router real world speed

[Joseph Kahle]

i need help understanding the Portable Product Sheets - Routing Performance. I have planned to have my ISP provide a 20 Megabit ethernet connection to my business. Reading the sheet leads me to beleive that a 2621 will not have sufficient procesing power.

Does a 2651 ro 2691 have enough? Or am i Forced to purchase a 2811.

[adamclarkuk_2]

Hi

It looks like the min is the 2691 with CEF switching turned on :-

The 2621 can do the following

Process Switched

1500 PPS

0.768 Mbps

Fast/CEF switched

25000 PPS

12.80 Mbps

2651

Process Switched

2000 PPS

1.024 Mbps

Fast/CEF Switched

37000 PPS

18.94 Mbps

2691

Process Switched

7,400 PPS

3.7888 Mbps

Fast/CEF Switched

70000 PPS

35.84 Mbps

2821

Process Switched

11,500 PPS

5.888 Mbps

Fast/CEF Switched

170000 PPS

87.04 Mbps

Router performance Sheet

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

[Joseph W. Doherty]

If you want to be able to substain 20 Mbps (duplex) bandwidth, from their specs I don't believe any 26xx model would be suitable.

The 2811 might just work. When you see the Mbps rating on the Portable Product Sheets, you need to double it to support duplex, and perhaps double it again to support additional services and/or the some process switched packets. (Ideally you want a reserve cushion for CPU processing.) For 20 Mbps the 2821, 2851 or 3825 would be safer to chose from.

PS:

Since it's a Ethernet connection, depending on your feature needs, a small L3 switch might work well for you, such as the 8 port 3560.

[adamclarkuk_2]

Fair point joseph, and the ISR is a better router all over anyway.

[Joseph Kahle]

Am routing between subnets and not familiar with how a 3560 would do that. i have a 6513 and know about turning an ethernet interface from a switchport to a routed interface by giving it an IP address. However, since I only need two ports wouldn't I end up with wasted ports on the 3560? Does the IOS on teh Cat 3560 work the same as the IOS on a 2xxx router?

[Joseph W. Doherty]

I think the 3560 might support routed interfaces. I know it supports routed VLANs.

In some ways the IOS for the 3560 works likes routers, but often it's missing more advanced features. NAT would be one.

Also, just as routers offer different features dependent on the IOS feature package, so do 3560s (although not as many choices).

Yes, you might "waste" ports on a 3560. But a bigger question, how does the price compare for a 3560 with "wasted" ports and perhaps an ISR with the performance you need? (Also, you might be able to use the 3560 for additional LAN routing.)

Again though, even if the price of the 3560 is very attractive vs. an ISR, insure either has the feature support you require.