Network

Saturday, November 13, 2010

switching dumps loaded on 12

Dumps:

http://www.examcollection.com/cisco/Cisco.CertifyMe.642-813.v2011-01-13.by.Petter.500q.vce.file.html

http://www.examcollection.com/cisco/Cisco.CertKey.642-813.v2011-02-01.by.Ellen.482q.vce.file.html

Use vce reader and crackers links to open dumps..

even then u can't, please mail me for instructions...

vasanth_md1988@ymail.com

Exact switch exam simulation:

http://www.certprepare.com/

use packet tracer to practice simulations

Monday, November 8, 2010

ccnp routing dumps uploaded on feb 11

Routing Dumps Link

Here i provided 3 links to download dumps, there may be slight changes or can also be similar between these 3 dumps.. please download and check it out., it better to read all..

http://www.examcollection.com/cisco/Cisco.PassGuide.642-902.v2011-01-22.by.BOB.273q.vce.file.html

http://www.examcollection.com/cisco/Cisco.Braindump.642-902.v2011-01-25.by.ChikenRice.13q.vce.file.html

http://www.examcollection.com/cisco/Cisco.TestKing.642-902.v2010-10-21.by.irshad.484q.vce.file.html

Use vce reader and crackers links to open dumps..

even then u can't please mail me for instructions...

vasanth_md1988@ymail.com

For exact routing exam simulation:

http://www.digitaltut.com/

Sunday, May 9, 2010

Saturday, May 1, 2010

TO START THE REVIEW FROM BASIC CONCEPTS CLICK ON 2009 ICON ON LEFT SIDE OF THE PAGE

Friday, April 2, 2010

Master/slave or DR/BDR election:

This is a second election process in OSPF to exchange information without collision in the network.

Parameters for election process are

1. Priority (by default the priority is 1) - first preference.

2. Highest router-id - second preference.

Master/Slave election takes place in point-to-point nature i.e, when routers connected using serial interface.

Master router will collect the information about all the router with a Area, and then it will exchange the information to all other router in the network, thus collision can be avoided. Slave router will also have the same information what master has but it will act as normal router performing its work only.

DR/BDR (Designated Router Back-up Designated Router) election takes place in broadcast nature i.e., when routers connected using Ethernet interface.

Master router will collect the information about all the router with a Area, and then it will exchange the information to all other router in the network, thus collision can be avoided. BDR is a back-up to DR whereas when DR goes down immediately BDR will become DR to continue the process. The remaining router will be DR others by performing their work only.

Wednesday, March 31, 2010

OSPF elections

1. Router ID election

The router ID is used to specify a particular router in a area, which is in ip address format.. the parameter used for router ID election are

a. Manual ID - Statically assigned id.

b. Loopback Address - Dynamically assumed from configuration.

c. Highest Interface

Address - Dynamically assumed from configuration.

In these three parameter's first preference is given to Manual id(if any) else it will check for loopback address(if any) this is second preference else it'll go for last option of choosing highest interface address.

2. Master/slave or DR/BDR election.

OSPF tables

Routing table : Basic table, it holds routing information.

Neighbor table : Maintains information of its neighbor routers.

Database table : Maintains the entire protocol's database information.

Sunday, March 28, 2010

Redistribution:

Redistribution is a process used to make communication between two different routing protocols and also two different Autonomous Systems in IGRP and EIGRP protocol.

Redistribution can be performed in intermediate router only. Intermediate router means "it is a router where two different protocols or two different AS is enabled".

Example for redistribution with different protocols and commands:

Assume RIP and EIGRP is enabled in this router.

router(config)#router rip

router(config-router)#redistribute eigrp 10 metric 5

(The range of metric is 0-16, it is RIP metric). Do you know why metric is specified? we are redistributing EIGRP in RIP, does RIP knows how EIGRP calculates metric? no. that's y metric is specified, whatever metric it receives with EIGRP update will be converted into the metric what is specified.

router(config-router)#exit

router(config)#router eigrp 10

router(config-router)#redistribute rip

(The range of metric is 1- 4294967295, it is EIGRP metric).Do you know why metric is specified? we are redistributing RIP in EIGRP, does EIGRP knows how RIP calculates metric? no. that's y metric is specified, whatever metric it receives with RIP update will be converted into the metric what is specified.

Example for redistribution with different AS and commands:

Assume IGRP 20 and 30 is enabled in this router.

router(config)#router igrp 20

router(config-router)#redistribute igrp 30

Here, it is not necessary to specify the metric, y because both are igrp(same protocol).

router(config-router)#exi

router(config)#router igrp 30

router(config-router)#redistribute igrp 20

Here, it is not necessary to specify the metric, y because both are igrp(same protocol).

What is Autonomous System number?

Autonomous System number is numeric value with the range from 1 to 65535 is used to express a network or a group of network comes under single administration with same routing policy.

IGRP and EIGRP uses AS number, OSPF also uses AS number in the form of Process ID.

In IGRP and EIGRP different AS number will not communicate(exchange update) by default, to make them communicate we need to go for redistribution process.

whereas in OSPF no such issues different AS will communicate by default.

commands:

router(config)#router igrp 10

router(config)#router eigrp 100

router(config)#router ospf 20

Sunday, March 21, 2010

Protocol and standards.

Protocol	Standard	Developer
RIP	Open.	RFC (Request For Comment), 1988.
IGRP	Only for CISCO routers.	CISCO, Mid-1980’s.
EIGRP	Only for CISCO routers	CISCO.
OSPF	Open.	RFC 2328, 1998.
IS-IS	Only for defense department.	OSI.
BGP	Open.	CISCO, RFC, 1990’s.

Sunday, March 7, 2010

What is ICMP Protocol?

ICMP - Internet Control Message Protocol

ICMP is a control protocol, meaning that it does not carry application data, but rather information about the status of the network itself. ICMP can be used to report.

· errors in the underlying communications of network applications.

· availability of remote hosts.

· network congestion.

What is RARP?

RARP – Reverse Address Resolution Protocol.

The RARP protocol is used to find the unknown IP address for the Known MAC(Media Access Control)address.

What is ARP?

ARP – Address Resolution Protocol.

The ARP protocol is used to find the unknown MAC(Media Access Control) address for the Known IP address.

Protocol and Port Number:

TCP	UDP
FTP 20, 21	DNS 53
TELNET 23	TFTP 69
SMTP 25	SNMP 161
HTTP 80
HTTPS 443

Saturday, March 6, 2010

What is Classless and Class full Routing?

While sending routing update packet, if it sends subnet mask information also with that packet it is called as classless routing. If it sends packet without subnet mask information then it is called class full routing.

Define Passive Interface?

The router will receive the routing information through that interface but it wont send the routing information through that interface this concept is called Passive Interface. By default it is disabled.

To enable

router#config ter

router(config)#router rip

router(config-router)#passive interface serial 0

Now the routing information is received via serial 0 interface but no routing information is send via it.

Define Split Horizon?

image2

image 3

The Router will not resend the same routing information from which interface it learnt that information is called Split-Horizon. The use of this concept is to avoid the routing loops in Network.

Explanation with Example:

LOOK AT SECOND IMAGE

Here in RA router the 30.0.0.0 information was received via RIP protocol on s0 interface but it wasn’t resend on same interface, it sending only 10.0.0.0 information. Here Split-horizon was enabled.

Lets see what happens when disabled

LOOK AT THIRD IMAGE

Now RA Router is resending the 30.0.0.0 information via s0 interface. It creates routing loops.

This is Split-horizon concept.

Route Propagation:

RIPv1 - Broadcast - 255.255.255.255.

RIPv2 - Multicast - 224.0.0.9.

EIGRP - Multicast - 224.0.0.10.

OSPF - Multicast - 224.0.0.5 - Hello packet 224.0.0.6 - Routing Update.

Protocol Special Properties:

Parameter/Protocol	RIPv1	RIPv2	IGRP/EIGRP
summarization	Auto	Auto	Auto and Manual
VLSM support	No	Yes	Yes
Classless Support	No (Class full)	Yes	Yes
Discontiguous support	No	Yes	Yes
Convergence	Slow	Slow	Fast/Very Fast
Authentication	No	Yes(clear text and MD5)	yes(MD5 only)
Route computation	Bellman-Ford	Bellman-Ford	DUAL

Parameter/Protocol	OSPF
summarization	Manual
VLSM support	Yes
Classless Support	Yes
Discontiguous support	Yes
Convergence	Fast
Authentication	Yes( clear text and MD5)
Route computation	Dijkstra algorithm

Protocol Timers:

Parameter/protocol	RIP	IGRP
Update	30 sec	90 sec
Invalid	180 sec	270 sec
Hold Down	180 sec	280 sec
Flush	240 sec	630 sec

Parameter/Protocol	OSPF
Hello	10 sec
Wait	40 sec
Dead	40 sec

Parameter/protocol	EIGRP
Hello	5 sec
Hold down	15 sec
Active	Manually assigned

Metric Calculation Formula:

RIP

Hop count- To Reach Destination how many router it has to pass.

IGRP

10⁷/Least Bandwidth + ∑ Delay

EIGRP

256*[10⁷/Least Bandwidth + ∑ Delay]

OSPF

10⁸/Bandwidth

Friday, March 5, 2010

Protocols and their Metric Parameters:

RIP

1. Hop count.

IGRP & EIGRP

2. Bandwidth.

3. Reliability.

4. delay.

5. Load.

6. MTU(Maximum Transmission Unit).

OSPF

7. Cost.

What is Metric?

Metric is numeric value used to calculate the best path to the destination. The lowest metric value is considered as best route to the destination. The metric calculation varies based on the type of protocol.

lets take RIP protocol for example,

The RIP protocol calculates metric based on hop count(0-15). To reach a destination one route has metric value 3 and one more route has metric value 5, The route with metric 3 is choosed as best path to reach destination.

What is Administrative Distance?

The Administrative Distance(AD) is the Numerical value that ranges between 0 -255. AD shows the Trust-worthiness of the Protocol.

If AD is high, Trust-worthiness is Less.

If AD is Less, Trust-worthiness is High.

Example and explaination:

You are advertising the same network using RIP and EIGRP Protocol, but the router will take the routes advertised by EIGRP. Why because the AD of EIGRP is 90 and the AD of RIP is 120, the router will prefer the route with low AD(high trust-worthiness) only. thus it takes EIGRP routes.

Protocols and its Administrative Distance

1. Directly Connected - 0.

2. Static Route - 1.

3. External BGP(Border Gateway Protocol) - 20.

4. Internal EIGRP - 90.

5. IGRP - 100.

6. OSPF - 110.

7. IS-IS(Intermediate sys- Intermediate sys)- 115.

8. RIP - 120.

9. ODR(On Demand Routing) - 160.

10.External EIGRP - 170.

11.Internal BGP - 200.

12.Unknown - 255.

Thursday, March 4, 2010

What is Hybrid Protocol?

This Protocol has both Distance Vector and Link State protocols characteristics, thus it is called as Hybrid Protocol.

EIGRP belongs Hybrid Protocol.

What is Link State Protocol?

The Link State Protocol is also called as Shortest path Protocol. Here it maintains three tables neighbor table, LSA (Link State adjacency) table, routing table. Link state protocol send updates containing the state of their own links to all routers on the network.

OSPF is a Link State protocol.