Cisco Solution: December 2007

Cisco CCNP / BSCI Exam Tutorial: EIGRP Stub Routing

Passing the BCSI exam and earning your CCNP certification requires you to know OSPF stub areas inside and out. Stub areas, total stub areas, a little study on not-so-stub stub areas ... and pretty soon your head is swimming. Then when you hear that EIGRP offers stub routing, your first reaction may be unprintable! But while EIGRP stub routing is effective in the right situation, it's not as complex as OSPF stub routing. Let's take a look at basic EIGRP stub routing.

While EIGRP does not have the stub area options that OSPF does, EIGRP does allow a router to be configured as stub. This is commonly done with a hub-and-spoke configuration where the spoke routers do not have the resources to keep a full routing table. Since the spoke's next hop will always be the hub, all the spoke really needs is a default route. For this reason, the only neighbor an EIGRP stub router can have is the hub router. (Obviously, the hub would never be configured as stub.)

Configuring EIGRP stub routers also combats the SIA problem. EIGRP stub routers are not queried for routes when the hub does not have a feasible successor for a successor route that has gone down.

By default, EIGRP stub routers advertise information about two types of routes back to the hub - directly connected networks and summary routes. To change this default, use the eigrp stub command followed by the types of routes you want the stub to advertise back to the hub. (The eigrp stub command run by itself configures the router as stub.)

R1(config)#router eigrp 100 R1(config-router)#eigrp stub ?

connected Do advertise connected routes

receive-only Set IP-EIGRP as receive only neighbor

static Do advertise static routes

summary Do advertise summary routes

For example, consider a network where R5 is the hub and R4, R6, and R7 are the spokes.

As long as R4, R6, and R7 have a neighbor relationship only with the hub, they can be configured as stub routers. They will then advertise their directly connected networks and summary routes back to the hub and will receive only a default route back from the hub. If R5 loses a successor and has no feasible successor, it will not send a query packet to any of the stub routers.

EIGRP stub routing doesn?t give us all the options that OSPF stub routing does, but it is much simple to configure and can greatly reduce unnecessary Query packet transmission in a hub-and-spoke network.
Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, and The Ultimate CCNA and CCNP Study Packages. For a copy of his FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies!

Labels: 1_academy_academy_basics_ccna_cisco_cisco_guide_lab_networking_networking_networking_program_program_study, cisco_system, cisco_used

Cisco CCNP Exam Tutorial: Defining Collision Domains

CCNA exam success depends on mastering the fundamentals, and two important fundamentals are knowing exactly what the terms "collision domain" and "broadcast domain" mean. In this free Cisco tutorial, we'll take a look at the term "collision domain" and how a collision domain is defined.

A collision domain is an area in which a collision can occur. Fair enough, but what "collision" are we talking about here? We're talking about collisions that occur on CSMA/CD segments, or Carrier Sense Multiple Access with Collision Detection. If two hosts on an Ethernet segment transmit data at exactly the same time, the data from the two hosts will collide on the shared segment. CSMA/CD exists to lessen the chances of this happening, but collisions can still occur. To lessen the chances of collisions occurring, we may decide to create multiple, smaller collision domains.

Let's say we have four hosts on a single Ethernet segment. The entire segment is a collision domain; any data sent by one of the hosts can collide with data sent by any of the other hosts. We have one collision domain containing four devices.

To create smaller collision domains, we'll need to introduce some type of networking device into this example. Hubs and repeaters have their place as far as extending the reach of a network segment and cutting down on attenuation, but these OSI Layer One devices do nothing to define collision domains. We could connect each host into a separate port on a hub (a hub is basically a multiport repeater) and we'd still have one single collision domain with four hosts in it.

The most common and most effective way to create multiple collision domains is to use a switch. If we connect each of these four hosts to their own separate switch port, we would now have four separate collision domains, each with one host; each switch port actually acts as a single collision domain, making collisions between these four hosts impossible.

Passing the CCNA is all about knowing the details of how things work, and knowing CSMA/CD theory and how to define collision domains is one of the many details you've got to master. In the next part of this CCNA tutorial, we'll take a look at broadcast domains, and how defining broadcast domains in the right places can dramatically cut down on unnecessary traffic on your network.

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, and The Ultimate CCNA and CCNP Study Packages. For a copy of his FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies!

Labels: 4th_ccnp_ccnp_certification_cisco_edition_library_self_study_system, cisco_used, cisco_voip, cisco_wireless

Cisco CCNP / BSCI Exam Tutorial: Using The OSPF Command "Area Range"

Your BSCI and CCNP exam success depends on knowing the details, and one such detail is knowing the proper way to summarize routes in OSPF. Route summarization is not just a test of your binary conversion abilities, but knowing where and when to summarize routes. It will not surprise any CCNA or CCNP certification candidate that OSPF gives us the most options for route summarization, and therefore more details to know!

OSPF offers us two options for route summarization configurations. In a previous tutorial, we looked at the "summary-address" command, and today we'll look at the proper use of the "area range" command.

The "area range" command should be used on an Area Border Router (ABR) to summarize routes being advertised from one OSPF area to another. In this tutorial, R1 is acting as an ABR, with interfaces in both Area 0 and Area 1. Four loopbacks have been placed into R1's Area 1.

R1(config)#router ospf 1

R1(config-router)#network 12.0.0.0 0.255.255.255 a 1

R1(config-router)#network 13.0.0.0 0.255.255.255 a 1

R1(config-router)#network 14.0.0.0 0.255.255.255 a 1

R1(config-router)#network 15.0.0.0 0.255.255.255 a 1

The routing table of an OSPF neighbor, R2, shows all four routes.

R2#show ip route ospf

12.0.0.0/32 is subnetted, 1 subnets

O IA 12.12.12.12 [110/65] via 172.12.123.1, 00:18:52, Serial0

13.0.0.0/32 is subnetted, 1 subnets

O IA 13.13.13.13 [110/65] via 172.12.123.1, 00:18:42, Serial0

14.0.0.0/32 is subnetted, 1 subnets

O IA 14.14.14.14 [110/65] via 172.12.123.1, 00:18:32, Serial0

15.0.0.0/32 is subnetted, 1 subnets

O IA 15.15.15.15 [110/65] via 172.12.123.1, 00:18:32, Serial0

To keep the routing tables of downstream routers smaller but still have the desired IP connectivity, we can use the area range command on R1 to summarize these four routes. The key to keep in mind with the area range command is that the area number given in the command is the area containing the destinations, NOT the area that will receive the summary route.

R1(config)#router ospf 1

R1(config-router)#area 1 range 12.0.0.0 252.0.0.0

R2 now shows a single summary route that can be used to reach all four remote networks.

R2#show ip route ospf

O IA 12.0.0.0/6 [110/65] via 172.12.123.1, 00:00:21, Serial0

Interestingly enough, there's now an additional route in R1's routing table.

R1#show ip route ospf O 12.0.0.0/6 is a summary, 00:07:53, Null0

When you configure summary routes in OSPF, a route to null0 will be installed into the OSPF routing table of the router performing the summarization. This helps to prevent routing loops. Any packets destined for the routes that have been summarized will have a longer match in the routing table, and packets that do not match one of the summarized routes but do match the summary route will be dropped.

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNP and CCNA tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies. Pass your CCNP exam with The Bryant Advantage!

Labels: 2nd_authorized_cisco_cvoice_edition_guide_guide_ip_over_self_self_study_study_voice, cisco_networking

Cisco CCNP / BSCI Exam Tutorial: Using OSPF's "Summary-Address" Command

BSCI exam success, not to mention earning your CCNP, can come down to your OSPF route summarization skills. There are a few different commands and situations you need to be ready for, and one of these situations is the proper use of the "summary-address" command.

The summary-address command should be used on an ASBR in order to summarize routes that are being injected into the OSPF domain via redistribution. In the following example, four routes are being redistributed into OSPF on R1, making R1 an ASBR.

interface Loopback16

ip address 16.16.16.16 255.0.0.0

!

interface Loopback17

ip address 17.17.17.17 255.0.0.0

!

interface Loopback18

ip address 18.18.18.18 255.0.0.0

!

interface Loopback19

ip address 19.19.19.19 255.0.0.0

R1(config)#router ospf 1

R1(config-router)#redistribute connected subnets

These four routes are seen on downstream router R2 as External Type-2, the default for routes redistributed into OSPF.

R2#show ip route ospf

O E2 17.0.0.0/8 [110/20] via 172.12.123.1, 00:00:07, Serial0

O E2 16.0.0.0/8 [110/20] via 172.12.123.1, 00:00:07, Serial0

O E2 19.0.0.0/8 [110/20] via 172.12.123.1, 00:00:07, Serial0

O E2 18.0.0.0/8 [110/20] via 172.12.123.1, 00:00:07, Serial0

To summarize networks learned by redistribution, use the OSPF command summary-address. You can probably do this summarization in your head, but do so before continuing with the lab.

R1(config)#router ospf 1

R1(config-router)#summary-address 16.0.0.0 252.0.0.0

Look at the change in R2's OSPF table.

R2#show ip route ospf

O E2 16.0.0.0/6 [110/20] via 172.12.123.1, 00:00:05, Serial0

The external routes have been successfully summarized. Note that the summary route is still marked as an E2 route.

There's an interesting route installed into R1's OSPF table as well.

R1#show ip route ospf

O 16.0.0.0/6 is a summary, 00:01:51, Null0

When you configure summary routes in OSPF, a route to null0 will be installed into the OSPF routing table. This helps to prevent routing loops. Any packets destined for the routes that have been summarized will have a longer match in the routing table....

C 17.0.0.0/8 is directly connected, Loopback17

C 16.0.0.0/8 is directly connected, Loopback16

C 19.0.0.0/8 is directly connected, Loopback19

C 18.0.0.0/8 is directly connected, Loopback18

O 16.0.0.0/6 is a summary, 00:03:10, Null0

O 12.0.0.0/6 is a summary, 00:07:53, Null0

.. and packets that do not match one of the summarized routes but do match the summary route will be dropped.

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNP and CCNA tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies. Pass your CCNP exam with The Bryant Advantage!

Labels: 2nd_authorized_cisco_cvoice_edition_guide_guide_ip_over_self_self_study_study_voice, cisco_gatekeepers_gateway_networking_technology_voice

Cisco CCNA Exam Tutorial: Why Do We Need Private Address Ranges?

When you're studying to pass the CCNA, you're introduced to "private addresses", the address ranges formally referred to as RFC 1918 Private Addresses. (RFC stands for Request For Comment; to see a typical RFC, just put that term in your favorite search engine.)

There are three ranges of 1918 Private Addresses, one in each major network class.

Class A: 10.0.0.0 /8

Class B: 172.16.0.0 /12

Class C: 192.168.0.0 /16

Be careful - these masks are not the classful network masks you're familiar with!

The need for private address ranges arose when we started running out of IP addresses. (A lot of us never thought that would happen, but a lot of us used to think we'd never need storage units bigger than floppy disks, too.) You can imagine that as networks began to be installed in offices and schools worldwide, the finite number of IP addresses became a restrictive factor.

Many devices that were using these precious IP addresses did not need to communicate with any device outside its own local area network (LAN). Therefore, these devices could be assigned an IP address that could be used on another device in another LAN - but these devices would not be able to communicate across the Internet.

It was decided to create network address ranges that would be used exclusively for such devices. That's why when you go from one local area network to another, you'll usually see hosts with IP addresses from the above three ranges.

Of course, as time went on, more and more of these devices did need to reach hosts across the Internet. That's where NAT - Network Address Translation - comes into play. But that is a subject for another tutorial!

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage , home of free CCNA and CCNP tutorials! Pass the CCNA exam with Chris Bryant!

Labels: 3_academy_basics_ccna_cisco_companion_companion_guide_guide_intermediate_networking_program_routing_switching

Cisco CCNP/BSCI Exam Tutorial: A Guide To IPv6 Addressing

Learning IPv6 is paramount in your efforts to pass the BSCI exam and go on to earn your CCNP, and it's going to help in your real-world networking career as well. IPv6 can be confusing at first, but it's like anything else in Cisco or networking as a whole - learn one part at a time, master the fundamentals, and you're on your way to success. In today's article we're going to take a look at IPv6 address types.

In IPv4, a unicast address is simply an address used to represent a single host, where multicast addresses represent a group of hosts and broadcasts represent all hosts.

In IPv6, it's not quite that simple. There are actually different types of unicast addresses, each with its own separate function. This allows IPv6 to get data where it's supposed to go quicker than IPv4 while conserving router resources.

IPv6 offers two kinds of local addresses, link-local and site-local. Site-local addresses allow devices in the same organization, or site, to exchange data. Site-local addresses are IPv6's equivalent to IPv4's private address classes, since hosts using them are able to communicate with each other throughout the organization, but these addresses cannot be used to reach Internet hosts.

Site-local and link-local addresses are actually derived from a host's MAC address. Therefore, if HostA has HostB's IPv6 address, HostA can determine HostB's MAC address from that, making ARP unnecessary.

Link-local addresses have a smaller scope than site-local. Link-local addresses are just that, local to a physical link. These particular addresses are not used at all in forwarding data. One use for these addresses is Neighbor Discovery, which is IPv6's answer to ARP.

You can identify these and other IPv6 addresses by their initial bits:

001 - Global address

(first 96 bits set to zero) - IPv4-compatible address

1111 1111 ? Multicast

1111 1110 11 - Site local

1111 1110 10 - Link Local

As a future CCNP, you're more than familiar with the reserved IPv4 address classes. You also know that they're not exactly contiguous. The developers of IPv6 took a structured approach to IPv6 reserved addresses - any address that begins with "0000 0000" is an IPv6 reserved address. One of these is the IPv6 loopback address, and this will give you some practice with your zero compression!

IP v6 Loopback: 0000:0000:0000:0000:0000:0000:0000:0001

Using Leading Zero Compression Only: 0:0:0:0:0:0:0:1

Combining Leading Zero and Zero Compression: ::1

Zero compression looks pretty good now, doesn't it? You just have to get used to it and keep the rules in mind. You can use all the leading zero compression you want, but zero compression ("double-colon") can only be used once in a single address.

IPv6 is here to stay, not only on your BSCI and CCNP exams, but in the real world as well. Learning it now will not only aid you in passing your Cisco exams, but in supporting IPv6 in the future.
Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com ), home of free CCNA and CCNP tutorials, and The Ultimate CCNA and CCNP Study Packages. For a copy of his FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies!

Labels: 1_academy_basics_ccna_cisco_companion_companion_guide_guide_networking_networking_program

Cisco CCNA Exam Tutorial: The Best Time To Schedule Your Exam

In preparing for CCNA exam success, one of the basic steps is to schedule your exam! And when should you do that?

Schedule your exam NOW.

I can hear you now -- " Why should I schedule my exam now? I haven?t started studying yet!"

From experience, I can tell you that this technique works. People complain about timetables and deadlines, but the truth is that people do their best work with a deadline. ?Stress? is not the dirty word that we?ve made it out to be. A diamond is only a lump of coal that was put under pressure.

I wish I had a nickel for every time I?ve heard this:

"I?ll schedule my exam when I?m ready."

You know when "ready" is? For many people, NEVER. I know someone who?s been preparing for his CCNA for years ? literally! He?s going to schedule that exam when he?s ready. He?s been getting ready for years!

By scheduling your exam now, you give yourself a mental deadline. You?ll be surprised at how focused your mind becomes when you know the date of your exam before you start. I have used this technique for my CCNA, CCNP, and CCIE exams. It will work for you!

You can schedule your exam with Prometric or VUE right now! Just search for either of those companies in your favorite search engine, and register online today.

Both sites have test center locators, so no matter where you are in the world, you can find the testing center nearest you.

We all have times of the day that we?re mentally sharper than others. I personally am a "morning person", so I always schedule my exams for first thing in the morning. If you?re stronger in the afternoon, schedule an afternoon exam. Regardless of the time of day you?re going to take the exam ? schedule it now, right now!

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNA and CCNP tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies. Pass your CCNA exam with The Bryant Advantage!

Labels: 2_academy_basics_ccna_cisco_companion_companion_guide_guide_networking_program_router_routing

Cisco CCNA/CCNP Home Lab Tutorial: Cabling Your Access Server

A Cisco home lab is an invaluable study tool when you're preparing for CCNA and CCNP exam success. Once you've gotten a couple of routers and switches, you'll quickly get tired of moving that blue console cable every time you want to configure a different device. The solution to this problem is purchasing and configuring an access server (AS).

For those of you new to access servers, note that these are not white boxes running Microsoft operating systems. These are Cisco routers that allow you to connect to all the routers and switches in your home lab without moving a cable. You can physically or logically connect to the access server and work with all your devices from there.

When you're pricing access servers, please remember that you do NOT need an expensive AS. Right now on ebay there are access servers costing up to $5000 - this is NOT what you want to buy. What you're looking for is something like a 2509 or 2511, which is going to run you anywhere from $100 - $200. It's money well spent, because once you get an AS, you'll really wonder how you ever did without it.

The only additional hardware you need is the cable that will physically connect your AS to the other routers and switches in your home lab. The cable you need is called an octal cable, so named because one end of this cable is actually eight ends, all terminated with a numbered RJ-45 connector.

The large end of the cable is going to be connected to the AS itself. The cable will connect to a port on the AS that will have "async 1-8" directly above the physical port. It is this port that makes an AS different from other Cisco routers.

Once you've got your AS and this cable, you're ready to configure your AS. Connect the cable to the AS as described above, and then you will connect one of the RJ-45 connectors to the console port of each one of your routers and switches. Make sure to note the number that's on the cable itself right below the connector, because that's very important. In the next part of this home lab tutorial, I'll tell you exactly how to configure your access server for best results, along with a few troubleshooting tips.
Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNA and CCNP tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies. Pass your CCNA exam with The Bryant Advantage!

Labels: 2nd_authorized_cipt_cisco_edition_guide_ip_self_self_study_study_telephony, cisco_college_junior, cisco_pix, cisco_vpn

Cisco / MSCE Exam Study: Creating A Road Map To Success

Planning for success on the CCNA, CCNP, and other Cisco exams is much like taking a trip in your car. You've got to plan ahead, accept the occasional detour, and just keep on going until you get there. But what do you do before you get started?

Create a road map - for success.

If you were driving from one side of the country to another, you certainly wouldn't just get in your car and start driving, would you? No. You would plan the trip out ahead of time. What would happen if you just got in the car and started driving in the hope that you would someday arrive at your final destination? You would never get there, and you'd spend a lot of time wandering aimlessly.

Don't spend your study time and slow your progress by studying for a Cisco exam without planning the trip. Schedule your study time as you would an appointment with a client, and keep that appointment. Make sure that your study time is quality study - turn your TV, iPod, and cell off. If you hit a bump in the road and don't get your certification the first time you take the exam, regroup and create another plan. Study until you get to the point that on exam day, you know that you are already a CCNA or CCNP and you?re just there at the testing center to make it official.

The journey to success is not a straight line. When you look at a chart that shows a company's financial progress, the line never goes straight up. there are some ups and downs, but the overall result is success. The path to your eventual career and certification exam success may not be a direct one, but the important part is to get started - and to get any journey started, you've got to create a road map for a successful arrival at your destinationChris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNA and CCNP tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies. Pass your CCNA exam with The Bryant Advantage!

Labels: 1_academy_academy_basics_ccna_cisco_cisco_guide_lab_networking_networking_networking_program_program_study

Cisco CCNP/BSCI Exam Tutorial: IP Version 6 Zero Compression

BSCI exam success is all part of becoming a CCNP, and part of that success is now learning the basics of IP Version 6, or IPv6. One of the most difficult parts of learning IPv6 concepts is the radically different addressing scheme that IPv6 uses as compared to IPv4. Just look at these sample addresses:

Typical IPv4 address: 129.14.12.200

Typical IPv6 address: 1029:9183:81AE:0000:0000:0AC1:2143:019B

As you can see, IPv6 isn't exactly just tacking two more octets onto an IPv4 address!

I haven't met too many networkers who really like typing, particularly numbers. You'll be happy to know there are some rules that will shorten those addresses a bit, and it's a very good idea to be fluent with these rules for your exam.

You remember from your CCNA studies that there's no difference between an upper-case letter and lower-case letter in hexadecimal. That's one of three basic rules you need to know when working with IPv6 addressing. The other factors deal with all the zeroes you'll run into in IPv6 addresses! One of these rules is the rule of zero compression.

The rule of zero compression states that if an address contains consecutive fields of zeroes, they can be expressed with two colons. It doesn't matter if you have two fields or eight, you can simply type two colons and that will represent all of them. The key here is that you can only do this once in an IPv6 address. This is referred to as zero compression. Here's an example:

Original format: 1234:1234:0000:0000:0000:0000:3456:3434

Using zero compression: 1234:1234::3456:3434

Again, you must remember that you can only do this once in an IPv6 address expression.

What if there are zeroes in the address that don't quite fit this rule? The next part of our IPv6 tutorial will deal with leading zero compression, another tool you can use to shorten these long, long addresses!
Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNA and CCNP tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies. Pass your CCNA exam with The Bryant Advantage!

Labels: 3_academy_basics_ccna_cisco_companion_companion_guide_guide_intermediate_networking_program_routing_switching, cisco_ip_phone

Cisco CCNP / BCMSN Exam Tutorial: Dynamic Trunking Protocol (DTP)

When you're studying to pass the BCMSN exam on the way to earning your CCNP certification, you're going to add to your CCNA knowledgebase every step of the way. Nowhere is that more than configuring a trunk between two switches.

You know that IEEE 802.1Q ("dot1q") and ISL are your two choices of trunking protocols, and you know the main differences between the two. What you might not have known is that there's a third trunking protocol that's running between your Cisco switches, and while it's a transparent process to many, you had better know about it for your BCMSN and other CCNP exams!

The Cisco-proprietary Dynamic Trunking Protocol (DTP) actively attempts to negotiate a trunk link with the remote switch. This sounds great, but there is a cost in overhead - DTP frames are transmitted every 30 seconds. If you decide to configure a port as a non-negotiable trunk port, there's no need for the port to send DTP frames.

DTP can be turned off at the interface level with the switchport nonegotiate command, but as you see below, you cannot turn DTP off until the port is no longer in dynamic desirable trunking mode. (Dynamic desirable is the default mode for most Cisco switch ports.)

SW2(config)#int fast 0/8

SW2(config-if)#switchport nonegotiate

Command rejected: Conflict between 'nonegotiate' and 'dynamic' status.

SW2(config-if)#switchport mode ?

access Set trunking mode to ACCESS unconditionally

dynamic Set trunking mode to dynamically negotiate access or trunk mode

trunk Set trunking mode to TRUNK unconditionally

SW2(config-if)#switchport mode trunk

SW2(config-if)#switchport nonegotiate

When you're working with Cisco switches in a home lab or rack rental environment, run IOS Help regularly to see what options are available for the commands you're practicing with. Cisco switch ports have quite a few options, and the best way to find them is with one simple symbol - the question mark!

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage , home of free CCNA and CCNP tutorials! Pass the BCMSN exam with Chris Bryant!

Labels: 3rd_authorized_bsci_building_cisco_edition_guide_guide_internetworks_scalable_self_self_study_study, cisco_college_junior, cisco_iphone, cisco_memory, cisco_pix

Cisco CCNA Exam Tutorial: A Guide To RAM, ROM, NVRAM, and Flash

CCNA exam success depends on knowing the details, and nowhere is this more true than knowing the various components of a Cisco router. This is also where you can quickly start drowning in acronyms! The terms "RAM" and "ROM" probably aren't new to you, but keeping up with "what goes where" with RAM, ROM, NVRAM, and Flash Memory can be quite a challenge! In this tutorial, we'll take a look at all four of these components and their contents.

ROM stands for Read-Only Memory. ROM stores the router's bootstrap startup program, operating system software, and power-on diagnostic test programs (the POST).

Flash memory is generally referred to as "flash" The Cisco Internetwork Operating System (IOS) images are held here. Flash is erasable and reprogrammable ROM. Flash memory content is retained by the router on power-down or reload.

RAM is short for Random-Access Memory. RAM on a Cisco router stores operational information such as routing tables and the running configuration file. RAM contents are lost when the router is powered down or reloaded.

NVRAM is non-volatile RAM. By "non-volatile", we mean that the contents of NVRAM are not lost when the router is powered down or reloaded. Where RAM holds the running configuration file, NVRAM holds the startup configuration file. If NVRAM is empty when the router reloads, you will be prompted to enter setup mode.

Success on the CCNA exam depends on keeping these terms straight and knowing their contents. Know the contents of each, pay special attention to what is lost on a reload and what is not, and you're on your way to CCNA exam success!

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNA and CCNP tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies. Get your CCNA certification with The

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Cisco CCNP / BCMSN Exam Tutorial: Dynamic VLANs and VMPS

Knowledge of Dynamic VLANs and VMPS is important in your efforts to pass the BCMSN exam and earn your CCNP, and it's also a great skill to have for your networking career.

As a CCNA and CCNP candidate, you know how and why to configure static VLANs. Static VLANs can be a powerful tool for reducing unnecessary broadcast and multicast traffic, but if hosts are moved from one switch port to another, you've got to make those changes manually on the switch. With Dynamic VLANs, the changes are made - how else? - dynamically.

The actual configuration of dynamic VLANs is out of the scope of the BCMSN exam, but as a CCNP candidate you need to know the basics of VMPS - a VLAN Membership Policy Server.

Using VMPS results in port VLAN membership changes being performed dynamically, because the port's VLAN membership is decided by the source MAC address of the device connected to that port. (Yet another reason that the first value a switch looks at on an incoming frame is the source MAC address.)

In my home lab network, I've got a host connected to switch port fast0/1 that resides in VLAN 12. What if we had to move Host 1's connection to the switch to port 0/6? With static VLANs, we'd have to connect to the switch, configure the port as an access port, and then place the port into VLAN 12. With VMPS, the only thing we'd have to do is reconnect the cable to port 0/6, and the VMPS would dynamically place that port into VLAN 12.

I urge you to do additional reading regarding VMPS. Use your favorite search engine for the term configuring vmps and you'll quickly find some great official Cisco documentation on this topic.

To review, the VLAN membership of a host is decided by one of two factors. With static VLANs, the host's VLAN membership is the VLAN to which its switch port has been assigned. With dynamic VLANs, it is dependent upon the host's MAC address.

Chris Bryant, CCIE #12933, is the owner of The Bryant Advantage (http://www.thebryantadvantage.com), home of free CCNP and CCNA tutorials! For my FREE "How To Pass The CCNA" or "CCNP" ebook, visit the website and download your copies. Get your CCNP with The Bryant Advantage!

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