[j-nsp] Juniper M-series vs 72xx/NPE-G2

[TCIS List Acct]

Hi all,

We're operate two Data Centers offering typical Co-lo, Managed Hosting, and some
business connectivity services.  We are looking to upgrade our edge routing
platform from Cisco 72xx/NPE400 routers to something with a little more growth
potential.  Right now, we are taking 3 x DS-3's for transit (no full routes at
the moment) and have an OC-3 on order, as well as the possibility for a Gig-E
handoff (175M commit) from a provider in the next 12 months.

In any case, we are looking at our options in the Juniper world (vs a new 
72xx/NPE-G2).  New Juniper gear is outside of the budget, so we are looking for 
used M-series routers.  I know the Juniper used market isn't as  robust as 
Cisco, but I wanted to get the advise of others on the list.

I had a few basic questions:

- M5, M10, M20, or M7i - what is my best bet for the traffic levels mentioned
above?  We need the basics - BGP, OSPF, GRE tunnel capability, and some basic
ACLs.  Nothing fancy like MPLS, etc.
- What is the difference between the non-"i" series vs the newer "i"-series?
e.g. M10 vs M10i.  How about the "Enhanced" vs non-Enhanced chassis?
- What M-series router should I be looking for on the used market?
Specifically, what one should have the greatest availability.
- What routing engine should I be looking for?  I see a lot of RE-333's out
there, but don't see a "performance chart" anywhere on Juniper's site
- Does anyone have advise regarding Juniper's recertification process on used
gear?  We would need at least basic support/JUNOS upgrades on whatever we buy
- Does anyone have a suggestion on who to source the used gear from?

TIA.

--Mike