Dimensioning - do I need a C2800 or a C3800?

Answered Question
Jan 23rd, 2008

Can anyone refer me to Cisco specs on dimensioning of the 2800 and 3800 routers? I need to know what throughput they can handle, number of simultaneous NATs, number of firewall rules, etc.

I have looked at the specs on the Cisco webpage but nothing has that kind of detail.

Will a 3800 even handle more than a 2800 or is it just a bigger chasis (for add-on cards) with the same mainboard processing capabilities?

Any points to help choose the right model for my business would be great.

Thanks.

I have this problem too.
0 votes
Correct Answer by buchholr about 8 years 9 months ago

The 3845 is rated to T3 with concurrent services. Here a blurb from the portable product sheet:

"The ISRs are designed with the ability to run multiple concurrent services (FW, NAT, IDS, QoS, etc.) at wire-speed."

You should be fine with a 3845 right now. If you plan on stepping past a T3 in the lifetime of this router then I would recommend moving to a different platform. One possibility is a 6500 series chassis with WAN blades and a firewall services module. Other options include the 7200VXR series and the 7600.

Cost is often the driving factor. If it wasn't, then we would all be running a CRS-1. :)

Rob

  • 1
  • 2
  • 3
  • 4
  • 5
Overall Rating: 5 (2 ratings)
Loading.
Richard Burts Thu, 01/24/2008 - 09:14

Gerry

I do not have details to answer your question about capacity for simultaneous NATs, firewall rules, etc. But there is a routerperformance pdf from Cisco which makes it clear that the 3800 is a significantly different processor with higher capabilities than the 2800. The 2851 is shown to be capable of CEF switching 220,000 PPS and forwarding about 112 Mbps. The

3825 is shown as switching 350,000 and forwarding 179 Mbps while the 3845 switches 500,000 and forwards at 256 Mbps.

here is the link to it (I believe that it requires partner level privileges):

http://www.cisco.com/web/partners/downloads/765/tools/quickreference/routerperformance.pdf

HTH

Rick

buchholr Sun, 02/17/2008 - 18:04

Each of the routers is rated at different speeds. The routers are rated on the number of T1s they can handle at wire-speed. This includes the processing of NAT, ACLs, etc. I have listed out the specs below.

2801 - 1 T1

2811 - 2

2821 - 4

2851 - 6

3825 - 14

3845 - 28

As to helping you choose the right model for your business, it would depend greatly on everything you want to do with the router. What is the overall goal for the router? Is it going to be your firewall? Is it going to support voice? Is it going to be doing IPS/IDS for your network? Are you supporting remote sites? There are lots more questions, but these are a start.

Let me know if this helps.

gmagillsiemens Tue, 02/19/2008 - 10:36

Thanks for the response.

My router will be required to do a lot of dynamic NATs (for around 1,400 ports) and it will be my firewall so it is likely to have 4-5 ACLs. It also must do traffic shaping for the six different types of data classes that will cross it. It will not serve as a remote access or VPN router and it will not do voice.

Uplink speed is currently 11 T1s but we plan to move to a T3 shortly.

I guess I am probably looking to go to a 3845 but I just dont feel safe with the parameters I need to be 100% confident. It seems so much is variable.

What are other installations using in a similar situation?

Correct Answer
buchholr Tue, 02/19/2008 - 11:50

The 3845 is rated to T3 with concurrent services. Here a blurb from the portable product sheet:

"The ISRs are designed with the ability to run multiple concurrent services (FW, NAT, IDS, QoS, etc.) at wire-speed."

You should be fine with a 3845 right now. If you plan on stepping past a T3 in the lifetime of this router then I would recommend moving to a different platform. One possibility is a 6500 series chassis with WAN blades and a firewall services module. Other options include the 7200VXR series and the 7600.

Cost is often the driving factor. If it wasn't, then we would all be running a CRS-1. :)

Rob

Actions

This Discussion