Archive for ‘ Routing ’

Calculating VLSM subnetworks 23 June 2008 at 12:43 pm by admin
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Bitmindframes cisco study guides.

Calculating VLSMs

Scenario: Your company has been given the network address 172.16.32.0/19.

10101100 . 00010000 . 001 00000 . 00000000

After careful planning, looking at current needs and expansion, you realize you need a maximum of three subnets of 1,000 hosts, three subnets of 250 hosts, and several subnets for serial point-to-point links.

There are several ways to do this, but you have decided that you will variably subnet your network as follows: (We did it this way just for the exercise and to keep it somewhat simple.)

Step 1 : The maximum number of hosts any of your subnets will need is 1,000, so you decide to make the initial subnets 172.16.32.0/22. Write out the eight /22 subnets in binary and decimal form:

1. 10101100 . 00010000 . 001 000 00 . 00000000 172.16.32.0/22

2. 10101100 . 00010000 . 001 001 00 . 00000000 172.16.36.0/22

3. 10101100 . 00010000 . 001 010 00 . 00000000 172.16.40.0/22

4. 10101100 . 00010000 . 001 011 00 . 00000000 172.16.44.0/22

5. 10101100 . 00010000 . 001 100 00 . 00000000 172.16.48.0/22

6. 10101100 . 00010000 . 001 101 00 . 00000000 172.16.52.0/22

7. 10101100 . 00010000 . 001 110 00 . 00000000 172.16.56.0/22

8. 10101100 . 00010000 . 001 111 00 . 00000000 172.16.60.0/22

Step 2 : You only need three /22 subnets, so you reserved the first three for those subnets needing 1,000 hosts. Which ones are they?

1. 10101100 . 00010000 . 001 000 00 . 00000000 172.16.32.0/22

2. 10101100 . 00010000 . 001 001 00 . 00000000 172.16.36.0/22

3. 10101100 . 00010000 . 001 010 00 . 00000000 172.16.40.0/22

Step 3 : You decide to sub-subnet the fourth subnet (172.16.44.0/22) for the three subnets each needing 250 hosts. A /24 will work well for this. What are the three /24 sub-subnets you will use?

4. 10101100 . 00010000 . 001 011 00 . 00000000 172.16.44.0/22

4a. 10101100 . 00010000 . 001 011 00 . 00000000 172.16.44.0/24

4b. 10101100 . 00010000 . 001 011 01 . 00000000 172.16.45.0/24

4c. 10101100 . 00010000 . 001 011 10 . 00000000 172.16.46.0/24

4d. 10101100 . 00010000 . 001 011 11 . 00000000 172.16.47.0/24

Step 4 : The last (fourth) of the /24 sub-subnets (172.16.47.0/24), you decide to use for you serial point-to-point links. List the first five /30 sub-sub-subnets (if there is such a term):

4d. 10101100 . 00010000 . 001 011 11 . 00000000 172.16.47.0/24

4d1.10101100 . 00010000 . 001 011 11 . 000000 00 172.16.47.0/30

4d2.10101100 . 00010000 . 001 011 11 . 000001 00 172.16.47.4/30

4d3.10101100 . 00010000 . 001 011 11 . 000010 00 172.16.47.8/30

4d4.10101100 . 00010000 . 001 011 11 . 000011 00 172.16.47.12/30

4d5.10101100 . 00010000 . 001 011 11 . 000100 00 172.16.47.16/30

etc.

4d5.10101100 . 00010000 . 001 011 11 . 111111 00 172.16.47.252/30

Tags: ip, switch, study, interface

+ cisco IOS command basics By admin 20 June 2008 at 11:43 pm and have Comments Off

Bitmindframes cisco study guides.

This will show you the basics of the cisco IOS command line interface and the different modes.

After several lines of information on the screen you should eventually see:
Would you like to enter the initial configuration dialog? [yes/no]: n

On some routers and switchesyou may see the following message.
Would you like to terminate autoinstall? [yes/no]: y Router> or Switch>

Privilege Mode
Router> enable
If you are prompted for a password type: class or if that does not work, type cisco

Use the “?” to view the list of available commands or command options
Router> ?

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+ EIGRP routing protocol summary By admin 20 June 2008 at 11:21 pm and have Comments Off

Bitmindframes cisco study guides.

This is a basic rundown of the EIGRP routing protocol Concepts.

EIGRP is an advanced distance-vector routing protocol that relies on features commonly associated with link-state protocols.
Administrative Distance
• Internal 90; Summary 5; External 170 Features of EIGRP
• Classless Routing Protocol (VLSM, CIDR)
• Faster convergence times
• Multiprotocol support:
• Rapid Convergence and Better handling of routing loops – (DUAL)
• Efficient Use of Bandwidth
– Partial, bounded updates: Incremental updates only to the routers that need them.
– Minimal bandwidth consumption: no more that 50% of link’s bandwidth EIGRP packets.
• PDM (Protocol Dependent Module)
• Unequal-cost load balancing
Metrics: Bandwidth, Delay, Reliability, Load

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+ EIGRP routing basic commands By admin 20 June 2008 at 11:12 pm and have Comments Off

Bitmindframes cisco networking study guides

EIGRP Commands

Enabling EIGRP Routing

Router(config)# router eigrp AS number (Must be the same on all routers)

Router(config-router)# network network-address [wildcard mask]

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