Cisco 1841 and 10M link

[nayanpanchal]

We want to terminate new 10M link via Ethernet interface on Cisco 1841 router. We have free Gig port on the router. We also have HWIC-FE module inserted in the router. However, our implementation team said that Cisco 1841 doesn't support 10M link. It is not designed to cater to such high Bandwidth.

Please suggest.

[paolo bevilacqua]

A 1841 is OK for 10 Mbps.

A 1921 would be better.

[JAN MARIS]

it depends on the nature of the traffic that is forwarded.

# PPS, VOIP packets (EF), multicast, ACLs, ...

[nayanpanchal]

It's a normal traffic. Not a delay-sensitive one.

[letsgomets]

So let me understand this. The router comes with 1Gig Ethernet ports but it doesn't support 10 Meg Ethernet?

The router doesn't cater to such high bandwidth?

Whoever is telling you this needs to think about that for a few more minutes.

Amazing.

[paolo bevilacqua]

letsgomets wrote:
So let me understand this. The router comes with 1Gig Ethernet ports but it doesn't support 10 Meg Ethernet?
The router doesn't cater to such high bandwidth?
Whoever is telling you this needs to think about that for a few more minutes.
Amazing. 

Actually a 1841 router comes with 100 Mbps interface, not 1 Gb.

And in fact is very common for the CPU-based routers to perform just a fraction of the physical access speed, so the doubt can be justified.

I'm afraid you're the one that has to think about few minutes

[letsgomets]

Negative. A 100 dollar cable modem can do 10 Meg an 1800 can easily do it.

Sent from my iPhone

[Leo Laohoo]

So let me understand this. The router comes with 1Gig Ethernet ports but it doesn't support 10 Meg Ethernet?

Your understanding is almost there.

Just because a router has 1Gig interface doesn't mean it WILL or MUST support 1Gig.  For example, the 1941 has a number of 1Gig ports but it also has a throughput of 153 mbps.  This is why it has Gig ports instead of FE ports.

[letsgomets]

We are talking about 10 Meg not 1 gig

Sent from my iPhone

[johnlloyd_13]

we have 1841s on our branch offices with 10 meg metro e/leased line circuits. it should be fine even without the added HWIC-FE module inserted.

[Utair Corporation]

There is a big difference if router performs CEF switching or Process switching.

Usual routing is CEF, but NAT is Process switching and thus it's performance is waaaay lower.

Also, routers have performance measured in PPS and real throughput depends on traffic type.

google for routerperformance.pdf

As of real numbers - i have tried to NAT on 2611 and it almost did 10Mbit/s, with 100% CPU load.

1841 is 5 times faster, according to routerperformance.pdf, so it will handle NATed 10Mbps with ease.

[paolo bevilacqua]

There is a big difference if router performs CEF switching or Process switching.
Usual routing is CEF, but NAT is Process switching and thus it's performance is waaaay lower.

Incorrect, NAT is CEF switched.

NAT takes a little more CPU than regular, but not much.

[nicholas_ong]

If you follow Cisco suggestion it will be as follows

ISR performance with concurrent services (Note: This is an old document hence ISR G2 is not included.)

     1841: 1 T1/E1  

     2801: 1 T1/E1

     2811: 2 T1/E1

     2821: 4 T1/E1

     2851: 6 T1/E1

     3825: 14 T1/E1

     3845: 1 T3/E3

Extracted from http://www.cisco.com/web/partners/downloads/765/tools/quickreference/isr.pdf

Edit: Add on for ISR G2

http://www.cisco.com/en/US/prod/collateral/routers/ps10536/Routing_Poster.pdf

Of course, the higher the end device that you buy, the more you know where the money goes.

Depending on the utilization pattern in your organisation.  If you are using it to route normal internet traffic on that 10Mbps, I would think that C1841 should be sufficient.  If you are using a lot of features though (QoS + Packet Shaping + ACL + Voice, etc)  I would suggest that you don't take any chances and opt for the new generation of routers  like C1941 (it costs about the same as a C1841 currently) or or higher end device like C2821 (if there are spares internally).

Hope this helps.

Cheers.

Message was edited by: nicholas_ong

[Mohamed Sobair]

Hi,

According to the Router performance from Cisco, the 1841 can surly support the 10 Mbps CEF Switching capacity and more,So its not a problem.

Regards,

Mohamed

[Petar Milanov]

Hi,

We have Cisco 1811 in the office and our WAN connection is 25Mbit/s. We have no problem. If I fill the bandwidth up to the 25Mb/s, the processor usage goes over 90%, but it still does its job. But I guess you will not use the maximum of your bandwidth all the time, so do not worry.

You have just perfect device.

Regards,

Tihomir Yosifov