Did one of you break t'internet?

[~YuckFou~]

Network performance drop 23/11/02 16:00 - 17:30


A Distributed Denial Of Service attack launched against Zen's network, starting around 4PM, adversely affected network performance.

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Don't think they are out of the woods yet, been iffy tonight.

 

[Flamin_Squirrel]

Im having problems with zen myself. Uploads abysmally slow (10-20, rather than 30 that i used to get) poor pings, loss and choke.

However when i phoned them (took about a week to convince them there was a problem) they told me it was the BT network overloaded.

I was tempted to migrate to nildram, but that costs £35, and im told ill be stuck on the same crappy overloaded BT hardware. This might be a lie to keep me on zen i dunno, but its a £35 gamble.

 

[lovedaddy]

balls to that, im leaving zen and no mistake, they are piss poor

 

[Flamin_Squirrel]

lol. yep i think ill give em a couple of weeks then switch and hope that solves it.

 

[~YuckFou~]

Slow Downloads ** Update 2 **


BT Wholesale have released the following official statement. Zen will be providing a full update for customers once the implications have been fully discussed with BT on Friday.


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BT IPStream Product Performance
Briefing - November 2002

This briefing is being issued to provide an update on product performance in the following areas:
Contention and the BT IPStream Product Portfolio.
How this relates to current product performance.
The Impact of fragmentation on product performance.
Next Steps.
1. Contention on the BT IPStream Product Portfolio

The BT IPStream products are contended services. This means they are dimensioned so that end users share the bandwidth available across the platform. This is standard practice on all networks, based on the fact that not all End Users are on line and sending data at the same time. As defined in SIN 329 the current specification regarding contention of the products within BT Wholesale’s Broadband portfolio are:

IPStream 500 50:1
IPStream Home 500 50:1
IPStream S 500, 1000 & 2000 20:1
IPStream Office 500, 1000, 2000 20:1
2. How this relates to current product performance

The ratio at which our BT IPStream services are contended is based on our experience (we constantly monitor network utilisation and performance) of what the average usage is per End User. Therefore the contention ratios are correctly set so that under normal usage conditions, and bearing in mind that the products have been designed to carry "bursty" IP traffic such as that typically generated through Internet browsing, this sharing of bandwidth is virtually transparent to the End User and doesn't significantly impact upon the end user experience.

End users currently using the BT IPStream products will therefore not see the stated worst case contention levels being applied and currently experience a network performance better than that which is detailed in the specification of the products.

It should be noted that the overall end user experience is also dictated by the performance of the Internet itself.

3. Impact of fragmentation on product performance

Fragmentation is caused by IP packets being sent across the network which are larger than the network has been configured to handled. The impact of any fragmentation on the current network design is that IP packets have to be dissembled and reassembled as they transit through the IP network. This in turn places a larger requirement on the relevant network components, restricting and undermining the total volume of traffic that each component can handle. The impact to the network is that any IP Packet which is larger than 1458 bytes and up to 1500 bytes will be fragmented because the Broadband platform uses a default MTU size of 1500 bytes.

With fragmentation in the network, there will be an impact on components within that network. This could affect the throughput experience that End Users will receive whilst passing traffic to and from their Service Provider. Even if the End User perceives this to be a degradation of their service, the experience may still fall within the product specification.

BT Wholesale is aware that we are currently seeing increasing levels of fragmentation on the Broadband platform. This is a situation that we wish rectify and as such have plans in place to do so. Whilst the product currently performs in excess of the stated product specification, our planned remedial action, as detailed below, is to eliminate fragmentation from the Broadband platform.

BT Wholesale’s plan to eliminate fragmentation from the network has a target completion date of end May 2003. This end date shall be achieved through a phased set of programmes commencing in mid January 2003 and will require major upgrade to both software and hardware network components. The programme, therefore, will include extensive testing and trials prior to full deployment. As each of the phases are delivered, Customers will see an incremental improvement in network performance.

Further updates on the plan will be issued through briefings via the Broadband Extra Website. To manage this deployment BT Wholesale has applied revised planning rules to ensure loads are capped and minimise any impact on performance. When fragmentation is eradicated it will be possible to reset the planning rules.

4. Next Steps

As outlined above, the BT IPStream products are contended services delivered over a shared platform. The access speed achieved by End Users can vary and this variation is dependant on several factors which include, but are not limited to:
Bandwidth of installed product;
Time of day end user is accessing the internet;
Day of week end user is accessing the internet;
Location of destination portal;
Application being employed; and
Number of End User’s currently active on the BT Central on which the end user is accessing the internet.
These factors need to be considered when analysing perceived speed issues as reported by an End User. If a fault is reported to BT Wholesale, the more information that can be supplied will always assist in the investigation and we are looking at the ways where we can include requests such as:
What does the End User mean by slow throughput?
What is the URL of the site were they were attempting to access?
What were they trying to do at the time?
Do they have any measures gathered from a speed-test website?
What time of day were they experiencing problems?
How often have they had the problem?
What about other times of the day?
When did they first notice a reduction in throughput?
At what size is the MTU set?
Whilst it is possible for Customers to advise their End Users on how to change MTU settings, Customer feedback has indicated that BT Wholesale should consider an automated solution to enable End Users to automatically configure their MTU. This work is currently being evaluated. If this type of solution is developed we expect to be able to implement it in the near future. A further update shall be provided within the next fourteen working days.

BT Wholesale is focused on improving the diagnostic capabilities of the network, and we expect to indicate detailed information in the coming months.