CCNA 5 – CCNA Study Guide

GNS3 0.7.2 Free

Posted by admin on August 4, 2010 No comments | 2,203 views

GNS3 0.7.2 is released. Here is a list of the changes in this version:

Lot of small fixes (relative paths, link removal, .net loading, Ethernet switch connection to a Cloud etc.)
Qemuwrapper: random MAC address for devices
NPE-G2 option for c7200 routers (need a specific and uncompressed IOS image and C7200-IO-2FE, C7200-IO-GE-E, PA-2FE-TX and PA-GE are unlikely to work)
Simulated switches: daisy chaining support
Improved directory selection for new projects
New translations: Bulgarian, Italian and Ukrainian
Frame Relay capture option for all serial links
Dialog to display an Ethernet switch MAC address table

Cisco Packet Tracer 5.3 Free

Posted by admin on August 4, 2010 1 comment | 5,670 views

Cisco Packet Tracer is a powerful network simulation program that allows students to experiment with network behavior and ask “what if” questions. As an integral part of the Networking Academy comprehensive learning experience, Packet Tracer provides simulation, visualization, authoring, assessment, and collaboration capabilities and facilitates the teaching and learning of complex technology concepts.

Packet Tracer supplements physical equipment in the classroom by allowing students to create a network with an almost unlimited number of devices, encouraging practice, discovery, and troubleshooting. The simulation-based learning environment helps students develop 21st century skills such as decision making, creative and critical thinking, and problem solving.

Border Gateway Protocol (BGP)

Posted by admin on August 4, 2010 No comments | 936 views

Border Gateway Protocol is an exterior gateway protocol, which is different from the interior gateway protocols discussed so far. The distinction is important since the term autonomous system is used somewhat differently with protocols such as EIGRP than it is with BGP. Exterior gateway protocols such as BGP route between autonomous systems, which are assigned a particular AS number. AS numbers can be assigned to an office with one or several BGP routers. The BGP routing table is comprised of destination IP addresses, an associated AS-Path to reach that destination and a next hop router address. The AS-Path is a collection of AS numbers that represent each office involved with routing packets. Contrast that with EIGRP, which uses autonomous systems as well. The difference is their autonomous systems refer to a logical grouping of routers within the same administrative system. An EIGRP network can configure many autonomous systems. They are all managed by the company for defining route summarization, redistribution and filtering. BGP is utilized a lot by Internet Service Providers (ISP) and large enterprise companies that have dual homed internet connections with single or dual routers homed to the same or different Internet Service Providers. BGP will route packets across an ISP network, which is a separate routing domain that is managed by them.

Integrated IS-IS

Posted by admin on August 4, 2010 No comments | 823 views

Integrated Intermediate System – Intermediate System routing protocol is a link state protocol similar to OSPF that is used with large enterprise and ISP customers. An intermediate system is a router and IS-IS is the routing protocol that routes packets between intermediate systems. IS-IS utilizes a link state database and runs the SPF Dijkstra algorithm to select shortest paths routes. Neighbor routers on point to point and point to multipoint links establish adjacencies by sending hello packets and exchanging link state databases. IS-IS routers on broadcast and NBMA networks select a designated router that establishes adjacencies with all neighbor routers on that network. The designated router and each neighbor router will establish an adjacency with all neighbor routers by multicasting link state advertisements to the network itself. That is different from OSPF, which establishes adjacencies between the DR and each neighbor router only. IS-IS uses a hierarchical area structure with level 1 and level 2 router types. Level 1 routers are similar to OSPF intra-area routers, which have no direct connections outside of its area. Level 2 routers comprise the backbone area which connects different areas similar to OSPF area 0. With IS-IS a router can be an L1/L2 router which is like an OSPF area border router (ABR) which has connections with its area and the backbone area. The difference with IS-IS is that the links between routers comprise the area borders and not the router. Each IS-IS router must have an assigned address that is unique for that routing domain. An address format is used which is comprised of an area ID and a system ID. The area ID is the assigned area number and the system ID is a MAC address from one of the router interfaces. There is support for variable length subnet masks, which is standard with all link state protocols. Note that IS-IS assigns the routing process to an interface instead of a network.

Enhanced Interior Gateway Routing Protocol (EIGRP)

Posted by admin on August 4, 2010 No comments | 1,211 views

Enhanced Interior Gateway Routing Protocol is a hybrid routing protocol developed by Cisco systems for routing many protocols across an enterprise Cisco network. It has characteristics of both distance vector routing protocols and link state routing protocols. It is proprietary which requires that you use Cisco routers. EIGRP will route the same protocols that IGRP routes (IP, IPX, Decnet and Appletalk) and use the same composite metrics as IGRP to select a best path destination. As well there is the option to load balance traffic across equal or unequal metric cost paths. Summarization is automatic at a network class address however it can be configured to summarize at subnet boundaries as well. Redistribution between IGRP and EIGRP is automatic as well. There is support for a hop count of 255 and variable length subnet masks.

Interior Gateway Routing Protocol (IGRP)

Posted by admin on August 4, 2010 No comments | 649 views

Interior Gateway Routing Protocol is a distance vector routing protocol developed by Cisco systems for routing multiple protocols across small and medium sized Cisco networks. It is proprietary which requires that you use Cisco routers. This contrasts with IP RIP and IPX RIP, which are designed for multi-vendor networks. IGRP will route IP, IPX, Decnet and AppleTalk which makes it very versatile for clients running many different protocols. It is somewhat more scalable than RIP since it supports a hop count of 100, only advertises every 90 seconds and uses a composite of five different metrics to select a best path destination. Note that since IGRP advertises less frequently, it uses less bandwidth than RIP but converges much slower since it is 90 seconds before IGRP routers are aware of network topology changes. IGRP does recognize assignment of different autonomous systems and automatically summarizes at network class boundaries. As well there is the option to load balance traffic across equal or unequal metric cost paths.

Routing Protocols: IGRP vs EIGRP

Posted by admin on August 4, 2010 No comments | 1,229 views

IGRP, which stands for Internet Gateway Routing Protocol, is a relatively old routing protocol that was invented by Cisco. It has been largely replaced by the newer and more superior Enhanced-IGRP, more commonly known as EIGRP, since 1993. Even in Cisco the Cisco curriculum, IGRP is only discussed as an obsolete protocol as an introduction to EIGRP.

The main reason behind the advent of EIGRP is to move away from classful routing protocols like IGRP because of the rapidly depleting IPv4 addresses. IGRP simply assumes that all elements in a given class belong to the same subnet. EIGRP utilizes variable length subnet masks (VLSM) to make more efficient use of the short supply of IPv4 addresses, prior to the advent of IPv6 .

What is difference RIPv1 & RIPv2

Posted by admin on August 4, 2010 No comments | 752 views

The main difference between RIPv1 and RIPv2 is classless routing. RIPv2 incorporates the addition of the network mask in the update to allow classless routing advertisements. This is extremely important for the flexibility needed to efficiently utilize network assignments for an ever-shrinking pool of IP addresses.

There are other differences, as well. In RIPv2, the destination address for the updates is multicast, instead of broadcast, as in RIPv1. This reduces the burden on the network devices that do not need to listen to RIP updates. With broadcast, every device on the broadcast domain must at least open the IP packet and process the initial information to determine relevance. With multicast addressing, if a device needs that information, it will listen to that specific address. If it does not need the RIP information, it does not have to process the multicast address. The multicast address RIPv2 sends to is 224.0.0.9.

Another addition to RIPv2 is authentication. Authentication is used to ensure that routes being distributed throughout the network are coming from authorized sources.

WildPackets IP Subnet Calculator 3.2.1

Posted by admin on August 1, 2010 1 comment | 1,560 views

The WildPackets IP Subnet Calculator application was designed to be a popular free utility for computing information about IP addresses.

The Address Info Tab displays the class of address and range of addresses for that class, a color-coded bit map for that class of address, the binary representation of that address, and the hexadecimal representation of the address.

The Subnet Info Tab allows you to enter subnet information in five different ways: by number of subnet bits, number of total mask bits, number of subnets, number of hosts, or just the subnet mask in dotted decimal notation. For the information entered, the Calculator generates a color-coded bit map breaking down the network, subnet and host portion, shows you the subnet host address range, the subnet ID and subnet broadcast address.

The Subnet/Hosts Tab generates a table showing the subnet ID, host range of IP addresses, and the subnet broadcast address over a range of user-selectable subnets.

The CIDR (Classless Inter-Domain Routing) Tab is particularly interesting for ISPs or corporations with many Class C addresses as it displays information on supernetting (collecting multiple IP addresses together).
Within the CIDR Tab, you can enter an IP address and the number of supernet bits you wish to use, and the Calculator will display the number of possible supernets and their address allocation range. The route address and supernet masks used are displayed in dotted decimal and dotted hexadecimal notation.

Here are some key features of "WildPackets IP Subnet Calculator":
· Given an IP class A, B or C address, several pieces of information can be displayed about that address by selecting one of four tabs: the Address Info, Subnet Info, Subnet/Hosts or CIDR tab.

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Advanced IP Address Calculator 1.1

Posted by admin on August 1, 2010 No comments | 755 views

The Advanced IP Address Calculator is a freeware Windows 95/98/NT/2000/XP utility that lets you to calculate every aspect of your subnet configuration in a few mouse clicks! It was designed for any network engineer who needs a fast way to determine subnets. Note: Download That periodically updates software info, pricing of Advanced IP Address Calculator from the developer. Please confirm all information before relying on it. Software piracy is theft and impact the entire global economy. Distribution of Advanced IP Address Calculator cracked software is generally an illegal act of copyright infringement. Using crack, password, serial numbers, registration codes, key generators is illegal. We donot support crack software licensing and distribute these releases of Advanced IP Address Calculator.

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