Or those of us in W. Hartford (at least as late as 87) who got phone service via an experimental cable design laid down 10 or more years earlier. If the ground was wet, your modem connection was 300 bps tops. Maybe. :)
I'm guessing the DSL boom 10 years later forced them to dig it up and replace it. :)
Yep, very few five-nine plans survive the lowest bid contractor.
Bonsoir Steinar,
You're right, and I have to detail a little more. For each layer network it exists a specific protection mechanism than can be used (carried out) or not by the carrier.
If the transport network is connectionless, at the IP layer network you have rerouting in case of failure. It is the specific protection of this layer network.
If the transport network is only oriented connection, without intermediate SDH terminations for Ethernet or ATM switching, or IP routing, it remains only eyes to cry in case of failure.
But there is a smart solution with SDH NG if the carrier implement it. With your example, we can imagine that layering :
IP > Ethernet > GFP > VC-4-16v > 4 x STM-4. If LCAS (a dynamic bandwidth management) is activated at both ends of the SDH transport network, you have these advantages :
In case of a failure of one STM-4 :
- either there is another STM-4 circuit free, and all the bandwidth is recovered
- either you have no free circuit, and you continue to use only 3 x STM-4 bandwidth, without lost the full STM-16 equivalent capacity.
The LCAS layer network protection is separated from the IP rerouting.
No, I won't write something you don't want to hear...
Regards, Michelot
Sorry, we don't like LCAS. We want circuits that we buy from the circuit provider to be either up or down. If up, everything is fine. If down, *we* want to reroute. We specifically *don't* want the circuit provider to give us a circuit with lower capacity.
Basically, the impression I get from our discussions is that you describe all these wonderful abilities that SDH offers, and I'm saying "sorry, I don't want it. Just give me unprotected point to point links, and I'll handle the redundancy myself".
Steinar Haug, Nethelp consulting, snipped-for-privacy@nethelp.no
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