(04) Foundation: Establishing A BGP Session With An ISP.

If you look at traditional BGP books, like if you go to Cisco Press and grab their book on BGP, you'll find that there's gobs and gobs more concepts before they ever start touching the configuration, which is wise because there is a lot to BGP. But a lot of times if you go at it that way, it's just kind of boring. You get a lot of concepts, which you forget half of it before you even start, and then by the time you get to the config, you're like, wait a sec. How did that work? So I want to change that. I want to give you just a few more facts, my thought is five minutes or less. Well, how many times have you done that? You're at a data center or something. Your wife or husband calls and is like, hey, how much longer are you going to be? You're like just five minutes. I just need five minutes, and I'm done. And three hours later. So it won't be three hours, but nonetheless, I just want to talk about the facts-- it's funny, as I look at it, I'm like BGP relationships, the facts. I feel like I'm talking to my 10-year-old son or something. I'm like, son, there's something I need to tell you about BGP. So moving down, we've got BGP packets and process, like how does a neighbor form? And then I just want to go practical. I want to say, OK, let's bring up a connection to an ISP using BGP. How do we do it? What does it mean? What are we going to expect, when we do that, to receive? And just kind of talk about it a lot more practical and hands on than just concepts.

1. Neighbors never Discover Manual Config needed on Both Sides.So let me first tell you how you get to be part of the BGP neighborhood. How do those neighbors form? Well, differently than most routing protocols. Number one, routers never discover each other with BGP. And think back to OSPF, EIGRP, all of the major routing protocols that are out there. You go into the router configuration mode, type in some network commands, and as soon as you do, two things happen. Hang on. Let me-- I'm just walking around, need to sit down, grab a pen. So let's say we've got this router right here connected to a WAN link, a router on the other side. This interface has the IP address, 150.1.1.1. So if I were running EIGRP, I would go in and type in network, and let's just be lazy. I'll say, network 150.1.0.0. So what happens when I do that is two things, always two things. And I'll tell you, this is probably one of the hardest things for new people in Cisco to get. When I'm teaching CCNA, I dread this part because it takes some time to grasp. Q. What happens when we put Network Command in EIGRP ?Two things happen. First thing is the router looks around at all of its interface and says, do I have any that start with 150.1? Why that? Well, because by default, 150 is a Class B address, so it thinks by default, the first two octets are significant. Now, with EIGRP, I could also toss on a wild card mask. I could say 0.0.0.255, and that would say, well, let's look at 150.1.0, since we've got that third zero, but we're not doing that here. So it looks around for interfaces starting with 150.1 and does two things. One, sends hellos. So it says, oh, look. I've got an interface, a WAN link over there, serial port, with 150.1. Great. That qualifies. I'm going to start sending hellos because I want to form a neighbor relationship. The second thing it does is advertise that network, and this is where I think a lot of the confusion comes in because people go, oh, OK. So I'm going to advertise the 150.1 network. So my router will say, router one. They think, oh, well, so I'm going to go out, I'm going to say, hey, I know about the 150.1 network. No, no, no, no, no. That's not how it works. That's, I would say, the toughest piece to get, is this does not actually control the actual advertisement at all. What happens is the router looks around, identifies the interfaces. It goes, oh look. Serial zero. It's 150.1. Great. I'm going to send hellos, try and form a neighbor there. And second off, I'm going to advertise that network, meaning I'm looking at the serial zero interface, looking at the IP address command, and the IP address command says I've got 150.1.1.1/30, or 255.255.255.252 would be that subnet mask. So it says, I'm going to advertise the 150.1.1.0/30 network. That's what gets advertised, not 150.1.0.0. In BGP, Neighbors Discover each other Manually.Now, this is going to be relevant when it gets to BGP. So first off, neighbors never in BGP discover each other. I have to manually config. So right there, let me change my pen a little fatter. Does not send a hello. Does not say, hello, everyone. I want to form a neighbor, because there is hello packet to BGP. Neighbors have to be manually set up. 2. Network Command works differently with BGP than other Routing Protocols.Second thing, let me jump to the very bottom. It says the network command works differently with BGP than other routing protocols. If I were to type in, "Network 151.0.0," it doesn't look around at all the interfaces saying, do I have any interfaces starting with 150.1. It's going to look at the routing table and say, do I have exactly the route 150.1.0.0/16 in my routing table? It's not looking for any subset of it. I'm getting a little ahead, but we're going to talk about this when we get into the actual configuration of BGP. A lot to say about that, but it's very different than the traditional network command we use with OSPF and all that. So second checkpoint. Look, I'm already almost to my five minutes. I did it again. 3. Neighbors must be reachable on TCP 179.So neighbor must be reachable on TCP port 179. That's the port of BGP. That's how they form neighbors. So obviously, if there's a firewall, got to allow things through that port. 4. Multiple Sessioins to the same Neighbors not permitted (They Will Drop)Multiple sessions to the same neighbor are not permitted. They will drop. What that means is if I have redundant links, something like this, I can't go in and say, hey, I want to be a neighbor right here, and I want to be a neighbor right here, to both the IP address on this interface and the IP address on this interface. It doesn't work that way. It will try to form two neighbor relationships, but once it realizes it's the same neighbor-- by the way, they identify themselves by router IDs, kind of like a little IP address that says, hi, this is me. So once it realizes, once the router run goes, oh, that's the same guy, it's going to drop one of those sessions. The one with the lower IP address will end up winning as the session that's allowed. So you might say, wait a second. What if I want some redundancy there? I want to have both those links. I want to form a neighbor over both links so that way, if one goes down, I don't lose the neighbor. That's totally valid. I want to say that's a huge concern of people when they get into BGP. It can be done, but it's not by forming neighbors right here. What you do-- and I'm again getting a little ahead because I want to talk about this as we go-- what you do is you create a loop back interface. And I'll say, well, let's say the loopback interface, just for this example, is 1.1.1.1. I go on here, and there's many ways that you can pull this off, but I'm just I'm going to go old school on you. Actually, this is very common. Do an IP route. It's a static route. I'll do an IP route and I'll say, well, to reach 1.1.1.1, go here, and type in that IP address. That'll be the next hop. Then I do a duplicate IP route. IP route 1.1.1.1, again, exactly the same destination, and this time, go here. You would put the next hop one, and I'm just out of room-- next hop two right there. So you would have two routes to the same 1.1.1.1 with BGP. Then you would configure your neighbor at 1.1.1.1. You would say, hey, I want to peer with 1.1.1.1. So what happens is Router One down here looks at its routing table, sees two equal cost paths in its routing table to the same place, 1.1.1.1. It goes, oh, sweet. I can load balance. So what you do is you end up load balancing over both of those links to reach and form that BGP neighbor. There's a little more to it than that, but what I want to give you, just at this-- I know that we're still. Good grief. I need a wireless headset, people. I keep stepping on myself. The reason I wanted to show this to you is I want you to see how BGP relies on the foundation routing protocol, meaning I just plugged some static routes right there, but like I said, that's kind of old school. You don't have to go that way. You could use OSPF to do the same job for you a little easier, or EIGRP. BGP uses an internal routing protocol, or static routes-- I'll put IGP right here-- in order to reach its neighbors and form BGP relationships kind of on top of that. Does that make sense? This is such a huge concept. I'm going to be repeating this again and again. The IGP lays the foundation. This is the road, right? Let me take out these redundant links, and this is like the road to Rome. You've got there's this nice, long road that's paved of [INAUDIBLE] and IGP. BGP doesn't even care about it. It's like, hey, I just want to talk to 1.1.1.1. What you did was make a killer road by doing some load balancing between some links, but BGP is just like, hey, I'm happy. Got a lot of bandwidth. I can peer with 1.1.1.1. So we will see that concept again and again and again all throughout, because I know for me, when I got into BGP, I was like, huh? I know. You're looking at that going, why was that confusing? That wasn't that bad. But you'll start seeing when we get to IBGP and things like that, it starts getting a little wacky.

So one of the beautiful things about BGP's neighbor process is it's so amazingly simple. There is a lot that can go wrong. I will say that. You'll be troubleshooting with BGP. But if you know the process and you know where things get stuck, it's kind of like you'll know exactly where to look. You'll be like, oh, it's not working. OK, I know what that is. So it's not like OSPF. OSPF is a lot more complex. 1) BGP PacketsSo here it is. Four packets BGP uses. 1.1) Open PacketNumber one is the Open message. Open is the closest thing to a hello that BGP has. So the only reason an Open is sent is because you manually configured a neighbor. You said, I want to be a neighbor with 1.1.1.1, just like we were talking about, so it sends an Open message saying, hey, 1.1.1.1, let's hook up. Let's form a neighbor relationship. And you'll actually see the message in a debug. It'll say Open sent, and then 1.1.1.1, if he's configured for you, he'll reply back and say, oh hey, 2.2.2.2, lets talk. And he'll have an Open Confirm Debug that's sent. So Open is kind of how they form relationships. 1.2) UpdateUpdates are just that. Hey, got some news for you. Here's an update. Here's a route that just went up. Here's my routing table. Updates are pretty much everything else that BGP sends that's of value. 1.3) Keep aliveA Keepalive is, well, it's a Keepalive. It does rely on the TCP Keepalives, and essentially, every single time an update's sent or Open is sent, that kind of thing-- and by the way, Open is only sent to form the session. That's why I said it's kind of like a hello message. But it doesn't continually send open messages. Once it's open, it's done. So the Keepalive is there because BGP can, depending on how you use it, be quiet for a long time. It might be batching a whole bunch of updates over five minutes, and TCP can say, well, the session's OK but have you ever played with TCP? It's so-- what's the word? I can't think of the word. It lives forever. I had a laptop that I was using to SSH two way, router and configure it remotely, and I was sitting on my couch. The battery died or something, it went into Hibernate, and I was like, oh, jeez. So I went and found my power supply, plugged it in. This was over a course of five, six minutes. Laptop powered back up out of Hibernate mode, and I hit the Enter key, and I'm still there. TCP is like, hey, life is good. I'm assuming the session is still alive. No kill was sent or anything like that. I was like, wow, look at that. So the reason I bring that up is TCP is not an accurate live indicator. TCP has great acknowledgements so you know that everything that you sent was received by the other side, but it doesn't really tell you that the other side is truly alive because 10 minutes could go by if nobody's talking, and TCP will just be like, hey, our session is good. So BGP will generate a Keepalive every now and then. It's just some traffic to make sure the other side really is there. 1.4) NotifcationAnd then we have notifications. Notifications, think of yourself in grade school, if teacher was like, hey, Johnny, I've got a notification for you, that's usually a bad thing. And with BGP, anytime you see a notification, it's bad. Something bad is about to happen. It's about to tear down the session, something didn't match with a neighbor. So if you're doing a debug and you see a notification, look there. That's where the problem is. It's going to say something like, authentication mismatch, or peer and wrong remote autonomous system, or something to that nature. That will be in the notification. So that's it. That's the four packets that BGP uses.

2) BGP StatesNow, the transition that BGP goes through when it's forming a neighbor process is right on the right hand side, Idle Active, Open Sent, Open Confirm, and Establish. And we'll be working through this more as we go.

2.1) IdleIdle means I've got a neighbor configured, I haven't tried to talk to him that. 2.2) ActiveActive means I'm trying to start the communication, and I'll leave it at that because that's where a lot of bad things happen. Maybe I'm trying to start the communication, but the other guy doesn't recognize me. Or I'm trying to start the communication, but I don't know how to reach the neighbor's IP address that you've set up. For example, let's say I said to peer with 1.1.1.1 over here, but I forgot to type in these static routes. So Router One doesn't know how to reach 1.1.1.1. You might type in neighbor 1.1.1.1 in BGP, it's like, yeah, I'm just kind of active. I'm active on that neighbor. I want to form a neighbor relationship, but I don't know how to get there. So you'll see the neighbor relationship go from Idle to Active, Idle to Active. It kind of bounces back and forth.

2.3) Open SentOpen Sent. That's a good one. That means I've sent an open message. I'm hoping that we get one back. 2.4) Open ConfirmOpen Confirm. I got one back. Looks like life is good and we are established.

During this, there's a big check that's taking place. Does all of our attributes that need to match up matching up, for instance, like authentication? So that's it. That's the foundation concepts that I wanted to give you before we get into the actual configuration of BGP, and the rest of them will come as we go. I'm going to configure stuff and you'll see stuff happening, and then I'll explain it using more concepts.

GNS3 IntroductionSo before we get going, I know some of you probably recognize the graphics that I have on the screen here. This is my little simple BGP scenario. And I want to mention that I am going to be using-- I have fallen in love with this little tool-- GNS3 for this entire series. Let me give you the fly by commercial on GNS3, and I say commercial loosely, because it's free. I'm not like, buy now. It's free. Go download it. Go to gns3.net, that's our little URL right there. And GNS3 is made by a guy named Jeremy, which immediately caused a bond between us. He's actually in France, though. And he took something called Dynamips, which was an open source IOS emulator, that actually boots real IOS image for Cisco. I'm talking the real software for Cisco, and allows you essentially to trick it, to make it believe it's running on a router when it's really running on a PC. Well, Dynamips was kind of a world changing thing for a lot of people that lived in the Linux world. What Jeremy did is he created GNS3, which is a graphical front end to Dynamips. Why can't I say that? The Q one, which allows you to do a lot of ASA, like PIX ASA. You can actually emulate Junos. I don't know why you would want to do that, but maybe you wanted to see, well, this is why I like Cisco better, than you might give that a whirl. But this is really cool. Recently, it actually added VirtualBox, which hang on, let me show you this screen shot here. So anyway, what Jeremy did is he created this graphical front end for it where all you have to do is drag and drop the routers onto the white pavement, and it automatically does all the Dynamips, Linuxy, text file configuration for you from behind the scenes. So it makes it really easy to do this kind of stuff. And I say really easy tongue in cheek, because there is a little bit of setup that you're going to have to do. You'll have to learn a little bit about, for instance, idle PC timers so it doesn't destroy your processor. Ironically, here's the funny thing. CBT Nuggets and me created an absolutely free, excellent video called GNS3 Overview and Operation which, if you're new to GNS3, if is your first time using it, check that out. It'll save you a lot of pain. I'm just talking about how to get it set up and how to get going on there. But one of the neat things, I was saying that they added Virtual Box, is-- let me see if they have a picture of it. Well, this isn't it, I don't think, but you can actually put a little PC on there. And now that they have Virtual Box, you can actually boot Windows XP or Windows 7, if you're brave-- you can boot an actual operating system on the PC within there. Or Linux. Throw Ubuntu on there to get a quick Linux system up and running, to where you actually have real hosts that you can ping, you can run web servers on. It's like building your own little world. So the GNS3 is so amazingly excellent. The reason that I use it, the big reason, is because it is free, and it allows you to do the same things that I'm doing. There's been series I've created for CBT Nuggets. I just finished CCNA Lab, Cisco for the Real World, where I used GNS3 and just built a ton of lab scenarios, and I'm planning on doing the same thing for BGP. So I'm going to make available all of my topology files. So this, by the way, is the topology file that matches the screenshot that you see. So that you're able to walk through exactly the same stuff that I am, just by downloading the topology files and plugging it into your GNS3.

Simple BGP Scenario

So that all being said, let me give you a quick description, then we'll get into the config. What we've got is we've got Router One. Let me grab a pen here. Down here, this is you, and you're Autonomous System 500. Public Autonomous System NumberNow, where would you get that number? Well, autonomous system numbers have to be registered. You have to go to ICAN or some government entity to say, I have an autonomous system number that is public. It is recognizable by the world. Now, that being said, you only need a real autonomous system number if you plan to be really on the internet. I know, everybody's like, isn't that the point? Private Autonomous System NumberYes it is, but usually, you only get a real autonomous system number if you've got a couple slash 16s, you're an ISP, I mean, you're the real deal. This kind of thing, where you've got a Class C network where you would want to advertise that to the world through a couple ISPs, you would most likely use a private autonomous system number, and I'll give this to you now. Private BGP autonomous system numbers are 64,512 through 65,535. That is considered the private autonomous system range. So for instance, you could get Autonomous System, we'll say 64512, that both of these ISPs agree to peer too, but as soon as your network gets advertised through them, it's kind of like NAT where you've got private IP addresses. They're going to strip that bad boy off, get rid of it, and replace it with their autonomous system. So as they advertise your little 200 network to the rest of the world, it looks like it came from Autonomous System 111. It looks like it came from Autonomous System 222. I'll say if you're an enterprise customer, that's what most of you will end up doing, is getting a private autonomous system. Really, only true service providers or just massive organizations need a real autonomous system.

So with that being said, we're just using 500 for fun. We have our autonomous system down here, 500. We would like to peer with both ISPs. We've got ISP1. And by the way, I just put some junk networks in there so that we could receive some routes. 151.x.x.x, those routes are all originating from ISP1's autonomous system. We've got 152.x.x.x, which all originate from ISP2. And then I've got these guys, which originate from some other autonomous system, 153.1.1.0, and 153.2.2.0. Now truth be told, I'm actually originating both of these from both autonomous systems. There's no mystical link behind the scenes linking these guys or anything like that. What I want you to see is how a router handles it when he gets two routes to the same destination. For instance, ISP1 is going to say, hey, I know about 153.1.1.0. This guy's going to say the same thing. Now the question will be, which one's Router One going to choose, and why would it choose that way, and can we influence that choice? All those kind of things, because that's really going to lead us into where we're going with BGP. So let's get started. Let me bring up my terminal here. Router One. So I've got Router One configured right here. Let me just get you oriented. I'm going to do a Show IP Interface brief. And right here, you can see that I've got serial zero. That's actually a connection to ISP1. Serial 0/1, that's the connection to ISP2. And then I've got fast ethernet zero, which is my connection to that 200.x.x.x network down here, the 200.1.1.0 network. So very, very simple topology. I'm going to do-- again, this is starting off really basic-- Show IP Protocols, just to show there are no routing protocols running at all, including BGP. So if I'm ready to set up BGP, here's what I do. I'm going to go into Global Config and type in Router BGP, followed by my autonomous system number. Now, that would be documented somewhere. The ISPs would we give it to you because they need to type that in. When they're setting up their manual neighbor relationship to you, they're going to need to know what your autonomous system is. So chances are, they'll give it to you if you're using a private autonomous system. So I'm going to say 500 in this case. From there, I'm going to go in and show you-- well, I'll hit the question mark and you can see, this is a decent amount of commands underneath here, but not that many. Almost every command that you type under the BGP process starts with the word, "neighbor." You can see that right here. Now, you're used to neighbors, maybe from OSPF and all that, but look at this. I'm going to hit the question mark here. Hang on, let me just type something in there, hit the question mark here. Look at this. Oh yeah, just completely dwarfs the amount of commands that even the Route BGP process has. Almost everything starts with the word "neighbor." So the first one you always have to type-- and usually in Cisco, the commands aren't order specific, but usually the first one that you'll type is neighbor remote AS. Wait a sec, did I say-- no, always. Always the one that you have to type first with BGP is neighbor remote AS. So I'm going to type in neighbor-- let me hit the question mark because a little out of order here. Neighbor, and I type in their address. And I look, OK, ISP1 is 150.1.1.1. That would also have to be documented, and I'd have to know that they were coming from that. Because for instance, if they were using a loop back, maybe we had that little scenario that I just showed you. I would need to know that they're coming from that address. The neighbor IP has to match exactly what they're sending me. So I'm going to go in and type in neighbor 150.1.1.1, and again, there's our laundry list of commands. The first one that you must type, and then everything else can be whatever order, we'll do Remote AS, and then it says, what is the remote autonomous system number? So I'm going to type in, in this case, 1.1.1. Type that in. We now have a neighbor. Now, I'm going to jump out and do a Show IP BGP Summary. This is, I would say, the number-- man, I missed it. You can see right there, right before I hit the Enter key, it says BGP neighbor is up. This command, I would say, is the MVP command of everything BGP. It gives you some stuff up here, it's like, yeah, yeah, yeah, yadda, yadda. Ignore that. This is it. You want this. This is kind of like the Show IP Interface Brief of BGP to where I'm going, OK, I've got a neighbor right here. Here's the remote autonomous system. You can say, well, it's BGP Version Four. Everybody uses BGP Version Four. Remote Autonomous System right here. This how many messages sent, received. This right here is the big one. What is the current state? What you want to see here is a number. State is the ones that I just showed you a moment ago, the Idle, the Active, the Open Sent, Open Confirm, the Establish, all of these guys right here. The only reason that you would see one of those states right here is actually one of two reasons. One, you're either really fast, like you're sitting here doing Show IP BGP Summary with your up arrow again and again and again to see it go through those states, or most commonly, something's wrong. If you go in and you see State Idle-- let me show you right here. I'll Do Router BGP 500. By the way, once you go into an autonomous system, you can't change that. It's going to say, whoa, sorry. BGP is already in Autonomous System 500. You need to destroy the whole process before you go into another autonomous system. So the router is a part of one autonomous system. It's not like OSPF with the multi-area where you can kind of have one arm in each area. It's one autonomous system for the whole router. So I'm going to go under here and type in neighbor, let's just do 150.1.1.90, Remote AS, we'll just say 600, hit the Enter key. Do a Show IP BGP Summary. And right there, now you can see, this is what I wanted to show you. Right here, it's saying Idle. The neighbor is just kind of stuck on Idle. And it's going to say there. It's never even going to go active. I'm hitting the up arrow, just to see if anything changes. Never going to go Active because what it's saying is, I don't know how to get to that guy. Let me do a Show IP Route right there, and I'm looking right here. I've got no routes to the 150.1.1.90 network. I've got 150.1.0.0/30, I've got some little subnets right there, but nothing that will be able to reach 90. So it's just going to sit there in Idle, and that's where you would see the word there, and that's where it's showing the state. What you want to see is that number, which is the number of prefixes you've received from that neighbor. Now in this case, it says I have received six prefixes. Want to count them? One, two, three, four, five, six. That's literally the number of routes that you've received from that neighbor. Now, they've all shown up here in the routing table as BGP routes that we're able to see. I'm getting a little ahead of myself, but for now, let's just know, OK, I've now formed a neighbor. He's sent me some routes. Let me go back into the router, BGP 500. I'm going to first off, remove that bogus neighbor, get him out of there, and also assign a description. Let's hit the up arrow a couple times, go back here. I have that neighbor, 150.1.1.1. One of the things that I can type in there is description because as you configure BGP on your router, you're going to start getting more neighbors most likely, and you're going to want to be able to see real quick with a Show Run what this guy is. So I'll say ISP1, and now that's added to the neighbor. And again, you're just going to go down, down, down, typing in all kinds of different things associated with your neighbor. Now, one of the things that you probably won't want to do-- we're going to see going throughout this series, adding next hop self, maximum prefix, all these different criteria to the neighbor. Let's say you want to take a neighbor down for testing. What you don't want to do is type that in. No Neighbor 150.1.1.1. Because as you do that, what happens? All of the config, you might have 12 different lines of a commands applied to that neighbor, and they're just blown away out of the configuration, and now you've got to type them all back in there again. So instead, what Cisco allows you to do is do a neighbor such and such shut down. So at that point, let me do a Show Run Section Router BGP. Now I can see that the neighbor's config is saved, everything I've typed about that neighbor, but it's shut down. So you can see it's now gone into an Admin Down state. So that's kind of fun that you're able to see that. Now, looking at the time, I've got to jump into another Nugget here, but last thing I want to show you is just how the neighbors form. Let's do a Do Debug IP BGP, let's go All. We'll just kind of toss it all out there. And I'm going to go out there and do a No Neighbor Shut Down, and that way, we're able to see this neighbor form. So check it out. We've got immediately right here, went from Idle to Active. That tells us that the router thinks it knows how to reach this next hop address, the neighbor it's trying to form with. So it says, OK, I went Active, I'm talking to him from my local address. Then I went from Active to Open Sent. Remember, that was one of the packets that we saw. Open Sent, I sent my Open to him. So sending Open, my Version Four, here's my autonomous system. Here's my Hold Time. Hold Time is how long you think until the other neighbor's considered dead, meaning I need to hear something from you within 180 seconds before I consider you dead. So you sent some messages, and then it says, wait a sec. I received an Open. So he sent an Open back to me. He's running Version Four. His Hold Time is 180 seconds. Great, we can talk. Let's do this. Let's send some capabilities, start sending some route refresh parameters-- which again, I'll save that until later-- which pretty much says I don't have to destroy the neighbor to receive the routes, and they just kind of exchange all their capabilities. Then they finally say, OK, Open Sent to Open Confirm. We're good after we've sent all our open messages, I've received everything from them, and now we move over to an established state. And right after that, you see the neighbor go up. Now, in a production environment, that can take some time. For instance, if you're preparing for the CCIE, it can take 30, 60 seconds from the moment that you type in the neighbor command before the neighbor completely forms. And I say that because I've gone to the CCIE a couple times, and I know how nerve wracking it is. You type in the neighbor statement, and you're sitting here, and the seconds on the clock are like [TICKING NOISE], and you're like, [GASP], something's wrong. It's not forming. And you're going into action, removing commands, and all the time, it's kind of like, if you just grab the paper bag, breathe, [PANTS], and wait 30 to 60 seconds, you're going to be good. The neighbor's going to form and you're going to have success. So that's the foundation. Let me stop there. I know we just kind of got started in the config, but that's a good stopping point just with the connection to ISP1. In the next Nugget, we'll bring up that connection to ISP2. I'm really saving that one because once we go there, it's going to bring up a whole lot more discussion points, and BGP topology table and all of that. So for now, we've talked about the BGP relationship, the facts of how it forms, looked at the packets it sends. It's where you've got the Open message, the Keep Alive message, the Update and the Notification message. And then the process it goes through when it forms, we actually saw that happen before our eyes in the debug. And then I'll say we got a quarter way through configuring what I would call core BGP process. So for now, I hope this has been informative for you, and I'd like to thank you for viewing.