[c-nsp] T3 or Ethernet delivery?

[Seth Mattinen]

Bill Wichers wrote:
> I've found that some carriers consider Ethernet something of a "toy"
> whereas TDM and SONET circuits are considered more "mission critical".
> Basically our local engineering gusy say that the Ethernet links are
> just a "bunch of jumpers in COs", and by that they mean a single link
> patched through to where it needs to go with no protection or management
> anywhere. The T3 links, while not always path diverse, are typically at
> least provisioned as 4 fiber handoffs within the carrier's network so
> you at least have some protection against a dead optic. This seems to be
> especially an issue for intercity links since the T3s are typically
> protected around a ring between the cities and the Ethernet rarely, if
> ever, is protected at all. This is just the ILEC (ATT here) though, most
> of the CLECs offer protection options for their Ethernet offerings.

Good to know; mine is going a POP in another state since where I am
isn't exactly a major stop on the internet for anyone to put an L3 POP
in state.


> Personally I've been burned before with carriers not provisioning
> circuits as "protected" as one would expect (which includes TDM/SONET
> links). I try to keep all our core links on our own fiber where we
> control the physical routing and protection, but we have a few remote
> POPs that are not economical to build fiber to and those are the ones
> with the leased links. I'm not a big fan of Ethernet for the links to
> these POPs, but the Ethernet links we use from our gear to the customer
> premises do tend to work OK.
> 
> Regarding monitoring, use a routing protocol that has keepalives to
> detect an outage. If you are using a switch you can probably determine
> link state on the circuit too (although this probably won't give you an
> indication of end-to-end circuit status since the carrier probably has a
> switch serving you that will give you a link regardless of the "rest" of
> the circuit working). 
> 

I probably should have mentioned that I will be running BGP. I have an
existing multihomed network and this circuit will be just adding another
transit circuit.

For added fun, they're going to use some circa 1997 existing fiber
equipment (thus qualifying for lit building pricing), complete with a
blinking "fault" light on one side of the ring. I will make them aware
of that before I sign anything. ;)

~Seth