WANs Flashcards
LAN
Local Area Network:
A network that connects computers/devices in a relatively small area, typically a single building or small group of buildings
WAN
Wide Area Network:
A geographically distributed network that connects multiple LANs
MAN
Metropolitan Area Network:
A network that connects computers/devices in a geographic area larger than a LAN but smaller than a WAN
VPNs
Provides a virtual tunnel between private networks across a shared public network (ex: Internet)
Traffic traveling over the tunnel is encrypted & only readable by the authorized users on both sides
User can share data over the tunnel as if they were connected with a dedicated private link
Allow an organization to use the same physical links for connectivity to the Internet & between offices
Because they use shared infrastructure, VPN connections are typically less expensive than dedicated links
Site-to-Site VPN
Terminated on a router/firewall in each office
Software does not need to be installed on user desktops
IPsec typically used for encryption
Site-to-Site VPN: Configuration Options
IPsec Tunnel
–Open standard, does not support multicast
GRE (Generic Routing Encapsulation) over IPsec Tunnel
–Adds support for multicast
IPsec VTI (Virtual Tunnel Interface) --Cisco proprietary simplified configuration, supports multicast
DMVPN (Dynamic Multipoint VPN)
–Cisco proprietary. Scalable simple hub/spoke style configuration enables direct full mesh connectivity between all offices
FlexVPN
–Cisco proprietary. Very similar to DMVPN, newer tech
GETVPN (Group Encrypted Transport VPN)
–Cisco proprietary. Scalable centralized policy for VPN over non-public infrastructure (ex: MPLS)
Remote Access VPN
Between a router or firewall in the office & VPN software installed on an individual user’s device
The user can access the VPN from anywhere with internet connectivity
They usually use SSL (sometimes IPsec) for encryption
MPLS
Multi Protocol Label Switching:
Uses a shared core infrastructure at the service provider. It can be used for connectivity to the internet and/or connectivity between offices over VPN
Satellite
Can be used for connectivity to the internet, for direct connectivity between offices and/or connectivity between offices over VPN
Optical Fiber
More suitable for longer distances than copper
Commonly used for ISP backhaul connections
FTTx Services: Fiber to the Home Fiber to the Premises Fiber to the Building Fiber to the Neighborhood
SONET & SDH
SONET (North America) and SDH (rest of the world) are the standards used in service provider optical fiber networks
DWDM
Dense Wavelength Division Multiplexing:
Combines multiple optical signals in one optical signal transmitted over a single fiber strand
Each signal is assigned a different wavelength
DWDM allows more capacity to be added to existing infrastructure without expensive upgrades
DWDM is used in all modern long haul optical connections
Dark Fiber
Many ISPs laid optical fiber cabling in the past and then found they didn’t require it
–DWDM was a major reason for this
The unused cabling can be offered to customers as “dark fiber”
WAN Backup & Small Office Solutions
Less expensive options often aimed at home user internet access can be used as Internet VPN WAN backup options in corporate environments
There will typically be no corporate level SLA with these services
These can be used as the primary WAN connection method corporate network from smaller offices and for home users
- -DSL
- -Cable
- -Wireless (4G/5G)
Legacy WAN Options
PSTN (Public Switched Telephone Network) ISDN (Integrated Services Digital Network) Frame Relay ATM (Asynchronous Transfer Mode) X.25
