loc), which refers to the endpoint of the connection. Together, A-End and B-End define the geographic and logical boundaries of a service, such as leased lines, MPLS, Ethernet over fiber, IP VPN, or other types of links.
A-End in the Context of Network Design
In telecom service design and delivery, A-End represents:
- The physical location where the customer receives the service (e.g., office site, data center rack, network node)
- The equipment to which the service is connected (router, switch, patch panel)
- The technical interface through which the link is delivered (fiber port, copper port, or virtual interface for cloud-based access)
For example, in the case of a long-distance leased line, the A-End may be located in the customer’s own data center, while the B-End may be in another city, country, or provider point of presence (PoP). Some technical documentation may also refer to a “Loopback A-End” when setting up test or backup configurations on the client’s side.
Example: When ordering an L2 Ethernet service between two offices, the A-End might be located at the client’s building in Moscow, and the B-End in the Saint Petersburg office. Both ends are defined in the service contract, SLA specifications, and technical support routing.
When Understanding the Term A-End Is Crucial
- When agreeing on connection terms and handoff conditions
- During cable installation and patching
- While diagnosing outages and link issues
- When defining areas of responsibility between parties
In technical and operational documentation, alternative terms may be used: A-Side, Local End, or Point A. However, in contractual and engineering practice, especially in the telecom industry, the term A-End is most commonly applied.
Frequently Asked Questions
A-End is the starting point of a telecom channel or connection. In leased line services, it designates the location of customer equipment where data transmission begins.
A-End is the source of the connection, while B-End is the destination. Together, they define the two endpoints of a link, such as between two data centers. The provider delivers the service as a unified connection between A-End and B-End.
It is widely used in telecom for designing and delivering L2/L3 links, IP VPNs, dark fiber leases, and data center connections, as well as in service contracts and network transport documentation.
A-End specifications include the handoff point (address, rack, port), equipment parameters, access level, interface type, and installation requirements — all essential for accurate setup and coordination between the provider and client.
