I'm trying to define interfaces of a 3925 CISCO router. This router will be interconnected with multiples WAN interfaces (WAN across macrowave network, WAN across optical fiber network,...). Theses WAN interfaces will be 100Mbps or 1Gbps interfaces, so I expect to use the three natives CISCO ports (GigabitEthernet 0/0,GigabitEthernet 0/1,GigabitEthernet 0/2) to interconnect with theses interfaces. For all additional WAN acces, I will add routed port HWIC card.
1) I expect to integrate 1000BASE-T SFP transceiver module into HWIC card. The CISCO technical notes notice this SFP is used for Category 5 copper wire. So is it a minimal requirement? I suppose this SFP could be used with upper copper wire category without impact the performance of the global link, couldn't it?
This router will be also interconnected with LAN through cipher unit and a backup 3925 CISCO router configuring with HSRP link.
2) For theses two acces I wonder if routed port are necessary or if layer 2 port can't be enough?
3) More generally, what is the difference between layer 2 and layer 3 port ?
(I know that contrary to layer 2 interfaces, you can assign IP address on routed interface, but you can also set up link with layer 2 interfaces by means of Vlan-Interfaces. In the same way, routed interface can act as layer 2 interface by means of Sub-interfaces.)
Thank you for your responses