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[TheBoy]

Lol, ow how ill informed we are on 21CN.

Its not the cheapest option by any means, IP backhaul still has a high Capex and Opex compared to the older (and already there) TDM systems. Its also not as reliable to!). THye could eaily install mapper cards in the current setup at low cost to take the IP based traffic from newer soft swicth based exchange setups!

21CN is a dogs arse of a setup as there are to many vendors supplying the kit and some of the kit was not mature when selected!

I on the other hand dont mind, whilst 21CN is falling over, BT are buying loads of OMS1600 to keep shoring the TDM setup up which is my baby (or was, I am now running development of the next gen layer 2/3 kit)

They are looking at medium term reductions - at lot of the kit is getting way past its sell-by date, and because of the mis-mash of bits bolted on, a sod to support, invariably involving lots of different teams to resolve relatively simplistic issues  (Not that 21CN will solve that last issue from what I've seen of it so far  ).

When the decision was made, they obviously believed that IP would become the cheaper transit technology, and have an added benefit of being about to reduce capital expenditure renewing the tired old X and Y exchanges (an early plan was to basically stick a Cisco badged HP DL380 in each exchange to do the work of the switching part of the exchange, just leaving simplistic analogue to VoIP linecards).

The reality seems to be, from someone now sitting on the periphery, that in true Civil Service style, its become a bloody mess, as they always insist on multiple vendors. And with it being immature technology, interworking between the vendors equipment seems to had introduced other problems.


It can work, in fact it does work reasonably well. It work probably have worked better and easier had it been managed better earlier on.

They decided an entire IP transport was the way to go, allowing a single transit network.  Were they jumping on a bandwagon? Yes, probably.  Though remember, BT have massive amounts of (different) VoIP, and it would appear that cost is very beneficial.

[Marks DTM Calib]

Agreed but, IP backhaul, its not needed and given the size and modern state of the TDM setup they have was some what crazy.

I can see the logic for upgrading the voice etc and converging on a single backhaul network (to get rid of the seperate PDH, SDH and Ethernet setups)

Thing is, you can load up PDH, Packet, SDH the lot onto what they already have.....so why re-invent the wheel!

Ethernet will never have a lower opex than a TDM setup because it uses MUCH more power and hence the electric bills and cooling plant costs are always going to be higher.

It also has piss poor standards bodies resulting in a lot of ambiguity in the interworking hence the probelms they are seeing!

Ethernet backhaul is also NOT mature, its a long way from being so and BT cant even decide which standard to back (it was T-MPLS, then they went down the PBB/MACinMAC route and are now considering MPLS-TP which as a standard is a good 18 months from full maturity).

[TheBoy]

Agreed but, IP backhaul, its not needed and given the size and modern state of the TDM setup they have was some what crazy.

I can see the logic for upgrading the voice etc and converging on a single backhaul network (to get rid of the seperate PDH, SDH and Ethernet setups)

Thing is, you can load up PDH, Packet, SDH the lot onto what they already have.....so why re-invent the wheel!

Ethernet will never have a lower opex than a TDM setup because it uses MUCH more power and hence the electric bills and cooling plant costs are always going to be higher.

It also has piss poor standards bodies resulting in a lot of ambiguity in the interworking hence the probelms they are seeing!

Ethernet backhaul is also NOT mature, its a long way from being so and BT cant even decide which standard to back (it was T-MPLS, then they went down the PBB/MACinMAC route and are now considering MPLS-TP which as a standard is a good 18 months from full maturity).

I think a lot of the decisions were made on the fact they thought a lot of the existing kit would be at the end of its service life, so reusing old kit never needed to be factored it.  Also, when the decisions to go entirely IP were made in the 90s, I suspect they thought that would be cheapest, as everyone then (even now!) thought IP over ethernet transit was the only future.  Trouble is, as you say, its too immature for inter-vendor operability.


As an aside, would the silicon improvements in power consumption bring the new stuff in line, from a power view, with the older transit stuff?

[Marks DTM Calib]

Nope.

On any ethernet or IP based setup you need processors, big bloody processors and loads of packet RAM.

Every packet (even 64 byte ones!) gets inspected and the headers etc looked at before passing to a que (i.e. VERY fast RAM).

So, it requries loads of functions for each transaction....which uses loads of power.

And remember, reductions in geometry for any chip will , in theory, reduce the power consumption but.....its reduces it for TDM as well as packet!

As an example, an OMS1600 with a 80G TDM switch, 4 10G line interfaces, full control set and a large raft of trib cards will be about 600W.

An smaller market leading packet device with an 80G switch and less than half the number of trib ports consumes 600W and only has 2 10G line ports!

The later is (from a release persepective) 3 weeks old and the former is 5 years old!

[VX1]

Manager (supervisor is what its called so they can get away with paying me less) for a parts distributor. Well known, Motaquip a part of peugoet/citreon

Paul

[TheBoy]

Nope.

On any ethernet or IP based setup you need processors, big bloody processors and loads of packet RAM.

Every packet (even 64 byte ones!) gets inspected and the headers etc looked at before passing to a que (i.e. VERY fast RAM).

So, it requries loads of functions for each transaction....which uses loads of power.

And remember, reductions in geometry for any chip will , in theory, reduce the power consumption but.....its reduces it for TDM as well as packet!

As an example, an OMS1600 with a 80G TDM switch, 4 10G line interfaces, full control set and a large raft of trib cards will be about 600W.

An smaller market leading packet device with an 80G switch and less than half the number of trib ports consumes 600W and only has 2 10G line ports!

The later is (from a release persepective) 3 weeks old and the former is 5 years old!

I was thinking more in terms of the (now) old stuff BT use against modern packet switched.

Saying that, I'm often in datacentres with my back to large routers (eg Cisco 12000), and the fans alone must pull a few hundred watts , I dread to think what the core processing boards are pulling

[gav mv6]

currently 'job seeker' ,
was self employed machine tool repairs ,maintenance , electrician until dec .
van currently for sale ....

[cem_devecioglu]

I work in IT support for a College.  Bit of a change from my previous employment, I used to be a lorry driver (hence the name 'Cybertrucker').

Well Integrity Engineer for a new oil company so no digs about fuel prices.

Steve

I never blame the oil companies for the high price of petrol/diesel.  They have to find it, drill it out, transport it, refine it, and deliver it to a Morrison's near you.  Then along comes the government and says "We'll have a slice of that action" and puts duty on.  And then puts VAT on the top, so you're paying tax on tax.  This is why around 75% of the cost of fuel is tax and goes to the govt.  If you want to see what fuel really costs see what the Yanks are paying for it, or see what you can buy red diesel for.  The difference doesn't go to nasty profiteering oil companies, as some would have us believe, it goes to the collection of charlatans and con-men that passes for our government.

no offense for anyone but here are some truth..

The owner of oil companies not only own oil companies.. Countless numbers of other areas including banking , mlitary production and other such critical area..

And political candidates need help of them before they are elected..

So none of them are innocent

[oceansoul]

Electrical/Instrumentation, Control & adminstration Apprentice for thames water

[Tropic Thunder]

Building Surveyor who has just been made redundant by a well known high street retailer, anyone got a job??

[unlucky mark mv6]

on the rock and roll.

[Pitchfork]

Intelligence Dept. 8-)

[ScottieMV6]

Was in logistics but gave up my job to be full time carer for my partner who is long term sick with a neurological condition.

[bertiecbx550]

I want TB and MDTm banned please as they are giving a migrane with all the techno babble..... :-?