N10-007.2 Flashcards
Trunk
In the context of an Ethernet network, this is a single physical or logical connection that simultaneously carries traffic for multiple VLANs. However, a trunk also refers to an interconnection between telephone switches, in the context of telephony.
Root Port
In an STP topology, every nonroot bridge has a single root port, which is the port on that switch that is closest to the root bridge, in terms of cost.
Supplicant
In a network using 802.1X user authentication, a supplicant is the device that wants to gain access to a network.
carrier-sense multiple access/collision detection (CSMA/CD)
Used on an Ethernet network to help prevent a collision from occurring and to recover if a collision does occur. CSMA/CD is only needed on half-duplex connections.
VLAN
A single broadcast domain, representing a single subnet. Typically, a group of ports on a switch is assigned to a single VLAN. For traffic to travel between two VLANs, that traffic needs to be routed.
Power over Ethernet (PoE)
Defined by the IEEE 802.3af and 802.3at standards, PoE allows an Ethernet switch to provide power to an attached device (for example, a wireless access point, security camera, or IP phone) by applying power to the same wires in a UTP cable that are used to transmit and receive data.
Designated Port
In an STP topology, every network segment has a single designated port, which is the port on that segment that is closest to the root bridge, in terms of cost. Therefore, all ports on a root bridge are designated ports.
Link Aggregation
As defined by the IEEE 802.3ad standard, link aggregation allows multiple physical connections to be logically bundled into a single logical connection.
Spanning Tree Protocol (STP)
Defined by the IEEE 802.1D standard, STP allows a network to have redundant Layer 2 connections while logically preventing a loop, which could lead to symptoms such as broadcast storms and MAC address table corruption.
Nondesignated Port
In STP terms, nondesignated ports block traffic to create a loop-free topology.
Full-Duplex
This connection allows a device to simultaneously transmit and receive data.
Authenticator
In a network using 802.1X user authentication, an authenticator forwards a supplicant’s authentication request on to an authentication server. After the authentication server authenticates the supplicant, the authenticator receives a key that is used to communicate securely during a session with the supplicant.
Default Gateway
The IP address of a router (or multilayer switch) to which a networked device sends traffic destined for a subnet other than the device’s local subnet.
Multicast
A multicast communication flow is a one-to-many flow.
Anycast
An anycast communication flow is a one-to-nearest (from the perspective of a router’s routing table) flow.
Variable-length subnet masking (VLSM)
The process of assigning various subnetwork IDs in the network to issue the appropriate number of IP addresses.
Extended Unique Identifier-64 (EUI-64)
A method in IPv6 to calculate a unique host address portion for a node using the MAC address of a device.
Neighbor Discovery
Any process whereby network elements can discover each other on the network. In the case of EIGRP, hello packets are used, for example.
Slash Notation/Prefix Notation
A method of indicating how many bits are in a subnet mask. For example, /24 is slash notation for a 24-bit subnet mask. Slash notation is also known as prefix notation.
Dual Stack
The ability of a network interface to run multiple protocols, such as IP and IPv6.
Automatic Private IP Addressing (APIPA)
Allows a networked device to self-assign an IP address from the 169.254.0.0/16 network. Note that this address is only usable on the device’s local subnet (meaning that the IP address is not routable)
Classless Interdomain Routing (CIDR)
Shortens a classful subnet mask by removing right-justified 1s from a classful mask. As a result, CIDR allows contiguous classful networks to be aggregated. This process is sometimes called route aggregation.
Block Size
The number of IP addresses in a subnet, including the subnet’s address and the subnet’s directed broadcast address.
Unicast
A unicast communication flow is a one-to-one flow.
Tunneling
Transmitting traffic with additional encapsulation.
Link-Local IP Address
A link-local IP address is a nonroutable IP address usable only on a local subnet.
Zeroconf
A technology that performs three basic functions: assigning link-local IP addresses, resolving computer names to IP addresses, and locating network services.
Loopback
A loopback interface on a network device is a logical (virtual) interface that is often used for testing purposes.
Enhanced Interior Gateway Routing Protocol (EIGRP)
A Cisco proprietary protocol. Although EIGRP is popular in Cisco-only networks, it is less popular in mixed-vendor networks. Like OSPF, EIGRP is an IGP with very fast convergence and high scalability. EIGRP is considered to be an advanced distance vector or a hybrid routing protocol.
Interior Gateway Protocol (IGP)
A routing protocol that operates within an autonomous system, which is a network under a single administrative control. OSPF and EIGRP are popular examples of IGPs.
Dynamic NAT (DNAT)
A variant of NAT in which inside local addresses are automatically assigned an inside global address from a pool of available addresses.
Routed Protocol
A protocol with an addressing scheme (for example, IP) that defines different network addresses.
Split Horizon
This feature of a distance-vector routing protocol prevents a route learned on one interface from being advertised back out of that same interface.
Routing Information Protocol (RIP)
A distance-vector routing protocol that uses a metric of hop count. The maximum number of hops between two routers in an RIP-based network is 15. Therefore, a hop count of 16 is considered to be infinite. RIP is considered to be an IGP.
Intermediate System-to-Intermediate System (IS-IS)
A link-state routing protocol similar in its operation to OSPF. IS-IS uses a configurable-yet-dimensionless metric associated with an interface and runs Dijkstra’s shortest path first algorithm. Although using IS-IS as an IGP offers the scalability, fast convergence, and vendor-interoperability benefits of OSPF, it has not been deployed as widely as OSPF.
