Cisco 2811 for ethernet point to point

rocconeri · ‎12-04-2011

Hello,

I have to configure a Cisco 2811 router that have 2 Fast Ethernet interface, in order to have

a p2p connection with my ISP.

The FastEthernet0/0 will be used for the p2p connection with the ISP,
the FastEthernet0/1 will be used to route my pubblic IP.

In order to make the connection the ISP assigned the subnet
240.xxx.xxx.226/30 and as gateway 240.xxx.xxx.225

On the FastEthernet0/1 I have to route my pubblic IP subnet that is:
80.xxx.xxx.0/21

The p2p connection will be 100Mbit.

Is there someone that can help me to configure the router posting an real example

TIA

Rocco Neri

johnlloyd_13 · ‎12-04-2011

hi rocco,

configure as below:

int f0/0

ip address 240.xxx.xxx.226 255.255.255.252

no shut

int f0/1

ip address 80.xxx.xxx.1 255.255.248.0

no shut

ip route 0.0.0.0 0.0.0.0 240.xxx.xxx.225

rocconeri · ‎12-04-2011

Thanks John,

that help and open my mind.

Any suggestion to manage connection speed and security

Best Regards

Rocco Neri

johnlloyd_13 · ‎12-04-2011

hi rocco,

thanks for the rating!

i would suggest to ensure that speed/duplex settings are matched on your router and with the SP for optimum performance.

as for network security, you can set up an IOS ZBFW on your 2811 or use a dedicated FW (ASA) if budget permits.

rocconeri · ‎12-18-2011

johnlloyd_13 ha scritto:

hi rocco,

configure as below:

int f0/0

ip address 240.xxx.xxx.226 255.255.255.252

no shut

int f0/1

ip address 80.xxx.xxx.1 255.255.248.0

no shut

ip route 0.0.0.0 0.0.0.0 240.xxx.xxx.225

Hello

I have the following problem on the router configuration,

from inside the router I can ping de default gateway 240.xxx.xxx.225

and I can ping my laptop connected to FastEthernet0/1 that have the own NIC setting IP 80.xxx.xxx.2 and default gateway 80.xxx.xxx.1

from my laptop I can ping 80.xxx.xxx.1 and 240.xxx.xxx.226 but I can't ping the route gateway 240.xxx.xxx.225

from an external internet connection I can ping 240.xxx.xxx.225 and 240.xxx.xxx.226 but not 80.xxx.xxx.1 or 2

there is something wrong with route?

The show ip route say:

Gataway of last resort is 240.xxx.xxx.225 to network 0.0.0.0

240.xxx.xxx.0/30 is subnetted, 1 subnets

C 240.xxx.xxx.224 is directly connected, FastEthernet0/0

80.xxx.0.0/21 is subnetted, 1 subnets

S* 0.0.0.0/0 [1/0] via 240.xxx.xxx.225

Any help is much appreciated.

Best Reagards

Rocco Neri

Joseph W. Doherty · ‎12-05-2011

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 whatsoever (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

BTW, a 2811 is underpowered to fully drive a 100 Mbps link.

rocconeri · ‎12-05-2011

JosephDoherty wrote:

Posting

BTW, a 2811 is underpowered to fully drive a 100 Mbps link.

Joseph,

thanks for your reply,

why do you think a 2811 is underpowered for a 100 Mbps? (I would like to use it because I already have one unused).

What Cisco serie you advise?

Best Regards

Rocco Neri

Joseph W. Doherty · ‎12-05-2011

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 whatsoever (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

Why underpowered for 100 Mbps? because wire-speed 100 Mbps (duplex) can require up to 298 Kpps and the 2811 is only rated at 120 Kpps. You also need to have CPU for the "other stuff" the router is required to do, such as NAT and security. (NB: I also have 1st hand experience seeing a 2811 top out at about 20 Mbps duplex.)

Whether you need faster than a 2811 really depends on how "busy" your 100 Mbps link would be.

If you already have the 2811, try it and see how it does. Just be prepared that it might be inadequate.

I've added Cisco's performance reference sheet.

rocconeri · ‎12-05-2011

JosephDoherty ha scritto:

Posting

Why underpowered for 100 Mbps? because wire-speed 100 Mbps (duplex) can require up to 298 Kpps and the 2811 is only rated at 120 Kpps. You also need to have CPU for the "other stuff" the router is required to do, such as NAT and security. (NB: I also have 1st hand experience seeing a 2811 top out at about 20 Mbps duplex.)

Whether you need faster than a 2811 really depends on how "busy" your 100 Mbps link would be.

If you already have the 2811, try it and see how it does. Just be prepared that it might be inadequate.

I've added Cisco's performance reference sheet.

Loooking at the performance sheet seems the 2900 series is more adequate, isn't it?

Joseph W. Doherty · ‎12-05-2011

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 whatsoever (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

Rocco Neri wrote:

Loooking at the performance sheet seems the 2900 series is more adequate, isn't it?

They are, but again, much depends on the volume of your actual traffic. Additionally, routers can often push more traffic as the packet size increases. Guaranteed wire-speed Ethernet is for minimal size packets, "normal" production traffic often is much larger and so you might often see actual performance 2 to 4 x better than worst case.