CH.1 Network types/topologies

[1.1] What is a network?

Two or more connected nodes that can exchange data or share resources.

[1.1] What is a physical topology?

The physical arrangement of devices / cables / and connections.

[1.1] What is a logical topology?

How traffic flows and how devices are organized for communication / such as VLANs and subnets.

[1.1] What is a single point of failure (SPOF)?

A component whose failure can interrupt a service because there is no working alternative.

[1.1] What is redundancy?

Additional devices / links / or resources that help a service continue after a failure.

[1.1] What is bandwidth?

The maximum data-transfer capacity of a connection / usually measured in bits per second.

[1.1] How does a star topology connect devices?

Each endpoint connects to a central device / usually a switch.

[1.1] In a star topology / one PC's cable fails. What is normally affected?

That PC loses its connection. other PCs connected to the switch can continue communicating.

[1.1] In a star topology / the central switch fails. What is affected?

Devices depending on that switch lose connectivity through it.

[1.1] What is a mesh topology?

A topology with multiple interconnections that can provide alternate paths.

[1.1] Full mesh versus partial mesh?

Full mesh directly connects every node to every other node. partial mesh connects only some node pairs directly.

[1.1] What is a major tradeoff of mesh networking?

Greater redundancy usually requires more links / ports / expense / and management.

[1.1] What is a hybrid topology?

A network arrangement that combines two or more topology types.

[1.1] What is a bus topology?

Devices share a common backbone medium. faults in the shared medium can affect many devices.

[1.1] What is a ring topology?

Devices form a loop. traffic follows the ring's design / with resilience depending on the implementation.

[1.1] What is a point-to-point connection?

A direct link between two endpoints.

[1.1] What is bounded versus unbounded media?

Bounded media uses a physical cable. unbounded media carries signals wirelessly.

[1.2] What is a client?

A device or application that requests a resource or service from a server.

[1.2] What is a server?

A device or application that provides resources or services to clients.

[1.2] What is a peer-to-peer network?

Devices can both request and provide resources directly to one another.

[1.2] What is a benefit of the client-server model?

It supports centralized management of shared services and access.

[1.2] What is a PAN?

A personal area network connecting nearby personal devices / such as a phone and Bluetooth headset.

[1.2] What is a LAN?

A local area network covering a limited area / such as an office or building.

[1.2] What is a WLAN?

A wireless local area network / commonly using Wi-Fi.

[1.2] What is a CAN in this chapter?

A campus area network connecting LANs across nearby campus buildings.

[1.2] What is a MAN?

A metropolitan area network spanning a city or metropolitan area.

[1.2] What is a WAN?

A wide area network connecting networks across large geographic distances.

[1.2] What is an overlay network?

A logical or virtual network built on top of an underlying network.

[1.2] What is an underlay network?

The underlying connectivity that transports an overlay's traffic.

[1.2] What is SDN?

Software-defined networking separates control functions from packet forwarding and supports centralized / programmable management.

[1.2] What is VXLAN?

Virtual Extensible LAN carries Layer 2 frames over a Layer 3 network to extend virtual network segments.

[1.2] What does MPLS use to forward traffic?

Labels associated with forwarding paths / rather than a fresh destination-IP lookup at every transit hop.

[1.2] Does GRE or multipoint GRE automatically encrypt traffic?

No. Tunneling and encapsulation do not inherently provide encryption.

[1.3] What is an ISP?

An internet service provider that supplies internet connectivity.

[1.3] What is a demarcation point?

The boundary between the provider's network responsibility and the customer's responsibility.

[1.3] What is a smartjack?

A provider-installed network interface device that can support diagnostics and remote monitoring at the demarc.

[1.6] What does ipconfig /all show?

Detailed Windows network configuration / including IP addresses / masks / gateways / DNS servers / and DHCP information.

[1.6] What does ping test?

Whether ICMP echo requests receive replies. it can also report round-trip time and loss.

[1.6] What does a successful ping to 127.0.0.1 prove?

The local IP stack responds. it does not prove the NIC / cable / Wi-Fi / or internet connection works.

[1.6] What does arp -a show?

Cached IPv4-to-MAC mappings on local interfaces.

[1.6] What does netstat -an show?

Network connections and listening endpoints using numeric addresses and port numbers.

[1.6] What does netstat -r show?

The local routing table.

[1.7-1.8] Which device normally connects different IP networks?

A router or a Layer 3 switch configured for routing.

[1.7-1.8] What should you identify when reviewing a network diagram?

Device roles / network boundaries / link paths / and single points of failure