Network+ 11 Flashcards
Hot Standby Router Protocol (HSRP): A Cisco proprietary approach to first-hop redundancy. CARP is an open-standard variant of HSRP. VRRP is an IETF open standard that operates in a similar method to Cisco’s proprietary HSRP. GLBP is another first-hop redundancy protocol that is proprietary to Cisco Systems. With each of these technologies, the MAC address and the IP address of a default gateway can be serviced by more than one router (or multilayer switch). Therefore, if a default gateway becomes unavailable, the other router (or multilayer switch) can take over, still servicing the same MAC and IP addresses. Link Aggregation Control Protocol (LACP), discussed in Lesson 4, enables you to assign multiple physical links to a logical interface, which appears as a single link to a route processor.
HSRP
Full: A backup of all of the data set. Although this is the safest and most comprehensive way to ensure data availability, it can be time consuming and costly.
Incremental: This backs up only data that has changed since the previous backup.
Differential: This is similar to an incremental backup in that it starts with a full backup, and then subsequent backups only contain data that has changed. The difference is that whereas an incremental backup only includes the data that has changed since the previous backup, a differential backup contains all of the data that has changed since the last full backup.
Backups
Quality of service (QoS) is a suite of technologies that allows you to strategically optimize network performance for select traffic types. Jitter is the uneven arrival of packets. Packet drops occur when a link is congested and a router’s interface queue overflows.
Best-effort treatment of traffic does not truly provide QoS to that traffic because there is no reordering of packets. Best effort uses a first-in, first-out (FIFO) queuing strategy, where packets are emptied from a queue in the same order that they entered the queue.
IntServ is often referred to as hard QoS because it can make strict bandwidth reservations. IntServ uses signaling among network devices to provide bandwidth reservations.
DiffServ, as its name suggests, differentiates between multiple traffic flows. Specifically, packets are marked, and routers and switches can then make decisions (for example, dropping or forwarding decisions) based on those markings. Because DiffServ does not make an explicit reservation, it is often called soft QoS.
QoS
Marking alters bits within a frame, cell, or packet to indicate how the network should treat that traffic.
Congestion Management : When a device such as a switch or a router receives traffic faster than it can be transmitted, the device attempts to buffer (or store) the extra traffic until bandwidth becomes available.
Marking Etc …
Policing and Shaping : Instead of making a minimum amount of bandwidth available for specific traffic types, you might want to limit available bandwidth, Policing can be used in either the inbound or the outbound direction, and it typically discards packets that exceed the configured rate limit. Shaping buffers (and therefore delays) traffic exceeding a configured rate. Therefore, shaping is recommended for slower-speed interfaces.
Policing and Shaping
tcpdump is a standard package analyzer that displays all TCP/IP packages and other packets transmitted/received over a network.
A BERT (bit-error rate tester) contains both a pattern generator (which can generate a variety of bit patterns) and an error detector (which is synchronized with the pattern generator and can determine the number of bit errors), and it can calculate a BER for the tested transmission link.
TCPdump
A butt set is a piece of test equipment typically used by telephone technicians. The clips on the butt set can connect a punch-down block (for example, a 66 block or a 110 block) connecting to a telephone. This allows the technician to check a line (for example, to determine whether a dial tone is present on the line or to determine whether a call can be placed from the line).
cable certifier : working with existing cable and want to determine its category, or if you simply want to test the supported frequency range (and therefore data throughput) of a cable.
butt set etc …
cable tester can test the conductors in an Ethernet cable. Notice the two parts that make up the cable tester. By connecting these parts of the cable tester to each end of a cable under test, you can check the wires in the cable for continuity (that is, check to make sure there are no opens, or breaks, in a conductor). In addition, you can verify an RJ-45 connector’s pinouts (that wires are connected to appropriate pins on an RJ-45 connector).
cable tester
use a multimeter to check a variety of a cable’s electrical characteristics. These characteristics include resistance (in ohms), current (in amps), and voltage (in volts). You could use the ohmmeter function of a multimeter (the resistance feature) to check continuity of an Ethernet cable (copper cabling).
protocol analyzer (also known as a network sniffer), You can use a protocol analyzer to capture traffic flowing through a network switch, using the port mirroring feature of a switch. ex : Wireshark.
Wi-Fi Analyzer : check W-Fi signal strengths.
multimeter etc …
A looking-glass server on the Internet allows users to connect to view the routing information from that server’s perspective. These are normally related to Border Gateway Protocol (BGP) routes.
Punch-Down Tool : When terminating wires on a punch-down block (for example, a 110 block), you insert an insulated wire between two contact blades. These blades cut through the insulation and make electrical contact with the inner wire. As a result, you do not have to strip off the insulation.
looking-glass server etc …
