Gigabit Campus Network Design

hi there..
actually i have 2 questions about Gigabit network.


Situation 1

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From the above diagram, i have fully gigabit device from core switch to access switch using fiber optic for switch uplink and utp cat6 from pc's to switch. If some of the pc's using 10/100 NIC connected to gigabit switch, can it cause a problem to the switch such as speed duplex, packet transfer etc2?


Situation 2

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Is it possible to connect from the core switch to multiple layer of distribution switch such the above diagram? Do there have rules or limitation to extend the network ?

Situation 1:

No, There should be no problem as far as I know.

Situation 2:

Sorry, I have no idea.

Do multimode fiber support 10Gbps network? If so, what is the maximum distance for 10Gbps running on multimode fiber?

A few things here:
Situation 1:
Agreed there shouldn't be any problems here but beware auto-negotiation problems. You might have to fix the speed and duplex mode on both ends of the copper link if you experience problems with some devices
Situation 2:
You can use dual uplinks like this as long as you do something to prevent loops. At the most basic if you have spanning tree running it will isolate one link and leave the other active. However I tend to see that as a waste - if you can, look into trunking or etherchannel type implementations where you can have both links active but still have resilience
Extra question:
Probably, but multimode will support it over smaller distances. To be certain (and you need to be certain before specifying and purchasing hardware) check the maufacturer's websites for the switch model(s) you are considering. For example, for a Gigabit interconnection with Cisco kit there are several options for the GBICs you need to buy depending on the fibre type and the distance you hope to run, and you'll need to specify the right one to achieve what you need

Extra question:

Yes, but depends on the implementation, as some references state. And as TheBishop said with smaller distances, (usually between 250 to 300 meters).

Here is what is shown in Cisco's academy material. These are some 10Gig Ethernet (IEEE 802.3ae) implementations:

* 10GBASE-SR – Intended for short distances over already-installed multimode fiber, supports a range between 26 m to 82 m
* 10GBASE-LX4 – Uses wavelength division multiplexing (WDM), supports 240 m to 300 m over already-installed multimode fiber and 10 km over single-mode fiber
* 10GBASE-LR and 10GBASE-ER – Support 10 km and 40 km over single-mode fiber
* 10GBASE-SW, 10GBASE-LW, and 10GBASE-EW – Known collectively as 10GBASE-W, intended to work with OC-192 synchronous transport module SONET/SDH WAN equipment

Also check here: (down in the last section):

www.hill2dot0.com/wiki/index.php?title=10_Gigabit_Ethernet

Situation 2:
You can use dual uplinks like this as long as you do something to prevent loops. At the most basic if you have spanning tree running it will isolate one link and leave the other active. However I tend to see that as a waste - if you can, look into trunking or etherchannel type implementations where you can have both links active but still have resilience

1- If using trunking or etherchannel , do i need to off the spanning tree function? Span tree is on layer 2 and trunking/ etherchannel is on layer 3 is it?

2- What is the maximum switch that can be installed such as situation 2 environment? If using RIP routing protocol, just 15 hops can deploy on the network. How about OSPF & EIGRP?