Overview
The first impression of Cisco 3845 router on me was that I felt it is too heavy. So, do not try to install it to rack alone. It has two internal power supplies (one by default). Don’t forget to order the redundant one, if you plan to run it for critical business.

The LAN connection is also redundant with two build-in Gigabit Ethernet interfaces. The good thing the GE 0/0 interface has SFP option. You can reach the far LAN Edge points on a Campus LAN. Another alternative is to use it for Metro Ethernet.

High capacity memory is another powerful feature of this router when compared with 2700 series routers. This router comes with 256 MB memory and you can upgrade it up to 1 GB. This is really cost too much if you use original Cisco memory, but OEM alternatives exist in the market.

There is one integrated Virtual Private Network (VPN) Module. This module is added for the performance of encryption and not mandatory for VPN, but as Cisco says, it increases the speed 10 times. I did not use VPN on this router, but it looks capable of handling higher loads.

There are 4 HWIC slots and 4 NM slots. It has almost every kind of modules (Etherswitch, wireless controller, ATM, T1/E1, NAM !!! ,FXS,FXO etc.)

My Experience
I use one of these routers for the Internet access with Advanced Enterprise IOS. BGP running on it with full table, cef enabled, Reflexive IP access list exist on the router. I also use it as a router firewall (Security guys call it as choke point). The CPU utilization is just about %2 – 3. I have to accept that this router was a bit oversized for my needs. I could have saved $3,500 (from list prices) if I use Cisco 3825 router.

You have to ask below mentioned questions before deciding to buy a Cisco 3845 Integrated Services Router.
- Do I need more than 256 MB memory?
- Do I have several voice clients?
- How much concurrent VPN connection is expected?
- Do I need speeds like E3/T3?
- Do I need different kind of functionalities on one router (e.g. Wireless, ATM, Etherswitch ports)?
It is waste to invest money unless your answers for more than two questions are in affirmative.