C3945E - how many extra Ethernet ports can be supported? (above the 4 GE)

[Harry0421]

I am using a C3945E for my CCTV network (IP cameras, NVRs, NAS)

How many extra Ethernet ports can be added?

Can I add more GE ports?

Currently using the 4 GE + 2 FE (HWIC)

[Leo Laohoo]

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@Harry0421 wrote:

Can I add more GE ports?

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What kind of "ports"?  Layer 2 or Layer 3 ports? 
If Layer 2, are they PoE or non-PoE? 

If they are PoE, the most important question that needs to be answered is what kind of power supply does the router have? 

2900/3900 have two different kind of power supplies:  One that supports PoE and the other that does not.  

The Data Sheets for these switching modules have been removed because they have gone past their end-of-support date.  The only "list" that I can find can be found HERE.  Go down to Table 1 and it will even specify how many will "fit" in each platform.    

[Harry0421]

I have existing switches, including some with PoE. (Used for PoE IP cameras. These each have 2 LAN/Uplink ports, which I am connecting to the router GE ports and the NVRs)

ideally I am hoping to add extra L3 routable ports, like the built-in GE ports or the additional FE ports on the HWIC-2FE.

I have purchased a HWIC-4ESW, a HWIC-D-9ESW and a NM-2FE2W.

However, I now need a SM-NM adapter...

I have been hunting for how the L2 ESW becomes part of the network..

I am revising my previous Cisco knowledge (from 15 years ago) and learning more.

Unfortunately I keep finding broken links on the Cisco website.

[Joseph W. Doherty]

L2 router switch modules generally allow L3 routing tied to SVIs (much like on a L3 switch using L2 ports and VLANs).

BTW, often router modules have capacity limits such that when using gig ports the module interface itself might be a bottleneck.  Further, your 3945E is, by Cisco, only recommended for 350 Mbps, so lots of gig ports could bump into the capacity limits of the router.  You might want to consider "fronting" your router with a gig capable L3 switch.

Another way to provide more gig ports would be to also "front" your router with a L2 switch with gig ports.  For additional bandwidth between the router and L2 switch, you might be able to create an Etherchannel between the router and switch.

[Harry0421]

Thanks.

The network got much less busy after my recent changes.

I think I can improve traffic a bit more by allocating the PoE cameras to the same network as the appropriate NVR.

Then the router will mostly only have to handle the non PoE devices, via the main switch.

Slot restrictions seem to leave me only one space (WIC 1) where I could add an EHWIC-1GE-SFP-CU.

I have a HWIC-4ESW, mainly for learning/training opportunities.

I have bought a NM-2FE2W (and a sm-nm adapter) for testing with laptops.

[Harry0421]

That list is only EtherSwitch products.

I found a NM-2FE2W but although the status LEDs on the sm-nm adapter and the NM, show green, no extra Ethernet ports are reported.

So it seems the 3945E doesn't support it.

[Leo Laohoo]

NM-2FE2W is not supported on ISR G2 (1900/2900/3900 routers).  

Please take the time to look at the supported modules link I have provided above.