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Cisco 3945 Total Builtin Gig ports?

ahmad82pkn
Beginner
Beginner

Hi, in Cisco 3945 product sheet its written "

  • 3 integrated 10/100/1000 Ethernet ports with 2 ports capable of  RJ-45 or SFP connectivity

"

Does that mean i can use 3 Gigabit Interface for sure , without buying any additional SFP cards?

and if i buy 2 SFP Cards with Copper output, i have total 5 Gig interfaces?

and can i use 1 SFP Port for Copper output and 1 for Fiber out put?

Any help would be appreciated.

14 Replies 14

Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend
Does that mean i can use 3 Gigabit Interface for sure , without buying any additional SFP cards?

Yes, that is correct.

and if i buy 2 SFP Cards with Copper output, i have total 5 Gig interfaces?

and can i use 1 SFP Port for Copper output and 1 for Fiber out put?

No.  The two ports are "dual-personality".  Meaning you can either use copper OR SFP.  Not both.

According to this URL,

i guess i can only use 1 builtin Gigabit for sure.

and then to use 2 more Gigabit, i will need to buy either 2 SFP Ports module for Copper Ethernet output or 2 SFP Port module for Fiber output.

Means Total 3 Ports i can use  and not 5.

am i correct?

http://www.cisco.com/en/US/prod/collateral/routers/ps10538/qa_c67_553891_ps10537_Products_Q_and_A_Item.html

Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend

Hmmmm ... What are you trying to achieve and what BANDWIDTH are you trying to push?

Hi,

i have attached an image with original post, if you see that, then Point 7 is confirm builtin Gig Copper port.

Then

about Point 5 and 7,  can i use Either both ports in 5 or both ports in 6?

or Point 7 and Point 6 is for sure builtin Gig with Copper output means totsal 3 builtin copper, and in point 5 i have choice to either use both ports as Fiber out or Copper out.

------------------------------------

In other word, my bandwidth from carrier is coming on Fiber, so i need 1 fiber out and 2 Copper out for LAN&DMZ, what would be my complete order to be give to my procurement guy

will appreciate your assistance

Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend

What bandwidth are you expecting from the carrier?

200Mbps

Leo Laohoo
VIP Community Legend VIP Community Legend
VIP Community Legend
200Mbps

May not work.

With CEF enabled, the 3945 is rated at 502.78 Mbps.  This value is expressed in HALF duplex and with no encryption.

At full duplex, the value drops to 251.39 Mbps.  My question is this:  Will you be running encryption?

If you are, then the 3945 may not be able to support 200 Mbps from your ISP.

Hi leolaohoo,   

Thank you for your interest in my query, This Router will be used for Internet + 2 Dozen GRE Tunnels + one IP out of public pool assigned by carrier will be assigned to a Cisco 3030 VPN concentrator , and that concentrator will make 1 Dozen IPSec VPN tunnels ( Thise router will not act as IPSec VPN end point but a pass through),  Does those IPSec tunnels put any load on 3945 performance?

Hi Ahmad,

Your understanding above is correct.  You basically have one fix 10/100/1000 port Gi0/0.  The other 2 ports you can use either copper (RJ-45) or fiber (SFP) for a total of 3 1Gig ports.

HTH

Hi Reza, is it possible to put one rj45 output and one Fiber port output in SFP modules at point 5(diagram reference)?

Regards,

ahmad82pkn wrote:

According to this URL,

i guess i can only use 1 builtin Gigabit for sure.

and then to use 2 more Gigabit, i will need to buy either 2 SFP Ports module for Copper Ethernet output or 2 SFP Port module for Fiber output.

Means Total 3 Ports i can use  and not 5.

am i correct?

http://www.cisco.com/en/US/prod/collateral/routers/ps10538/qa_c67_553891_ps10537_Products_Q_and_A_Item.html

You don't need to buy SFP's UNLESS you want to use fibre.

The two "dual purpose" ports have a copper port & an SFP port - BUT you can only use ONE of the pair - if you plug intot he copper port, then it works. If you plug in an SFP, you CAN'T use the associated copper port.

So yes - you have 3 (three) built-in ports available for use. Two fo them can be *either* copper or SFP based - but you don'd need a copper SFP because there's already a physical copper port available.

The points Leo brought up about throughput are valid - if you're running a 200 Mbps ISP link then a 3945 is going to have issues copeing with full duplex throughput - especially if you're running encryption.

Cheers.

Thank you for the explanation Darren, i understand till here.

last Q. if i opt to use 2 SFP ports, can i buy one SFP with Fiberout and one SFP with RJ45 out?

Also, Thank you for brining in my attention the 200Mbps throughput issue, can you recommend any other hardware for this requirement?  except 7200?

(Also want to thank you every one who contributed so far )

ahmad82pkn wrote:

Thank you for the explanation Darren, i understand till here.

last Q. if i opt to use 2 SFP ports, can i buy one SFP with Fiberout and one SFP with RJ45 out?

You can, but you're just wasting your money if you do. There's *already* an RJ45 port associated with the dual-purpose port - just use that.

Look, you've got two ports with 4 LOGICAL connections, of which you can only use TWO at a time.

Think of the port as a single port with a media adapter on the end - one outputs 1000BaseT, one outputs 1000baseF. If you put an RJ45 SFP into the SFP port then it's just a waste of the already existing, perfectly working RJ45 port in the convertor.

Get me?

Also, Thank you for brining in my attention the 200Mbps throughput issue, can you recommend any other hardware for this requirement?  except 7200?

Based on the requirements you've stated above for GRE and IPSec, I'd almost be tempted to use an ASA 5520, but I don't know what routing protocols you want.

You could go to an ASR1001, maybe - 2.5 Gbps throughput in the lowest spec model (license upgradable to 5 Gbps), 4 built in ethernet ports, although I'm not sure if they're SFP ports - if they are, you would need to buy RJ45 SFP's as well as your fibre SFP. I've never actually had one of those to play with, so I'm basing the comment about SFP's on what I can find in pictures on the web. Maybe someone who has one can confirm/deny the SFP situation.

If the ASR1001 does have SFP ports, and can handle your fibre, then you'll have plenty of throughput in the default configuration to do what you want.

Cheers.

Oh Man, now i understood, and my confusion is gone.

Actually i was thinking Vertical Grouping of 2 ports SFP+SFP , instead of Horzontal grouping of the ports SFP+RJ45:-s

Thank you very much Darren, and Reza and Leo.

And thankyou For router bottle neck issue as well,i will look for this.

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