[c-nsp] Aggregating IP DSLAMs to a single site

[Shane Amante]

Hi Kim,

Kim Onnel wrote:
> Hello,
> 
> If we have a bunch of IP DSLAMs with Ethernet uplinks on different sites and
> we want to aggregate them to a single Ethernet switch in the main exchange
> near to our internet gateway, what are the known cost-effective methods?
> (knowing that the Teleco company here does not provide Metro ethernet
> connectivity, so i have to convert from ethernet to something else and back
> again at the collection point)
> 
> Take into consideration that the IP DSLAMs sometimes provide 3-4 E1s worth
> of traffic, i.e: not because its an ethernet uplink it means we have alot of
> uplink traffic.

IMO, your most cost-effective option is to do Ethernet over TDM from the 
IP DSLAM back to your central Ethernet switch.  At the CPE side, where 
the IP DSLAM's reside, there are a bunch of vendors in the low-end N x 
T1/E1 space that have solutions in this space, except Cisco.  I would 
recommend you look at the following:
- Overture Networks ISG-140/180
- Anda Networks 2108
- RAD RICi-4E1, 4T1, 8E1, 8T1

At the head-end aggregation side, where your Ethernet switch resides, 
you didn't mention how many remote sites it would need to aggregate.  I 
don't have experience with Cisco ONS providing aggregation; however, 
there are probably a few options:
1) Book-ended.  If you have a small number of remote-sites you need to 
aggregate, just book-end the N x E1's with the same Overture, Anda or 
RAD EoTDM box.
2) Aggregation EoTDM switch.  Most of the 3 vendors sell modular, 
aggregation switches, however they are fairly small, but well-suited to 
a decent amount of N x T1/E1 EoTDM aggregation.  Specifically:
- Overture ISG-2200/5000
- Anda EtherReach 4000
- RAD EGATE-100: to my knowledge it's not modular, but can consume 1 x 
Ch/OC-3 or Ch/STM-1 of T1's/E1's.
3) Cisco 7200, or other Cisco, box capable of BCP/MLPPP for N x T1/E1. 
Note, I haven't played with the 7200 or SIP/SPA's in this role, so I'm 
not sure it actually works [well].

It's probably best you contact each vendor and ask them their specific 
capabilities & features.

-shane




> I'm not a transmission guy, but i heard the following:
> 
> 1) on the edge sites, convert the ethernet to E1s using CPEs and then
> collect back the E1s on a big router with alot of E1s links.(doesnt sound
> cost-effective at all)
> 
> 2) CPEs on the edges and then one MSTP device (like Cisco ONS) to collect
> the E1s and give one Ethernet uplink
> 
> 3) CPEs on the edges and then the teleco shall aggregate all the E1s to one
> MUX and give one cPoS interface on a router.
> 
> 4) MSTP devices on both sides
> 
> Please help, vendors are trying to rip me and i need to know which method is
> efficient and cost-effective, are these all the factors or am i missing
> something ?
> 
> Thanks in advance, private messages are welcomed.
> 
> Kim
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