Girl Geekette

 
Layer 1 Connection Types
Leased Lines - PPP or dedicated connection 
Circuit switching - Used with ISDN - for when customer doesn’t want dedicated, but needs a reliable connection 
Packet switching - Virtual circuits are used to provide end to end connectivity. The network itself shares a single PPP link to transport packets from source to destination. 

WAN Service Providers
CPE - Customer premises equipment - device at the subscribers location - end of responsibility for provider, start for customer 
Demarcation (demarc) - the place where the CPE ends and the local loop portion of the service begins - can be found in he phone closet 
Local loop - the cable from the demarc to the WAN providers central office (CO) 
Central Office Switch - switching facility that is the nearest POP for the providers WAN 
Toll network - The switches and facilities (trunks) inside the WAN providers cloud 

Layer 2 Encapsulation Protocols
HDLC - High level data-Link Control - default communication method for Cisco routers of synch links, proprietary; came after SDLC modified into LAP And LAPB
Transfer modes
NRM - normal response mode
ARM - async Response Mode
ABM - async Balanced mode
LAPB - Link access procedure balanced : built into x.25 
SDLC - Synchronous Data Link Control (SNA) PPP or multipoint; bound or unbound, circuit or packet setiched; primary and secondary node 
DDR - dial on demand routing - static 
PPP - point to point protocol
dial up or ISDN
PAP and CHAP 
SLIP 
X.25 / LAPB - PPP between DTE and DCE
DTE - data Terminal Equipment - router
DCE - data circuit terminating equip (modem CSU/DSU)
PSE - packet switching exchange
Full duplex protocol
Created SVC or PVC connections
PLP- Packet Layer Protocol
LAPB link access procedure Balanced
Make sure frames are error free and sequenced
I - information
S Supervisory
U unnumbered 
Frame Relay - shared bandwidth 
Can setup a CIR (committed information rate)
PVC’s are created at level 2 
DLCI - used to identify virtual circuit equipment; assigned by provider then mapped 
LMI used to determine the global significance of DLCI numbers 
ATM 

Frame Relay PVC connections
Local access Rate 
Virtual Circuit 
PVC 
SVC 
DLCI 
CIR 
Inverse ARP 
LMI 
BECN