Networks Articles

Computers » Networks | By Chris Bryant @ Monday, 17th April 2006 @ 8:56 AM

To pass the CCNA exam, you\'ve got to know how to work with IGRP and EIGRP unequal-cost load balancing. You may not see much IGRP in production networks anymore, but you\'ll see a lot of EIGRP, and part of fine-tuning your EIGRP network is making sure that all paths are in use while allowing for varying bandwidth rates. Using the variance command is the easy part - it\'s getting the metric that\'s the hard part with IGRP. With EIGRP, you just look in the topology table... more...

Computers » Networks | By Chris Bryant @ Thursday, 13th April 2006 @ 1:55 PM

Ever since you picked up your first CCNA book, you\'ve heard about multicasting, gotten a fair idea of what it is, and you\'ve memorized a couple of reserved multicasting addresses. Now as you prepare to pass the BCMSN exam and become a CCNP, you\'ve got to take that knowledge to the next level and gain a true understanding of multicasting. Those of you with an eye on the CCIE will truly have to become multicasting experts! Having said that, we\'re going to briefly re... more...

Computers » Networks | By Chris Bryant @ Thursday, 13th April 2006 @ 1:13 PM

RIP isn\'t exactly the most complex routing protocol on the CCNA exam, but that makes it easy to overlook some of the important details you must keep in mind in order to pass the exam! To help you review for the exam, here are just a few of those details! RIP’s default behavior is to send version 1 updates, but to accept both version 1 and 2 routing updates. R2(config)#router rip R2(config-router)#net 172.16.0.0 R2(config-router)#^Z R2#show ip protocolsmore...

Computers » Networks | By Chris Bryant @ Wednesday, 12th April 2006 @ 7:56 AM

In this section, you\'re going to be reintroduced to a networking model you first saw in your CCNA studies. No, it\'s not the OSI model or the TCP/IP model - it\'s the Cisco Three-Layer Hierarchical Model. Let\'s face it, just about all you had to do for the CCNA was memorize the three layers and the order they were found in that model, but the stakes are raised here in your CCNP studies. You need to know what each layer does, and what each layer should not be doing. This... more...

Computers » Networks | By Chris Bryant @ Saturday, 8th April 2006 @ 9:56 AM

You remember from your CCNA studies that when a port goes through the transition from blocking to forwarding, you\'re looking at a 50-second delay before that port can actually begin forwarding frames. Configuring a port with PortFast is one way to get around that, but again, you can only use it when a single host device is found off the port. What if the device connected to a port is another switch? A switch can be connected to two other switches, giving that local switch a redun... more...

Computers » Networks | By Chris Bryant @ Saturday, 8th April 2006 @ 9:56 AM

In my last ISIS tutorial, I mentioned that while ISIS and OSPF are both link state protocols, their actual operation differs greatly. To pass the BSCI exam and earn your CCNP, you\'ll need to know these differences! Today, we\'ll take a look at ISIS Hello types and the adjacency types that form through the use of these Hellos. Hello packets have been mentioned several times with ISIS, and with good reason. Hello packets are the heartbeat of OSPF and ISIS when heartbeats are no l... more...

Computers » Networks | By Chris Bryant @ Friday, 7th April 2006 @ 1:06 PM

To pass the BSCI exam and earn your CCNP, you\'ve got to know ISIS inside and out. There are many similarities between ISIS and OSPF, but one major difference is that ISIS has three different types of routers - Level 1 (L1), Level 2 (L2), and L1/L2. L1 routers are contained in a single area, and are connected to other areas by an L1/L2 router. The L1 uses the L1/L2 router as a default gateway to reach destinations contained in other areas, much like an OSPF stub router uses the ABR... more...

Computers » Networks | By Chris Bryant @ Friday, 7th April 2006 @ 9:23 AM

You may look at that feature\'s name and think, \"What is a BPDU Skew, and why do I want to detect it?\" What we\'re actually attempting to detect are BPDUs that aren\'t being relayed as quickly as they should be. After the root bridge election, the root bridge transmits BPDUs, and the non-root switches relay that BPDU down the STP tree. This should happen quickly all around, since the root bridge will be sending a BPDU every two seconds by default (\"hello ti... more...

Computers » Networks | By Chris Bryant @ Saturday, 1st April 2006 @ 11:57 AM

DNS behaviors of a Cisco router are important topics for both the CCNA exam and real-world production networks, and you probably didn't know there were so many DNS details before you began studying for the exam! In this tutorial, we'll look at the ip name-server command and its proper usage. When a command is mistyped on a Cisco router, the default behavior of the router is to attempt to resolve it via DNS. First, the router looks for an IP Host table on the local router to perf... more...

Computers » Networks | By Chris Bryant @ Saturday, 1st April 2006 @ 11:57 AM

In your BCMSN / CCNP exam study, it's easy to overlook some of the details of Spanning Tree Protocol (STP). After all, you learned all of that in your CCNA studies, right? Not necessarily! While some of the BCMSN material will be a review for you, there are some details regarding familiar topics that you need to learn. That includes the timers for STP - Hello Time, MaxAge, and Forward Delay. You may remember these timers from your CCNA studies as well, and you should also remember th... more...