Cloud Flashcards
What is KVM?
Kernel-Based Virtual Machine - Module lets Linux function as a hypervisor.
HOW does a network switch function?
How: Layer 2 uses MAC addresses to send packet to right place.
WHAT is a network switch?
Device for connecting devices together in a network.
What is a router? How does it function?
Device for forwarding packets at Layer 3 between networks.
How: Reads network packet header and uses routing table to forward the packet.
What is DHCP? Why?
Dynamic Host Configuration Protocol. Allows clients to retrieve and be dynamically assigned IP address.
Why: Automated, centralized, reuse/allocate IPs.
What is Address Resolution Protocol?
Layer 2 Protocol for a computer to retrieve a physical MAC address of another computer from using a IP address.
What is a VLAN?
Broadcast domain partitioned at Layer 2 (Data link layer). Used to logically segment networks independent of physical structure (ex: company departments).
What is vCenter?
Centralized management utility for VMware, and is used to manage virtual machines, multiple ESXi hosts
What is vMotion?
VMWare technology that allows live migration of a VM to be moved from one physical host server to another, while it is running and with no interruption in service.
What is ESXi?
VMWare enterprise-class, type-1 hypervisor
Hypervisor
What is is computer software, firmware or hardware that creates and runs virtual machines by running on a host machine and creates guest VMs?
What is the 2nd layer in OSI model?
Data link layer
WHY does data link layer exist?
Move packets between two nodes intra-network using framing, physical addressing.
HOW does data link layer work? (2 protocols, 2 explicit)
Medium access control (MAC) and logical link control (LLC).
ex: 802.3 Ethernet, 802.11 Wi-Fi
What is Layer 2 traffic which the sender does not know the network address. Broadcast, unknown-unicast, multicast.
BUM traffic
HOW does Address Resolution Protocol work? (3 steps)
Computer first checks ARP cache
If not found, send ARP broadcast on network requesting MAC for IP.
Dest computer answers.
WHAT is the 3rd layer in OSI model?
Network Layer
WHY does 3rd layer in OSI model?
Why: Break segments into packets, move between inter-networks to right place.
HOW does 3rd layer in OSI model work?
How: Routing and addressing (IP)
WHAT is the 4th layer in OSI model?
Transport Layer
WHY does 4th layer in OSI model?
Why: Breaks message data into segments for flow control & error control.
HOW does 4th layer in OSI model work?
How: TCP, UDP, and Ports.
What is Open vSwitch?
Open source distributed virtual multilayer switch
What is OpenFlow?
Communication protocol that allows remote administration of a layer 3 switch’s packet forwarding tables, by adding, modifying and removing packet matching rules and actions.
What is multiplexing?
Combining multiple signals over a shared medium
What is a port? WHY is port useful?
Numbered network endpoint for OS to identify a process/service. Allows computer to multiplex incoming data to specific process/service.
What is ICMP?
(Internet Control Message Protocol) L3 protocol to send messages indicating success or failure when communicating with another IP address
What is IPSec? What are its constituent protocols?
L3 Network protocol suite that authenticates and encrypts the packets of data to provide secure encrypted communication between two computers. (Authentication Header, Encapsulating Security Payloads, ISAKMP/Security Associations)
What port does IPSec use?
Port 500
What is Authentication Header (AH)?
L3 IPSec Protocol with a header that provides authentication and integrity (but not encryption). It uses a Integrity Check Value (ICV) hash.
What is Encapsulating Security Payload?
L3 IPSec Protocol with header and trailer that encrypts data in transport-mode, or encrypts data+ip header in tunnel-mode.
What is Security Association (SA) and what’s are 4 things it’s composed of?
L3 IPSec protocol(s) for authenticated simplex data connection between two endpoints. It’s an agreement on encryption algo (SHA/DES), key material, endpoint IPs, IPSec protocol (AH/ESP).
What is VXLAN?
Protocol encapsulates Layer 2 Ethernet frames in Layer 3/4 UDP packets, enables you to create virtualized Layer 2 subnets, or segments, that span physical Layer 3 networks.
Which IP blocks are for private/local networks?
10.x.x.x, 176.(16-31).x.x, 192.168.x.x
What is STT?
Stateless Transport Tunneling protocol for virtual network running on top of a physical network. Alternative to VxLAN.
What is VRRP?
Virtual Routing Redundancy Protocol: provides automatic assignment of available IP routers to hosts. Primary virtual router sends advertisements. If a backup device does not receive an advertisement for a set period, the backup device with the next highest priority (1 to 255) takes over as primary and begins forwarding packets.
