Has BT shut down its DSL management system?

DSL and fiber-optic network management software company ASSIA asserts that BT has shut down the dynamic line management (DLM) system for the DSL portions of its Next Generation Access (NGA) network in the wake of an unfavorable court ruling in the two companies' ongoing patent dispute. A BT spokesman did not directly confirm or deny ASSIA's announcement.

After failing to get BT to agree to license its DSL DLM technology as part of the carrier’s initiative to create its own DLM, ASSIA has alleged in court since 2011 that BT’s DLM infringes on a pair of patents, EP (UK) 1,869,790 and EP (UK) 2,259,495. In December of last year (with a follow-up ruling in January 2014), a UK High Court ruled that BT was safe from infringement of 495, but had infringed upon 790 (see "BT infringed on ASSIA DSL patent rules UK High Court"). BT appealed the 790 ruling, while ASSIA appealed the 495 ruling. Meanwhile, BT asserted that it had developed a "workaround" adjustment of the DLM that solved its 790 problems, and asked the court to agree.

Thus began a pair of legal tracks, one on the appeals and the other on the validity of BT's workaround. On November 11, the UK Court of Appeal in London handed ASSIA a double victory on the appeals, upholding the High Court ruling that BT infringed the 790 patent, while deciding that BT also infringed on the 495 patent after all.

On November 21, the Court of Appeal issued a final injunction that covers the fallout of its November 11 decision. Among other issues such as the payment of legal fees, it ruled that while the validity of the workaround remained unsettled, BT would have to pay ASSIA £250,000 each week the DLM remains in operation.

ASSIA says that BT has informed the company that it has decided to shut down the DLM rather than pay the weekly fee. A BT media relations contact first told Lightwave via email that the company would have no comment, then resent a statement BT made after the November 11 ruling. The statement reads:

BT has been defending a claim brought by ASSIA since November 2011. They had asserted three patents against BT but during the proceedings, they had to narrow their allegations and withdraw one of these patents entirely.
In January 2014, the High Court found BT was infringing on only a minor part of one patent, and the Court of Appeal, whilst invalidating the majority of the claims of ASSIA's other patent, ruled that BT's network infringes what remains of the other patent.
Although BT was disappointed with the ruling, we have made minor changes to our programming which means these two decisions have no material effect on the operation or performance of our networks.

When it was pointed out that this statement was first issued before the November 21 final injunction, the BT source responded that the statement "is current and still accurate."

Meanwhile, a hearing on whether BT’s "minor changes" to its DLM settled the 790 issues was held November 13. A ruling on that proceeding is expected at some point in December, according to ASSIA General Counsel Noah Mesel. Meanwhile, the new ruling affirming infringement of the 495 patent raises the possibility of the need for a second workaround. Mesel said it was unlikely that whatever BT has done to get around the 790 patent would also solve any 495 problems, as the latter patent is more fundamental to DLM operation.

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