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.
Articles needing additional references from December All articles needing additional references All articles with unsourced statements Ericason with unsourced statements from December Commons category link is on Wikidata. Nodes that have worked flawlessly for five months, so they might work flawlessly for another five months.
There was zero indication of the potential for this to happen, until it started happening this week. But it is much more than that.
Multiplexing Digital subscriber line. Ok, so what happened?
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 our service. Retrieved from ” https: Once they caught a cold, they kept it. An ECN looks like a 24 port ethernet network switch. Each modem on the aggregation card communicates with a single subscriber’s DSL modem. 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 ericcsson communications channel using multiplexing techniques.
Like modern airlines, all the routine causes of breakdowns have largely been engineered away. 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.
User traffic is mostly IP based. At that exit, those fibre links are attached to inter-exchange fibre paths, and overall what we construct in ericseon cases is a wide-area ring.
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. The intention of writing this down is transparency — eficsson we love. Archived from the original on Therefore, it cannot re-route traffic between multiple IP networks, only between ISP devices and end-user connection points.
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. It has been, and it remains, a very unusual failure mode, starting with this interesting fact — when things went wrong, rebooting the applicable parts of our equipment did not fix those network elements.
The anatomy of a complex fault. This page was last edited on 25 Octoberat During reboot, the DSLAM modules maintain physical line sync to the customer, but obviously data flow stops.
The DSLAM equipment collects the data from its many modem ports and aggregates their voice and data traffic into one complex composite “signal” via dslwm.
In response we proactively upgraded another significant proportion of the switches in the entire SA network. So far, updating an ECN to that ericssin software release has resolved the issue on all customers attached to that affected ECN.
They are boot servers, control nodes, statistical aggregation points, and a number of other things including, also, being the ethernet switches that they appear, at face value, to be. Ercisson also uses the best equipment and services it can obtain — because this is all a part of giving our customers the best possible service experience. Its been extremely fast and reliable. Unsourced material may be challenged and removed. This article needs additional citations for verification.
There is switch hardware, power control hardware, and a linux machine, all inside a small rack-mounted box. The only thing that has been demonstrated to stop the fault is to upgrade the ECN software to a newer release. From Wikipedia, the free encyclopedia. Internode The Web Search Search.
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.
DSLAMs are also used by hotels, lodges, residential neighborhoods, and other businesses operating their own private telephone exchange. Typically a single DSLAM aggregation card has 24 ports, but this number can vary with each manufacturer. This modem functionality is integrated into the DSLAM itself instead of being done via an external device like a ericsson voiceband modem.
Ethernet DSL Access unlocks the broadband mass market
Some weeks are more complicated than others. RSS feed for comments on this post.
Each DSLAM has multiple aggregation cards, and each such card can have multiple ports to which the customers’ lines are connected. Balanced pair cable has higher attenuation at higher frequencies. Our vendor has subsequently identified a bug that is consistent with our observed outcome, and on their advice, we upgraded to the next dsllam of the code concerned in which that specific bug had been fixed.
Posted in Broadband by Simon Hackett.
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.
Please help improve this article by adding citations to reliable sources. Last night we saw a few more switches not yet upgraded start to demonstrate the fault.
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