When you're preparing for CCNA and CCNP exam success, the best investment you can make is to put together your own home lab. There is no better way to learn Cisco technologies and prepare for the CCNA, BSCI, BCMSN, CIT, and other exams than by working with the many protocols and services you'll need to master in order to pass the exams.One of the most popular articles I've written over the few years dealt with buying and configuring a Cisco router as a frame relay switch. That article is still available on many websites (including my own), but I want to remind you that just because you configure a router as a frame relay switch, that doesn't mean you can't use it as a home lab router, too!The global command "frame-relay switching" allows a Cisco router such as a 2520 or 4000 to perform just that, frame relay switching, but this command doesn't disable IP routing. Depending on the router model you use, you will most likely have some extra serial connectors as well as an ethernet port that you can use with your other routers in your home lab.Let's say you have a 2520 router as your frame relay switch. This switch has four serial ports and an AUI port. You could connect to up to four routers to the 2520's serial ports in order to serve as the frame relay switch for those other routers, and still assign an IP address to the ethernet port and run a routing protocol on the 2520. If you're connecting to less than four other routers as the frame relay switch, you can assign IP addresses to the leftover serial ports as well.
CCNA and CCNP candidates who have their own Cisco home labs often email me about an odd situation that occurs when they erase a switch's configuration. Their startup configuration is gone, as they expect, but the VLAN and VTP information is still there!Sounds strange, doesn't it? Let's look at an example. On SW1, we run show vlan brief and see in this abbreviated output that there are three additional vlans in use:SW1#show vlan br10 VLAN0010 active20 VLAN0020 active30 VLAN0030 activeWe want to totally erase the router's startup configuration, so we use the write erase command, confirm it, and reload without saving the running config:SW1#write eraseErasing the nvram filesystem will remove all configuration files! Continue? [confirm][OK]Erase of nvram: complete00:06:00: %SYS-7-NV_BLOCK_INIT: Initalized the geometry of nvramSW1#reloadSystem configuration has been modified. Save? [yes/no]: nProceed with reload? [confirm]The router reloads, and after exiting setup mode, we run show vlan brief again. And even though the startup configuration was erased, the vlans are still there!Switch#show vlan br10 VLAN0010 active20 VLAN0020 active30 VLAN0030 activeThe reason is that this vlan and VTP information is actually kept in the VLAN.DAT file in Flash memory, and the contents of Flash are kept on a reload. The file has to be deleted manually.There's a little trick to deleting this file. The switch will prompt you twice to ask if you really want to get rid of this file. Don't type "y" or "yes"; just accept the defaults by hitting the return key. If you type "y", the router attempts to delete a file named "y", as shown here:Switch#delete vlan.datDelete filename [vlan.dat]? yDelete flash:y? [confirm]%Error deleting flash:y (No such file or directory)Switch#delete vlan.datDelete filename [vlan.dat]?Delete flash:vlan.dat? [confirm]Switch#The best way to prepare for CCNA and CCNP exam success is by working on real Cisco equipment, and by performing lab tasks over and over. Repetition is the mother of skill, and by truly erasing your VLAN and VTP information by deleting the vlan.dat file from Flash, you'll be building your Cisco skills to the point where your CCNA and CCNP exam success is a certainty.
To pass the CCNA exam, you've got to know the role of the bandwidth command with IGRP and EIGRP and when to use it. In this tutorial, we'll configure IGRP over a frame relay hub-and-spoke network using the following networks:R1 (the hub), R2, and R3 are running IGRP over the 22.214.171.124 /24 network. This is a T1 line.R1 and R3 are also connected on a different subnet, 126.96.36.199 /24. The bandwidth of this connection is 512 KBPS.R2 and R3 are also connected by an Ethernet segment, 172.23.0.0 /16.We'll configure IGRP on R1, R2, and R3 with the router igrp 1 command. IGRP will run on all interfaces in the 188.8.131.52 and 172.23.0.0 network.R1#conf tR1(config)#router igrp 1R1(config-router)#network 184.108.40.206The 1 in the router igrp command refers to the Autonomous System (AS). IGRP is a classful routing protocol, so wildcard masks are not used in the network statements.R2#conf tR2(config-if)#router igrp 1R2(config-router)#network 220.127.116.11R2(config-router)#network 172.23.0.0R3#conf tR3(config-if)#router igrp 1R3(config-router)#network 18.104.22.168R3(config-router)#network 172.23.0.0Run show ip route on R1. R1 will see three equal-cost paths to the Ethernet network. IGRP supports load-sharing over up to four equal-cost paths by default, so all three paths appear in the routing table. R1 will also see a route to the loopback address on R2 and two routes to the loopback address on R3. (You can also run show ip route igrp in order to see only the IGRP routes.)R1#show ip route igrpI 172.23.0.0/16 [100/8576] via 22.214.171.124, 00:00:02, Serial0[100/8576] via 126.96.36.199, 00:00:02, Serial1[100/8576] via 188.8.131.52, 00:00:01, Serial0Remember that the numbers in the brackets following the network number in the routes are the Administrative Distance and the IGRP metric, in that order.Note that classful masks are in use. IGRP does not support variable-length subnet masks (VLSM).There are two serial connections between R1 and R3. IGRP is assuming that both lines are T1 lines, running at 1544 KBPS. The 184.108.40.206 network is participating in equal-cost load sharing because of IGRPs bandwidth assumption - that all serial interfaces are connected to T1 lines.To give IGRP a more accurate picture of the networks bandwidth, configure bandwidth 512 on R1 and R3s Serial1 interface (the interfaces on the 220.127.116.11 network).R1#conf tR1(config)#interface serial1R1(config-if)#bandwidth 512R3#conf tR3(config)#interface serial 1R3(config-if)#bandwidth 512IGRPs assumption that all serial lines run at 1544 KBPS is overridden by the bandwidth 512 command. IGRP now believes this line runs at 512 KBPS.To see the effect of this command, clear your routing table on R1.R1#clear ip route *R1#show ip route igrpI 172.23.0.0/16 [100/8576] via 18.104.22.168, 00:00:24, Serial0/0[100/8576] via 22.214.171.124, 00:00:17, Serial0/0The routing table is cleared with clear ip route *. To see only the routes received in IGRP updates instead of the entire table, run show ip route igrp. One of the paths to 172.23.0.0 is now gone - the route that went through the 126.96.36.199 network. Now that IGRP sees that link as slower than the others, equal-cost load balancing will not occur over the 188.8.131.52 network.Its important to understand that the bandwidth command does not actually change the bandwidth of the connection; it changes IGRPs assumption of what the bandwidth is.In the next part of this IGRP load-balancing tutorial, we'll take a look at how to configure unequal-cost load balancing.
* What does certified mean?There are four accepted meanings of the adjective certified but only two of which satisfy the needed meaning. To be certified means to be endorsed with authority by an institution or a person with higher position after one successfully meets certain requirements. Another meaning is that a person is qualified to do a certain job as supported by an appropriate document better known and regarded as a Certification.* What certifications are there?If you are pertaining to online certifications, there are lots to be traced. To help you find one best certification that fits your ability and interest, you may log on to reliable sites in the internet. For now, the following are the basic IT certifications: IT Auditing Document Imaging E-Commerce Internet/Intranet Linux Networking Printing Project Management IT Security Servers Service Technician Technical Trainer Webmaster* Who benefits from certification?Primarily the one given a certification benefits more. Being certified means one can properly function on a certain job. This means, companies will easily hire a person with certification especially when certifications come from a reliable learning institution.In some ways, the company to which a certified person intends to apply for work will also benefit since the performance of the applying employee is being supported with a certification.* Is certification better than experience?The answer for that is a big "No." Certification means training. It is impossible for a person to send himself training without experiencing what it is he intends to do. For this reason, we cannot equate certification from experience since they do not share the same purpose. However, if you already have work experience, a certification is a big help for promotion, recognition and pay raises.On the other hand, companies are not solely after experience but after educational attainments and performances. In other words, having completed a course as proved by a certification is a chance to be hired.* Which certification program is best for me?The best certification program for you is the one that fits your interests and capabilities. Those two factors should be considered above all ese when finding the right and best certification program for you.* How much will getting certified cost?Almost all training packages from different training institutions are cost effective. The training cost will depend on the training you want to pursue and in which training institution you intend to enroll. Generally, a trainee should prepare to pay between $100 and $400 for each training program.* How long will certification take?There are training institutions that offer a 6-month online training program. The usual training timeframe is one year. This length of training may exceed to a maximum of 2 years depending on the program conducted.* Do I need a college degree to be certified?You do not need a college degree to be certified. Some certification programs require one to have at least finished high school upon enrolling in a certain course.* Will certification really help my career?A certification may help your career. Nowadays, competition in the jobs is getting tougher. For one to stay in his or her job or to be promoted to a higher position, one factor to consider is his or her educational achievements. That is one reason why mastering your field of work by means of studying and training can be a great boost for your career. That is where a certification program can make or break your career advancement.* Will I have to go somewhere for my certification training?While you can find local institutions where you can take classes and tests, most training is done online now. You do not need to go somewhere else for your training. You do not even need to attend classes personally for your lessons. Not only is training done mostly online now, but examinations for certification are also given online.
OSPF is a major topic on both the CCNA and CCNP exams, and it's also the topic that requires the most attention to detail. Where dynamic routing protocols such as RIP and IGRP have only one router type, a look at a Cisco routing table shows several different OSPF route types.R1#show ip routeCodes: C - connected, S - static, I - IGRP, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2, E - EGPIn this tutorial, we'll take a look at the difference between two of these route types, E1 and E2.Route redistribution is the process of taking routes learned via one routing protocol and injecting those routes into another routing domain. (Static and connected routes can also be redistributed.) When a router running OSPF takes routes learned by another routing protocol and makes them available to the other OSPF-enabled routers it's communicating with, that router becomes an Autonomous System Border Router (ASBR). Let's work with an example where R1 is running both OSPF and RIP. R4 is in the same OSPF domain as R1, and we want R4 to learn the routes that R1 is learning via RIP. This means we have to perform route redistribution on the ASBR. The routes that are being redistributed from RIP into OSPF will appear as E2 routes on R4:R4#show ip route ospfO E2 184.108.40.206 [110/20] via 220.127.116.11, 00:33:21, Ethernet0 18.104.22.168/32 is subnetted, 1 subnetsO E2 22.214.171.124 [110/20] via 126.96.36.199, 00:33:21, Ethernet0 188.8.131.52/16 is variably subnetted, 2 subnets, 2 masksO E2 184.108.40.206/30 [110/20] via 220.127.116.11, 00:33:32, Ethernet0O E2 18.104.22.168 [110/20] via 22.214.171.124, 00:33:21, Ethernet0 126.96.36.199/24 is subnetted, 1 subnetsO E2 188.8.131.52 [110/20] via 184.108.40.206, 00:33:32, Ethernet0E2 is the default route type for routes learned via redistribution. The key with E2 routes is that the cost of these routes reflects only the cost of the path from the ASBR to the final destination; the cost of the path from R4 to R1 is not reflected in this cost. (Remember that OSPF's metric for a path is referred to as "cost".) In this example, we want the cost of the routes to reflect the entire path, not just the path between the ASBR and the destination network. To do so, the routes must be redistributed into OSPF as E1 routes on the ASBR, as shown here. R1#conf tEnter configuration commands, one per line. End with CNTL/Z.R1(config)#router ospf 1R1(config-router)#redistribute rip subnets metric-type 1Now on R4, the routes appear as E1 routes and have a larger metric, since the entire path cost is now reflected in the routing table.O E1 220.127.116.11 [110/94] via 18.104.22.168, 00:33:21, Ethernet0 22.214.171.124/32 is subnetted, 1 subnetsO E1 126.96.36.199 [110/100] via 188.8.131.52, 00:33:21, Ethernet0 184.108.40.206/16 is variably subnetted, 2 subnets, 2 masksO E1 220.127.116.11/30 [110/94] via 18.104.22.168, 00:33:32, Ethernet0O E1 22.214.171.124 [110/94] via 126.96.36.199, 00:33:21, Ethernet0 188.8.131.52/24 is subnetted, 1 subnetsO E1 184.108.40.206 [110/94] via 220.127.116.11, 00:33:32, Ethernet0Knowing the difference between E1 and E2 routes is vital for CCNP exam success, as well as fully understanding a production router's routing table. Good luck in your studies!