Cisco 2811 w/ HWIC-4ESW - Routing Question

Answered Question
Apr 15th, 2012

Hi there... I don't consider myself a Cisco expert or anything, but I can get around. I'll give an overview of my current setup... I currently have a Cisco 2621 powering a network at our co-location facility... It's a simple setup and is working well. The colo provides a redundant HSRP uplink, so I have their two uplinks going into a Dell switch. From that Dell switch I have a uplink into FastEthernet0/0 on the 2621, configured with my routing network, and then FastEthernet0/1 gets an address from my block of routable IP. FastEthernet0/1 then plugs into another Dell switch where I have all my servers connected. The servers get public routable IP addresses and use the address on FastEthernet0/1 as their default gateway. This works well...

Colo Uplinks (2 cables) --> Dell Switch A --> Cisco 2621 FE 0/0

Cisco 2621 FE 0/1 --> Dell Switch B --> Servers

It's time to upgrade off the 2621, so I aquired a Cisco 2811 which has two FE interfaces, as well as a modular HWIC-4ESW switch. My question is, can I get rid of the Dell Switch A in the setup above and just use the internal switch on the 2811 to accomplish the same thing? And I if I did this, would my two uplinks from the colo plug into ports 1 and 2 of that HWIC, and then port 3 would physically connect into FE 0/0? Or can I logically do that via configuration in the Cisco? I'm not sure how all this works and haven't received the new router yet, so I thought I'd get a head start and reach out to the experts.

My second question is unrelated, but each port on the HWIC switch cannot be configured as a network interface right? I'm pretty sure they can't as they aren't considered network interfaces but just thought I'd ask.

Thanks for any direction, I always get pointed to the right place here.

Matt

I have this problem too.
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Correct Answer by Richard Burts about 2 years 23 hours ago

The table that Reza does suggest that the 2811 does not have routed ports and that is most definitely a problem with the table and not accurate information about the router.

From what I understand of Matt's situation I believe that he could use two of the switch ports to replace Dell switch A. Two of the switch ports would connect to the colo uplink. You would probably create a separate VLAN for them and configure a VLAN interface which would have the IP address and would establish connectivity to the colo upstream. You would not need FastEth0/0 for this. So you would have a routed interface and two additional switch ports available for some future use.

In case it is not clear let me address Matt's question about configuring the HWIC ports as network interfaces. The HWIC ports are switch ports and operate at layer 2. As such you can not configure them as layer 3 network ports. But you can configure VLAN interfaces for the HWIC and the VLAN interface is a layer 3 interface and provides the network functionality. As with most switches you could have all the switch ports in a single VLAN but I believe that in your case it would be better to have the 2 uplink ports in a separate VLAN with their own VLAN interface.

HTH

Rick

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Reza Sharifi Sun, 04/15/2012 - 12:32

Matt,

Unlike the 2621 routers, the 2811 routers don't come with any on board routed interfaces.  If you need on board interface you need to get a 2821, or a 2801.  2801 comes with 2 on board 10/100 and the 2821 comes with 2 on board 10/100/1000  interfaces. Or if you want to go with 2811, you need to order network interface cards for it.

Have a look at table-7 in this doc:

http://www.cisco.com/en/US/prod/collateral/routers/ps5854/ps5882/product_data_sheet0900aecd8016fa68_ps5854_Products_Data_Sheet.html

HTH

mattlager Sun, 04/15/2012 - 12:40

I'm a bit confused... The show vers output from this router shows 2 FastEthernet interfaces... The same way my 2621 does... The pictures of the device show two physical Ethernet ports as well... Are you saying these two FastEthernet interfaces cannot be used in the same way as my 2621 uses them? This is the router I've purchased on EBay. Hopefully I didn't make a mistake. I purchased the HWIC separately. The following Cisco page shows 2 integrated fast Ethernet ports:

http://www.cisco.com/en/US/products/ps5881/index.html

Cisco 2811 (revision 53.50) with 249856K/12288K bytes of memory.

Processor board ID FTX1006C38L

2 FastEthernet interfaces

1 Serial interface

1 Virtual Private Network (VPN) Module

DRAM configuration is 64 bits wide with parity enabled.

239K bytes of non-volatile configuration memory.

62720K bytes of ATA CompactFlash (Read/Write)

On the data sheet you linked to, I got the feeling that if the next column was blank it simply meant it was the same as the previous column....

Reza Sharifi Sun, 04/15/2012 - 14:44

Matt,

I apologize for misinforming you.  Since I don't have any 2811, I was going based on the documentation, but obviously we know the doc is wrong.

Sorry

Reza

mattlager Sun, 04/15/2012 - 15:04

No worries at all! I saw that table before and made the assumption that if the value to the right was blank it meant it was the same as the column to the left, bad formatting but I'm glad it looks like everything will work out for me.

As always, I appreciate everyone's comments and advice!

Paolo Bevilacqua Sun, 04/15/2012 - 13:05
 

Unlike the 2621 routers, the 2811 routers don't come with any on board routed interfaces.  If you need on board interface you need to get a 2821, or a 2801.  2801 comes with 2 on board 10/100 and the 2821 comes with 2 on board 10/100/1000  interfaces. Or if you want to go with 2811, you need to order network interface cards for it.

Have a look at table-7 in this doc:

http://www.cisco.com/en/US/prod/collateral/routers/ps5854/ps5882/product_data_sheet0900aecd8016fa68_ps5854_Products_Data_Sheet.html

HTH

Incorrect. All the ISR routers, including the 2811, have two onboard Ethernet interfaces.

mattlager Sun, 04/15/2012 - 13:15

That's what I thought, thanks goodness as I almost thought I made an expensive mistake. That being said, and back to my original question, I'm pretty certain I can configured the addition HWIC switch to use the colo's uplink and that have that route to FE 0/0 and/or FE 0/1... I did some reading and it looks like you should never connect a cable from the HWIC to either of the FE ports on the same switch, so it looks like I'll just need to research how to configure this.

Paolo Bevilacqua Sun, 04/15/2012 - 13:35

No need to connect any cable across ports. Simply configure vlan interfaces and the assign vlan to the switched module interfaces.

What you bough is a small switch that goes into the router. There are other cards that are instead routed ports without switch module.

Please remember to rate useful posts clicking on the stars below.

Correct Answer
Richard Burts Sun, 04/15/2012 - 13:24

The table that Reza does suggest that the 2811 does not have routed ports and that is most definitely a problem with the table and not accurate information about the router.

From what I understand of Matt's situation I believe that he could use two of the switch ports to replace Dell switch A. Two of the switch ports would connect to the colo uplink. You would probably create a separate VLAN for them and configure a VLAN interface which would have the IP address and would establish connectivity to the colo upstream. You would not need FastEth0/0 for this. So you would have a routed interface and two additional switch ports available for some future use.

In case it is not clear let me address Matt's question about configuring the HWIC ports as network interfaces. The HWIC ports are switch ports and operate at layer 2. As such you can not configure them as layer 3 network ports. But you can configure VLAN interfaces for the HWIC and the VLAN interface is a layer 3 interface and provides the network functionality. As with most switches you could have all the switch ports in a single VLAN but I believe that in your case it would be better to have the 2 uplink ports in a separate VLAN with their own VLAN interface.

HTH

Rick

mattlager Sun, 04/15/2012 - 13:29

This really helps thanks... I'll create the VLAN that contains two of the HWIC ports as the uplink and assign the VLAN the appropriate address. I have two blocks of routable ip addresses on different subsets so I could configure FastEthernet0/0 with the first subnet and FastEthernet0/1 as the second subnet and I should be good to go. Each of those could go into separate switches, each with their own respective networks. Optionally they could go into a single switch configured with VLANs.

Thanks again.

Richard Burts Sun, 04/15/2012 - 14:26

Matt

I am glad that our discussion helped lead you to a better understanding of the options available for you and to a solution for your question. Thank you for using the rating system to mark this question as answered. It makes the forum more useful when people can read a question and can know that a solution was found. Your rating has contributed to this process.

HTH

Rick

Paolo Bevilacqua Sun, 04/15/2012 - 13:40

Richard Burts wrote:

The table that Reza does suggest that the 2811 does not have routed ports and that is most definitely a problem with the table and not accurate information about the router.

Reading a row from let to right, each item applies to all models, until a new item appears in the same row.

Yes, it is a poorly formatted table.

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Posted April 15, 2012 at 11:37 AM
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