Smart's contention ratio?

Richard Dower

So someone explain this to me please, they say no contention ratio...so in essence what this means is if you have a 5MB pipe and 100 people on that pipe all at once fighting for bandwidth then there rated 2MB broadband is worthless...no?

Without contention it is very likely that very quickly you'll see alot of people signing up and fighting for a limited amount of bandwidth, yeah yeah i heard that guy say stuff about 100 people not being online or downloading at the same time.

But i guarantee at this low price and speed and no cap people WILL be downloading 24/7 and grabbing all sorts of crap and movies. Thus in reality it's highly unlikely that one customer will be able to pull down 2MB of data over the life of the contract.

Now please correct me if i am wrong here or explain it better, on paper the deal sounds excellent...but what happens when people start getting 56k speeds?

SeaSide

In the International networks the operators dont quote contention ratios. They would say that once their pipes reach XX% they upgrade them. So the pipes that they have never run at full capacity. If a pipe is not running at full capacity there is no contention for bandwidth. So you could have twenty thousand people using the same pipe which by your view would give a contention of 20000:1 but if they fail to fill the pipe they are not contended.

The contention ratio that you are worried about is soooooooo twentieth century

Moriarty

What seaside said, basically ^

Sponge Bob

And also what Garfield said about every exchange having 2.5Gbps backhaul or multiples thereof .

Most Eircom exchanges (out of their 1100) with fibre have 34Mbits fibre.

crawler

Most of Smart's network is built using Luminous Networks Optical equipment.

The platform is a packet based MSPP ( Multi Service Provisioning Platform ) which allows a number of different services to be run from any Port - i.e. voice, video, data etc...Each network element can be flat or built in a ring topology which makes the most of the resilient Packet Ring functions of the vendor kit.

Backhaul from each node is done using DWDM (dense Wave Division Multiplexing). At the moment each DWDM lambda will carry 2.5Gbps and depending on how many transponders (each one carried 2.5Gbps ) are in each node willl dictate the capacity of each node. New transponders soon to be available will carry 10Gbps.

At the access level SMART are using DSLAMS or Mini DSLAMS to provide the DSL function. These back off on Ethernet ports to the transmission kit.

At the Transit level SMART are using transit providers to terminate global traffic - The transit ports are 100Mbps and 1000Mbps. The transit providers are based in Dublin.

The entire system is packet based end to end with such items as MPLS/Qos/VLAN tagging being used to keep different traffic apart.

Some of the regional backhaul is via ESB with local Fibre access in the main being leased from e-net. All traffic needs to get back to Dublin to access the transit providers.

In terms of contention I think the world has become obsessed with this. eircom use ATM via 2Mbps/34Mbps/155Mbps bearers to move traffic about in their DSL backhaul world. ATM carries a large overhead and is far more limited than new pure optical systems therefore contention needs to be applied. When compared to new optical kit running single transponders @ 10Gbps on DWDM, ATM is not really at the races.

So is the system perfect - no, it is not. Issues begin to appear when you try to run lots of different services. As Smart now know this is not an easy thing to do and you begin to find that the correct configs for MPLS and multicast/unicast become much more of an issue. When it comes to Video you also have to remember that an MPEG-2 stream ( standard used for most TV broadcast ) uses up 6/8Mbps of capacity and that is for one single channel. An ASI card in the Luninous box uses 270Mbps of backhaul.

In any pure optical system you can also have other cost related problems - for example you buy transit at a per MB / per month level - having big pipes full of traffic will push up the transit bill and will also fill the network that could be used for other applications such a VOD etc.

There is also the difference between pure layer 1 transmission and higher layer protocols such as Ethernet etc - the further up the layers you go the more you have to correctly have a trade off.

So contention - well the nodes have sufficient capacity. Regional backhaul is more limited ( you pay ESB per 100Mbps service ) - transit can be limited and the DSLAMs are what they are.

Naturally Smart may choose to reduce capacity at any point throughout the network or limit transit so it could introduce "contention".

Anyway...that's what I think...I dont work for Smart so some of the above may be slightly inaccurate but the topology is right....personally I would say if you have ANY Broadband service and are happy with it, then forget about contention, even if you have issues it may not always be contention.

BigMoose

personally I would say if you have ANY Broadband service and are happy with it, then forget about contention, even if you have issues it may not always be contention.

Too right. I never noticed any difference between IOL moving me from 48:1 to 20:1 (or whatever it was) and when I lived in the UK contention was never mentioned as part of the marketing for what you got. From the various Cable options and various ADSL offerings over there the actual contention varied but was never advertised as something to worry about. I assumed Eircom made a big thing of reducing it last year as a smoke screen to the fact that things people really care about got no better - speed, cap and price. You only care about contention when you're hit by it. Is there any xDSL in Ireland actually affected by contention?

crawler

BigMoose wrote:

Too right. I never noticed any difference between IOL moving me from 48:1 to 20:1 (or whatever it was) and when I lived in the UK contention was never mentioned as part of the marketing for what you got. From the various Cable options and various ADSL offerings over there the actual contention varied but was never advertised as something to worry about. I assumed Eircom made a big thing of reducing it last year as a smoke screen to the fact that things people really care about got no better - speed, cap and price. You only care about contention when you're hit by it. Is there any xDSL in Ireland actually affected by contention?

Well with the RADSL product eircom allow up to 192 sessions active at the same time - if you happen to be on an oversubscribed segment then you may notice slow reaction due mainly to packet retry but apart from that, not really. But as per above that is only one of the potential "contention" points.

crawler

BigMoose wrote:

Too right. I never noticed any difference between IOL moving me from 48:1 to 20:1 (or whatever it was) and when I lived in the UK contention was never mentioned as part of the marketing for what you got. From the various Cable options and various ADSL offerings over there the actual contention varied but was never advertised as something to worry about. I assumed Eircom made a big thing of reducing it last year as a smoke screen to the fact that things people really care about got no better - speed, cap and price. You only care about contention when you're hit by it. Is there any xDSL in Ireland actually affected by contention?

Well with the RADSL product eircom allow up to 192 sessions active at the same time on a single 2MB bearer - if you happen to be on an oversubscribed segment then you may notice slow reaction due mainly to packet retry but apart from that, not really. But as per above that is only one of the potential "contention" points.

The Fool

crawler wrote:

In terms of contention I think the world has become obsessed with this. eircom use ATM via 2Mbps/34Mbps/155Mbps bearers to move traffic about in their DSL backhaul world. ATM carries a large overhead and is far more limited than new pure optical systems therefore contention needs to be applied. When compared to new optical kit running single transponders @ 10Gbps on DWDM, ATM is not really at the races.

Have to pick you up on your ATM bashing Eircom may have a restricted ATM setup but that is not the fault of the technology. Many other carriers use ATM at OC48 (2.4G)and posibly OC192 (10G not sure is this is used widely).

The Fool

crawler wrote:

In terms of contention I think the world has become obsessed with this. eircom use ATM via 2Mbps/34Mbps/155Mbps bearers to move traffic about in their DSL backhaul world. ATM carries a large overhead and is far more limited than new pure optical systems therefore contention needs to be applied. When compared to new optical kit running single transponders @ 10Gbps on DWDM, ATM is not really at the races.

Have to pick you up on your ATM bashing Eircom may have a restricted ATM setup but that is not the fault of the technology. Many other carriers use ATM at OC48 (2.4G)and posibly OC192 (10G not sure if this is used widely).

netman

I have a couple of questions.

1) Will I be able to use my existing broadband equipment, namely the Netopia WiFi router (3374W) supplied by eircom?

2) What happens if my line fails your broadband check?
I've been using broadband for about two years, I'm with eircom at the moment, and my line doesn't pass their line check. I've never had issues with the service, it's always been working perfectly, but the line test comes out as failed more often than it passes. Will I still be on eircom broadband if your test fails?

3) The web site, and your agents, are very keen to sign people up, but it looks like an order process instead of registration. I'd like someone to tell me that I can avail of the offer before I sign any contracts. Call me what you will, but I've learned it the hard way, and I'm just afraid that I'll end up with my eircom broadband being ceased, calls moved to Smart telecom and no way to get back. I've already been through hell with NTL's phone offering. How about offering a registration process that doesn't require customers to sign contracts first?

crawler

The Fool wrote:

Have to pick you up on your ATM bashing Eircom may have a restricted ATM setup but that is not the fault of the technology. Many other carriers use ATM at OC48 (2.4G)and posibly OC192 (10G not sure if this is used widely).

You are 100% correct - I was only talking in relation to eircom....ATM does have a high overhead though