1. Straight through cable: This is also known as patch cable. A straight through cable is used to connect a computer to a hub or a switch.
2. Crossover cable: A crossover cable is used to connect one computer to the other computer B without using a switch or hub.
3. Rollover cable: A rollover (also known as console cable) is used to connect to routers for configuration purpose.
Also, you can't connect the Ethernet port on PC to another Ethernet port on a router using a straight through cable. You need crossover cable for this purpose. Also, the PC need to have a network card, and appropriate networking protocol stack properly installed and configured.
1000BaseSX, 1000BaseLX/LH, or 1000BaseZX are IEEE 802.3z- compliant.
1000BASE-ZX Gigabit Ethernet transmission using single mode fibre and supports at least 70 km between nodes.
1000BASE-LX is specified to work over a distance of up to 5km single-mode fiber.
1000BaseSX operates on ordinary multi-mode fiber optic link spans of up to 550 m in length.
1000BASE-T (also known as IEEE 802.3ab) is a standard for Gigabit Ethernet over copper wiring. Each 1000BASE-T network segment can be a maximum length of 100 meters (330 feet), and must use Category 5 cable or better (including Cat 5e and Cat 6). 802.3ab standard defines1000BASE-T Gbit/s Ethernet over twisted pair at 1 Gbit/s (125 MB/s).
Infrastructure mode: The wireless network consist of at least one access point (AP) connected to the wired network and a set of wireless nodes (WN). This configuration is called a Basic Service Set (BSS). Extended Service Set (ESS) is a set of two or more BSSs (multiple cells).
Ad hoc mode: Also called "IEEE ad-hoc mode" or "peer-to-peer mode". This configuration is called Independent Basic Service Set (IBSS) and is useful for establishing a network where wireless infrastructure does not exist or where services are not required.
The following are true about HDLC encapsulation over serial links:
a. HDLC encapsulation used on Cisco routers is proprietary (uses a Type field), and may not be compatible with routers manufactured by other vendors
b. It is recommended to use other encapsulation schemes such as PPP when connecting between a Cisco router and a non-Cisco router instead of HDLC encapsulation.