Cisco Router for 400down/20up NAT throughput

[Felix Troeger]

Hi all!

I know, yet another throughput question. But it is acutally not too easy to get these numbers and to pick a suitable router.

I recently ordered a brand new 400Mbps down / 20Mbps up cable connection with static IP. So I connected my 1941 to that cable "modem" (which is actually a router but not really acting as such) through GigEthernet and simply configured the static IP, a default route and NAT. With NAT enabled the 1941 is maxing out at 210Mbps down. When connecting my PC to the cable box directly I get the full lovely speed of 433Mbps. It looks like the 1941 is bottlenecking me here.

Is there any chance for a not totally overkill, super expensive Cisco Router that could handle my scenario? I was looking at a 2951 at best. Everything above would unfortunately be out of my ballpark.

I would appreciate any suggestions or help.

Cheers

Felix

[Mark Malone]

Hi a 2951 wont give you 400 , you would need a 3900 series minimum or higher , best scenario with 2951 you will get a couple of hundred mb , they say closer to 300 but that's not real world you have to take into consideration all the other features in use in the router

[Felix Troeger]

I did some research on the web before I started this thread and indeed was quite sceptical that a 2951 could handle the bandwidth. Somehow I was hoping it would do it at least with NAT only and without any additonal services enabled.

But even if it would do 400 with NAT, where is the benefit if I can't use other features in the future....

....meeeh, I'm sad.

Thanks for your quick feedback though.

[Joseph W. Doherty]

Disclaimer

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Posting

Just saw this post, after posting my other post.

For NAT performance, alone, see table 6 in the reference I provided.

[Felix Troeger]

Thanks very much for your input.

The 210mbps on a 1941 is actually the reason why I am still digging deeper into this. Because like you said, it might be possible that I can squeeze more out of these Routers due to my "light" traffic mix.

But 3900 is simply too expensive. Maybe I get the chance to test a 2951 and see how far I get with it.

[Joseph W. Doherty]

Actual traffic, is a huge variable to an ISRs performance.

Table 1 shows performance for both minimum and standard maximum size packets.  Unfortunately, they show the former in Kpps and the latter in Mbps, but the formula, for minimal size is 1.448 Mpps is needed for 1 Gbps.

[Joseph W. Doherty]

Disclaimer

The Author of this posting offers the information contained within this posting without consideration and with the reader's understanding that there's no implied or expressed suitability or fitness for any purpose. Information provided is for informational purposes only and should not be construed as rendering professional advice of any kind. Usage of this posting's information is solely at reader's own risk.

Liability Disclaimer

In no event shall Author be liable for any damages wha2tsoever (including, without limitation, damages for loss of use, data or profit) arising out of the use or inability to use the posting's information even if Author has been advised of the possibility of such damage.

Posting

For 420 Mpbs of aggregated bandwidth, Cisco would recommend a 4K ISR, as even the 3945E is recommended only for 350 Mpbs.

Might you go smaller?  Sure, although you're more likely to run out of router performance.  However, if you were able to hit 210 Mbps on your 1941, which Cisco recommends only for 25 Mbps (of WAN, i.e. duplex) bandwidth, shows your current traffic mix, and router configuration, may not require a "good" a router as Cisco recommends.

It's difficult to recommend what you need.  You might benefit from reviewing:

https://supportforums.cisco.com/sites/default/files/attachments/discussion/white_paper_c11_595485_17.pdf

[szechyjs7]

Can you post your config? I have a 2951 with a 110/10 connection and I can only squeeze 45/10 out of it.

I'm very interested in what I can do to get better speeds through the 2951. All I'm running on the router is NAT, and during speed tests I only see about 12% CPU usage, so I know there is plenty of room for improvement.

I also get my ISP advertised speeds when connecting a PC directly to the modem.

[benhanson]

In case anyone else stumbles on this zombie thread, 3 things that helped with my 1921, getting me from 30mbit to 100mbit . . .

ip cef,  removing all extraneous ACLs, converting extended ACLs to standard ACLs if the extended functionality wasn't needed.

[Arthur Nersisyan]

2951 with NAT gives 240-250 Mbps - down and 260-290 Mbps - up

[paul driver]

Hello

Cisco meraki MX have more better throughput, please review here