What do the NEAX exchanges use for backhaul?

Forums › Spark New Zealand (including Skinny and BigPipe) › What do the NEAX exchanges use for backhaul?

SomeoneSomewhere

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#171114 7-Apr-2015 04:02

Idle curiosity and a discussion elsewhere prompts this one.

Do they have dedicated fibres (ATM?), or are they encapsulated in other networks? Does this vary by geography?

How are interconnects between the legacy NEAX system and other providers' VoIP/cellular networks handled? International?

How do international calls travel? Same fibres as general internet traffic, dedicated fibres in the same cable, or dedicated cables? What about before intercontinental comms cables became common?

Please dump information!

BarTender

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#1278126 7-Apr-2015 08:07

I suggest you look up "SS7".. And be prepared to have your mind explode.

kiwitrc

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#1278129 7-Apr-2015 08:15

Considering how old they are I am pretty sure they have a morse code interface as backhaul, and a backup of tins and string.

BarTender

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#1278130 7-Apr-2015 08:19

kiwitrc: Considering how old they are I am pretty sure they have a morse code interface as backhaul, and a backup of tins and string.

Find me another piece of digital technology that is 30 years old that is still running a countrys worth of voice calls.
I think they are remarkable pieces of engineering.

kiwitrc

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#1278135 7-Apr-2015 08:28

BarTender:
kiwitrc: Considering how old they are I am pretty sure they have a morse code interface as backhaul, and a backup of tins and string.

Find me another piece of digital technology that is 30 years old that is still running a countrys worth of voice calls.
I think they are remarkable pieces of engineering.

Relax, Im just saying they are old.

ubergeeknz

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#1278139 7-Apr-2015 08:40

SomeoneSomewhere: Do they have dedicated fibres (ATM?), or are they encapsulated in other networks? Does this vary by geography?

I'm not sure about this part tbh, but you're probably on the right track. Someone from Alcatel may be able to answer.

How are interconnects between the legacy NEAX system and other providers' VoIP/cellular networks handled? International?

Interconnects with other carriers are E1 circuits using SS7 for control signalling, with physical handovers in each major exchange where the other carrier wants to do business (in most cases).

How do international calls travel? Same fibres as general internet traffic, dedicated fibres in the same cable, or dedicated cables? What about before intercontinental comms cables became common?

Nowadays, mostly SIP/VoIP over the public Internet. As for Spark I'm not sure. They are likely using dedicated IP circuits to carry voice to international carriers.

kiwitrc

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#1278142 7-Apr-2015 08:45

BarTender:
kiwitrc: Considering how old they are I am pretty sure they have a morse code interface as backhaul, and a backup of tins and string.

Find me another piece of digital technology that is 30 years old that is still running a countrys worth of voice calls.
I think they are remarkable pieces of engineering.

I was told (someone correct me if its not true) that Spark also use their internal oscillators as holdover for their sync network in case of GPS failure, so they really are getting good mileage out of them.

SomeoneSomewhere

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#1278288 7-Apr-2015 12:56

BarTender: I suggest you look up "SS7".. And be prepared to have your mind explode.

Ah... I'd read about that before, but not properly comprehended it. Didn't realise that it went all the way down to OSI Layer 1 - I thought it was more of a Layer 3/4 protocol.

Do you know if we use MTP over E1s everywhere, or do some locations stick it in Ethernet/IP? It seems like a waste of fibres to reserve them for voice traffic only at 2Mb/s.

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ubergeeknz

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#1278297 7-Apr-2015 13:16

SomeoneSomewhere: It seems like a waste of fibres to reserve them for voice traffic only at 2Mb/s.

Who said fibre? Local interconnects are done with copper pairs. For backhaul I assume they mux/demux.

SomeoneSomewhere

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#1278299 7-Apr-2015 13:19

Huh... I thought E1s could also be run over fibre for long distances. Maybe not.

I wouldn't expect 2Mb/s to go all that far on copper.

ubergeeknz

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#1278304 7-Apr-2015 13:31

SomeoneSomewhere: I wouldn't expect 2Mb/s to go all that far on copper.

No it does not, about 650ft according to google. Which is why the interconnects are done within the same physical building in most cases.

If you need to take it further you put it over a different carrier; could be fibre (but you'd probably want to mux several E1 circuits to make this worthwhile) or SHDSL (and again you could mux several over a 10Mbps SHDSL circuit)

SomeoneSomewhere

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#1278306 7-Apr-2015 13:33

ubergeeknz:
SomeoneSomewhere: I wouldn't expect 2Mb/s to go all that far on copper.

No it does not, about 650ft according to google. Which is why the interconnects are done within the same physical building in most cases.

If you need to take it further you put it over a different carrier; could be fibre (but you'd probably want to mux several E1 circuits to make this worthwhile) or SHDSL (and again you could mux several over a 10Mbps SHDSL circuit)

Ah, I was talking about backhaul. 200m isn't much use for backhaul.

Aren't Conklins supposed to be on E1s? How do they handle that?

ubergeeknz

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#1278310 7-Apr-2015 13:37

SomeoneSomewhere: Aren't Conklins supposed to be on E1s? How do they handle that?

Probably over SHDSL

NealR

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#1279788 9-Apr-2015 16:19

The fundemental building block for PSTN services is a 64kbps timeslot within G.703 framing structure.
Thus NEAX platforms are connected by G.703 E1 (2Mbps) links/trunks which are muxed into PDH (Plesiochronous Digital Heirarchy) or SDH (Synchronous Digital Heirarchy) systems that then get carried mainly over fibre systems but in some cases Microwave Radio and/or Copper systems are also used.

Systems used vary based on technical capability within the region.

VoIP networks are connected to PSTN/NEAX platforms using G.703. NEAX's don't have IP.

The same fibre might carry Internet, Business Data and PSTN traffic but these are separated by wavelengths and thus never impact on each other.

Back in the dimm dark days before fibre the world was connected by a combination of under sea Coax and Copper cables. Now it's all wavelengths and a tiny tiny tiny bit of Satellite.

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