Posts with #cisco technology - it news tag
DHCP, Dynamic Host Control Protocol, is a Protocol that operates at Application layer and automatically assigns IP Addresses to requesting Hosts. DHCP eliminates the manual task by a network Administrator. It also provides a central database of devices that are connected to the network and eliminate duplicate resource assignments. DHCP uses UDP (User Datagram Protocol) to send its request messages to the DHCP Server on Port number 67.
A DHCP Server can provide to a host alot of information when the host is requesting an IP address from a DHCP Server. Here's a list of the information a DHCP Server can provide:
- IP Address
- Subnet Mask
- Domain Name
- Default Gateway (routers)
- WINS information
How DHCP Server is Discovered by Client to get IP address?
The client broadcasts messages on the physical subnet to discover available DHCP servers. Network administrators can configure a local router to forward DHCP packets to a DHCP server from a different subnet. This client-implementation creates a User Datagram Protocol (UDP) packet with the broadcast destination of 255.255.255.255 or the specific subnet broadcast address. Addresses in the Packet for DHCP Server Discovery can be as follows;
Source IP = 0.0.0.0
Source Port = 0
Destination IP = 255.255.255.255
Destination Pot = 67
A DHCP client can also request its last-known IP address. If the client remains connected to a network for which the IP is valid, the server may grant the request.
When a DHCP server receives an IP lease request from a client, it reserves an IP address for the client and extends an IP lease offer by sending a DHCPOFFER message to the client. This message contains the client's MAC address, the IP address that the server is offering, the subnet mask, the lease duration, and the IP address of the DHCP server making the offer. Source and Destination addresses in the server’s DHCP Offer message are as follows;
Source IP = 192.168.1.1
Source Port = 67
Destination IP = 255.255.255.255
Destination Pot = 68
A client can receive DHCP offers from multiple servers, but it will accept only one DHCP offer and broadcast a DHCP request message. Based on the Transaction ID field in the request, servers are informed whose offer the client has accepted. When other DHCP servers receive this message, they withdraw any offers that they might have made to the client and return the offered address to the pool of available addresses. The DHCP request message is broadcast, instead of being unicast to a particular DHCP server, because the DHCP client has still not received an IP address. Also, this way one message can let all other DHCP servers know that another server will be supplying the IP address without missing any of the servers with a series of unicast messages.
Upon Receiving DHCP acknowledgment message on server, server sends IP Address, lease duration and other info to the client that requrested, and IP address Assignment process to the client by DHCP Server is completed.
More related: How to Configure DHCP on a Cisco ASA 5505?
Cisco OnPlus Service is offered at a list price of $250, which includes an OnPlus Network Agent appliance.
Expanding on its offerings to small business partners, networking specialist Cisco announced a cloud-based service called OnPlus that offers channel partners a way to provide network assessment, management and advisory services to their small business customers. By enabling value-added resellers (VARs) to create or expand their managed services practice, OnPlus aims to help to evolve the customer relationship from reactive and tactical to more proactive and strategic.
OnPlus Service is offered at a list price of $250, which includes a three-year subscription to the OnPlus service and an OnPlus Network Agent appliance. A separate appliance and subscription service is required for each network being managed. Native applications for Apple and Android mobile devices are available free of charge in the Apple App Store and the Android Market.
The announcement builds on Cisco's Partner Led sales model designed to elevate channel partners' ability to drive sales in the small business and midmarket segments. Earlier this year, Cisco announced it would invest $75 million in its Partner Led initiative throughout 2012, for enablement, systems and support capabilities to help channel partners profitably grow their business.
OnPlus is designed for VARs that are looking to create or expand their managed service offerings, providing remote visibility of the network and the devices attached to the network, through a scalable cloud-based service, OnPlus helps VARs deploy advanced network services for their small business customers from anywhere at any time. To monitor a customer network, VARs plug the OnPlus Network Agent appliance into a switch or router on their customer's network. The OnPlus Agent then transmits information about the customer's network to a secure data center for access by the VAR.
In addition to discovery and monitoring of anything with an IP address from any supplier, OnPlus enables remote connectivity to manageable network devices to facilitate troubleshooting and configuration. For select Cisco devices, OnPlus provides enhanced capabilities that automate typical administrative tasks. In addition, the network-centric capability of OnPlus complements existing classes of managed services tools such as remote monitoring and management and professional services automation.
"Liberty Technology focuses on making technology easy for both consumers and businesses. With Cisco OnPlus, you're able to get a more complete, 360-degree picture of your customer's network," said Ben Johnson, president of Liberty Technology, a Cisco certified partner. “We've used OnPlus in a number of scenarios from doing network surveys to quickly troubleshooting and identifying problems with customer's networks, which has greatly saved us time and of course money."
More Related: If you need to know more details of Cisco OnPlus, you can visit: http://blog.router-switch.com/2011/12/cisco-onplus-cloud-based-managed-services-launched-aimed-at-smbs/
Cisco steps back from close partner VMware to help firms build a private cloud using Microsoft Hyper-V and VMware ESX Server, plus Cisco blades By Charles Babcock from InformationWeek
Cisco Systems Tuesday took a step back from its close cloud partner VMware, and launched CloudVerse, a set of integrated components to allow enterprises to build out private clouds running multiple hypervisors.
CloudVerse manages a combined set of pooled resources--including virtualized networking and storage as well as virtual servers--to create a highly automated cloud operation in the enterprise data center.
One of CloudVerse's components, Intelligent Automation for the Cloud, is a new software management system for the private cloud. That cloud can include Microsoft's Hyper-V, Red Hat's KVM, and IBM or HP hypervisors for their AIX or HPUX environments, respectively, as well as VMware's ESX Server, said Lew Tucker, Cisco CTO for cloud computing, in an interview.
Cisco calls CloudVerse a "framework" rather than a new product. It takes software components contributed by Tidal Software and newScale, both recent acquisitions, and puts them together in the Intelligent Automation for the Cloud product. The software components work with Cisco blades and networking to provide an automated operations environment for virtual servers.
CloudVerse's automated end user server provisioning depends on a service catalog and self-service portal engineered by newScale, which Cisco acquired for an undisclosed amount in April. It acquired Tidal Software in May 2009 for $105 million and its software provides insight into what resources an application was using. That helps when it comes to provisioning end user servers and rightsizing their resources.
An end user who needs applications on a new server in the enterprise "should get them out of a service catalogue, like downloads to the iPhone," said Tucker, who is the former head of cloud computing at Sun Microsystems. The future private cloud will account for 50% of enterprise data center computing by 2014, Tucker added. He based the statement on Cisco's first annual study of network traffic, the Cisco Cloud Index, which forecasts a rapid uptake in private cloud computing. Cisco is trying to get into a position, similar to IBM, HP, and Dell, where it's one of the primary hosts of those future workloads.
Cisco, for example, is already a close partner of VMware in the production of VCE integrated cloud server racks. VCE is a manufacturing consortium formed by Cisco and EMC, with VMware and Intel providing additional investment. VCE-integrated units, built with Cisco blades, EMC storage, and VMware virtualization, have gone into several prominent cloud data centers, including the New York Stock Exchange's Mahway, N.J., data center and SunGard's six cloud data centers.
But the VCE consortium's units are for cloud service suppliers. To reach private cloud builders, Cisco wanted an integration approach that included hypervisors in addition to VMware's, hence its CloudVerse approach. As usual, Cisco comes at the problem from the networking side. "The network used to terminate at the server," pointed out Tucker. "With CloudVerse, the network continues through the server port, goes through the Nexus 1000V switch, and terminates at the virtual server."
CloudVerse works with Cisco's Unified Computing System blades and Cisco networking, along with another new software component, Cisco Network Services Manager, to deploy virtualized assets. Network Services Manager handles the virtualized network side of a cloud deployment, making sure the virtual server has the correct amount of network bandwidth and network security. That makes it a competitor with HP's CloudSystem Matrix and Dell's Virtual Integrated System.
One of the strengths of Cisco's UCS is its ability to offload converged network and storage traffic from virtual machines through the Nexus 1000V switch to its nearby network switching fabric. That allows smoother I/O for multiple virtual machines on a single host.
In 2012, Cisco will offer ASR 1000 and 9000 Series routers, which will allow virtual machine administrators to identify workloads and move them between the enterprise data center and the cloud--or different cloud data centers. That will be enabled though another CloudVerse software component, Cloud-to-Cloud Connect, Tucker said.
In effect, Cisco is trying to pave the route to future hybrid cloud computing by offering its CloudVerse integration framework today, with some elements, like the ASR routers, still to come. Early adopters of the CloudVerse approach include Silicon Valley Bank, Orange Business Services, Verizon Terremark, Telstra, Fujitsu, Telstra, and ACS, a Xerox company.
The first Cisco study of cloud network traffic, as reported in its cloud index, projected that global cloud traffic will grow more than 12 times its current level by 2015, to 1.6 zettabytes a year. That's equivalent to four days of "business class" video for every person on Earth, the cloud index report said. One zettabyte is a billion terabytes. In 2009, the Internet was estimated to contain one half zettabyte of information, according to Wikipedia.
TheInfoPro study finds Cisco and Juniper down, Check Point and Palo Alto up in firewall popularity contest
In the security popularity contest of the moment, Cisco and Juniper are down and Palo Alto Networks and Check Point are up when it comes to network firewalls, according to one research firm.
Research firm TheInfoPro asked 182 IT security professionals -- said to hail from the Fortune 1000 companies -- about what security products they're using, what they're considering changing and where their priorities and budgets are for next year. In summing up the results, which TheInfoPro treats much like an enterprise security popularity meter, Palo Alto Networks has jumped over the past year from less than 1% in its poll to 4%.
Though still top dog overall, Cisco, which two years ago had 55% of the hearts of the IT security managers in the poll, is now down to 40%, losing ground in network firewalls mainly to Check Point, now at 39%, and Palo Alto at 4%, with Juniper Networks at 11%. Other firewall vendors used by the enterprises include SonicWall, McAfee, Fortinet, WatchGuard, open source, Nortel, Nokia, Citrix and CA.
According to Daniel Kennedy, research director for information security and networking at TheInfoPro, a division of 451 Group, "it's the application tracking" that's the big lure in today's firewall choices, and Palo Alto Networks, though only just beyond the startup phase with its application-aware firewall with this focus, is showing a clear pull in popularity.
Palo Alto was named the "most exciting vendor" in the poll the research firm did for this study; FireEye came in second with its anti-botnet products, even though anti-botnet products per se were not rated to be very high on the list of immediate plans by the respondents.
According to TheInfoPro report, entitled "Information Security Wave 14," about 37% of the poll respondents expect to see an increased security budget in 2012, with most others saying spending is expected to stay at current levels.
Sourcefire and McAfee are reportedly the "top vendors respondents will spend more with in 2011." Data-loss prevention was considered a priority, and there Symantec led the pack. In its assessment of what security vendors are the "most vulnerable" to the possible loss of their existing customers, Fortinet topped the list.
When it comes to endpoint anti-malware (antivirus/anti-spam) protection in the enterprises of those security managers polled, Symantec wins the favor of 39%, McAfee 34%, Trend Micro is at 15%, Sophos at 5%, with the remainder a collection of several "others." Although Russia-based anti-malware firm Kaspersky Lab has been working hard to break into the enterprise market in a big way, Kennedy said he sees no evidence that this has yet happened in the North American market.
Kennedy says researchers at TheInfoPro also discussed the topic of virtualization with the 182 IT security professionals, asking if they were concerned about it from a security point of view. He says many seem to be "up in the air" about decisions in this regard. "I'd say it's confused," says Kennedy. "They want to use their existing security in virtualized environments. Sometimes this seems to apply, other times not." He said many seem to be sorting out what to do, particularly in the terms of any anticipated cloud-security development.
Cisco's home Wi-Fi unit will keep its own brand but stop making devices as it creates a domestic super-router
Cisco Systems' Home Networking Business Unit will keep both its Linksys brand and its place in the parent company as Cisco pares down its business, but the unit is also sharpening its focus.
Linksys has stopped making devices that connect to networks and is strictly focused on the networks themselves, said Brett Wingo, general manager of the business unit, in an interview last week. Like Cisco itself, which discontinued the Flip video camera and the Umi consumer telepresence product earlier this year, the home networking unit is going back to what it's best known for: wireless routers.
However, those routers are taking on a larger role at the center of consumers' use of multimedia, particularly video, Wingo said. Users want to watch video from a variety of sources and on many different devices, but many home networks can't effectively link all those components, he said.
"What consumers want is, they want this problem solved," Wingo said.
Linksys routers are designed to deliver the best quality possible by detecting all the devices connected to a home wireless network, determining what their capabilities are for playing different types of content, and making sure the network is secure. The routers also can tell where the wireless signal is strong enough to deliver what's desired, Wingo said.
But Cisco wants those routers to take on an even bigger role, serving as the main meeting place between the home network and the Internet or service-provider network. Rather than have carrier gateway boxes, Internet-connected thermostats, smart TVs and other devices all linking to the outside world on their own, consumers can have one box that handles many connectivity functions.
Routers are "sitting idle and not doing things a lot of the time, and you can have them do more and you can run more services on them," Wingo said. "The hardware that's capable of moving video around the house or displaying software onto a screen ... those types of things can be done in the router in a lot of cases."
Through industry standards, Cisco plans to make its routers into hubs for devices from all vendors, so consumers aren't locked into just buying Linksys, he said.
Cisco has a strong faith in IEEE 802.11n wireless to deliver video around a home. In fact, it expects wireless to win out over all other types of home networks, partly because so many consumer electronics devices are equipped with wireless technologies. However, Linksys routers do include provisions for incorporating wired technologies such as powerline and coaxial cable.
What allows Cisco to become the center of home networks is the company's expertise in video across service provider, enterprise and home networks, Wingo said. The engineering teams at Linksys and Cisco's enterprise businesses now pass ideas back and forth, he said. It brings intelligence from that experience into the software in Linksys wireless routers, which are more than just routers or access points but video processing devices that can do part of the work of delivering video appropriately to TVs, tablets and other devices, Wingo said.
Some of these intelligent routers will be delivered and managed by service providers. But part of Cisco's strategy involves changing the way consumers buy home networking gear in stores. Routers and other gear are often sold on price, and consumers end up with networks and consumer electronics that don't work well together, Wingo said. The problems can be complex, involving wireless bandwidth, processor performance and broadband speed, but failures often just end in frustration.
Cisco thinks it can solve consumers' problems in one trip to the store and simultaneously rise above the price wars. It won't do this by building the Linksys or Cisco equivalent of Apple stores, but will instead train sales staff at retailers such as Best Buy, Wingo said. Sales representatives should start asking about a shopper's home network as soon as they start shopping for anything that might need the network, such as a game console, he said.
It shouldn't be too hard for Cisco to make its Linksys routers into the central device in a home network, even with multiple vendors' equipment, said Parks Associates analyst Kurt Scherf. But the key to doing so will be selling them as gateways through service providers, he said.
"Consumers are much more happy to allow their service providers to be the IT manager," Scherf said. "You will still buy products off the shelf and connect them to a home network, but gateways will be doing the managing and monitoring."
Scherf applauded Cisco's strategy of helping train retailers to sell networks and networked products, which he said was a key to the success of Linksys before it was acquired by Cisco in 2003.
But he wasn't so quick to dismiss wired networks in homes, citing the wide variety of types of homes and infrastructure around the world. "I don't think you can say that one networking technology is going to win," Scherf said.
Notes: More news and info about Cisco, Internet, Networking and IT, etc., you can visit http://blog.router-switch.com/
Cisco provides a network that can securely and reliably handle all types of traffic, throughout the entire network, over virtually any media, while providing consistent service delivery to all users.
Cisco is proud of being a recognized worldwide leader in networking. Now, when the technology industry is going through a period of dramatic change, it remains the market leader in multiple areas, such as routing and switching, unified communications, mobility, and security. The company helped catalyze the industry's move toward IP, and, now that it is fully under way, Cisco is at the center of fundamental changes in the way the world communicates.
Innovation, something indispensable, helps Cisco and famous companies win customers’ praise. And this reputation is caused in part by the Cisco development strategy of "build, partner, and acquire." Beyond corporate innovation, Cisco also helps to shape innovation throughout the industry by actively participating in virtually every group concerned with networking standards.
To be simple, as a company whose own success depends on its network systems, Cisco fully understands this relationship. In today's environment of mergers, acquisitions, and global expansion, businesses now require network systems that enable technology innovation and business-critical services not only at the headquarters, but across geographically disparate corporate campuses, throughout the branches, and out to remote workers. Cisco can provide an end-to-end network, composed of systems specifically designed to address the unique needs of each place in the network, connected by a common infrastructure and a common operating system and manageable from a central location as a single, cohesive entity.
Because Cisco envisions the network as a whole, it designs and develops products, technologies, and solutions that provide business benefits across the entire network. Consider, for example, the enablement of advanced technologies. Advanced technologies, such as voice over IP (VoIP), require the support of intelligent network services. Although many networking vendors support these services, the level and methods of support often vary from one device to another and from one place in the network to another, making configuration and interoperation difficult. With Cisco network systems, intelligent network services, such as quality of service (QoS) and encryption, are consistently supported and preserved across the entire network, enabling the same secure and high-quality service delivery regardless of whether the user is at headquarters or in a local branch.
Cisco applies this same broad view to network management, providing tools to manage the network as a whole. For example, the Cisco integrated services routers use 802.1ag to provide end-to-end service manageability. Another example is the Cisco Network Application Analysis (NAPA) Solution, which also takes a holistic approach to management, providing an end-to-end view as it monitors and analyzes the entire network to optimize the relationship between application performance and network resources.
Moreover, Cisco understands the relationship between all elements of the network: that an improvement in management or security capabilities can often mean a decrease in performance. Cisco is constantly looking for innovative ways to eliminate these types of tradeoffs. One such innovation is the Cisco Catalyst 6500 Supervisor Engine 32 Programmable Intelligent Services Accelerator (PISA), which eliminates the tradeoff by providing hardware acceleration of intelligent services, such as stateful application intelligence and day-zero security services, at multigigabit speeds.
In most cases, the network of a company or organization is not a single island. It is likely made up of multiple networks, including one or more campuses, some number of branches, remote teleworkers, and one or more data centers, all connected through a WAN or MAN. These businesses and organizations require solutions that work across the entire network, throughout all "places in the network."
Cisco understands and addresses the unique requirements of each place in the network:
• Campus: Market factors are causing a shift in corporate structures. Reduced time to market translates to a greater need for interaction throughout a company. And as these companies become more adept and more dependent on technologies for this interaction, the network must provide a platform that enables and promotes enhanced communication and collaboration.
Cisco provides a platform designed for collaboration with the Campus Communication Fabric, which enables application proficiency, secure multimedia communications, improved productivity and innovation, business continuity, and efficient operations over a flexible infrastructure.
• Branch/WAN: Historically, branch users have not been given the same priority as users at headquarters, enduring less-than-optimal response times, receiving a subset of services, and experiencing downtimes that are not tolerated at headquarters. But this is changing. Because of the increased number of acquisitions and mergers, along with the focus on local presence and global expansion, remote office workers have gained significant importance in the equation for business success. Today's branch users require the same consistent delivery of services and applications as headquarters users.
Cisco gives branch users an equal status with the Empowered Branch, which integrates the widest set of services and applications while optimizing their interoperability and performance for a consistent branch experience. At the WAN headend, Cisco offers services aggregation solutions that combine virtualized services integration, bandwidth optimization, and application intelligence to provide secure, intelligent routing of applications across the enterprise WAN.
• Data center: The rapid proliferation of new applications combined with the increased complexity of these applications mean that IT managers require data center architectures that are more resilient, more adaptable, more manageable, and capable of serving users across geographically dispersed locations.
Cisco data center solutions are built on the principles of consolidation, virtualization, and automation to provide the security, availability, manageability, and optimized application delivery that enable superior service delivery and application performance.
Network Systems Components You Need to Know
When you look closer into each of these network systems, you find components that are industry leaders in their own right. Cisco provides one of the most robust, intelligent lines of integrated services routers, along with one of the most comprehensive, feature-rich portfolios of network switches.
Cisco routers allow organizations to build a foundation for an intelligent, self-defending network, featuring best-in-class security services and routing technologies for a low total cost of ownership and a high return on investment. These routers offer:
For the branch, Cisco provides a portfolio of routers designed for secure wire-speed delivery of concurrent wireless, data, voice, and video services with superior investment protection. Cisco integrated services routers embed security, mobility, LAN switching, and voice services inside the router as a single resilient system for ease of deployment, simplified management, and lower operating costs. They also support leading-edge WAN technologies, such as:
In addition to convenience, the Cisco integrated services routers provide investment protection. The integrated design enables a 70 percent reduction in operational expenses when compared to deploying multiple overlaid components in a branch to achieve the same services. Additionally, the modular design of the Cisco integrated services routers allows for easy integration of new services as well as the expansion of existing ones.
At the headend, Cisco offers an extensive WAN and MAN aggregation platform portfolio, which also provides a comprehensive set of highly secure, concurrent, and integrated services. Cisco services aggregation routers provide exceptional performance with aggregation speeds of up to 2 Mpps and support for as many as 16,000 Point-to-Point Protocol (PPP) sessions and 5000 VPN sessions per chassis. For optimization, these routers also support Network-Based Application Recognition for application optimization and OER. To help ensure the security of your network, these routers include support for IP Security (IPsec) encryption, an integrated stateful firewall, and support for identity-based access control.
Cisco offers a comprehensive portfolio of intelligent network switches, with a continuously expanding suite of intelligent services and advanced technologies to strengthen, simplify, and extend the value of the network infrastructure. As a leader in switching technology innovation, Cisco is constantly developing new ways to enable its customers to get more from their network infrastructure. Many Cisco innovations have evolved into industry standards, including Cisco EtherChannel (now the 802.3AD standard), Power over Ethernet (now the 802.3af standard), Multiple Instance Spanning Tree (now the 802.1s standard), and Interswitch Link (now the 802.1q standard).
Cisco Catalyst switches are based on a superior design that employs a centralized architecture, which simplifies expansion and upgrades. They also use application-specific integrated circuit (ASIC) technology, which is better suited than merchant silicon (used by many other switch vendors) for the delivery of advanced features.
Additionally, Cisco Catalyst switches provide:
• Superior service delivery from the wiring closet to the core, from the data center to the WAN edge with 10/100/1000 to the desktop, Fast Ethernet through 10 Gigabit Ethernet connections, and predictable wire-rate switching performance (even with QoS enabled)
• High level of availability with In-Service Software Upgrade (ISSU) and hot-swappable modules, which enable easy upgrades without service interruption, and nonstop forwarding with stateful switchover (NSF/SSO), which reduces the mean time to repair (MTTR) by allowing extremely fast supervisor switchover that is virtually transparent
• Exceptional scalability through options such as virtualization, which provides for the centralization of services and security policies while preserving the high-availability, manageability, security, and scalability benefits of the existing campus design (centralized management and security), and Power over Ethernet, which simplifies the addition of new endpoints
• Superior security with integrated support for identity-based access control and Cisco Catalyst integrated security features, as well as Cisco firewall and intrusion detection modules
For your business growth and success, this network should be a Cisco network. When you join the intelligent, resilient routing offered by the Cisco routing portfolio with the innovative high-performance switching offered by Cisco Catalyst switches; connect them through reliable, scalable Cisco IOS Software innovation; and manage them with the automated, integrated management offered by the Cisco network management portfolio, the result is a highly available, adaptable infrastructure that delivers secure, pervasive services through a cohesive network platform upon which you can deploy technology solutions that address today's business challenges and enable tomorrow's business success.
Having Cisco network systems throughout your network helps to accelerate deployment of new technologies, reduce the learning curve in your IT staff, protect the integrity of your network and the data that crosses it, and enables your users to achieve higher levels of productivity and responsiveness.
Add to this Cisco industry leadership, financial stability, commitment to innovation, and dedication to customers, and it is clear that Cisco is an excellent choice for your network systems: yesterday, today, and tomorrow.
Right, interview is so common for us, but the more important is some famous companies' special interview. If you need to finish a interview like CISCO'S, how will you answer these questions as follows:
1) What are the names of your technical round interviewers
2) Do you know my name?
3) Tell me about yourself, your family background... so on..
4) What are you looking for in Cisco” or what attracts you or why do you want to join cisco.
5) Tell me a situation/ issue where you identified a problem on your own, and drove to resolve it.
6) Tell about most difficult team project u have worked on.
7) What type of work environment is suitable and which environment you hate/is frustrating?
8) Tell about the mistake you learned from
9) Tell about accomplishment you are proud of...
10) what have you learnt in 4 years of your BTech.
11) Give an example of biggest/most demanding team leading or you have talked about something to a group like given a presentation or seminar etc..
12) Describe a situation where you and your partner/professor had a conflicting view, but you were still able to get across your point or how did u get around obstacles that prevented you from completing the task/project.
13) Tell a situation in which you took the lead without being asked to do so and why? or you saw some opportunity which came suddenly and how did u react? or you found some your results or your work which were not up to the mark, what did u do to rectify? or done more than what was required? Or situations in which you found the job could be done much easier and others weren’t following it..? Or did some job which doesn’t come under your job role/description but was beneficial?
14) Tell me about your values in your life.
15) Tell us what you know about our company.
16) Tell me some of your strengths and weaknesses..
17) Interested in doing MS?
Cisco IOS software is installed in the manageable Cisco switches for better LAN management. It delivers network services and enabled networked applications. The Cisco IOS has a command line interface that helps users to execute the Cisco IOS commands.
Cisco Switch Commands
The Cisco switch IOS has different EXEC modes with distinctive prompts. These modes execute different Cisco switch commands. Each mode has a set of specific commands.
The fundamentals of the Cisco IOS User Interface are as follows:
- Uses a command line interface
- Operations vary on different series of switches
- Type or paste entries in the console command modes
- Enter key instructs device to parse and execute the commands
- Two primary EXEC modes are user mode and privileged mode
- Command modes have distinctive prompts
Cisco IOS Software Exec
There are two main EXEC modes for entering the Cisco switch commands:
- Limited switch examination
- Command prompt on the switch is switch
- Detailed switch examination
- Enables configuration and debugging
- Prerequisites for other configuration modes
- Command prompt on the router is switches#
Cisco Telnet Commands
There are two primary ways to access a Cisco manageable switch to use command line interface.
- Out of band Console connection
- Via Ethernet through Telnet
Telnet is a utility used for remotely logging into a device. To telnet a Cisco IOS switch from a computer, type the following command on the CMD computer’s terminal:
Telnet IP address of the switch
Just like: Telnet 192.168.0.253
Cisco Catalyst 1900 Switch Commands
The following are some basic Cisco Catalyst 1900 switch commands:
- Show running-config: This command displays the memory status of the Cisco Catalyst 1900 switch
- Show interfaces: This command displays detailed information about all the interfaces of Cisco Catalyst 1900 switch.
- Show interfaces Ethernet 0/1: This command displays detailed information about a specific 10baseT Ethernet interface of the Cisco Catalyst 1900 switch
- Show interfaces Fast Ethernet 0/26: This command displays the detailed information about a specific 100baseT Fast Ethernet interface of the Cisco Catalyst 1900 switch
- Show ip: This command displays the ip configuration of the Cisco Catalyst 1900 switch
- Show Mac-address-table: This command displays the Mac addresses of the devices that are currently connected to the Cisco Catalyst 1900 switch.
- Show Mac-address-table security: This command displays the address table size and the addressing security of each interface of the Cisco Catalyst 1900 switch.
- Show VLAN: This command displays the status of current VLANs enabled on the Cisco Catalyst 1900 switch.
- Show VLAN-membership: This command displays the VLAN membership of all the ports on the Cisco Catalyst 1900 switch.
- Show Spantree 1: This command displays the complete information about the spanning tree protocol 1 that is enabled by default on the Cisco Catalyst 1900 switch.
- Copy nvram tftp: //host/dst_file: This command sends the configuration to a TFTP server.
- Copy tftp: //host/src_file nvram: This command downloads the configuration from a TFTP server.
- Delete nvram: This command resets the system configuration to factory defaults.
Show Cisco Switch Commands
Here are some show commands of Cisco switches:
- Show version: This command displays the hardware and software status of the Cisco switch
- Show flash: This command displays the files and directories in the flash of the Cisco switch
- Show interfaces: This command displays the detailed information about all the interfaces of the Cisco switch
- Show interfaces fast Ethernet 0/x: This command displays the detailed information about the specific interface of the Cisco switch
- Show interfaces VLAN 1: This command displays the ip address configuration of VLAN 1
- Show running-config: This command displays the status of RAM
- Show startup-config: This command displays the status of NVRAM
- Show-mac-address-table: This command displays the MAC address of the devices that are directly connected to any switch port.
- Show port-security: [interface] [address]: This command displays the port security options on the interface
- Show history: This command displays the last ten commands that are executed in the switch configuration
- Show line: This command is used to view the brief information about all the Cisco switch lines
- Show line console 0: This command is used to view the detailed information about the specific line of the Cisco switch
- Erase startup-config: This command is used to erase the nvram of the Cisco switch
Cisco Switch Configuration Commands
- Configure terminal: This command is used to enter the global configuration mode of the Cisco switch
- Hostname: This command assigns the Cisco switch’s hostname
- Enable password: This command sets the enable password of the Cisco switch
- Enable secret: This command sets the encrypted password of the Cisco switch that is used for entering into the privileged mode
- Interface VLAN 1: This is a global configuration command used to configure the VLAN interface of the Cisco switch
- Interface fast Ethernet 0/x: This command configures the specific interface of the Cisco switch
- IP address: This command configures the ip address of any interface of the Cisco switch
- IP default-gateway: This is an interface configuration command to set the default gateway
- Speed: This command sets the speed for the interface of the Cisco switch
- Duplex: This command sets the duplex setting for the interface of the Cisco switch
- Line console 0: This command is used to enter in the specific line configuration mode of the Cisco switch
- Password: This command sets the password of any line of the Cisco switch
Upgrading IOS on Cisco routers and network switches is highly recommendable because of the following reasons
Patch critical vulnerabilities: Just like any other network device or application, Cisco routers and switches are also prone to security holes. And because routers and switches are critical to network infrastructure, you should plug these security holes as soon as possible.
Incorporate new features: Unless an update is simply a bug fix, every new release of the Cisco IOS includes new features. Upgrading your routers and switches in a timely manner means you’ll have more features to potentially make your job easier.
Stay current: “Staying current” with the latest IOS may sound like a flimsy justification to upgrade, especially when you consider your daily task list. However, when you consider the many different tools that communicate with the router’s IOS, staying current can take on a new importance. For example, if you’re using a SNMP network management tool, it may require your router to run a certain version of the IOS.
Things You'll Need
Microsoft Windows 7 computer with telnet client and TFTP service installed
IP address of the Microsoft Windows 7 computer
Cisco router with telnet service enabled
IP address of the Cisco router
Cisco IOS image located in the TFTP service root directory
Password for the Cisco router telnet connection
Privilege Exec mode password for the Cisco router
Steps to upgrade IOS on Cisco router
1. Click the "Globe" button, then select the "Search" box, and then type "cmd." Right-click on the command line icon that appears and click "Run as Administrator." The command line window will appear.
2. Enter "telnet x.x.x.x," on the command prompt, replacing the "x.x.x.x" with the IP address of a Cisco router, and then press the "Enter" key. Telnet will then connect to the Cisco router.
3. Enter the telnet password when requested on the command prompt, and then tap the "Enter" key.
4. Enter "enable" on the command prompt, and tap the "Enter" key. Type the Privilege Exec password for the Cisco router when requested, and press the "Enter" key.
5. Enter the "copy tftp flash" command on the command prompt, and then tap the "Enter" key.
6. Enter the IP address of the Windows 7 computer on the command line as the IP address of the TFTP server from which to copy the new IOS image, and then tap the "Enter" key.
7. Enter the exact name of the IOS file on the command prompt when requested, and then tap the "Enter" key.
8. Enter the name of the IOS file as the destination file name and tap the "Enter" key.
9. Type "Y" when the "Erase flash: before copying? [confirm]" message appears, and press the "Enter" key. The new IOS file will then be copied to the router flash drive.
10. Enter "configure terminal" on the command line, and then tap the "Enter" key.
11. Type "no boot system" and press the "Enter" key. Then type "boot system flash:ios_filename," except replace the "ios_filename" with the exact name of the IOS file that was just transferred to the Cisco router, and then tap the "Enter" key.
12. Type the "exit" command at the command prompt and tap the "Enter" key, and then type "write memory" and tap the "Enter" key.
13. Enter the "reload" command on the command prompt, and then press the "Enter" key. The Cisco router will restart and boot into the new IOS.
What is a Network Protocol?
A protocol is a set of rules that governs the communications between computers on a network. These rules include guidelines that regulate the following characteristics of a network: access method, allowed physical topologies, types of cabling, and speed of data transfer.
Types of Network Protocols
The most common network protocols are:
- Local Talk
- Token Ring
The follow is some common-used network symbols to draw different kinds of network protocols.
The Ethernet protocol is by far the most widely used. Ethernet uses an access method called CSMA/CD (Carrier Sense Multiple Access/Collision Detection). This is a system where each computer listens to the cable before sending anything through the network. If the network is clear, the computer will transmit. If some other node is already transmitting on the cable, the computer will wait and try again when the line is clear. Sometimes, two computers attempt to transmit at the same instant. When this happens a collision occurs. Each computer then backs off and waits a random amount of time before attempting to retransmit. With this access method, it is normal to have collisions. However, the delay caused by collisions and retransmitting is very small and does not normally affect the speed of transmission on the network.
The Ethernet protocol allows for linear bus, star, or tree topologies. Data can be transmitted over wireless access points, twisted pair, coaxial, or fiber optic cable at a speed of 10 Mbps up to 1000 Mbps.
To allow for an increased speed of transmission, the Ethernet protocol has developed a new standard that supports 100 Mbps. This is commonly called Fast Ethernet. Fast Ethernet requires the use of different, more expensive network concentrators/hubs and network interface cards. In addition, category 5 twisted pair or fiber optic cable is necessary. Fast Ethernet is becoming common in schools that have been recently wired.
Local Talk is a network protocol that was developed by Apple Computer, Inc. for Macintosh computers. The method used by Local Talk is called CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance). It is similar to CSMA/CD except that a computer signals its intent to transmit before it actually does so. Local Talk adapters and special twisted pair cable can be used to connect a series of computers through the serial port. The Macintosh operating system allows the establishment of a peer-to-peer network without the need for additional software. With the addition of the server version of AppleShare software, a client/server network can be established.
The Local Talk protocol allows for linear bus, star, or tree topologies using twisted pair cable. A primary disadvantage of Local Talk is speed. Its speed of transmission is only 230 Kbps.
The Token Ring protocol was developed by IBM in the mid-1980s. The access method used involves token-passing. In Token Ring, the computers are connected so that the signal travels around the network from one computer to another in a logical ring. A single electronic token moves around the ring from one computer to the next. If a computer does not have information to transmit, it simply passes the token on to the next workstation. If a computer wishes to transmit and receives an empty token, it attaches data to the token. The token then proceeds around the ring until it comes to the computer for which the data is meant. At this point, the data is captured by the receiving computer. The Token Ring protocol requires a star-wired ring using twisted pair or fiber optic cable. It can operate at transmission speeds of 4 Mbps or 16 Mbps. Due to the increasing popularity of Ethernet, the use of Token Ring in school environments has decreased.
Fiber Distributed Data Interface (FDDI) is a network protocol that is used primarily to interconnect two or more local area networks, often over large distances. The access method used by FDDI involves token-passing. FDDI uses a dual ring physical topology. Transmission normally occurs on one of the rings; however, if a break occurs, the system keeps information moving by automatically using portions of the second ring to create a new complete ring. A major advantage of FDDI is speed. It operates over fiber optic cable at 100 Mbps.
Asynchronous Transfer Mode (ATM) is a network protocol that transmits data at a speed of 155 Mbps and higher. ATM works by transmitting all data in small packets of a fixed size; whereas, other protocols transfer variable length packets. ATM supports a variety of media such as video, CD-quality audio, and imaging. ATM employs a star topology, which can work with fiber optic as well as twisted pair cable.
ATM is most often used to interconnect two or more local area networks. It is also frequently used by Internet Service Providers to utilize high-speed access to the Internet for their clients. As ATM technology becomes more cost-effective, it will provide another solution for constructing faster local area networks.
The most recent development in the Ethernet standard is a protocol that has a transmission speed of 1 Gbps. Gigabit Ethernet is primarily used for backbones on a network at this time. In the future, it will probably be used for workstation and server connections also. It can be used with both fiber optic cabling and copper. The 1000BaseTX, the copper cable used for Gigabit Ethernet, is expected to become the formal standard in 1999.
Compare the Network Protocols
Twisted Pair, Coaxial, Fiber
Linear Bus, Star, Tree
Twisted Pair, Fiber
Linear Bus or Star
4 Mbps - 16 Mbps
Twisted Pair, Fiber
Linear Bus, Star, Tree
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