Cisco router for a 1gbit/200mbit connection

[secretAlpaca]

Hello,

I got a Cisco 1921 router, with 2 gigabit ports, and my ISP gives me a 1gbit/200mbit connection, so today I went for a speed test and I get the results between 90/90 and 280/200(after the Cisco 1921),

My setup is the following->  ISP Router -> Cisco 3750x switch vlan100-> 1921 Router-> Cisco 3750x switch vlan1 -> LAN

ISP IP: 192.168.1.1 - 255.255.255.0 

LAN IP: 10.14.50.255 - 255.0.0.0

If i put my computer on VLAN 100 (link between ISP and 1921 router) I get the full speed, but soon as I tag the port for VLAN 1 the speed test gives me the results I said above... After a few googling I found out that the 1921 router doesn't support throughput over 250mbit, but I'm almost sure I have had the full speed before on this router, but can't be sure! Needless to say, I host a few servers with a few hundred clients... the ISP's router's CPU doesn't handle my traffic and is always at 100% so I DMZ tagged the Cisco 1921 and I open the needed ports over there...

Is this anything to do with the fact that ISP LAN is on subnet 255.255.255.0 and my LAN  is on 255.0.0.0 ??

If this is a router limitation, would the Cisco 3925 do the thing for me?

Thanks in advance!

[balaji.bandi]

here is the document yes this is the limit of the product.

what is the maximum throughput you looking, so we can suggest the model.

[secretAlpaca]

To be honest I don't quite know, I just wanted to be able to get the full gigabit speed  my ISP provides...

[balaji.bandi]

3925 is end of life. another question what is the Role of 1921 Router here ?

look at the below models  which can give you higher throughput ?

https://www.cisco.com/c/en/us/products/routers/4000-series-integrated-services-routers-isr/models-comparison.html

[secretAlpaca]

The role of 1921 is dchp, dns, portforwarding

[balaji.bandi]

How big your network. ?

If it is only 2 switches and 100 - 200 users 

i will introuduce FW here, which can do NAT and Portfoward for you, and also protect your LAN users. (rather just only do routing job) - i do not see major routing here in your network.

So it looks like below your network change.

ISP Router -> FW (Cisco 5506-X ) Cisco 3750x switch vlan100->  Cisco 3750x switch vlan1 -> LAN  (if you like you can stack 3750X for more resiliance for the users)

or 

ISP Router -> Cisco 3750x switch vlan100->  FW 5560X -> Cisco 3750x switch vlan1 -> LAN

Do you Agree and Make sense ? (this is based on the role you confirmed the router)

[secretAlpaca]

  the only problem is that the ISPs router is allways at 100%cpu that's why I got the 1921 in the first place, now should I get a 3925? 

My server is composed mainly of 5 servers and 1 3750x switch... This houses a Gaming / voice hosting company, so I have about 500/600 inbound connections...

Just to be clear here, the 1921, that nonsense, just pop it into the trash, correct? 

[balaji.bandi]

As i have suggested 3925 is end of Life. So i would not suggest, again it is all your business call.

Since you mentioned they are Servers, FW will protect your Servers from any other attacts.

Is your ISP router you managed ? then what causing the high CPU, what is that router ?

500/600 is small traffic and 5506-X  FW can handle easily,  by introducting FW, your switches also will be secured behind FW.

Just think and understand and take decision, any more asistance happy to help you.