Welcome to Jeremy’s IT Lab. This is a free, complete course for the CCNA. If you like these videos, please subscribe to follow along with the series. Also, please like and leave a comment, and share the video to help spread this free series of videos. Thanks for your help. In this video we will continue our studies of OSPF. In part 1 I introduced the basic functions of OSPF. In this video I will cover more important OSPF topics which you need to know for the CCNA. To review, OSPF is item 3.4 on the official exam topics list. You already know the basics of configuring single area OSPFv2, and you know about the OSPF router ID. Let’s see what we’ll cover in this video. We’ll cover three main topics. First up OSPF’s metric, which as you know is called cost. It’s not so difficult to understand, so you should know it well for the exam. The next topic will be how routers become OSPF neighbors. I’ve mentioned OSPF neighbors previously, but haven’t actually shown you the actual process. We’ll go in depth in this video. Finally I’ll introduce some more OSPF configurations. Make sure to stick around until the end of today’s video for a bonus question from Boson ExSim. ExSim is a set of practice exams for the CCNA which I used to prepare for my CCNA and CCNP exams. I highly recommend them, so make sure to check out that bonus question and follow the link in the video description to get Boson ExSim for yourself. Let’s talk about OSPF’s metric. As you already know, OSPF’s metric is called ‘cost’. It is automatically calculated based on the bandwidth, which is basically the speed, of the interface. You can also manually configure the cost of each interface, but I’ll show you that later. The interface’s cost is calculated by dividing a value called the ‘reference bandwidth’ by the interface’s bandwidth. The default OSPF reference bandwidth is 100 megabits per second. So, for example a regular Ethernet interface with a speed of 10 megabits per second has an OSPF cost of 10, because 100 divided by 10 equals 10. A FastEthernet interface, with a speed of 100 megabits per second, has an OSPF cost of 1, because 100 divided by 100 is 1. Now, what about a gigabit Ethernet interface, with a speed of 1000 megabits per second? It has a cost of 1, even though 100 divided by 1000 equals 0.1. And what about a 10-gig Ethernet interface, with a speed of 10000 megabits per second? It also has a cost of 1, even though 100 divided by 10000 equals 0.01. Why is that? Well, in OSPF all values less than 1 will be converted to 1. Therefore FastEthernet, Gigabit Ethernet, 10Gig Ethernet, etc. are equal and all have a cost of 1 by default. Let me show you in the CLI. So, here is the same network topology as before. Let’s check out the cost of R3’s F2/0 interface. I used the SHOW IP OSPF INTERFACE F2/0 command. Can you find the cost? It’s actually displayed in two places. Here and here. As I said, the default cost of a FastEthernet interface is 1, because it has a speed of 100 megabits per second and the reference bandwidth is 100 megabits per second by default. Now let’s check out the default OSPF cost on R3’s G0/0 interface. I entered SHOW IP OSPF INTERFACE G0/0, and as you can see the cost here is 1 as well. Clearly the default situation is not ideal. Fortunately, you can change this. You can, and should, change the reference bandwidth with this command, from OSPF configuration mode. AUTO-COST REFERENCE-BANDWIDTH, followed by the reference bandwidth in megabits per second. Let’s take a look at that command. As I showed in the previous slide, the reference bandwidth is configured in megabits per second. I configured 100,000, so what will the cost of FastEthernet and Gigabit Ethernet interfaces be? 100,000 divided by 100 is 1000, so that’s the cost of a FastEthernet interface. How about Gigabit Ethernet? 100,000 divided by 1000 is 100, so that’s the cost of a Gigabit Ethernet interface. Why configure such a large number for the reference bandwidth? Well, you should configure a reference bandwidth greater than the fastest links in your network to allow for future upgrades. The 100 (*100,000) megabits per second I configured as the reference bandwidth is equal to a 100 gigabit per second interface, which is 100 times faster than the fastest interfaces in this network, regular gigabit ethernet. Finally, notice this message that is displayed when you configure the reference bandwidth. ‘Please ensure reference bandwidth is consistent across all routers.’ So, to provide a consistent cost for each interface bandwidth across the network, you should configure the same reference bandwidth on all OSPF routers in the network. Okay, I set the same OSPF reference bandwidth of 100 gigabits per second on all of the routers. The OSPF cost to a destination is the total cost of the ‘outgoing’ or ‘exit’ interfaces. This is just like spanning tree cost. For example, R1’s cost to reach 192.168.4.0/24 is what? To reach 192.168.4.0, a packet would exit R1’s G0/0, R2’s G1/0, and R4’s G1/0. So that’s 100 plus 100 plus 100, for a total cost of 300. We’ll check R1’s routing table soon, but one more thing. Loopback interfaces have a cost of 1. So, what is R1’s cost to reach 2.2.2.2, which is R2’s loopback0 interface? To reach 2.2.2.2, the packet must exit R1’s G0/0 and R2’s loopback0. Now, it doesn’t actually exit any physical interface to reach the virtual loopback interface, but the cost of 1 is added to the metric. So, R1’s cost to reach 2.2.2.2 is 101. Here is R1’s routing table before changing the reference bandwidth on all of the routers, so they all have the default reference bandwidth of 100 megabits per second. Notice that it has two routes to 192.168.4.0, one via R2 and one via R3. Even though the connection between R3 and R4 is a slower FastEthernet connection, it has the same cost of 1 as the gigabit Ethernet interfaces. And here is R1’s routing table after changing the reference bandwidth of each router to 100,000 megabits per second. Now R1 only inserts one route to 192.168.4.0 in the routing table, and the cost is 300 as we calculated before. Notice the cost to 2.2.2.2 is 101, like we also calculated before. Now let me introduce how to manually configure the OSPF cost of an interface. The command is IP OSPF COST, followed by the cost you want to configure. You configure this directly on the interface, and this cost will take priority over the auto-calculated cost. For example, I configured the cost of R1’s G0/0 interface as 10,000, and now you can see the cost is 10,000 instead of 100. One more option to change the OSPF cost of an interface is to change the bandwidth of the interface with the BANDWIDTH command. To review, the formula to calculate OSPF cost is reference bandwidth divideded by the interface bandwidth. I showed you how to change the reference bandwidth, but you can also change the interface bandwidth. Now, I have to make clear the difference between interface ‘speed’ and ‘bandwidth’. Although the bandwidth matches the interface speed by default, changing the interface bandwidth doesn’t actually change the speed at which the interface operates. The bandwidth is just a value that is used to calculate OSPF cost, EIGRP metric, etc. To change the speed at which the interface operates, use the SPEED command. This is how you actually change the speed at which the interface physically sends data. If you change the bandwidth of a gigabit Ethernet interface to 100 megabits per second, it will still operate at 1 gigabit per second. However, for the purpose of OSPF’s cost calculation, the bandwidth of 100 megabits per second will be used. Because the bandwidth value is used in other calculations, not just the OSPF cost, it is not recommended to change this value to alter the interface’s OSPF cost. It is recommended that you change the reference bandwidth, and then use the ip ospf cost command to change the cost of individual interfaces if you want. However, if you want to change the bandwidth of the interface, here is the command. BANDWIDTH, followed by the bandwidth in kilobits per second. Note that this is different than the reference bandwidth, which is entered in megabits per second. The interface bandwidth command is entered in kilobits per second. Before you enter any command like this, I highly recommend using the question mark to check the units the command is entered in. For example commands involving time, some are entered in seconds, some are entered in minutes. For commands involving speed, some are entered in kilobits, some are entered in megabits, etc. Always check to make sure you’re entering the correct units. Let’s summarize. There are three ways to modify the OSPF cost. First is to change the reference bandwidth. The command is AUTO-COST REFERENCE-BANDWIDTH and then the reference bandwidth in megabits per second, entered in OSPF config mode. Next is to manually configure the OSPF cost of the interface with the command IP OSPF COST, entered in interface config mode. Finally you can also change the interface bandwidth, although this isn’t recommended. The command is BANDWIDTH, followed by the bandwidth in kilobits per second, entered in interface config mode. I already showed you the SHOW IP OSPF INTERFACE command, but here’s a quicker way to check the OSPF cost of each interface. SHOW IP OSPF INTERFACE BRIEF gives a convenient overview of each OSPF-enabled interface on the router. Okay, let’s move on to the next topic. This is another very important topic in OSPF, OSPF neighbors. Making sure that routers successfully become OSPF neighbors is the main task in configuring and troubleshooting OSPF. Once routers become neighbors, they automatically do the work of sharing network information, calculating routes, etc. So, you just have to make sure that OSPF is activated on the correct interfaces, and that the proper conditions are met to allow the routers to become neighbors. Of course, there are more advanced OSPF configurations you can do, but for basic OSPF operation they aren’t necessary. However, if routers can’t become OSPF neighbors, OSPF can’t operate at all, so this is very important. So, how do routers become OSPF neighbors? When OSPF is activated on an interface, the router starts sending OSPF hello messages out of the interface at regular intervals (determined by the hello timer). These are used to introduce the router to potential OSPF neighbors. By exchanging hello messages they check that they are compatible to become OSPF neighbors, and then negotiate their neighbor relationship. By the way, the default hello timer is 10 seconds on an Ethernet connection. Remember this number! OSPF hello messages are multicast to the IP address 224.0.0.5, which is the multicast address for all OSPF routers. Do you remember RIP’s multicast address? It’s 224.0.0.9. How about EIGRP? 224.0.0.10. Also, OSPF messages are encapsulated in an IP header, and the ‘protocol’ field of the IP header has a value of 89 to indicate OSPF. If you need a review of the IP header, go back and watch Day 10 of the course again. Okay, for OSPF routers to become neighbors they have to go through various neighbor states. I’ll give a basic overview of each of the neighbor states. I recommend taking notes for this section. Although it will be just a basic overview, I’m going to give you a lot of information over the next few slides. So, let’s assume OSPF is already activated on R2’s G0/0 interface. Then, OSPF is activated on R1’s G0/0 interface. It sends an OSPF hello message to 224.0.0.5. There are more fields in the hello message, but two important ones are R1’s router ID and the neighbor’s router ID. However, R1 doesn’t know about R2 yet, so the neighbor router ID field is 0.0.0.0. R1 doesn’t know about any OSPF neighbors yet, so the current neighbor state is Down. This is the first OSPF neighbor state, ‘Down’. When R2 receives the Hello packet, it will add an entry for R1 to its OSPF neighbor table. In R2’s neighbor table, the relationship with R1 is now in the Init state. Note that R1 still doesn’t know about R2, so it will have no entries in its OSPF neighbor table. Basically, the Init state means that a Hello packet was received, but R2’s own router ID is not in the Hello packet. R2’s router ID is 2.2.2.2, but the neighbor router ID in R1’s Hello packet is 0.0.0.0. So, that’s the Init state. The next state is the 2-way state. R2 will send a Hello packet containing the RID of both routers. R1 will insert R2 into its OSPF neighbor table in the 2-way state. Then, R1 will send another Hello message, this time containing R2’s RID. Now both routers are in the 2-way state. The 2-way state means the router has received a Hello packet with its own RID in it. If both routers reach the 2-way state, it means that all of the conditions have been met for them to become OSPF neighbors. They are now ready to share LSAs to build a common LSDB. On the other hand, if they fail to reach this 2-way state, you know that you have to troubleshoot and find what’s stopping them from reaching it. In some network types, a DR (Designated Router) and BDR (Backup Designated Router) will be elected at this point. I will talk about OSPF network types and DR/BDR elections in Day 28, so don’t worry about them for now. I just wanted to introduce the terms, DR and BDR. At this point, the routers are already OSPF neighbors. Over the next few neighbor states they will share LSAs and form a full OSPF adjacency. Let’s go to the next neighbor state. After the 2-way state, the two routers will now prepare to exchange information about their LSDB. Before that, they have to choose which one will start the exchange. So, they will decide which one will be the Master router and which will be the Slave router. Note that these are different than the DR and BDR I mentioned in the last slide. This Master/Slave relationship is only needed for this initial exchange of LSDB information. They decide which will be the Master and which will be the slave in the Exstart state. The router with the higher RID will become the Master and initiate the exchange. The router with the lower RID will become the Slave. So, in this case R2 will be the master and R1 will be the slave. To decide the Master and Slave, they exchange DBD (Database Description) packets. DBD packets are also important in the next state, so I will talk more about them in the next slide. Basically, the Exstart state is just to prepare for the next state. R1 sends a DBD packet claiming to be the master. However R2 corrects R1. R2 has the higher router ID, and says that it will be the master. In the next state, the Exchange state, the routers exchange DBDs which contain a list of the LSAs in their LSDB. These DBDs do not include detailed information about the LSAs, just basic information telling their neighbor what LSAs they have. Basically the routers are telling each other, ‘I have these LSAs’, but they aren’t actually sending the LSAs yet. The routers compare the information in the DBD they received to the information in their own LSDB to determine which LSAs they must receive from their neighbor. After exchanging DBDs, they move to the next state. The next state is the Loading state. In the Loading state, routers send Link State Request (LSR) messages to request that their neighbors send them any LSAs they don’t have. In the Exchange state they exchanged DBD packets, so they know which LSAs their neighbors are holding. So, these LSRs are used to request any missing LSAs to make sure each router has the same LSAs. I’ll just show one side of the exchange, but R2 will also send R1 LSRs for any missing LSAs. Then the LSAs themselves are sent in Link State Update, LSU, messages. R2 sends R1 the requested LSAs in an LSU like this. R1 will also do the same for R2. Finally, The routers send LSAck messages, another kind of OSPF message, to acknowledge that they received the LSAs. Now the loading state is complete, and the routers have the same LSDB. We’ve reached the final OSPF state. In the Full state, the routers have a full OSPF adjacency and identical LSDBs. But that doesn’t mean things are complete. They continue to send and listen for Hello packets, once every 10 seconds by default, to maintain the neighbor adjacency. To maintain the adjacency another timer called the ‘Dead’ timer is used. Every time a Hello packet is received, the ‘Dead’ timer, which is 40 seconds by default, is reset. However, if the Dead timer counts down to 0 and no Hello message is received, the neighbor is removed. If the neighbors remain up, the routers will continue to share LSAs as the network changes to make sure each router has a complete and accurate map of the network. This is the main advantage of dynamic routing protocols, the routers automatically react to changes in the network and add, remove, or change routes as necessary. Let’s summarize that process. First of all, the connection between R1 and R2 comes up, or OSPF is activated on the interfaces, which starts the process. The first state is the Down state, R1 and R2 don’t know each other yet, but they will send hello packets out of their interfaces. Let’s assume that R1 sends the first Hello packet. The Init state is when R2 receives that first Hello packet from R1, but R2’s own router ID isn’t in the packet yet. In the 2-way state, the routers exchange more hello packets, but R1’s router ID is included in R2’s Hellos, and R2’s router ID is included in R1’s Hellos. In some kinds of OSPF connections an election for the designated router and backup designated router takes place. I will talk about this more in Day 28. Next is the Exstart state. The routers exchange DBD packets to determine which will be the Master and which will be the Slave. The Master is the router that starts the DBD exchange in the next state, the Exchange state. They exchange DBD packets to tell each other about the contents of their LSDB. The next state is the Loading state. They use LSRs, Link State Requests, to request LSAs from each other. The LSAs are sent in LSU, Link State Update, packets. Finally, LSAck packets are sent to acknowledge that they received the LSAs they requested. Finally, the routers reach the Full state, and they have a full OSPF adjacency. Do you remember this slide from Day 26? The three main steps in the process of sharing LSAs and determining the best routes to each destination are 1, become neighbors, 2, exchange LSAs, and 3, calculate the best routes. Looking at this process again, these first three states involve becoming neighbors, these three involve exchanging LSAs to synchronize the LSDB, and then the routers use the metric I taught you to calculate the best route to each destination. That’s a basic overview of how OSPF works. Also, here’s a quick summary chart of the 5 different OSPF message types. Notice that they are numbered from 1 to 5, 1 being Hello, 2 being DBD, etc. I already described the basic purpose of each of these messages, so you can pause the video here or take a screenshot if you want to use this chart to review. After that overview, let’s take another look at a few OSPF show commands, you should understand the output a little better now. Here is SHOW IP OSPF NEIGHBOR, I entered it on R1. Note the full state with both neighbors R2 and R3. Also, both R2 and R3 are DRs. Again, I will explain DRs in the next video. Also notice the dead time. This counts down from 40, but resets as soon as R1 receives a Hello packet from the neighbor. So, assuming a Hello packet is received every 10 seconds, it should count down to 30, reset to 40, count down to 30, reset to 40, etc. Now let’s take another look at SHOW IP OSPF INTERFACE, looking at R1’s G0/0 interface. You can see the default Hello and Dead timers of 10 and 40 here. Hello due in 7 seconds means that R1 will send a Hello message out of this interface in 7 seconds, as it does once every 10 seconds. Neighbor count is 1, adjacent neighbor count is 1. R1 has only 1 neighbor connected to its G0/0 interface, that’s R2. In the next video I’ll tell you the difference between a neighbor and an adjacent neighbor. Finally, adjacent neighbor 2.2.2.2, designated router. As we saw above in SHOW IP OSPF NEIGHBOR, R2 is a designated router. Again, I’ll talk about that in Day 28, but feel free to do a Google search to learn about it if you’re curious. Okay, that’s all for OSPF neighbors for today, we will cover a few more details in Day 28. Let’s move on to look at a little bit more OSPF configuration. I already showed you a few new OSPF configurations when we talked about OSPF metric, specifically the AUTO-COST REFERENCE-BANDWIDTH command and IP OSPF COST command. So, let’s just look at a couple additional configurations. First off, do you remember the purpose of the NETWORK command? It’s the same for RIP, EIGRP, and OSPF. It simply tells the router which interfaces to activate the routing protocol on. Well, you can actually enable OSPF directly on an interface, without using the NETWORK command. For example, let’s assume that R1 has no OSPF configurations on it yet. Here’s how to enable OSPF on the interfaces. You can activate OSPF directly on an interface with this command: IP OSPF, followed by the process ID, then AREA, and the area ID. Note that this is done from interface configuration mode. Now OSPF is enabled on those interfaces and I haven’t even entered OSPF configuration mode. Next, another method to configure passive interfaces. Can you see the difference? You can configure all of the router’s interfaces to be OSPF passive interfaces by default with the command PASSIVE-INTERFACE DEFAULT. Then, you can use the command NO PASSIVE-INTERFACE to remove that only from specific interfaces. This is simply another way to configure passive interfaces. Depending on the number of passive interfaces you need to configure, this method might be faster, or perhaps the normal method is faster. Either way, the effect is the same. If you configure OSPF directly on the interfaces, you’ll see slightly different output from SHOW IP PROTOCOLS. The ‘routing for networks’ section is empty, and instead the interfaces you activated OSPF on are displayed here, ‘routing on interfaces configured explicitly’. The rest of the output is the same, however. Before moving on to today’s quiz, let’s review what we covered. First up I showed you OSPF’s metric, called cost. By default it is automatically calculated by dividing the reference bandwidth by the actual bandwidth of the interface. However, if the result is a value less than 1, it is converted to 1. The default reference bandwidth is 100, so anything equal to or faster than 100 megabits per second has an equal cost of 1. You can modify the reference bandwidth with the AUTO-COST REFERENCE-BANDWIDTH command. You can also manually configure the cost of an interface with the IP OSPF COST command. One more option to modify an interface’s cost is to change the bandwidth with the BANDWIDTH command, although this isn’t the recommended method. Finally, a route’s metric is the total cost of the outgoing interfaces in the route. Next we studied the process routers use to become OSPF neighbors. Here’s the summary diagram. This is probably the most difficult section of this lecture. I recommend watching it a few times, and perhaps doing a google search for ‘ospf neighbor states’ to learn more about the process. Finally I introduced a couple more OSPF configurations. Instead of using the NETWORK command, you can activate OSPF directly on an interface with this command. As an alternative method of configuring passive interfaces, you can configure all interfaces as passive with the PASSIVE-INTERFACE DEFAULT command, and then only make specific interfaces active after. Make sure to watch until the end of today’s quiz for a bonus question from Boson ExSim for CCNA, a set of practice exams for the CCNA and the best tool to get ready for the real CCNA exam. Okay, let’s go on to quiz question 1. Put the OSPF neighbor states in the correct order. Here are the neighbor states, order them from 1 to 7. Pause the video now to think about your answer. Here’s the answer. Down, Init, 2-way, Exstart, Exchange, Loading, and Full. A full explanation of each state would take too long, so go back in the video if you don’t remember the order and purpose of each state. Let’s go to question 2. Which statement about OSPF’s default cost is correct? a) All interfaces have the same cost. b) Ethernet and FastEthernet interfaces have the same cost. c) FastEthernet, Gigabit Ethernet, and 10Gig Ethernet interfaces have the same cost. And d) Ethernet, FastEthernet, Gigabit Ethernet, and 10Gig Ethernet interfaces have the same cost. Pause the video to think about the answer. The answer is C, FastEthernet, Gigabit Ethernet, and 10Gig Ethernet interfaces have the same cost by default. The cost is calculated by dividing the reference bandwidth by the interface bandwidth. The default reference bandwidth is 100 megabits per second, so a FastEthernet interface has a cost of 1. However, anything faster than that will have a cost of 1 as well, because all values less than 1 are converted to 1. Let’s go to question 3. In which OSPF neighbor state are the Master and Slave roles decided? A, Exstart. B, 2-way. C, Exchange. Or D, Loading. Pause the video to think about the answer. The answer is A, Exstart. A Master and Slave need to be decided in the Exstart state. The Master is the router that will start the Database Description, DBD, exchange in the following state, the Exchange state, which is option C. In option B, 2-way, a designated router and backup designated router are selected in some cases, but not a Master and Slave. In D, the Loading state, LSRs, LSUs, and LSAcks are exchanged, but a Master and Slave are not decided. Let’s go to question 4. Which of these commands can be used to make a FastEthernet interface have an OSPF cost of 100? A, AUTO-COST REFERENCE-BANDWIDTH 100. B, 1000. C, 10,000. Or D, 100,000. Pause the video to think about your answer. The answer is C, AUTO-COST REFERENCE-BANDWIDTH 10,000. Once again, the cost is calculated by dividing the reference bandwidth by the interface bandwidth. A FastEthernet interface has a bandwidth of 100 megabits per second. 10,000 divided by 100 equals 100, so you should set the reference bandwidth to 10,000. Let’s go to question 5. What are the default OSPF Hello / Dead timers on an Ethernet connection? All times are in seconds. A, Hello, 2 seconds, Dead 20 seconds. B, Hello 10 seconds, Dead 40 seconds. C, Hello 30 seconds, Dead 120 seconds. Or D, Hello 60 seconds, Dead 180 seconds. Pause the video to think about your answer. The answer is B, the default Hello timer on an Ethernet connection is 10 seconds and the default Dead timer is 40 seconds. Now, I haven’t mentioned this in this video, but for some other kinds of connections the default OSPF timers are actually 30 and 120, as in option C. However, for Ethernet connections the defaults are 10 and 40. I’ll talk about some other kinds of connections in Day 28. Okay, that’s all for the quiz. Let’s take a look at a bonus question from Boson ExSim for CCNA. Okay, here is today's Boson ExSim practice question. You administer the OSPF network shown in the diagram above. The AUTO-COST REFERENCE-BANDWIDTH 1000 command has been issued on every router in the network. What is the cost of the route from RouterA to RouterC? A, 11. B, 3. C, 12. D, 2. And E, 20. Pause the video to think about your answer. Okay, let's check. So, you set the reference bandwidth to 1000 megabits per second on each router, so that would mean that these gigabit ethernet connections, 1 gigabit per second, have a cost of 1, because 1000 divided by 1000 equals 1. On the other hand, these 100 megabit per second fastethernet interfaces have a cost of 10 because, of course, 1000 divided by 100 is 10. So, ideally we will avoid any fastethernet interfaces because they cost 10 times as much as a gigabitethernet interface. So, the shortest route without passing through any fastethernet interfaces is from RouterA to RouterB, that is a cost of 1. RouterB to RouterE, plus 1 so 2. RouterE to RouterC, plus 1 so 3. So the total cost from RouterA to B to E to C is 3. Let's check the answer. Okay, that is correct. Here is Boson's explanation, quite detailed. And they of course show you the diagram with the same path that I chose. RouterA to B to E to C. Okay, so you can pause the video here if you want to read Boson's explanations. And they also include some references, or a reference in this case, to Cisco documentation. OSPF Design Guide: OSPF Cost. This Cisco documentation is available free online, and it's another great study resource. So I highly recommend checking it out. Okay, so if you want to get a copy of Boson ExSim, please follow the link in the video description. These are the practice exams I used myself for both my CCNA and CCNP exams, so I highly recommend them. Once again, follow the link in the video description. There are supplementary materials for this video. There is a flashcard deck to use with the software ‘Anki’. There will also be a packet tracer practice lab so you can get some hands-on practice. That will be in the next video. Sign up for my mailing list via the link in the description, and I’ll send you all of the flashcards and packet tracer lab files for the course. Before finishing today’s video I want to thank my JCNP-level channel members. Thank you to Marko, Florian, Daming, Venkatesh, Kone, Joshua, Jhilmar, Samil, Ed, Value, Magrathea, Justin, John, funnydart, Scott, Hassan, Gerrard, Tibi, Joyce, Marek, Velvijaykum, C Mohd, Johan, Mark, Miguel, Yousif, Sidi, Boson Software, Charlesetta, Devin, Lito, Mike, Yonatan, and Vance. Sorry if I pronounced your name incorrectly, but thank you so much for your support. One of you is still displaying as Channel failed to load, if this is you please let me know and I’ll see if YouTube can fix it. This is the list of JCNP-level channel members at the time of recording by the way, August 11th 2020. If you signed up recently and your name isn’t on here don’t worry, you’ll be in future videos. Thank you for watching. Please subscribe to the channel, like the video, leave a comment, and share the video with anyone else studying for the CCNA. If you want to leave a tip, check the links in the description. I'm also a Brave verified publisher and accept BAT, or Basic Attention Token, tips via the Brave browser. That's all for now.