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Solutions - Managed Security

Asymmetric Digital Subscriber Line MAX


What is ADSL MAX?

ADSL MAX is the next generation of ADSL services offering speeds of up to 8Mbs download and 832Kbs upload with the enhanced business service and up to 8Mbs download and 448Kbs upload with the standard service.

How does ADSL MAX work?

ADSL Max works by using RATE ADAPTIVE TECHNOLOGY.This means that each connection will synchronise with the DSLAM at the local exchange and sync up to he highest possible speed available, while still offering the highest possible stability. With every ADSL connection speed is still determined by the line length and quality of copper between your premises and local exchange.

Are MAX services available from every UK telephone exchange?

BT currently have in the region of 5500 exchanges enabled for ADSL all of these exchanges apart from around 180 can get the new MAX service.

What speed can I expect with ADSL Max?

As stated earlier ADSL MAX is a true RATE ADAPTIVE technology and customers experiencing true 8Mbs connectivity will be few. Customers currently receiving a standard 2Mbs service from their Internet Service Provider should receive anywhere between 4Mbs and 7Mbs through put.

Will I have to upgrade my router or modem to run ADSL MAX?

Most ADSL routers and modems were designed to handle up to 8Mbs and shouldn't see a problem. If you do have a problem check with your ISP or upgrade your firmware.

Can I migrate ADSL MAX connections?

You can migrate any ADSL service terminating through the BT IPSTREAM network. If you have a connection through a Local Loop Unbundler (LLU) then you may have to cease and re provide. Check with your current ISP for further details.

MAX provisioning - 10 Day Stabilisation period

This period is used to determine the best possible speed for your line. Your router or modem will sync with the DSLAM at your telephone exchange and the two devices will send packets of data back and forth. Over the 10 day stabilization period you may experience drops in connection, the connection will also differ in speed, so one day you may get 6.5Mbs throughput and the next 3.5Mbs although the line will settle and stabilize as you near the end of the 10 day period to set a Maximum Stable Rate (MSR) and Fault Threshold Rate (FTR).

Maximum Stable Rate (MSR)

What is Maximum Stable Rate (MSR)?

The MSR is the best possible speed your line can run at and is decided over the first 10 days. The MSR doesn't stop your line from running at at higher speed or lower speed the MSR is used to set the FTR.

Fault Threshold Rate (FTR)

What is Fault Threshold Rate (FTR)?

The FTR is derived from the MSR and determines whether the line had a speed fault. The FTR is set at 30% of the MSR less 0.5Mbs. An ADSL Max connection should not drop below the FTR for longer than 8 hours in any 7 day period. If it does this may indicate a fault and you should contact you service provider

How can I increase my MAX speed?

ADSL Max is more sensitive to local wiring issues and strange telephony issues. If you think your Max line is running poorly check your Micro filter and ensure your internal wiring is good. Often moving your broadband modem or router to the master socket will improve speed.

General Performance

ADSL Max uses some other technologies to confuse you even more designed to ensure reliable performance. One is Dynamic Line Management (DLM) and the other is called interleaving.

Dynamic Line Management (DLM)

DLM is a process which operates in the background. gathering information about your connection over time. Should the performance of your line improve or degrade over time then DLM will set a new MSR and FTR. If DLM can see that a connection can support an increase in speed for a minimum of 3 consecutive days it may increase your speed upwards by 0.5Mbs. If a connection becomes unstable for more than 75 minutes then DLM will reduce the speed and attempt to re-stabalise the connection.

What is Interleaving?

Interleaving is a part of Dynamic Line Management (DLM) and is used to maintain connection stability if errors occur on the line. Interleaving is particularly useful for customers on long lines or at extreme range of service. The use of interleaving on a line will provide some latency (typically 20-40ms) however it generally provides a more stable experience, however if you are a business or running critical applications then the latency may cause problems especially when running Voice Over Internet Protocol (VOIP) applications. Interleaving can be turned on off as customers wish, although you will have to request this through your service provider

DSL Variants

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