Ericsson is this week re-entering the market for DSLAMs with an innovative Ethernet access card that it says will unlock the mass market for DSL services by . DSLAM units are typically located in telephone exchanges or distribution points. They allow for the high-speed transmission of DSL technology. Ericsson’s EDA solution is the most widely deployed IP/Ethernet DSLAM with over 60 contracts globally, utilizing the latest ADSL2+ technology.

Author: Tokora Bragar
Country: Jamaica
Language: English (Spanish)
Genre: Music
Published (Last): 26 March 2006
Pages: 65
PDF File Size: 16.30 Mb
ePub File Size: 13.58 Mb
ISBN: 309-2-39421-116-6
Downloads: 28855
Price: Free* [*Free Regsitration Required]
Uploader: Kesida

So far, updating an ECN to that newer software release has resolved the issue on all customers attached to that affected ECN.

This sort of resiliency is at the heart of why these systems are generally just rock solid in practice. Like modern airlines, all the routine causes of breakdowns have largely been engineered away. Nodes that have worked flawlessly for five months, so they might work flawlessly for another five months. There is switch hardware, power control hardware, and a linux machine, all inside a small rack-mounted box. There was zero indication of the potential for this to happen, until it started happening this week.

The failure mode resulted in some downstream 12 port DSLAM modules spontaneously rebooting, and after boot, those modules started complaining of being handed invalid configuration data and commenced another reboot and… so on. But because it was a truly unusual failure mode, and also just because we care a hell of a lot about such things, we dropped everything to resolve it.

This page was last edited on 25 Octoberat Our vendor has subsequently identified a bug that is consistent with dslaam observed outcome, and on their advice, we upgraded to the next revision of the code concerned in which that specific bug had been fixed.

It is important to appreciate that the current software release the faulty one was rolled out very carefully as all upgrades normally areand it has been flawlessly for around five months until this fault developed. A digital subscriber line access multiplexer DSLAMoften pronounced DEE-slam is a network device, often located in telephone exchangesthat connects multiple customer digital subscriber line DSL interfaces to a high-speed digital communications channel using multiplexing techniques.


This is not a trivial decision, because we are upgrading to a new software release — which brings in the potential for there to be some other, as yet unknown, issue for ericssom service. Based on vendor advice, we are edicsson looking at how best to upgrade the rest of the network, to guard against a further recurrence elsewhere.

Digital subscriber line access multiplexer

It also uses the best ericzson and services it can obtain — because this is all a part of giving our customers the best possible service experience. The intention of writing this down is transparency — something we love. RSS feed ericssln comments on this post. This has been a complicated week! DSLAMs are also used by hotels, lodges, residential neighborhoods, and other businesses operating their own private telephone exchange.

Customer-premises equipment that interfaces well with the DSLAM to which it is connected may take advantage of enhanced telephone voice and data line signaling features and the bandwidth monitoring and compensation capabilities it supports.

Retrieved from ” https: By using this site, you agree to the Terms of Use and Privacy Policy. The current theory, based on vendor feedback, is that the software fault is a latent, load triggered, memory leak that makes the ECN lose the plot in a manner that corrupts some critical item inside one of the ECN systems — an item that remains corrupted after it is rebooted or power cycled.

Digital subscriber line access multiplexer – Wikipedia

Ok, so what happened? Balanced pair cable has higher attenuation at higher frequencies. This article needs additional citations for verification. From Wikipedia, the free encyclopedia. In response we proactively upgraded another significant proportion of the switches in the entire SA network.

Views Read Edit View history.

This is due to the nominal line impedance measured in Ohms but comprising both resistance and inductance of balanced lines being somewhat lower than that of UTP, thus supporting ‘weaker’ signals however the solid-state electronics required to construct such digital interfaces are more costly.

A DSLAM may or may not be located in the telephone exchange, and may also serve multiple data and voice customers within a neighborhood serving area interfacesometimes in conjunction with a digital loop carrier. Therefore, it cannot re-route traffic between multiple IP networks, only between Ericdson devices and end-user connection points. Last night we saw a few more switches not yet upgraded start to demonstrate the fault. No Comments No comments yet.


The only thing that has been demonstrated to stop the fault is to upgrade the ECN software to a newer release.

InterComms – The International Communications Project

An ECN looks like a 24 port ethernet network switch. Multiplexing Digital subscriber line. At that exit, those fibre links are attached to inter-exchange fibre paths, and overall what we construct in most dspam is a wide-area ring.

Please help improve this article by adding citations to reliable sources. User traffic is mostly IP based. This modem functionality is integrated into the DSLAM itself instead of being done via an external device like a 20th-century voiceband ds,am. Its been extremely fast and reliable. But it is much more than that. Thursday, April 1st, by Simon Hackett.

In other projects Wikimedia Commons. Sorry, the comment form is closed at this time. This compensation capability also takes advantage ericssn the better performance of ” balanced line ” DSL connections, providing capabilities for LAN segments longer than physically similar unshielded twisted pair UTP Ethernet connections, since the balanced line type is generally required for its hardware to function correctly.

Each DSLAM has multiple aggregation cards, and each such card can have multiple ports to which the customers’ lines are connected. We obviously had a fault. Unsourced material may be challenged and removed. Typically a single DSLAM aggregation card has 24 ports, but this number can vary with each manufacturer.

Designing and Deploying Triple-Play Services. Like traditional voice-band reicsson, a DSLAM’s integrated DSL modems are usually able to probe the line and to adjust themselves to electronically or digitally compensate for forward echoes and other bandwidth-limiting factors in order to move data at the maximum possible connection rate.