When it comes to private line services, there’s been a major shift from the days of Time Division Multiplexed (TDM) offerings like DS-0, DS-1, and DS-3. Back then, the requirements discussion was pretty straightforward. However, with the advent of Ethernet services, things have become more nuanced, making upfront discussions about business objectives and requirements an essential step.

The key difference lies in the connection approach. Traditional TDM private lines utilized a dedicated physical path between the two endpoints, which you could trace. In contrast, most modern Ethernet services employ a virtual connection methodology with different performance metrics.

This distinction is akin to the difference between a live voice conversation and a text exchange using voice dictation on your smartphone. With an actual voice call, you pick up on the speaker’s voice, tone, inflection – the full nuances of human speech. Not only that, but you can also engage in a real-time, back-and-forth dialogue, even interrupting the speaker if needed. Text-based virtual conversations, on the other hand, simply convey the words themselves (assuming accurate translation), stripped of the speaker’s vocal characteristics and real-time dynamics.

The ability to support these nuances of communication could be termed “transparency” – something that dedicated services naturally provide, but that virtual services may lack.

While virtual Ethernet services are often sufficient for basic data transmission between devices like routers and servers (where transparency isn’t crucial), certain use cases demand that transparency. A prime example is LAN-to-LAN switching, which requires full transparency to enable layer 2 routing and management protocols to function properly.

Another key consideration is latency – the delays involved in transmitting data across the connection. Certain applications, like those used in radiology, have stringent latency requirements, with round-trip times needing to be under 15ms. Such low latencies often necessitate (and push the limits of) dedicated circuit services.

Virtual communication services like Virtual Ethernet essentially operate like the postal service, with packets taking varied paths and facing potential delays or losses due to network congestion (akin to seasonal delays with mail). Higher-layer protocols like TCP help account for these vagaries. However, the performance metrics of latency (from 30ms to 100ms+), jitter, and packet loss need to be evaluated.

An alternative to virtual services is to use wave services – essentially a form of dedicated Ethernet private line service. Wave services typically offer a LAN-PHY ethernet handoff option, alongside interfaces like SONET, ONT, and wave division multiplexing.

Inevitably, many client requests (even from government bodies) still use legacy terms like “leased lines” or “private lines” – terminology that was unambiguous back when TDM was the norm, but which requires further clarification in today’s Ethernet/IP world. The associated acceptance testing procedures tend to be geared towards dedicated services, covering extended test durations, high availability, latency, and packet loss, but often lack insight into average performance over longer periods.

When such ambiguous “private line” requests come in, it’s crucial to dig deeper by asking questions like:

  1. What is the underlying business requirement?
  2. Are there specific latency requirements, and what applications will run over this connection?
  3. Will this involve router-to-router or server-to-server connections? (This helps gauge transparency needs; if L2 tunneling or control protocols are involved, a dedicated/transparent service is likely required.)

If a dedicated service seems to be the appropriate solution, another key consideration is redundancy and reliability in the face of scenarios like fiber cuts. Most dedicated offerings provide various levels of path diversity and redundancy, but the differences between providers can be significant and subtle. Engaging technical sales support may be needed to properly evaluate design options, but having the core requirements sorted out is a great start.

The key is to convey these pertinent details to your pricing and technical sales teams from the get-go, allowing them to quote the right solution upfront. If redundancy is required, you’ll already be ahead of the game in securing the complete, resilient solution.

As networking technologies continue to evolve and diversify, traditional terminology often acquires new shades of meaning. By taking the time upfront to truly understand the client’s requirements, you can avoid potential mismatches between the solution you provide and their actual needs – potentially saving all parties from costly rework down the line.

Positioning yourself as a knowledgeable advisor who can illuminate these nuances and clearly map requirements to solutions is a surefire way to strengthen client trust and credibility. So for those “simple” private line requests, be sure to peel back the layers – you may uncover valuable insights that allow you to deliver the perfect fit.