Virtual channel is normally a connection from one source to one destination, although multicast connections are also permitted. The other name for virtual channel is virtual circuit.
v A Default Route (also known as the gateway of last resort) is a special type of static route.
v Where a static route specifies a path a router should use to reach a specific destination, a default route specifies a path the router should use if it doesn’t know how to reach the destination.
v Default Route is the network route used by a router
when there is no other known route exists for a given IP datagram’s destination address.
All the IP datagrams with unknown destination address are sent to the default route.
It is because UDP is un-sequenced and unreliable. It is not capable of creating virtual circuits and acknowledgments.
ARP is Address Resolution Protocol which is used to map an IP address to a physical machine.
RARP is Reverse Address Resolution Protocol which is used to map MAC address to the IP address.
Private IP: It is used within the local LAN.
Public IP: It is used across the Internet.
OSPF uses the Dijkstra straight Path First algorithm to decide the shortest path and Link-State Advertisements.
The few types of LSA are:
* External LSA
* Network LSA
* ASBR Summary LSA
* Network summary LSA
* Router LSA
A data packet consists of sender’s information, recipient’s information, and the data contained. It also has the numeric identification number that defines the packet number and order. When data is sent across the network, that information is segmented into data packets. In short, data packets carry the information and routing configuration for your transferred message.
It is a problem that can ruin TCP performance. This problem occurs when data are passed to the sending TCP entity in large blocks, but an interactive application on the receiving side reads 1 byte at a time.
The most common two letter combinations are called as digrams. e.g. th, in, er, re and an. The most common three letter combinations are called as trigrams. e.g. the, ing, and, and ion.
1.Interface Mode(Router physical interface configuration mode):-
2.Sub Interface Mode(Router sub-interface configuration mode):-
3.Line Mode(Router line configuration mode – console, vty etc):-
4.Router Configuration Mode(Routing protocols configuration mode):-
1.User Mode; 2.Privilege Mode; 3.Global Configuration Mode;
Each Mode has access to different set of IOS commands.
A. erase running-config
B. erase startup-config
C. erase NVRAM
D. delete NVRAM
Correct Answer: B. erase startup-config
It is the protocol the routers in neighboring autonomous systems use to identify the set of networks that can be reached within or via each autonomous system.
This may happen when the hold-down timer has already expired, or when the router received a processing task that incidentally was proportional to the number of links in the internetwork.
Logical Topology refers to the signal path through the physical topology. Physical Topology is the actual layout of the network medium.
The hostname and the Interfaces. The hostname is the name of your router. The Interfaces are fixed configurations that refer to the router ports.
For a network administration, segmenting a network would help ease network traffic and ensures that high bandwidth is made available at all times for all users. This translates to better performance, especially for a growing network.
There are actually five types of passwords that can be used. These enable secret, virtual terminal, console, and auxiliary.
From a data transmitter’s point of reference, data from the end user is converted to segments. Segments are then passed on to the other layers and converted into packets or datagrams. These packets are then converted into frames before passing on to the network interface. Finally, frames are converted to bits prior to actual data transmission.
It is a collection of routers under the control of a single administrative authority and that uses a common Interior Gateway Protocol.
It is a protocol used to advertise the set of networks that can be reached with in an autonomous system. BGP enables this information to be shared with the autonomous system. This is newer than EGP (Exterior Gateway Protocol).
It is a protocol formerly
used to exchange routing information between Internet core routers.
It is a set of rules defining a very simple virtual terminal interaction. The NVT is used in the start of a Telnet session.
It is a host that has a multiple network interfaces and that requires multiple IP addressesis called as a Multi-homed Host.
Route Poisoning is the process of inserting a table entry of 16 to a route, making it unreachable. This technique is used in order to prevent problems caused by inconsistent updates on a route.
– allows full duplex data transmission and reception
– media rate adaption
– easy and efficient migration
Packets are the results of data encapsulation. These are data that have been wrapped under the different protocols of the OSI layers. Packets are also referred to as datagrams.
Hold-downs prevent regular update messages from reinstating a downed link by removing that link from update messages. It uses triggered updates to reset the hold-down timer.
Bandwidth refers to the transmission capacity of a medium. It is a measure of how much volume a transmission channel can handle, and it is measured in Kbps.
1. It is a One to Many communication.
2. In Multicast, the sender transmit only one copy of data and it is delivered and/or processed to many devices who are interested in that traffic(Not as delivered and processed by all devices as in Broadcast).
3. Devices which are interested in a particular Multicast traffic must join to that Multicast group to receive the traffic.
4. IP Multicast Groups are identified by Multicast IP Addresses (IPv4 Class D Addresses)
HDLC stands for High-Level Data Link Control protocol. It is a propriety protocol of CISCO. It is the default encapsulation operated within CISCO routers.
To access privileged mode, you enter the command “enable” on the prompt. In order to get back to user mode, enter the command “disable.”
It can be done in three possible ways:
– using Dotted-decimal. For example: 192.168.0.1
– using Binary. For example: 10000010.00111011.01110010.01110011
– using Hexadecimal. For example: 82 1E 10 A1
– routed protocols that is configured on the router.
– the address assigned on each interface.
– the encapsulation method that was configured on each interface.
In cases when you need to configure a router remotely, the most convenient is to use the Cisco AutoInstall Procedure. However, the router must be connected to the WAN or LAN through one of the interfaces.
The five OSPF packet types are:
An OSPF adjacency is a theoretical link to a neighbour over which Link State Advertisements can be sent.
OSPF must send recognition of each newly conventional LSA. LSAs are retransmitted until they are approved. The link-state retransmit-interval defines the time among retransmissions. We can utilize the command IP OSPF retransmit-interval to place the retransmit-interval.
BDR and DR solve two problems in OSPF:
* Excessive LSA flooding
* High No. of Adjacencies
The advantages of using OSPF summarization are:
* OSPF Summarization reduces numeral of update messages
* OSPF Summarization minimizes the quantity of information stored in routing tables
* OSPF Summarization reduces the weight on Router processor and recollection resources
* OSPF Summarization reduces the bandwidth practice
Presentation layer supports many standards, which ensures that data is presented correctly. These include PICT, TIFF, and JPEG for graphics, MIDI, MPEG and QuickTime for Video/Audio.
It’s because UDP is unreliable and unsequenced. It is not capable of establishing virtual circuits and acknowledgments.
1. It is a One to One Communication.
2. Unicast is a type of communication, where there is only one sender & one receiver.
1) Browsing a website. (Webserver is the sender and your computer is the receiver.)
2) Downloading a file from a FTP Server. (FTP Server is the sender and your computer is the receiver.)
A layered network offers many advantages. It allows administrators to make changes in one layer without the need to make changes in the other layers. Specialization is encouraged, allowing the network industry to make progress faster. A layered model also lets administrators troubleshoot problems more efficiently.
Subnetting is the process of creating smaller networks from a big parent network. As a part of a network, each subnet is assigned some additional parameters or identifier to indicate its subnet number.
VLANs allow the creation of collision domains by groups other than just physical location. Using VLANs, it is possible to establish networks by different means, such as by function, type of hardware, protocol, among others. This is a big advantage when compared to conventional LANs wherein collision domains are always tied to physical location.
There are two types of IPX access lists
Standard Access List can only filter the source or destination IP address. An Extended Access List uses the source and destination IP addresses, port, socket, and protocol when filtering a network.
The initial thing to do is to enable IPX routing by using the “IPX routing” command. Each interface that is used in the IPX network is then configured with a network number and encapsulation method.
Frame Relay is a WAN protocol that provides connection-oriented communication by creating and maintaining virtual circuits. It has a high-performance rating and operates at the Data Link and Physical Layers.