If the Bootstrap program is not able to find a valid IOS image, it will act as ROM Monitor.
The maximum limit is 15 hop counts. Anything higher than 15 indicates that the network is considered unreachable.
Latency is the amount of time delay that measures the point from which a network device receives a data frame to the time it sends it out again towards another network segment.
In Cut-Through LAN switching, as soon as the router receives the data frame, it will immediately send it out again and forward it to the next network segment after reading the destination address.
MTU stands for Maximum Transmission Unit. It refers to the maximum packet size that can be sent out onto the data line without the need to fragment it.
This is Ethernet that makes use of fiber optic cable as the main transmission medium. The 100 stands for 100Mbps, which is the data speed.
FLASH, TFTP Server
It is an authentication service developed at the Massachusetts Institute of Technology. Kerberos uses encryption to prevent intruders from discovering passwords and gaining unauthorized access to files.
The Bootstrap program is responsible for
1.Initializing hardware
2.Finding where IOS program is located and then
3.Loading IOS image
It is an Internet routing protocol that scales well, can route traffic along multiple paths, and uses knowledge of an Internet’s topology to make accurate routing decisions.
It is using a router to answer ARP requests. This will be done when the originating host believes that a destination is local, when in fact is lies beyond router.
It is a very simple protocol used for transmission of IP datagrams across a serial line.
It is a simple protocol used to exchange information between the routers.
It is a sequence of IP addresses identifying the route a datagram must follow. A source route may optionally be included in an IP datagram header.
They read the entire frame and check CRC before forwarding.
The three types of routing tables are fixed, dynamic, and fixed central. The fixed table must be manually modified every time there is a change. A dynamic table changes its information based on network traffic, reducing the amount of manual maintenance. A fixed central table lets a manager modify only one table, which is then read by other devices. The fixed central table reduces the need to update each machine’s table, as with the fixed table. Usually a dynamic table causes the fewest problems for a network administrator, although the table’s contents can change without the administrator being aware of the change.
The HELLO protocol uses time instead of distance to determine optimal routing. It is an alternative to the Routing Information Protocol.
Interior gateways connect LANs of one organization, whereas exterior gateways connect the organization to the outside world.
Type 3 LSA Is used for Inter region communication. For communication with other protocols or external routes, type 4 and 5 will be utilized.
The process in which a network node is carrying more data that can’t be handled on the network, and owing to which loss of packets or information happens on the network node and the receiver can’t receive appropriate information is termed as Network Congestion.
In half-duplex, the transmission of information or communication is from one direction only.
Example: Walkie-talkie
In full-duplex, the transmission of information or communication is from both the directions.
Example: Talking on the telephone.
DNS uses UDP for communication between servers. It is a better choice than TCP because of the improved speed a connectionless protocol offers. Of course, transmission reliability suffers with UDP.
User Mode is used for regular task when using a CISCO router, such as to view system information, connecting to remote devices, and checking the status of the router. On the other hand, privileged mode includes all options that are available for User Mode, plus more. You can use this mode in order to make configurations on the router, including making tests and debugging.
The Application Layer supports the communication components of an application and provides network services to application processes that span beyond the OSI reference model specifications. It also synchronizes applications on the server and client.
BootP is a protocol that is used to boot diskless workstations that are connected to the network. It is short for Boot Program. Diskless workstations also use BootP in order to determine its own IP address as well as the IP address of the server PC.
A resource record is an entry in a name server’s database. There are several types of resource records used, including name-to-address resolution information. Resource records are maintained as ASCII files.
Switch: A Switch is used to receive the signal to create a frame. It forwards the packets between various LAN segments. It is the platform for packet control when the data is sent at a Data Link layer or Network layer of the OSI model. It supports a single broadcast domain and multiple collision domains.
Routers: Router is defined as a networking gateway device that is used to forward data packets to the computer networks. A router is connected by at least a single LAN with its IP address or with LAN or WAN. A router supports two broadcast domains.
Hub: In the hub, if anything comes in its port then it sends it out to the others. It is less expensive and the least complicated. It has a single collision domain and a single broadcast domain.
Switch is used to receive the signal to create a frame. It forwards the packets between various LAN segments. It supports packet control when the data is sent to the Data Link layer or Network layer of the OSI model.
While sending packets, the signal gets enabled and can be accessed by reading the destination address and forwards the frame to the appropriate frame, hence we use switches.
The four router types are:
* Autonomous System Boundary Routers = An OSPF Router which advertises exterior routes into the OSPF Domain.
* Internal Routers = An OSPF Router whose all interfaces belong to the same area.
* Area Border Routers = An OSPF Router which has interfaces in more than one area
* Backbone Routers = An OSPF Router which is inside the Router in Area 0
Basically, there are 7 layers of the OSI model. Each layer has its own functionality in the OSI model.
They are:
* Layer 1 – Physical
* Layer 2 – Data Link Layer
* Layer 3 – Network
* Layer 4 – Transport
* Layer 5 – Session
* Layer 6 – Presentation
* Layer 7- Application
Some of the steps required are:
* State Request (LSR) packets, Link State, inform (LSU) packets.
* Two-way announcement
* Database Synchronization which means a switch of Database Description packets, Link
* After Database synchronization is complete, the two Routers are measured as adjacent.
Some of them are:
* Equal Cost Routes management: CEF Load corresponding
* Protocol Type of OSPF: Link State
* Transport: IP (Port89) submit to network walks website
* Metric of OSPF: Cost (Bandwidth)
* Standard: RFC2328 (OSPFv2), RFC2740 (OSPFv3/IPv6)
OSPF Router ID should not be misused after the OSPF method is started and the OSPF neighborships are recognized. If we change the OSPF Router ID, we need to either refill the IOS or use “#clear IP OSPF process authority for changed RID to take effect.
OSI is a reference model that tells how information and data are communicated over a network. It is a conceptual framework that understands the relationships of transmission.
BOOTP sends a UDP message with a subnetwork broadcast address and waits for a reply from a server that gives it the IP address. The same message might contain the name of the machine that has the boot files on it. If the boot image location is not specified, the workstation sends another UDP message to query the server.
External Data Representation is a method of encoding data within an RPC message, used to ensure that the data is not system-dependent.
The Mount protocol returns a file handle and the name of the file system in which a requested file resides. The message is sent to the client from the server after reception of aclient’s request.
A pseudo tty or false terminal enables external machines to connect through Telnet or rlogin. Without a pseudo tty, no connection can take place.
Anonymous FTP enables users to connect to a host without using a valid login and password. Usually, anonymous FTP uses a login called anonymous or guest, with the password usually requesting the user’s ID for tracking purposes only. Anonymous FTP is used to enable a large number of users to access files on the host without having to go to the trouble of setting up logins for them all. Anonymous FTP systems usually have strict controls over the areas an anonymous user can access.
A Management Information Base is part of every SNMP-managed device. Each SNMP agent has the MIB database that contains information about the device’s status, its performance, connections, and configuration. The MIB is queried by SNMP.
A TCB is a complex data structure that contains a considerable amount of information about each connection.
RIP relies on the number of hops in order to determine the best route to a network. On the other hand, IGRP takes consideration many factors before it decides the best route to take, such as bandwidth, reliability, MTU and hop count.
The LLC sublayer stands for Logical Link Control. It can provide optional services to an application developer. One option is to provide flow control to the Network layer by using stop/start codes. The LLC can also provide error correction.
CISCO Catalyst 5000 uses the Store-and-forward switching method. It stores the entire frame to its buffers and performs a CRC check before deciding whether or not to forward that data frame.
Not really. What a bridge actually does is to take the large network and filter it, without changing the size of the network.
A Window refers to the number of segments that are allowed to be sent from source to destination before an acknowledgment is sent back.
Network congestion occurs when too many users are trying to use the same bandwidth. This is especially true in big networks that do not resort to network segmentation.
When a switch receives a signal, it creates a frame out of the bits that were from that signal. With this process, it gains access and reads the destination address, after which it forwards that frame to the appropriate port. This is a very efficient means of data transmission, instead of broadcasting it on all ports.
The job of the Data Link layer is to check messages are sent to the right device. Another function of this layer is framing.
Routing is the process of finding a path on which data can pass from source to destination. Routing is done by a device called routers, which are network layer devices.