Posted: 26th Jun, 2006 By: MarkJ
ADSLGuide has published a briefing issued by BTWholesale to ISP's, which covers one of the problems (speed stability) that people have experienced with ADSLMax (up to 8Mbps) technology:
'BLIP LOGIC' FIX To improve the experience for end user customers we have introduced a fix which takes account of the historical stability of the line when encountering a one off low synchronization event. This is known as the Blip logic fix.
The Blip Logic fix introduces the ability for stable BT IPstream Max (or BT IPstream Max Premium) line not to wait 3 days to move to a higher BRAS profile after a single isolated event of low line rate synchronization. A stable line will be classed by the blip logic as a BT IPstream Max line that over the previous 14 days has not had a line rate change that has instigated a downward change in their BRAS profile.
Therefore, if a stable line has a single, isolated low synchronization event that instigates a downward change of BRAS profile then as long as the next line rate synchronization event is higher the BRAS will be reset to the appropriate level for this higher line rate within 75 minutes. This bypasses the normal wait for 3 days of a constant higher line rate.
If the line rate increases on subsequent synchronization events, further upward BRAS profile changes will also be allowed within 75 minutes as long as there is not another downward move in the BRAS rate in the mean time. If another downward move of BRAS profile does occur within 14 days of the first one then the line will not be classed as stable by the Blip logic and the 3 days of a constant higher line rate will need to elapse before the BRAS profile is changed upwards.
Before the line is once again classed as stable by the Blip logic another 14 days will need to elapse during which time the line must not have had a downward move of BRAS profile.
Please note that BT systems generate a heartbeat synchronization event every night. This will be registered by our systems as standard synchronization event. If the line has a modem or router that is constantly switched on it may prevent the line from synchronizing at a higher line rate before the heartbeat event is generated. Therefore, the heartbeat event may be detected by the Blip logic as a second low synchronization event and the 3 day rule for changing the BRAS profile will apply.To cut a long and rather techno-babble filled story short, users should experience a greater period of speed stability because the system is now able to better reflect a lines overall performance.
It's still not perfect, but I for one have noticed fewer 'low speed' periods over the past few days. We'd like to hear from others on ADSLMax, especially those that have experienced similar problems. Post your comments.