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Showing posts from December, 2011

Difference between TCP and UDP

1-TCP converts upper layer data in to segments and the segments are numbered and sequenced so that the destination TCP can place them in the same order, and can easily detect a missing segment. But in UDP data is broken in to segments and the segments are numbered but not sequenced. 2-TCP is connection oriented because it creates a virtual circuit between the source and destination before sending data. But UDP does not create any virtual circuit before sending data. 3-TCP uses acknowledgement to resent missing segments, but there is no acknowledgement in UDP. 4-So we can say TCP provide reliable communication but UDP provides unreliable communication. 5-Since TCP is creating virtual circuits, TCP is costly in terms of bandwidth. But UDP has low overhead

Difference between Router-Switch-Hub-Bridge

Hubs work at the Physical layer. A hub is a totally dumb device. If it gets a data signal, it just forwards the signal to all devices. It cannot do any kind of filtering or addressing. Performance is not so good because a hub can't establish a direct connection from one computer to another. If a switch gets a data packet, it will try and find the destination device, and then send it to that device only, i.e. it establishes a point-to-point connection between the sending and receiving devices. But the devices must be on the same subnet. A switch won’t send data packet to computers on different subnets. A switch breaks up collision domains but it does not break up broadcast domains unless we use VLANs. Like Switches, Bridges operate at the Data Link layer and filter packets based on the MAC address. Generally bridges are used to extend the distance capabilities of the network while minimizing overall traffic, and switches are used mainly fo...

CCNA Quiz 2

1 . Which of the following describes the function of a WAN? connects peripherals in a single location. connects multiple networks in a single building. provides connectivity on a LAN. provides connectivity over a large geographic area. 2 . An internetwork must include which of the following? (Choose three.) switching. static addressing. IETF standardization. dynamic or static routing. consistent end-to-end addressing. 3 . Which of the following devices are used in the construction of a WAN? (Choose three.) hubs. routers. communication servers. transceivers. modems. multi-port repeaters. 4 . During the initial configuration of a 2600 series Cisco router, which cable is required for connecting a PC to the console port? twisted. crossover. rollover. straight. 5 . Which of the following layers of the OSI model are incorporated in WAN standards? (Choose two.) physical layer. application layer. transport layer. data link layer. session...

Internship in Networking

IT Internee required for Maple Pharma-Karachi with knowledge of Computer Hardware and Networking. Email CVs at fahad.memon@maplepharma.com

Youngest MCP Aarifa Karim Hospitalised

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 Arfa Karim Fights For Life After a Heart Attack Arfa Karim, 16, who became world’s youngest Microsoft Certified Professional in 2004 is suffering from a serious medical condition after a heart attack on December 28, 2011. She’s still not in senses and her condition is further deteriorating. Doctors say they are doing their best but there aren’t much hopes as the condition is really critical and she’s still on machines. Her father has appealed for the prayers. She was an asset not only to her family and Pakistan, but also to the world. P.S media coverage isn’t allowed by the family right now, that’s why you won’t find updates on media probably.

NOC Manager

NOC Manager : 1-3 years related exp. Please email your resumes to mariam.sharif@peoplelogic.com.pk. Mention the position title in the subject line.

Saudi Arabia ll Huawei Access NOC expert ll Min 4 years experience

Hi LCC Saudi Arabia is currently looking for Huawei Access NOC expert. Below is the job description: Monitoring the operations of SDH and GPON Huawei networks Having experienc of monitoring from NMS (iManager T2000) and Netviewer Provide technical Support to the Front Office and FME Solid knowledge of Huawei GPON and OSN products Analyzing and rectification of of Alarms  Working in shifts 24 x 7   Dont send CVs if you dont have above relevant experience. Send resumes at saad_jamal@lcc.com

Core Network Engineer (IP-MPLS) || Saudi Arabia

Dear all We are looking for candidate engineers with the following skills and experience. Function:  Core Network Engineer. Location:  Saudi Arabia In-depth knowledge of network switching and routing protocols and other technologies:   OSPF .   BGP .   IS-IS   MPLS and TE.   VPN (layer2, and 3),Metro Ethernet, Q-in-Q, and GRE .   Layer 2 and Layer 3 switching   Bridging, VLANs , Trunking, and Spanning Tree,   Ethernet Technologies, Link aggregation,   DHCP , NAT, NTP , VRRP , SNMP , and DNS .   Multicasting .   VLSM , Route Summarization , Policy based routing, Route Filtering, and Redistribution   Quality of Service.   High Availability and failover technologies.   Network Security, Firewalls, IPSec , and IPS .   IPv6.   Good experience in EMS and NMS .   Shall able to translate HLD into LLD,able to develop Network Implementation Plan (NIP),Network Ready for Use ( NRFU ), Network Migra...

Hardware Engineer Required In Faisalabad

A Textile firm in Faisalabad  need a person who has the knowledge about Computer Hardware. mail: umerusman62@yahoo.com

Customer Support Executive

We at TRG are looking for Customer Support Executives. Qualification: BE/BCS, excellent communication skills in Urdu; ability to multi-task; Flexible in working 9 hours within the 24 hours. Location Karachi. Send your CV’s to hiring@trgworld.com and CC aziz.rehman@trgworld.com

Network/Hardware Administrator

Hello, We currently require the services of a network/hardware administrator, who will incorporate the following features into our network: 1. Endpoint security - security appliances/software must be installed and managed from a centralised location (sort of a gateway), intercepting any and all viruses, malware, remote hacking attempts e.g. denial of service, patching vulnerabilities, Intrusion detection, auditing etc for all traffic going in and out of the system, in addition to monitoring individual hardware devices on the network for the introduction of these security vulnerabilities. Everything going in or out must be visible, with reports. 2. Hardening the wifi network - modems and routers must be optimally configured such that hacking attempts are extremely difficult, preference would be given to an approach where the network does not even broadcast its' signature. 3. Hardening the Operating systems - patches, firewalls, turning off unnecessary services, file sharin...

Junior Network Support Engineer

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System and Database administrator,

candidate must having good knowledge of SAP basis administration and 2 - 3 years of experience. Interested candidates please send your profiles on sikandarrizvi@cbl.com.p

Assistant System Administrator

URGENTLY looking for Assistant System Administrator for our company located in Islamabad. Candidates having Bachelors degree in CS along with additional certifications in networking (Preferably CCNA) and minimum 1 year relevant experience can apply at recruitment.ebiz@gmail.com or saad_majeed@ymail.com

Lecture 4: Network Cabling and Tools

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3 Types of Ethernet cable are used in Networking 1-Straight through Cable 2-Cross Over Cable 3-Roll over cable Straight through cable, Cross over Cables are used for data transfer While Rollover cable is used to configure routers / switches / network devices. To remember which type of cable you should use, follow these tips:  To connect two serial interfaces of 2 routers we use serial cable .   To specify when we use crossover cable or straight-through cable, we should remember: Group 1: Router, Host, Server Group 2: Hub, Switch One device in group 1 + One device in group 2: use straight-through cable Two devices in the same group: use crossover cable For example: we use straight-through cable to connect switch to router, switch to host, hub to host, hub to server… and we use crossover cable to connect switch to switch, switch to hub, router to router, host to host HOW TO MAKE A NETWORK CABLE: 1. Unroll the required length of network cable and add a little extr...