[c-nsp] Cisco backbone upgrade

[Nicolas Visentin]

Hello,

I have to upgrade my company Internet backbone. It is currently running 
with Cisco 7206 with NPE-G1 as Core Routers and Cisco 3550-24 as access 
routers to connect my customers (FastEthernet only).
Core routers are running BGP for Internet Transit (full tables) and OSPF 
with access routers for internal routing (customers aggregation). Core 
routers are currently pushing a maximum of 100 Mbps.
1 of my customers need to upgrade their FastEthernet port in GigE and 
the trafic will increase near 1 Gbps in the futur.

I imagined the following two case to support this traffic :

- The first one is to keep the same network topology and upgrade Cisco 
7206 with NPE-G2 and 3550-24 with 3550-12G to have a full Gbps backbone 
and to be able to provide GigE for my customer

- The second is to replace Cisco 7206 routers by Catalyst 6506 with 
Supervisor Engine II / MSFC2 and 16 GigE ports. In this case, I would 
use Cisco 7206 routers as transit routers and Cat6506 as Core routers. 
7206 would run eBGP with the Internet providers and iBGP with the 
Cat6506 to send them Internet routes. Cisco 3550-24 would be directly 
connected to the Cat6506 via Gbps uplink and would run OSPF with them 
for internal subnets routing. Customers which need GigE port would 
directly connected to a Cat 6506.

Which of the above cases seem to be the best ?

The cost of equipment is an important parameters !

thank for your help.

Best Regards,

Nicolas VISENTIN