CCIE Topic: 1.1d EtherChannel - Part 1

hey everyone i'm charles judd and welcome to this part 1 video covering blueprint subsection 1.1c dedicated to etherchannel ether channel is a port link aggregation technology where we bundle together multiple physical interfaces into a single logical link and that gives us the ability to have higher bandwidth and redundancy so let's examine some important ether channel concepts listed on the blueprint starting with lacp lacp stands for link aggregation control protocol this is an ieee industry standard and that standard is 802.3ad to be exact and this protocol defines how we can bundle two or more links together into a single logical link i'll also briefly mention that the pag p protocol is cisco's proprietary version of a dynamic link aggregation protocol pagp is not found on the new ccie blueprint so we're not going to discuss this protocol we're going to stick with lacp both lacp and p again those are both dynamic protocols for negotiating ether channel but we can also statically define ether channel as well and we'll examine static configuration a bit later in this video when we configure a physical switch port to run lacp we can set that to either active or passive mode you can probably guess how these work it's very intuitive with active mode that port is going to actively try to form an lacp ether channel with a remote switch port whereas a port in passive mode is simply going to wait for a remote switch port to initiate the lacp negotiation so it's fairly simple an active lacp port is going to send lacp packets or pdus to the multicast group mac address seen here and these are sent out to all interfaces identified as being part of an ether channel bundle so needless to say at least one side of an ether channel connection when you're using lacp at least one side needs to be in active mode if both sides are passive then those lacp packets are never going to be sent out and an ether channel will not form i'm going to be working with a very simple topology i have just a couple of switches interconnected together using four redundant links currently there is no ether channel configured here between these switches but we do want to configure that on a topology diagram ether channel links are indicated by a circle around those links as we see here so first of all let's just run a show command let's say show spanning hyphen tree and here on switch one you can see that our gig zero slash zero interface is listed as the root and the other three interfaces are in the blocking state so that's exactly what we would expect to see with spanning tree so even though we have redundancy in place right now we still aren't using our full bandwidth capabilities we're essentially only using 25 of that available capacity so let's change that by configuring an ether channel so let's go under global configuration mode and let's go ahead and say interface range gig 0 0 through zero slash three so we can get all of those interfaces at once and what we wanna say is channel hyphen group and we wanna identify that by a number that number is gonna be one through two fifty five so i'll just start with one here and then if we look at contextual help you'll see that we need to indicate the mode of our ether channel interface we'll look at help once more and we'll see all of the options that we have at our disposal we see our p options again those being outside the scope of this exam and additionally we see our two lacp modes we see our active mode and our passive mode and we also see the option for on which is how we would statically configure that in my case since we're starting out looking at lacp i'm going to go ahead and say active as the mode here and hit enter going to receive a message saying that our port channel interface is being created we see our interfaces go down and eventually we're going to get an error message stating that lacp is not enabled on the remote port currently and here we see that has come into the console and that's exactly correct we haven't done anything on switch 2 yet so let's actually jump over there and fix that again under global configuration mode interface range gig zero slash zero through zero slash three let's say channel hyphen group we'll call that group one as well we wanna set the mode this time instead of active let's just say passive we see the message that our interface is being created and we see our interfaces go down briefly and now they're back into the upstate we see that happening we see gig zero slash two zero slash zero zero slash one and zero slash three all coming into the upstate and finally we see our interface port hyphen channel one has gone into the upstate so that's perfect let's break out of here and let's run a verification let's say show ether channel summary and you can see that we have one ether channel group in use we can see the port channel is po1 we see two flags we see the s and the u flags by our port channel one interface if we look up here above that the u tells us that this port channel is in use currently the s tells us that this is a layer 2 ether channel down by our individual ports we see each of those have the p flag the p tells us that these ports are bundled into a port channel so that's good we can also say show lacp neighbor and we can see some information about the neighboring device we can also say show ip interface brief and we can just again verify that we do have a port channel interface and that interface is in the upstate now one common thing we can do with a port channel such as this is we could configure that as a trunk port between our switches and we would do that exactly as we would if we were configuring a single interface as a trunk link we would just go under port channel interface configuration mode so i'll just show you how to do that we would just say interface po1 in this case and then we could just set our encapsulation method to dot 1q we could change the mode to trunk very easy to do let's actually remove this configuration and let's look at static configuration so let's say interface range gig zero slash zero through zero slash three we'll arrow up to that original command we'll prepend that with a no we'll remove our port channel interface as well and let's jump over to switch one and do the exact same thing arrow up we'll say no we'll remove our port channel interface as well clear off a little space and let's just say show ip interface brief just to verify that our port channel interface is gone so that's good so now we're ready to try a static configuration and it's really simple to do and it's actually really similar so back under global configuration mode interface range gig zero slash zero through zero slash three we'll recreate channel group one this time if we look at our mode options remember the on keyword is going to statically set that so we'll say mode on and hit enter you can see that we are creating a port channel interface the interface has gone into the up state we do something very similar on switch to interface range zero slash zero through zero slash three channel hyphen group one mode on we will see our port channel interface created and we're all set now if we say show etherchannel summary again you'll notice that our port channel interface we see the su flag letting us know this is in use and that we have a layer to ether channel just as we would expect to see now i do also want to say that although we can use a static configuration like this it's generally recommended to use a negotiation protocol such as lacp and the reason for that is if we have interfaces with different configurations or different speeds let's say we unintentionally bundle an access and a trunk port together or maybe we bundle a 10 meg interface with a 100 meg interface those things can cause problems but static configuration it doesn't care it's going to bundle those together regardless whereas lacp would recognize some of those issues and it would alert us also it's much easier to unintentionally introduce a switching loop when you're performing static configuration so generally speaking the preferred method is using a dynamic protocol such as lacp so that's a look at how we would configure a very basic layer 2 ether channel so let's talk about layer 3 ether channel and very simply a layer 3 ether channel is similar to an interface on a router it doesn't switch traffic but instead it routes traffic and we can give that poor channel interface an ip address so let's again go in and tear out our current ether channel configuration and the reason we need to do that is that once we create a port channel interface it's going to automatically inherit all of the settings from the physical interface so the first thing we need to do is actually configure our interface for layer 3 mode before we group those together so here on switch 2 let's say interface range gig zero slash zero through zero slash three no channel hyphen group one mode on and we'll say no interface po1 to remove the port channel interface if we look at our interfaces we'll verify that's gone now we're already under interface range configuration mode so let's say no to remove that and we'll take our port channel interface out quick verification to make sure we're good and that all looks good so now we can begin our interface configuration and again the first thing we want to do is configure our interfaces for layer 3 mode so let me clear off a little space go back under interface range gig zero slash zero through zero slash three and let's configure all of these as layer three interfaces with the command no switch port that's going to put all these interfaces in layer 3 mode now we can create our channel group as normal and you see those interfaces go down and come back into the upstate now we can say channel hyphen group we'll call that group 1 mode i'm going to go back to using lacp this time i'll use passive mode on switch 1 just to change it up i'll hit enter you can see that we have created a port channel interface the lines are going to go down we're going to get an error in just a moment because we haven't configured our remote switch just yet there we see that lacp is not enabled on the remote port so that's okay now let's go back to global configuration mode and now what we can do we can go under our port channel interface by saying interface po1 and we can assign an ip address to that just as we would a router interface let's say ip address i'll make this 10.1.1.1 make it a slash 24 subnet mask and i'll say no shut if we end if we break out and say show etherchannel summary now you'll notice that we have the r d flag r meaning layer three d of course means down because we haven't configured our remote switch yet but previously we saw this s flag for layer two so it's good that we now see the layer three flag that's exactly what we'd expect to see let's jump to switch two now clear off a little space i'll go under interface range gig zero slash zero through zero slash three i wanna say no switch port switch those to layer three mode so we have that in place now we can create our channel group so we'll say channel hyphen group 1 mode since i made switch 1 passive mode i want to make this active mode so that this will initiate a port channel formation through lacp we see that it tells us it's creating a port channel interface give this just a moment here and we see our port channel is in the upstate now let's exit and go under interface p01 which is our port channel interface and let's also give this side an ip address i'll give this one 10.1.1.2 same subnet mask and i'll say no shut we'll break out say show ether channel summary and now you see we have the r u flag u being in use of course r being layer three so we've successfully formed a layer three ether channel one more thing let's just try to ping the other side of this ether channel we'll try to paint 10.1.1.1 and that is successful we had 80 success rate as that was resolving if we try it again we should get a hundred percent and we do so why would we do this why would we use layer 3 ether channel well that allows us to of course separate broadcast domains which is a similar concept to creating a separate vlan so we could use an ether channel going out maybe to a high utilization server or maybe an uplink router and we would be able to separate those devices from the rest of our network traffic so that they're not getting slammed with all of the other broadcast traffic on the network one more thing let's say show interface gig zero zero and i want to point out the bandwidth here you see the bandwidth listed as 1 million kilobits per second or 1 gigabit so we have gig interfaces on this particular switch and we've bundled four of those interfaces into port channel one so let's say show interface port channel one look at the bandwidth listed for our port channel notice we have four times the bandwidth listed here as that of a single physical interface we have four gig listed here and this increase is a big reason that we see ether channel configured as trunk links that might feed out to hosts so if we have a single gig connection between two switches and one of those switches is downlinked to our hosts maybe our traffic for all those hosts require more than one gigabit per second of bandwidth which we could solve with an ether channel connection so that's a look at how we can implement static and dynamic ether channel and also how we can configure both layer 2 and layer 3 ether channel in the next video we're going to examine how we can perform load balancing over a port channel interface and we'll explore etherchannel misconfiguration guard i hope you found this content useful and i want to thank you sincerely for watching

Channel: Charles Judd

Views: 1,363

Keywords: cisco, ccie, cisco enarsi, ccie enterprise infrastructure, cisco enarsi 300-410, cisco encor 350-401, ccie lab, my ccie journey, ccie training, ccie blueprint, dtp, access port, 1.1d etherchannel, etherchannel, ether channel, link aggregation control protocol, LACP, layer 2 etherchannel, layer 3 etherchannel, static etherchannel, PAgP etherchannel, PAgP

Id: C_XOfzWV-fc

Length: 17min 5sec (1025 seconds)

Published: Mon Aug 03 2020