When you're working on your BCMSN exam on your way to CCNP certification, you'll read at length about how Cisco routers and multilayer switches can work to provide router redundancy - but there's another helpful service, Server Load Balancing, that does the same for servers. While HSRP, VRRP, and CLBP all represent multiple physical routers to hosts as a single virtual router, SLB represents multiple physical servers to hosts as a single virtual server.
In the following example, three physical servers have been placed into the SRB group ServFarm. They're represented to the hosts as the virtual server 210.1.1.14.
The hosts will seek to communicate with the server at 210.1.1.14, not knowing that they're actually communicating with the routers in ServFarm. This allows quick cutover if one of the physical servers goes down, and also serves to hide the actual IP addresses of the servers in ServFarm.
The basic operations of SLB involves creating the server farm, followed by creating the virtual server. We'll first add 210.1.1.11 to the server farm:
MLS(config)# ip slb serverfarm ServFarm
MLS(config-slb-sfarm)# real 210.1.1.11
MLS(config-slb-real)# inservice
The first command creates the server farm, with the real command specifying the IP address of the real server. The inservice command is required by SLB to consider the server as ready to handle the server farm's workload. The real and inservice commands should be repeated for each server in the server farm.
To create the virtual server:
MLS(config)# ip slb vserver VIRTUAL_SERVER
MLS(config-slb-vserver)# serverfarm ServFarm
MLS(config-slb-vserver)# virtual 210.1.1.14
MLS(config-slb-vserver)# inservice
From the top down, the vserver was named VIRTUAL_SERVER, which represents the server farm ServFarm. The virtual server is assigned the IP address 210.1.1.14, and connections are allowed once the inservice command is applied.
You may also want to control which of your network hosts can connect to the virtual server. If hosts or subnets are named with the client command, those will be the only clients that can connect to the virtual server. Note that this command uses wildcard masks. The following configuration would allow only the hosts on the subnet 210.1.1.0 /24 to connect to the virtual server.
MLS(config-slb-vserver)# client 210.1.1.0 0.0.0.255
SLB is the server end's answer to HSRP, VRRP, and GLBP - but you still need to know it to become a CCNP! Knowing redundancy strategies and protocols is vital in today's networks, so make sure you're comfortable with SLB before taking on the exam.
четверг, 7 мая 2009 г.
Cisco CCNA Certification Exam Tutorial: Configuring Dialer Profiles
The most common method of configuring ISDN is with dialer maps, but dial information can also be configured on a logical interface. To pass the CCNA exam, you must know how to configure and troubleshoot both dialer maps and dialer profiles.
Dialer Profiles allow different dialing information to be configured onto logical interfaces. The logical interfaces may have different dialing destinations, different remote router names, etc., but they’ll be using the same physical interface.
Dialer strings are used on dialer profiles. Note that each logical interface has a different IP address, a different remote router to dial, and a different dialer string, but they will be using the same physical interface to dial out. The commands dialer pool and dialer pool-member are used to link the logical and physical interfaces. The number following each command must match for the logical interface to correctly bind to the physical interface.
R1(config)#interface dialer0
R1(config-if)#ip address 172.16.1.1 255.255.255.0
R1(config-if)#encapsulation ppp
<. The encapsulation type is placed on both the logical and physical interfaces. >
R1(config-if)#dialer remote-name Remote0
R1(config-if)#dialer pool 1
<>
R1(config-if)#dialer string 5551212
<>
R1(config-if)#dialer-group 1
<>
R1(config)#interface dialer1
R1(config-if)#ip address 172.16.1.2 255.255.255.0
R1(config-if)#encapsulation ppp
R1(config-if)#dialer remote-name Remote1
R1(config-if)#dialer pool 1
R1(config-if)#dialer string 5551234
R1(config-if)#dialer-group 1
R1(config)#interface bri0
R1(config-if)#no ip address
<>
R1(config-if)#encapsulation ppp
<>
R1(config-if)#dialer pool-member 1
<>
R1(config-if)#isdn spid1 0835866101
R1(config-if)#isdn spid2 0835866301
When configuring dialer profiles, the encapsulation type should be placed on both the physical BRI interface and the logical dialer interfaces. The SPIDs are configured on the physical interface as well.
Configuring dialer profiles can be a little tricky at first, and the best way to master this skill is to get real hands-on practice in your own CCNA / CCNP home lab or a rack rental service. Either way, hands-on is the best practice. Best of luck in your CCNA studies!
Dialer Profiles allow different dialing information to be configured onto logical interfaces. The logical interfaces may have different dialing destinations, different remote router names, etc., but they’ll be using the same physical interface.
Dialer strings are used on dialer profiles. Note that each logical interface has a different IP address, a different remote router to dial, and a different dialer string, but they will be using the same physical interface to dial out. The commands dialer pool and dialer pool-member are used to link the logical and physical interfaces. The number following each command must match for the logical interface to correctly bind to the physical interface.
R1(config)#interface dialer0
R1(config-if)#ip address 172.16.1.1 255.255.255.0
R1(config-if)#encapsulation ppp
<. The encapsulation type is placed on both the logical and physical interfaces. >
R1(config-if)#dialer remote-name Remote0
R1(config-if)#dialer pool 1
<>
R1(config-if)#dialer string 5551212
<>
R1(config-if)#dialer-group 1
<>
R1(config)#interface dialer1
R1(config-if)#ip address 172.16.1.2 255.255.255.0
R1(config-if)#encapsulation ppp
R1(config-if)#dialer remote-name Remote1
R1(config-if)#dialer pool 1
R1(config-if)#dialer string 5551234
R1(config-if)#dialer-group 1
R1(config)#interface bri0
R1(config-if)#no ip address
<>
R1(config-if)#encapsulation ppp
<>
R1(config-if)#dialer pool-member 1
<>
R1(config-if)#isdn spid1 0835866101
R1(config-if)#isdn spid2 0835866301
When configuring dialer profiles, the encapsulation type should be placed on both the physical BRI interface and the logical dialer interfaces. The SPIDs are configured on the physical interface as well.
Configuring dialer profiles can be a little tricky at first, and the best way to master this skill is to get real hands-on practice in your own CCNA / CCNP home lab or a rack rental service. Either way, hands-on is the best practice. Best of luck in your CCNA studies!
Cisco CCNP Certification: Using The BGP Command “Update-Source”
When you start preparing for your CCNP exam, particularly the BSCI exam, you're introduced to Border Gateway Protocol (BGP) configurations. BGP is unlike any protocol you learned during your CCNA studies, and even the similarities are a little bit different!
BGP forms neighbor relationships, much like EIGRP and OSPF do. The interesting thing with BGP is that potential neighbors, or "peers", do not need to be directly connected and can use their loopback interfaces to form the peer relationships.
It may well be to your advantage to use loopbacks to form peer relationships rather than the actual interface facing the potential neighbor. This can be done because BGP uses static neighbor statements rather than any kind of dynamic neighbor discovery process.
Consider a router that has two paths to a BGP speaker. The interfaces are numbered like this:
Router1: Serial0, 172.1.1.1 /24, Serial2, 179.1.1.1 /24, loopback0, 1.1.1.1 /32.
Router2: Serial0, 172.1.1.2/24, Serial2 179.1.1.2/24, loopback0, 2.2.2.2 /32.
We could configure Router1 like this:
router bgp 200
neighbor 172.1.1.2 remote-as 200
In this case, BGP would automatically use 172.1.1.1 as the source for the TCP connection that has to be set up with the neighbor before updates can be exchanged; this address is known as the best local address. However, if the remote peer's serial0 interface is shut down or goes down for another reason, the peer relationship would be lost even though Router2 is still available.
Instead of using one of the physical interfaces, we can use the loopbacks on each router to establish the TCP-based peer connection. The configurations would look like this:
Router1:
router bgp 200
neighbor 2.2.2.2 remote-as 200
neighbor 2.2.2.2 update-source loopback0
Router2:
router bgp 200
neighbor 1.1.1.1 remote-as 200
neighbor 1.1.1.1 update-source loopback0
In this case, losing one of the physical connections does not necessarily mean the BGP peering is lost; as long as the routers have a valid path to each other's loopback addresses, the BGP peer relationship will stay in place. And better yet, we avoid the dreaded “single point of failure
BGP forms neighbor relationships, much like EIGRP and OSPF do. The interesting thing with BGP is that potential neighbors, or "peers", do not need to be directly connected and can use their loopback interfaces to form the peer relationships.
It may well be to your advantage to use loopbacks to form peer relationships rather than the actual interface facing the potential neighbor. This can be done because BGP uses static neighbor statements rather than any kind of dynamic neighbor discovery process.
Consider a router that has two paths to a BGP speaker. The interfaces are numbered like this:
Router1: Serial0, 172.1.1.1 /24, Serial2, 179.1.1.1 /24, loopback0, 1.1.1.1 /32.
Router2: Serial0, 172.1.1.2/24, Serial2 179.1.1.2/24, loopback0, 2.2.2.2 /32.
We could configure Router1 like this:
router bgp 200
neighbor 172.1.1.2 remote-as 200
In this case, BGP would automatically use 172.1.1.1 as the source for the TCP connection that has to be set up with the neighbor before updates can be exchanged; this address is known as the best local address. However, if the remote peer's serial0 interface is shut down or goes down for another reason, the peer relationship would be lost even though Router2 is still available.
Instead of using one of the physical interfaces, we can use the loopbacks on each router to establish the TCP-based peer connection. The configurations would look like this:
Router1:
router bgp 200
neighbor 2.2.2.2 remote-as 200
neighbor 2.2.2.2 update-source loopback0
Router2:
router bgp 200
neighbor 1.1.1.1 remote-as 200
neighbor 1.1.1.1 update-source loopback0
In this case, losing one of the physical connections does not necessarily mean the BGP peering is lost; as long as the routers have a valid path to each other's loopback addresses, the BGP peer relationship will stay in place. And better yet, we avoid the dreaded “single point of failure
What Is MCSE?
MCSE stands for Microsoft Certified Systems Engineer. What is this term, really? While the term sounds like a degree that you would get in Microsoft, it is not really an engineering degree, per say. In fact, that is one of the biggest complaints about this learning process. Nevertheless, MCSE is a training course of sorts that is designed to teach individuals who want to learn how to handle various aspects of Microsoft skills. The goal is to have a group of people who are knowledgeable in the areas that Microsoft is specific. Let’s explain.
Microsoft developed this type of training to allow individuals to get a specific training course, or several in various types of skills that pertain to Microsoft. The thing about this training is that it is specific to Microsoft. While you may learn to install a program in another course which would teach a broad range of information about all ways in which to do so, in the MSCE, you will learn strictly how it is done through Microsoft.
So, How Does MSCE Work?
In most cases, the training can be done in several ways. Students can take classes through certified teachers in school or they can study on their own. Some individuals feel that they have enough experience in the various uses of Microsoft to be able to take the test without taking a training class. The test is given at specific areas at specific times. In order to be considered, you must pay a fee of about $125 for each of the tests and certifications that you plan to take. The tests range in knowledge levels and in most cases, it is wise to take the training courses for MSCE prior to taking the test as it can be quite challenging.
You will find more information about MSCE throughout the web.
Microsoft developed this type of training to allow individuals to get a specific training course, or several in various types of skills that pertain to Microsoft. The thing about this training is that it is specific to Microsoft. While you may learn to install a program in another course which would teach a broad range of information about all ways in which to do so, in the MSCE, you will learn strictly how it is done through Microsoft.
So, How Does MSCE Work?
In most cases, the training can be done in several ways. Students can take classes through certified teachers in school or they can study on their own. Some individuals feel that they have enough experience in the various uses of Microsoft to be able to take the test without taking a training class. The test is given at specific areas at specific times. In order to be considered, you must pay a fee of about $125 for each of the tests and certifications that you plan to take. The tests range in knowledge levels and in most cases, it is wise to take the training courses for MSCE prior to taking the test as it can be quite challenging.
You will find more information about MSCE throughout the web.
Passing The CCNA and CCNP: Three Myths About Cisco Exams
One of the drawbacks to the Internet is that it allows myths and "friend of a friend" stories to spread quickly, and usually the story becomes more exaggerated as it's passed along. Cisco exams are no exception. Here are three often-repeated myths and exaggerations regarding the CCNA and CCNP exams.
1. The survey you fill out before the exam determines the questions you'll get. Before you actually start your exam, Cisco presents you with a survey asking how you prepared and how comfortable you feel with certain technologies. It's a little awkward to rate yourself on Frame Relay, ISDN, etc., especially since the exam you're about to take covers those subjects. It's human nature to think that these questions impact your exam, but they do not.
I've seen posts on the Net saying that if you rank yourself as "great" in a subject, your exam will have harder questions on that topic, and if you rank yourself lower in that same subject, your exam will be filled with questions on this topic. Cisco has debunked this myth, so get it out of your mind. Don't think too much when you're filling out the survey.
2. If you miss a question, the exam keeps asking you about that topic until you get one right. This is known as "adaptive testing", and Cisco does not use this kind of testing in its exams. Your questions are drawn from a large question pool before you start the test. Those of us who remember adaptive testing from Novell exams years ago don't particularly miss this kind of testing! (For those who haven't taken an adaptive exam, you never knew how many questions you were going to get, only that there was a minimum around 15 questions. Your exam could end at any time after that. Nerve-wracking!)
3. If you use an extra command in the simulator questions, it'll be marked wrong. The Cisco simulator engine in the CCNA and CCNP exams acts just as a router or switch would. You are not going to be penalized for using an extra command. If the engine doesn't accept a command, you'll be told that when you use it. Just configure it as you would a router or switch.
When you walk into the exam room totally prepared with a combination of theoretical knowledge, hands-on experience, and configuration troubleshooting skills, you are ready to pass. Don't let Internet gossip distract you from the task at hand -- passing!
1. The survey you fill out before the exam determines the questions you'll get. Before you actually start your exam, Cisco presents you with a survey asking how you prepared and how comfortable you feel with certain technologies. It's a little awkward to rate yourself on Frame Relay, ISDN, etc., especially since the exam you're about to take covers those subjects. It's human nature to think that these questions impact your exam, but they do not.
I've seen posts on the Net saying that if you rank yourself as "great" in a subject, your exam will have harder questions on that topic, and if you rank yourself lower in that same subject, your exam will be filled with questions on this topic. Cisco has debunked this myth, so get it out of your mind. Don't think too much when you're filling out the survey.
2. If you miss a question, the exam keeps asking you about that topic until you get one right. This is known as "adaptive testing", and Cisco does not use this kind of testing in its exams. Your questions are drawn from a large question pool before you start the test. Those of us who remember adaptive testing from Novell exams years ago don't particularly miss this kind of testing! (For those who haven't taken an adaptive exam, you never knew how many questions you were going to get, only that there was a minimum around 15 questions. Your exam could end at any time after that. Nerve-wracking!)
3. If you use an extra command in the simulator questions, it'll be marked wrong. The Cisco simulator engine in the CCNA and CCNP exams acts just as a router or switch would. You are not going to be penalized for using an extra command. If the engine doesn't accept a command, you'll be told that when you use it. Just configure it as you would a router or switch.
When you walk into the exam room totally prepared with a combination of theoretical knowledge, hands-on experience, and configuration troubleshooting skills, you are ready to pass. Don't let Internet gossip distract you from the task at hand -- passing!
Be Certifiable! The Basics Of MCSE And MCP
It is not always who you know, but what you know. That is why obtaining Microsoft certification can be a valuable asset to your career. Of course, it does depend on what career path you want to take as to whether you want to get either MCSE training or MCP training or anything else for that matter. So what do those abbreviations MCSE and MCP stand for anyway?
MCP stands for Microsoft Certified Professional and MCSE is an abbreviation for Microsoft Certified Systems Engineer. What exactly does having a Microsoft certification mean anyway? We know that it looks good on a resume and opens new doors in your career. Did you know that being certifiable - in Microsoft anyway - sometimes will also boost your pay? Experience counts for a lot, but having a Microsoft certification or two does not hurt either!
So what does it take to be and MCP or MCSE? Lots of studying! The MCP courses and MCP exams are geared toward a more rounded technical professional. Candidates for MCP must pass one current certification test from Microsoft. Passing one of the exams demonstrates that the candidate has a consistent level of technical expertise.
With the Microsoft Certified Systems Engineer path, there are MCSE boot camps that help prepare candidates for the MCSE exams. These MCSE boot camps are intense classes often packed into a full two week period instead of the traditional weekly MCSE training classes in preparation for the MCSE exams. This path is more involved. MCSE certification is standard in the IT field and prepares you for anything from the design of a system’s infrastructure to analyzing the company’s needs before implementing a design.
Unlike those individuals who take the MCP training to prepare for MCP exams, students of MCSE have a course of study that is more intense. Instead of one test to prepare for, they have seven tests that they are required to pass to get their Microsoft certification. Yikes! Seven! They have five main exams to take as well as two electives. The five required MCSE exams are broken down into four operating system exams and one design exam. The two electives typically deal with other issues in design and implementation not covered in the five core tests.
After learning a few basics, it is easy to see that the MCP or Microsoft Certified Professional is really just a stepping stone to bigger and greater things in the world of Microsoft certification. The individuals who go for the MCP have a leg up on those peers who have no technical experience. They will have a better grasp on technical issues and usually stay a step ahead of trends. The MCSE is more specialized and appeals to the techno geek with a penchant for design and implementation. They like knowing how stuff works. So market yourself and become certifiable!
MCP stands for Microsoft Certified Professional and MCSE is an abbreviation for Microsoft Certified Systems Engineer. What exactly does having a Microsoft certification mean anyway? We know that it looks good on a resume and opens new doors in your career. Did you know that being certifiable - in Microsoft anyway - sometimes will also boost your pay? Experience counts for a lot, but having a Microsoft certification or two does not hurt either!
So what does it take to be and MCP or MCSE? Lots of studying! The MCP courses and MCP exams are geared toward a more rounded technical professional. Candidates for MCP must pass one current certification test from Microsoft. Passing one of the exams demonstrates that the candidate has a consistent level of technical expertise.
With the Microsoft Certified Systems Engineer path, there are MCSE boot camps that help prepare candidates for the MCSE exams. These MCSE boot camps are intense classes often packed into a full two week period instead of the traditional weekly MCSE training classes in preparation for the MCSE exams. This path is more involved. MCSE certification is standard in the IT field and prepares you for anything from the design of a system’s infrastructure to analyzing the company’s needs before implementing a design.
Unlike those individuals who take the MCP training to prepare for MCP exams, students of MCSE have a course of study that is more intense. Instead of one test to prepare for, they have seven tests that they are required to pass to get their Microsoft certification. Yikes! Seven! They have five main exams to take as well as two electives. The five required MCSE exams are broken down into four operating system exams and one design exam. The two electives typically deal with other issues in design and implementation not covered in the five core tests.
After learning a few basics, it is easy to see that the MCP or Microsoft Certified Professional is really just a stepping stone to bigger and greater things in the world of Microsoft certification. The individuals who go for the MCP have a leg up on those peers who have no technical experience. They will have a better grasp on technical issues and usually stay a step ahead of trends. The MCSE is more specialized and appeals to the techno geek with a penchant for design and implementation. They like knowing how stuff works. So market yourself and become certifiable!
Подписаться на:
Сообщения (Atom)