WAN:Week 1 Flashcards
- is a telecommunicarions network that spans over a relatively large geographical area and is required to connect beyond the boundary of the LAN.
- used to interconnect remote users, netoworks, and sites.
- are owned and managed by internet service, telephone, cable, and satellite providers.
- services are provided for a fee,
- providers offer low to high bandwidth speeds, over long distances.
WAN (Wide Area Network)
- provide networking services within a small geographic area,
- are used to interconnect local computers, peripherals, and other devices.
- is owned and managed by an organization or home user.
- no fee
- provide high bandwidth speeds using wired Ethernet and Wi-Fi services.
LAN (Local Area Network)
- is a connection that is dedicated to a single customer.
- provide : Guaranteed Service Level, Consistent Bandwidth, Security,
private WAN
-is typically provided by an ISP or telecommunications service provider using the internet. In this case, the service levels and bandwidth may vary, and the shared connections do not guarantee security
public WAN
what do we use (2) to connect remote sites.
telephone lines or internet
(WAN Topologies)
- employs a circuit between two endpoints
- involved a Layer 2 transport service through the service provider network.
- is transparent to the the customer network.
- connection between two sites
- traversing over the wide area network.
point-to-point topology
- can be interconnected through the hub router using virtual circuits and routed subinterfaces.
- can only communicate with each other through the hub router.
spoke routers
represents a single point of failure. If it fails, inter-spoke communication also fails.
hub router
(WAN Topologies)
- enables a single intrface in the hub ruter to be shared by alls poke circuits.
- same with star topology
- if the hub goes fown a,b, and c goes down.
- solution: just make sure that the hub does not go down.
hub-and-spoke topology
(WAN Topologies)
- offers enhanceed network redundancy, load balancing, distributed computing and processing, and the ability to implement backup service provider connections
- more expensive to implement than single-homed topologies. This is because they require additional, and more complex, configurations.
- you have two possible connections or two hubs to connect A,B, and C
- you have a backup, If one router goes down, the sites are still connected to another router (redundancy)
dual-homed topology
(WAN Topologies)
- uses multiple virtual circuits to connect all sites.
- the most fault-tolerant topology
- ultimate solution. There is no offline connectivity here. One site is directly connected to all other sites.
- Most Tolerant. One site goes down, the other connections are still up.
- Not practical, far from reality, expensive.
fully meshed topology
(WAN Topologies)
- connects many but not all sites.
- one site is crucial in the topology.
partially meshed topology
(carrier connections)
-is when an organization connects to only one service provider. An SLA is negotiated between the organization and the service provider.
single-carrier connection
(carrier connections)
- provides redundancy and increases network availability. The organization negotiates separate SLAs with two different service providers.
- when using this, make sure they are from two different companies.
- if the router connected on the corporate site, the network is disconnected from the internet.
dual-carrier connection
(evolving network)
- single LAN connected to a wireless router for sharing data and peripherals.
- connection to the internet is through a common broadband service- DSL
- IT support is contracted from the DSL provider.
small network
(carrier connections)
- distributed on offices worldwide
- site-to-site and remote access Virtual Private Networks (VPNs) enable the company to use the internet to connect easil and securely with employees and facilities around the world.
- they are already everywhere
- Solution-Connect their sites via Wide Area Network.VPN and Site-to-site - economical solutions to connect scattered sites.
- list-line-expensive
- we have a lot of possible technologies in WAN.
distributed network
(WAN Standards)
-TIA/EIA
Telecommunications Industry Association and Electronic Industries Alliance
(WAN Standards)
-ISO
International Organization for Standardization
(WAN Standards)
-IEEE
Institute of Electrical and Electronics Engineers
(WANs in the OSI Model)
- synchronous digital hierarchy (SDH)
- synchronous optical networking (SONET)
- dense wavelength division multiplexing (DWDM)
layer 1 protocols (physical)
(WANs in the OSI Model)
- Broadband
- wireless
- Ethernet WAN (Metro Ethernet)
- Multiprotocol Label Switching
- point-to-point protocol (PPP) (less used)
- high-level data link control (HDLC) (less used)
- frame relay (legacy)
- asynchronous transfer mode (ATM) (legacy)
layer 2 protocols (data link)
(common WAN Terminology)
- connects the subscriber LANs to the WAN communication device.’
- it is where you configure the clock rate-ow fast two routers exchange informatio. It pertains to how synchronous they are.
Date Terminal Equipment (DTE)
(Common WAN Terminology)
-Device used to communicate with the provider
Data Communications Equipment (DCE)
(Common WAN Terminology)
-this is the DTE and DCE devices located on the enterprise
Customer Premises Equipment (CPE)
(Common WAN Terminology)
-the point where the subscriber connects to the service provider network
point-of-presence (POP)
(Common WAN Terminology)
-the physical location in a building or complex that officially separates the CPE from service provider equipment.
demarcation point
(WAN Devices)
- dial-up modem
- uses telephone lines
- legacy device
voiceband modem
(WAN Devices)
-collectively known as broadband modems, these high-speed digital modems connect to the DTE router using Ethernet.
DSL modem/Cable Modem
(WAN Devices)
-digital-leased lines require both of these. It connects a digital device to a digital line.
CSU/DSU
(WAN Devices)
-connect fiber-optic media to copper media and convert optical signals to electronic pulses.
Optical converter
(WAN Devices)
-devices are used to wirelessly connect to a WAN provider
Wireless router/access point
(WAN Devices)
-WAN backbone consists of multiple high-speed routers and Layer 3 switches.
WAN core devices
-transmits bits sequrntially over a single channel
serial connection
- simultaneously transmit several bits using multiple wires.
- is limited to very short distances.
- all bits will leave the source at the same time, but not all will arrive at the same time.
parallel communications
some bits are left behind; some have already arrived
clock skew
(types of switching)
- you need to establish a connection. It has to establish this before frowarding data. Applies to telephones.
- establoshes a dedicated circuit (or channel) between endpoints before the users can communicate.
- establishes a dedicated virtual connection through the service provider network before communication can start.
- all communication uses the same path
circuit switched network
two most common types of circuit-switched WAN technologies
Public Switched Telephone Network (PSTN) and Integrated Services Digital Network (ISDN)
(types of switching)
- no define direction. applies to computer networks
- network communication is most commonly implemented using this type switching.
- segments traffic data into pakcets that are routed over a shared network.
- much less expensive and more flexible than circuit switching.
packet-switched communication
-multiple inputs, singe output; single input, multiple outputs.
multiplexing (MUX)
-multiple inputs, single output
multiplexer
- single input, multiple output
- multiple computers connected to a device.
- if the data is already on the router, single output, delivered to ultiple outputs.
demultiplexer
(they needed their networks to connect to the local loop of a service provider.)
-only you;
dedicated lines
(they needed their networks to connect to the local loop of a service provider.)
-shared; economical
switched lines
(modern connectivity examples)
- fiber can be installed independently by an organization to connect remote locations directly together.
- dark fiber can be leased or purchased from a supplier.
dedicated broadband
(modern connectivity examples) (packet switched)
-replcaing many traditional WAN options
metro ethernet
(modern connectivity examples) (packet switching)
-enables sites to connect to the provider regardless of its access technologies.
MPLS
(modern connectivity examples)
-organizations are now commonly using the global internet infrastructure for WAN connectivity.
internet-based broadband
(wireless internet-based broadband)
- municipal wireless networks are available in many cities providing high-speed internet access for free, or for substantially less than the price of other broadband services.
- most do not have a mesh Wi-Fi network deployed. If is available and in range, then it is a viable option.
municipal wi-fi
(wireless internet based broadband)
- increasingly used to connect devices to the internet using radio waves to communicate through a nearby mobile phone tower. 3g/4G/5G and Long-term evolution are cellular technologies.
- with this option, coverage if often an issue, even within a small office or home office where bandwidth is relatively limited.
cellular
(wireless internet based broadband)
- typically used by rural users or in remote locations where cable and DSL are not available. A router connects to a satellite dish which is pointed to a service provider satellite in Geosynchronous orbit. Trees and heavy rains can impact the satellite signal.
- this optionis expensive and provides limited capacity per subscriber. Typically used when no other is available.
Satellite internet
(wireless internet based broadband)
-worldwide interoperability for microwave access (WiMAX) is described in the IEEE standard 802.16 Privides high-speed broadband servcice with wireless access and provides broad coverage like a cell phone network rather than through small Wi-Fi hotspots
WiMAX
(ISP Connectivity Options)
-single connection to the ISP using one link. Provides no redundancy and is the least extensive solution.
single-homed
(ISP Connectivity Options)
-connects to the same ISP using two links. Provides both redundancy and load balancing. However, the organization loses internet connectivity if the ISP experiences an outage.
dual-homed
(ISP Connectivity Options)
-the client connects to two different ISPs. This design provides increased redundacy and enables load-balancing, but it can be expensive.
multihomed
(ISP Connectivity Options)
-is the most resilient topology of the four shown. The client connects with redundant links to multiple ISPs. This topology provides the most redundancy possible. It is the most expensive option of the four.
dual-multihomed
limited bandwidth that is distance sensitive (in relation to the ISP central office). upload rate is proportionally lower compared to download rate.
DSL
-bandwidth is shared by many users. Therefore upstream data rate are often slow during high-usage hours in areas with over-subscription.
cable
