OSI for CCNA Layer 2: Data Link
The CCNA exam has extensive coverage of data routing. Data routing is handled by the data link layer of the OSI. The data link layer does the following:
Transmits the data on the physical medium.
Routes the data locally on the physical network medium. The data link layer uses physical addresses assigned to each physical network device in the local network to route data from one physical device to another.
Receives each packet from the network layer on the sending host and wraps it up in a data frame along with local routing data.
Sends each data frame down to the physical layer to code an electrical or optical signal to transmit the data frame over a wire or over the air (wireless transmission).
On the receiving host, the data link layer unwraps the data frame received to extract the packet and sends it up to the network layer.
Cisco switches are Layer 2 (data link layer) devices.
Cloud Computing Glossary
cloud computing
A networking solution in which everything — from computing power to computing infrastructure, applications, business processes to personal collaboration — is delivered as a service wherever and whenever you need.
Cloud Computing Glossary
cloud service
The delivery of software, infrastructure, or storage that has been packaged so it can be automated and delivered to customers in a consistent and repeatable manner.
Cloud Computing Glossary
deprovision
The release of cloud services that are no longer needed.
Cloud Computing Glossary
federating
Linking distributed resources together over the cloud.
Cloud Computing Glossary
hypervisor
An operating system that acts as a traffic cop, managing the various virtualization tasks in the cloud to ensure that they make things happen in an orderly manner.
Cloud Computing Glossary
multi-tenancy
The sharing of underlying resources by multiple companies over a cloud.
Cloud Computing Glossary
network attached store
Storage that has its own network address through which it is accessed by the network's workstation users. Acronym: NAS
Cloud Computing Glossary
service level agreement
A contract that stipulates the type of service you need from providers and what type of penalties would result from an unexpected business interruption. Acronym: SLA
Cloud Computing Glossary
solution stack
An integrated set of software that provides everything a developer needs to build an application.
Cloud Computing Glossary
storage area network
A storage systems that is flexible and scalable because it's available to multiple hosts at the same time. Acronym: SAN
Cloud Computing Glossary
vertical industry groups
Workgroups comprised of members from a particular industry such as technology and retail.
Cloud Computing Glossary
virtual memory
The portion of your hard drive that Windows uses to expand the available RAM
Cloud Computing Glossary
virtualization
Using computer resources to imitate other computer resources or whole computers to maximize performance and flexibility.
