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Fiber Connectivity

Hello,

We are going to connect 9 Switche for our 3 floor building. Please see the attached diagram.

Below my requirements

- All the floor switches should get connected to Core Switch 3750x with redudant links.

Kind clarify few queries.

- What type of fiber cable should I run between these switches ?

- I shall run 2 fiber for each individual switch to Building 2 Core Switch. How many cores this cable should be ?

- The link between these switches will be 1G. So what SFP and LC connectors I will need ?

- Connection will carry voice,data, web browsing and IP TV so does 1 GB link is enough ?

- Finally There will be fiber uplink between Building 1 and Building 2. This link should be 10G. What SFP and LC connectors I will need on both core switches

Thanks in advance.

  • LAN Switching and Routing
18 REPLIES
VIP Super Bronze

Fiber Connectivity

Hi,

What type of fiber cable should I run between these switches ?

Depends on the distance.  What is distance between the closet switches and the core 3750 switch in building 2?

What is the distance between building 2 and 1?

I shall run 2 fiber for each individual switch to Building 2 Core Switch. How many cores this cable should be ?

no need to worry about the cable core.  You just need to know what type fibe (single mode or multimode) to run.

The link between these switches will be 1G. So what SFP and LC connectors I will need ?

Depends on the fiber you are using (question 1)

Connection will carry voice,data, web browsing and IP TV so does 1 GB link is enough ?

usually yes

- Finally There will be fiber uplink between Building 1 and Building 2. This link should be 10G. What SFP and LC connectors I will need on both core switches

This also depends on the type of fiber you are using.

HTH

Fiber Connectivity

Hi Reza,

Thanks for your response.

We are going to run single mode fiber cable.

Thanks

Hall of Fame Super Gold

Fiber Connectivity

LC connectors I will need

LC is ALWAYS LC. 

You can either terminate your fibre optic tray (aka FOBOT, for Fibre Optic Break OuT) commonly with SC or LC.  Don't use MTRJ, ST because trying to find fibre optic patch cable is a nightmare (if not expensive).  If you plan to go 10 Gbps (and higher) think about future-proofing your fibre optic runs by using OM4 if possible on all runs.  Don't even accept quotes for OM1 or OM2.  OM3 is fine for 1 Gbps but I personally prefer OM4 for 10 Gbps. 

Personally I prefer the FOBOT to terminate as SC.  This is because sometimes, in Australia, the cablers don't follow instructions and they don't "twist" one end.  So if the FOBOT is terminated as LC we have to break the LC cable so we can twist it.  It's a pain. 

Cisco Employee

Fiber Connectivity

Hi,

For the fiber, please choose according to the distance between the switches.

For the SFP, please click on the below links:

For 1 G SFP:

http://www.cisco.com/en/US/docs/interfaces_modules/transceiver_modules/compatibility/matrix/OL_6981.html#wp162124

For 10 G SFP:

http://www.cisco.com/en/US/docs/interfaces_modules/transceiver_modules/compatibility/matrix/OL_6974.html#wp48759

(Please see the 3750X section in the above links for the SFP options available for your switch)

For the 1 G link being enough or not, it depends on two factors:

the amount of traffic

the type of traffic

For the first one i.e. amount it is clear that the link should not be oversubscribed and amount of traffic must be under 1G

For the second point i.e. the type of traffic I mean that what is the actual fluctuation in the traffic, if it is mostly bursty then you may see packets getting dropped many times because the average traffic flow is passed but the burst may get cut.

However, if you are looking for a general view about this question then 1 G link is enough to handle a single workstation and IP phone traffic.

I am assuming that you would be running QoS to give preference to the voice traffic.

Moreover, if you see drops on interfaces then you can increase the buffer and threshold of the specific queue if you would be using QoS.

Please rate the helpful posts. Thanks.

Fiber Connectivity

- For the fiber, please choose according to the distance between the switches.

The distance between B1 and B2 is 2 km

The distance between floors in B2 approx. 4 meters.

- For the 1 G link being enough or not, it depends on two factors:

the amount of traffic

the type of traffic

For every floor, we are going to have  80 PC,80 IP Telephones, 3 Cameras and 6 IP TV''.

Thanks

Hall of Fame Super Gold

Re: Fiber Connectivity

The distance between B1 and B2 is 2 km

You will need to use LH/LX fibre optic modules.   Fibre run will need to be single-mode. 

The distance between floors in B2 approx. 4 meters.

You will need to use MM fibre optic modules.  Fibre run will need to be multi-mode.

For every floor, we are going to have  80 PC,80 IP Telephones, 3 Cameras and 6 IP TV''.

1 Gbps is enough, however, you can consider thinking about 10 Gbps uplink to your core.

In most cases, I will disagree about QoS on a 1- or 10Gbps uplink.  I do not see any reason why you'll need to apply QoS on your LAN segment.  In our case, we had to TURN OFF our QoS cause it was causing issues with our VoIP system.

Re: Fiber Connectivity

I am also trying to understand about the Core Types for fiber.

I need to inform contractor about fiber type cable that will be single but I have not idea about cores.

The uplink between building 2 building will be 10GB.

I have prepared by requirements

Building 2 Core Switch

WS-C3750X-24S-E

10 GB Module and Transrecievers for WS-C3750X-24S-E

C3KX-NM-10G

SFP-10G-LR

Floor Switches

WS-C3560X-48P-S

1GB Module and Transrecievers for WS-C3560X-48P-S

C3KX-NM-1G

GLC-LH-SM

Building 2 6500 Switch

WS-X6708-10G-3C

X2-10GB-LR

Please let me know if am on righ track.

Thanks



Hall of Fame Super Gold

Fiber Connectivity

WS-C3560X-48P-S

Look into the newer 3650. 

I have not idea about cores.

Two cores = 1 pair of fibre strand.

I am also trying to understand about the Core Types for fiber.

You may be thinking about the differerent "thickness" of each strand:  OM1, OM2, OM3 and OM4.

New Member

Fiber Connectivity

Hi Leo,

I have small query on the below point you have mentioned above.

Don't even accept quotes for OM1 or OM2.  OM3 is fine for 1 Gbps but I personally prefer OM4 for 10 Gbps.

How to check that our fiber is OM4 & What are the specification for OM1-4 category.

Is it affect the overall performace / service degradation

Br/ Subhojit

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