[c-nsp] T1 aggregation boxes and some bonus info

[Justin M. Streiner]

On Fri, 25 Apr 2008, Marlow, Travis wrote:

> Hey everyone, I wanted to find out what everyone is using to aggregate
> customer T1 links.  We're using the 7206VXR platform with NPE-G2 filled
> to the hilt with PA-MC-2T3+ cards, including the PA Jacket card slot.
> The second question I have is if anyone else is using this same
> solution, how are you getting your T1 provisioned statistics?

I haven't used this exact setup, but I did use something pretty close to 
it, many moons ago.

Most of my T1 aggregation routers, from 1998-2003, were 7206VXRs with 
NPE-300s, or 400s and lots of PA-MC-T3+ or 2T3+s and the occasional 
PA-MC-8T1+ or PA-MC-2T3+.

We did have a small handful of 56k point-to-point customers that we picked 
up in the acquisition of another provider, however we ended up having to 
provision a separate channelized T1 to put them on because the LEC at 
the time (Bell Atlantic, soon-to-be Verizon) couldn't or wouldn't 
double-mux those circuits, i.e. bring a channelized T1 into a timeslot on 
one of my channelized DS3s then put the 56k customers on DS0 timeslots of 
that channelized T1.

> I'm not talking about bandwidth utilization, but how many DS0s have been
> configured for Serial interfaces, etc.  Today we have people monitoring
> a spreadsheet of configured T1s and I would like something a little more
> "accurate" and real time.  I was hoping to poll something in SNMP, but I
> haven't had any luck.

If you configure all 28 T1 timeslots on your router when you bring in a 
new channelized DS3 and you shut down the unused interfaces, you could:
1. snmpwalk ifDescr, look for anything with "Serial" in it, and get the 
associated ifIndex values
2. snmpwalk ifAdminStatus, looking for those ifIndex values.  If the 
status is up, it's a provisioned DS1.  If not, it either hasn't been 
provisioned yet or has been disco'd.
3. snmpwalk ifOperStatus or anything that had an admin status of up as a 
cross-check.  That will tell you if the DS1 is actually up, or at least if 
the router thinks that it's up.

Beyond that, you could poll the Cisco internal OID locIfDescr to get the 
description fron the serial interfaces.  I kept those in a standard format 
of "customer-name, customer-ID, LEC, circuit-ID", so that it would be 
relatively easy to write a script that could walk the router and parse the 
output of locIfDescr.  It was useful for outage planning - if I had to 
reboot a router, change a card, or if a LEC had to maintenance that would 
knock out a DS3, I could easily get a list of all customers that could be 
affected and notify them.

hope this helps
jms