Question | Answer |
virtualization | emulation of a computer,os,or application on a physical system |
virtual machines | virtual workstations |
All virtual machines | share the same cpu,hard disk,memory and network interfaces.yet each vm functions independently |
physical computer | host |
vm | guest |
virtual machine manager | hypervisor |
virtualization advantages | efficient use of resources,one pc to manage six machines,rather then six pcs,one pc to run one serice instead of six machines with 6 different services |
virtualization advantages | cost and energy savings,fewer pcs drawing less power |
virtualization advantages | fault and threat isolation,viruses |
virtualization advantages | simple backups,recovery and replication,upgrading easier |
virtualization | got a system and pretend to run another system on a system |
virtualization disadvantages | compromised performance,poor server or network |
virtualization disadvantages | increased complexity,administrators,managing |
virtualization disadvantages | increased licensing cost |
virtualization disadvantages | single point failures,six servers on one box, |
virtual machines | no processing |
user machine | does the processing |
vm appears to user | no different than physical computer |
hypervisor | manages virtual machines |
vmware | most widely implemented virtualization software today |
virtual adapter | vNIC |
vNIC | operates at the data link layer and provides the computer with network access |
every port on a physical switch | can be considered a bridge |
virtual bridges | ports on a virtual switch |
virtual switch | logically defined device that operates at the data link layer to pass frames bewteen nodes |
virtual bridges | connect vnics with a network and allows vms to communicate with each other and with nodes on a on a physical lan or wan |
virtual switches or bridges reside in | the ram of the physical computers that act as their hosts |
frequently used connection types | bridge NAT host only |
bridged | vnic access a physical network using the host machines nic,virtual and physical interfaced are bridged |
nat | vnic relies on the host to act as a network address translation device |
nat | vm obtains ip addressing from its host,rather than a server or router on the physical network |
nat | software acts as a dhcp server |
nat | default connection type selected when you create a vm in vmware |
host only | vms on one host can exchange data with each other and with their host but they cant communicate with any nodes beyond the host |
host only and nat | use the dhcp service in the hosts virtualization software to obtain ip address assignments |
virtual networks | refers to how vms connect with each other virtual and physical network nodes |
vlans | subnets,or broadcast domains,logically defined on a physical switch |
trunking | a single interface can carry the traffic of multiple vlans |
virtualization software refers to the physical nic | acting as an interface for vlans as a trunk |
remote access | a service that allows a client to connect with and log on to a lan or wan in a different geographical location |
remote access types | dial up networking |
dial up networking | refers to daling directly into a private networks or isps remote access server to log onto a network |
dial up transmission methods | pstn,x.25, or isdn |
dial up typically uses | pstn |
dial up networking disadvantages | low throughput |
ras | remote access service |
ras | requires software installed on both the client and the server |
ras | a server configured to accept incoming clients |
ras | client with sufficient privileges on the server to access the resources |
ras | dial up networking software |
rras | routing and remote access service |
rras | enables a computer to accept multiple remote client connections over any type of transmission path |
routing and remote access service | enables a server to act as a router,determining where to direct incoming packets across the network |
rras | incorporates multiple security provisions to ensure that data cannot be intercepted and interpreted by anone other than the intended recipient and to ensure that only authorized clients can connect to thr remote access server |
slip | serial line internet protocol |
ppp | point to point protocol |
slip and ppp | enable a workstation to connect to another computer using a serial connection |
dial up networking | serial connection refers to a modem |
slip and ppp | encapsulate higher layer networking protocols,such as tcp and ip,in their lower layer data frames |
slip | carry only ip packets |
slip | does not support data encryption |
slip | asynchronous transmission,stop and start sporadically |
slip | requires significant amount of setup |
ppp | point to point |
PPPoE | point to point over ethernet |
PPPoE | standard for connecting home computers to an isp via dsl or broadband cable |
ppp | supports both asynchronous and synchronous transmission |
remote virtual computing | allows workstation to remotely access and control another workstation |
remote virtual computing | host may allow clients a variety of privileges |
thin client | workstation that uses such software to access lan |
thin client | requires very little hard disk space or processing power |
thin client | relies on another host for the majority of processing and hard disk resources necessary to run applications and share files over the network |
remote virtual computing advantages | simple to configure |
remote virtual computing advantages | runs over any connection type |
remote virtual computing advantages | single host can accept simultaneous connections from multiple clients |
remote desktop port | 3389 |
listening port | 3389 |
rdp | carries session,licensing and encryption information |
virtual network computing | open source system designed to allow one workstation to remotely manipulate and receive screen updates from another workstation |
open source | public and modifiable |
vnc | operates at the application layerand boosts the ability to support multiple sessions on a single computer |
vpns | wide area networks that are logically defined over public transmission systems |
vpn | allows access to only authorized users |
vpn | provide a way of constructing a convenient and relatively inexpensive wan |
vpn | logically defined networks over public transmission systems |
vpn considerations | interoperability and security |
vpn types | site to site client to site |
tunnel | secured virtual connection between two nodes on a vpn |
tunneling | encapsulating one type of protocol in another |
enterprise wide vpn | can include elements |
vpn tunneling protocol | operates at the data link layer and encapsulates network layer packets |
two major types of tunneling protocols are used on contemporary vpns | pptp or l2tp |
point to point tunneling protocol | is a layer two protocol that expands on ppp by encapsulating ppp data for transmission over vpn connections |
pptp | operates with windows rras access services and can accept connections from multiple clients |
pptp | simple and less secure |
layer 2 tunneling protocol | l2tp |
l2tp | encapsulates ppp data for use on vpns |
l2tp | can connect two routers,router and a remote access server,or a client and a remote access server |
l2tp | more commonly used than pptp |
l2tp | tunnel endpoints do not have to reside on the same packet switched network |
data is transmitted from the clientto the vpn | using pptp |
cloud computing | flexible provision of data storage,applications or services to multiple clients over a network |
cloud computing features | self service and on demand |
cloud computing features | elastic |
elastic | services and storage capacity can be quickly and dynamically,sometimes even automatically,scaled up or down |
cloud computing features | support for multiple platforms |
cloud computing features | resource poolingand consolidation |
multitenant | multiple customers share storage locations or services without knowing it |
cloud computing features | metered service |
NaaS | network as a service |
NaaS | a service provider offers its customers a complete set of networking services |
XaaS | anything as a service |
private cloud | an arrangement in which shared and flexible data storage,applications,or services are managed on and delivered via an organizations internal network |
public cloud | an arrangement in which shared and flexible data storage,applications,or services are managed on and delivered over public transmission lines,such as the internet |