3600 series max routing speed

[spacemky]

I have a 3640 and 2 3620 routers all routing happily at 10Mbps over an ethernet WAN network (fiber interfaces). We're looking at possibly upgrading 2 of the locations to 100Mbps links, and I'm somewhat concerned that the poor 3600 routers won't be able to handle it. What is the maximum routing speed that 3620/3640 can do? I've seen the PDF documents with PPS and such, but a person with real-world experience with these routers could offer some good insight. If 100MBps is too much, how about 50? Thanks for any input.

[pkhatri · Accepted solution]

Hi,

Since you have some the router performance PDF, you would have seen that 20Mbps is the absolute maximum that you will get out of a 3620 and 36Mbps is the max out of a 3640/3640A.

YOu also have to keep in mind that these are the best-case figures, with no services enabled. Since the figures are quoted for a 64-byte packet, you are likely to be able to get better bps throughput with larger packets. Having said that, you still havwe to understand that this is raw throughput performance. You are likely to get much worse performance than this.

So as to your question, I would say that you have no hope at all of being able to push 50Mbps through a 3620/3640 platform. Even a 3660 would struggle to get that much through. We have tended to go with a platform such as 2821 when requiring such throughput.

Hope that helps - pls rate the post if it does.

Paresh

[mhcraig]

SpaceMonkey and Paresh-

We have a 3640 w/128mb running BGP with 2 ISPs along with a short ACL (ip/fw) for frontline protection. We have 100mb with 1 ISP and 20 mb with the other.

We frequently burst to 30 mb and sometimes sustain up to 25 mb without any issues. As a matter of fact, Yesterday we had a client host video and we pulled an average of 50-65 mb for 3 hours. That being said, from this recent personal experience I think anything over 50 mb is too much for a 3640 with my setup. Our network WAS definitely hurting yesterday - routers were CPU-pegged for a while. I don't feel comfortable with anything over 40 mb now (nice to have wiggle room).

I found this thread on the forum looking for advice on what a 3660 might be able to do for me. I would think with a 225 mhz processor with the 3660 as opposed to the 100 mhz processor I could squeeze another 20-30mb out of our network connection.

Thoughts? Paresh, do you think it would be a short-sighted investment to purchase 3660's expecting it to help? If so, which platform would get us a comfortable 80-90mb?

Thanks,

Hutch

[pkhatri]

G'day Hutch,

The reason you are able to get throughput rates higher than the Cisco ratings is because the boxes are rated using 64-byte packets. In reality, the average packet size will be much greater than that.

Having said that, I think you would be much better of looking at something lioke the 3845 for your requirements. It is a much gruntier box than the 3660 ever was and you could re-use a lot of the 3600 network modules within it. The rate throughput for it is 256Mbps.

Hope that helps - pls rate the post if it does.

Paresh

[mhcraig]

Paresh-

After re-thinking and reviewing the new line, I would have to agree - and good to know about the 64-byte size. Regardless our network was in pain at 50Mbps.

I guess my only question would be: Would it be possible to go the less expensive route and go with a 2800 series?

I see the comparison chart here:

http://www.cisco.com/en/US/products/ps5854/prod_models_comparison.html

...but I'm not clear on the rated throughput. I saw something around 400Mbps half dup, but that can't be right if the 3800's are 256Mbps. Assuming that is referring to internal switching speed(?).

In reality, we really only need 100Mbps, but having wiggle room is nice. I'll look at the pricing on the 3845's - perhaps I keep a 3662 around as the HSRP standby.

Thanks Paresh,

Hutch

[pkhatri]

Hi Hutch,

The 2821 will get you around 90Mbps. It is a good little box but the only reason I suggested the 3845 was its additional port capacity. If you reckon that the number of modules/HWICs supported on the 2821 is sufficient, go for it by all means. Just to let you know, we've done extensive testing on the 2821 in the lab and managed to hit the rated 90Mbps without any problems....

Paresh

[mhcraig]

We need 4 WAN ports - I can't see needing more at this point as we have a PIX pair behind them that we are using to subnet the network. These routers really would be for handling BGP.

Still, it does seem a bit short-sighted for us to not go for the 3845's as they are more than double the capacity for bandwidth and more flexible for growth with ports.

Thanks a lot for your help,

Hutch