[c-nsp] Learning the internals of an NSP

[Pete Templin]

Sami Joseph wrote:

> My major problem is that i need to be very familiar with the network and
> there's just alot to learn, what would you guys do to do that, i want to try
> to have it all in my head in the shortest time by looking at configs and
> show commands, i dont think anyone will explain much here, so i was thinking
> of an idea to document the network for myself, going to each PE router and
> learning how its IGP, BGP is configured, and the trunks interfaces, same at
> P and putting all that on a piece of paper, maybe visio, then going for the
> internet part, Internet here is in a VRF and then an internet gateway,
> there's another router with BGP(multihomed) customers, alot of BGP configs
> there.

Hopefully, for the sanity of you and everyone you work with, there is a 
set of configuration templates:

Out of the box, a "model X" "role Y" router has this config.
Be default, a <insert media here, such as T1> customer has this config.
etc.

Ask those questions, determine how the template is deployed, and learn 
the common model.  Then go back and ask where the skeletons lie.  :)

I hired someone 1.5 years ago.  I want him to know the entire network. 
But I need him to know how to configure and troubleshoot customers.  As 
a result, he's a whiz at customer port configuration and 
troubleshooting, and he doesn't need to know IGP/BGP stuff.  I try to 
include and involve him wherever possible, and coach him as time permits.

When in doubt, he knows to do a series of commands on the customer 
access routers:

sh ip ro <address in question>
if reachability for <address> is learned by BGP, sh ip b <address>
if reachability for <address> is learned by BGP, sh ip ro <neighbor>
sh ip os ne (is there the right number of neighbors?)
sh cdp ne (to figure out the topology)

hth,
pt