Ability to Reset Openreach FTTC Broadband DLM Profiles Arrives

At present if an ISP feels that the Dynamic Line Management (DLM) profile for a UK Fibre-to-the-Cabinet (FTTC / VDSL2) based broadband line needs a reset then it usually requires an Openreach engineer visit, but progress is being made on a new remote reset solution.

The DLM system is used to control the performance and stability of related lines, which in practice means that your speed may go up or down depending upon how stable / error prone DLM thinks the line is. Broadly speaking the DLM system on Openreach’s FTTC network works pretty well, although sometimes a connection’s profile may become stuck at a lower level or other problems can occur that might benefit from a profile reset.

Unfortunately ISPs have not previously been able to perform remote resets on FTTC circuits, which is partly because to do so would require an engineer visit (attracts a cost). Last year we mentioned that Openreach were working to improve DLM by tweaking how it works and also offering an “interim” solution for resetting the caution counters (technically a DLM reset), which would allow ISPs to “request a caution counter reset on a number of their lines each day“.

Since then several ISPs (e.g. Plusnet) have started offering the option of a remote DLM reset as part of a trial with selected customers. The reset seems to take place in phases and has in a few examples helped to return some FTTC lines back to a higher speed. Today Openreach issued an interesting update to tout an “interim” solution that “will allow [ISPs] to request a DLM reset and replaces the ability to request caution counter resets” (here).

The briefing itself isn’t public, although ISPs inform us that it does indeed extend the trial from a caution counter reset to a full DLM reset, which should fix banding problems and some other issues with DLM profiles; assuming of course that the original underlying problem has been resolved first. We understand that this change will come into play from the 19th February 2018.

Using this approach means that each day an ISP can submit a list of circuits to be reset, which is then applied overnight by Openreach. A limit of 1000 circuits per day per ISP remains in place, although we’ve not seen any complaints about this restriction. Obviously this is something that ISPs don’t expect to use a lot but it’s a useful tool for them to have and could save on engineer visits, as well as satisfying some users.