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Definition
| controls the flow of network traffic using policies and delineates broadcast domains by performing routing functions between virtual LANs (VLANs) defined at the access layer |
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Definition
| allow you to segment the traffic on a switch into separate subnetworks. |
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| where the distribution layer and core layer are combined into one layer. |
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Definition
| the number of devices that a packet has to cross before it reaches its destination. Keeping it low ensures low and predictable latency between devices. |
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Definition
| allows multiple switch port links to be combined so as to achieve higher throughput between switches. |
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Definition
| Cisco's proprietary link aggregation technology which allows multiple Ethernet links to be consolidated |
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| the process of combining voice and video communications on a data network |
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Definition
| the process of measuring the bandwidth usage on a network and analyzing the data for the purpose of performance tuning, capacity planning, and making hardware improvement decisions. |
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Definition
| the process of identifying various groupings of users and their impact on network performance. |
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Definition
| typically come with different sized chassis that allow for the installation of different numbers of modular line cards. |
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Definition
| allows you to interconnect up to nine switches using fully redundant backplane connections. |
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Definition
| the number of ports available on a single switch |
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Definition
| allows the switch to decide how many or what specific devices are allowed to connect to the switch |
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Definition
| notifies the other devices of a collision, so that they invoke a backoff algorithm. This backoff algorithm causes all devices to stop transmitting for a random amount of time, which allows the collision signals to subside. |
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Definition
| the integrated circuits and the accompanying machine programming that allows the data paths through the switch to be controlled. |
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Definition
| The network area where frames originate and collide is |
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Term
| store and forward switching |
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Definition
| when the switch receives the frame, it stores the data in buffers until the complete frame has been received. During the storage process, the switch analyzes the frame for information about its destination. |
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Term
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Definition
| the switch acts upon the data as soon as it is received, even if the transmission is not complete. The switch buffers just enough of the frame to read the destination MAC address so that it can determine to which port to forward the data |
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Term
| fast-forward cut-through switching |
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Definition
| immediately forwards a packet after reading the destination address. |
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Term
| fragment free cut-through switching |
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Definition
| the switch stores the first 64 bytes of the frame before forwarding. Can be viewed as a compromise between store-and-forward switching and cut-through switching. |
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Definition
| provides switched connections between ports with the same bandwidth, such as all 100 Mb/s ports or all 1000 Mb/s ports |
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Definition
| provides switched connections between ports of unlike bandwidth, such as a combination of 10 Mb/s, 100 Mb/s, and 1000 Mb/s ports. |
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Term
| Port-based memory buffering |
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Definition
| frames are stored in queues that are linked to specific incoming and outgoing ports. A frame is transmitted to the outgoing port only when all the frames ahead of it in the queue have been successfully transmitted. |
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Term
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Definition
| deposits all frames into a common memory buffer that all the ports on the switch share. The amount of buffer memory required by a port is dynamically allocated. The frames in the buffer are linked dynamically to the destination port. |
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Definition
| interface configuration command in the CLI to enable the automatic medium-dependent interface crossover (auto-MDIX) feature. |
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Definition
| allows you to see how well your network withstands attacks from intruders. |
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Definition
| When the number of secure MAC addresses reaches the limit allowed on the port, packets with unknown source addresses are dropped until you remove a sufficient number of secure MAC addresses or increase the number of maximum allowable addresses. You are not notified that a security violation has occurred |
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Term
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Definition
| When the number of secure MAC addresses reaches the limit allowed on the port, packets with unknown source addresses are dropped until you remove a sufficient number of secure MAC addresses or increase the number of maximum allowable addresses. In this mode, you are notified that a security violation has occurred. |
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Term
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Definition
| In this mode, a port security violation causes the interface to immediately become error-disabled and turns off the port LED. It also sends an SNMP trap, logs a syslog message, and increments the violation counter. |
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Term
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Definition
| allows a network administrator to create groups of logically networked devices that act as if they are on their own independent network, even if they share a common infrastructure with other VLANs. |
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Term
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Definition
| a VLAN that is configured to carry only user-generated traffic |
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Term
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Definition
| any VLAN you configure to access the management capabilities of a switch. |
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Term
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Definition
| assigned to an 802.1Q trunk port. An 802.1Q trunk port supports traffic coming from many VLANs (tagged traffic) as well as traffic that does not come from a VLAN (untagged traffic). |
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Term
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Definition
| Communicating with a device in the same VLAN |
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Term
| Switch Virtual Interface (SVI) |
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Definition
| a logical interface configured for a specific VLAN. You need to configure an ______ for a VLAN if you want to route between VLANs or to provide IP host connectivity to the switch. |
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Term
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Definition
| a point-to-point link between two network devices that carries more than one VLAN. Allows you to extend the VLANs across an entire network. |
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Term
| 802.1Q encapsulation header |
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Definition
| This header adds a tag to the original Ethernet frame specifying the VLAN to which the frame belongs. |
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Term
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Definition
| increases network available bandwidth by restricting flooded traffic to those trunk links that the traffic must use to reach the destination devices. |
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Term
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Definition
| occurs when there are so many broadcast frames caught in a Layer 2 loop that all available bandwidth is consumed. |
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Term
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Definition
| ensures that there is only one logical path between all destinations on the network by intentionally blocking redundant paths that could cause a loop. |
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Term
| Spanning Tree Algorithm (STA) |
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Definition
| used by STP to determine which switch ports on a network need to be configured for blocking to prevent loops from occurring. |
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Term
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Definition
| the message frame exchanged by switches for STP |
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Term
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Definition
| Switch ports closest to the root bridge |
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Term
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Definition
| All non-root ports that are still permitted to forward traffic on the network |
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Term
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Definition
| All ports configured to be in a blocking state to prevent loops. |
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Term
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Definition
| serves as a reference point for all spanning-tree calculations to determine which redundant paths to block. |
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Term
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Definition
| the sum of all the port costs along the path to the root bridge |
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Term
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Definition
| a customizable value that you can use to influence which switch becomes the root bridge |
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Term
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Definition
| contains the ID of the VLAN with which the BPDU is associated. |
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Term
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Definition
| exists on non-root bridges and is the switch port with the best path to the root bridge. Used to forward traffic toward the root bridge. Only one is allowed per bridge. |
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Term
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Definition
| exists on root and non-root bridges. For root bridges, all switch ports are these. For non-root bridges, a __________ is the switch port that receives and forwards frames toward the root bridge as needed. Only one is allowed per segment. |
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Term
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Definition
the time between each BPDU frame that is sent on a port.
This is equal to 2 seconds by default, but can be tuned to be between 1 and 10 seconds. |
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Term
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Definition
| the time spent in the listening and learning state.
This is by default equal to 15 seconds |
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Term
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Definition
| controls the maximum length of time a switch port saves configuration BPDU information.
This is 20 seconds by default |
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Term
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Definition
| the largest diameter that STP permits because of convergence times |
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Term
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Definition
| When a switch port configured with ________ is configured as an access port, that port transitions from blocking to forwarding state immediately, bypassing the typical STP listening and learning states. |
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Term
| Per-VLAN spanning tree protocol (PVST) |
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Definition
| Maintains a spanning-tree instance for each VLAN configured in the network. It uses the Cisco proprietary ISL trunking protocol that allows a VLAN trunk to be forwarding for some VLANs while blocking for other VLANs. |
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Term
| Rapid spanning tree protocol (RSTP) |
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Definition
| First introduced in 1982 as an evolution of STP (802.1D standard). It provides faster spanning-tree convergence after a topology change. |
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Term
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Definition
| Enables multiple VLANs to be mapped to the same spanning-tree instance, reducing the number of instances needed to support a large number of VLANs. It is an evolution of STP and RSTP. Provides for multiple forwarding paths for data traffic and enables load balancing. |
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Term
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Definition
| a switch port that is never intended to be connected to another switch device. It immediately transitions to the forwarding state when enabled. |
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Term
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Definition
| defines the ultimate purpose of a switch port and how it handles data frames. |
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Term
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Definition
| created when an interface is assigned to a VLAN and is removed when the last interface is moved to another VLAN. |
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Term
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Definition
| disables a PortFast-configured port or interface if the port or interface receives a BPDU |
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Term
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Definition
| a type of router configuration in which a single physical interface routes traffic between multiple VLANs on a network. |
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Term
| multiple input/multiple output (MIMO) |
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Definition
| splits a high data-rate stream into multiple lower rate streams and broadcasts them simultaneously over the available radios and antennae. This allows for a theoretical maximum data rate of 248 Mb/s using two streams. |
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Term
| Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) |
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Definition
| devices on a WLAN must sense the medium for energy (RF stimulation above a certain threshold) and wait until the medium is free before sending. If an access point receives data from a client station, it sends an acknowledgement to the client that the data has been received. This acknowledgement keeps the client from assuming that a collision occurred and prevents a data retransmission by the client. |
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Term
shared service set identifier
(SSID) |
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Definition
| a unique identifier that client devices use to distinguish between multiple wireless networks in the same vicinity. |
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Term
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Definition
| Wireless networks can operate without access points |
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Term
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Definition
| Frames used by the WLAN network to advertise its presence. |
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Term
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Definition
| Frames used by WLAN clients to find their networks |
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Term
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Definition
| The process for establishing the data link between an access point and a WLAN client. |
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Term
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Definition
| Find "Open" networks; use them to gain free Internet access
driving around a neighborhood with a laptop looking for wlan's to exploit |
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Term
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Definition
| Exploit weak privacy measures to view sensitive WLAN information and even break into WLANs |
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Term
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Definition
| Plug consumer-grade APs/gateways into company Ethernet ports to create their own WLANs |
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Term
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Definition
| an access point placed on a WLAN that is used to interfere with normal network operation |
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