IOS XR Introduction

okay so in our next section like I mentioned we're going to go over a brief introduction of iOS XR I'm not going to go through all of the features because as we go through class throughout the week and we go through the iGPS bgp MPLS and we're going to be looking at the configuration both on regular iOS and on X are side by side but what I want to do here first is just for those of you that aren't really that familiar with the interface I'm going to go over some of the the main functional differences between regular iOS and XR so here we see the command line one of the first notable differences from regular iOS to XR is that it always asks you for login authentication and exec authorization so there's always going to be a default username that you have to configure when you do the the initial upgrade from regular iOS to XR or like out of the box if it's not CRS or a ASR it's going to have some sort of admin login okay so we log in to the box here next thing that's going to be different is that there is a separate administration mode that is going to be used to control the actual Hardware of the chassis or in multiple chassis systems that is what's called the designated shelf controller that can control multiple physical racks in the in the data center so to get to this you type admin that's going to go into the admin mode in the lab exam if you type admin most likely it's going to say that that's not authorized because they don't want you changing like the hardware allocation of the actual actual box from here if we look at the the show run the only thing that I have in here so far is just a default username and password the key is that this particular user is in the group that is root - system it means that they're allowed to go into the particular admin mode now right now if we were to look at the you the show diag summary this is going to show what other particularly line cards that the the platform has in this case there's two PRPs which is the the route processor basically the theme of the general purpose CPU and then there's four specific line cards there's two four port Giggy cards and then there's two one part OC 48 a there's also on this particular platform on the 12,000 this is a twelve thousand and eight so it uses what's known as the clock scheduler card it's basically that allows you admittance to the fabric to control like how the packets are actually routed on the the backplane and then of the the fabric cards this is like the actual the backplane the actual fabric that controls how much bandwidth the the backplane has from here if we were to look at the the detail of show diag if you're running into a hardware problem on any of these platforms and for some reason any of your line cards are not actually showing up what you want to look at here is what is the state of the card now some of the other ones like the the switch fabric cards or just the clock scheduler card these don't actually run iOS X are they're just like used for like I said controlling whether packets are admitted to the fabric or the backplane their state should be empowered state basically just means that the card is on and nothing is nothing is broken with them the actual line cards whether it's the the route processor which in this case these are PRP 2's the state should say that it is in iOS dash X are run basically anything besides this means that there's a problem with the card it could be that the card is like in reset if you manually reboot the card if it just says that the state is powered it means that at least you can plug the card in and the lights are going to come up but it's not actually talking to the the fabric for some reason so if we were to say show diag and include just the state ideally I want to see that my six line cards which are the two PRPs and then the four actual card so the two Biggie's and then two OC 48 all of these that they're there states should be in the states should be in run i OS X are run so it looks like this particular card easy to bring down this means that it's currently being reset one thing that's different question you can do this as well yeah so this one actually I believe this is normal right now because this is configured basically is the backup PRP because this one is active I'm sorry slot 3 fabric is down reloading this maybe once once I assign it to the other SD RH it should be fine this hardware since it's twelve thousand eight is a little bit older and basically if you don't get to this state there's really not much you can do it's pretty much you have to just RMA the card in order to to to fix it so in the the actual exam whether they have multiple physical chassis x' or they have virtual routers in a single chassis that's going to be controlled from this from this admin mode now the way that I have the rest of the the rental rack set up is that there is a SDR which is the secure domain router is basically a virtual router as part of the other physical chassis so the scr has a name I'll call this one X r2 and then from here you allocate what particularly line cards are going to be assigned to this router so the location is talking about the basically like the slot numbering in this case these are cards 0 3 0 4 and 0 7 then I'm going to assign to this particular SDR the end result of it is going to look like this where X r1 has the PRP in the first lot and then the giegi card in the the second slot which is number one because it starts from zero then X r2 is allocated the a PRP a gig e card and then also the the POS cards unfortunately what you cannot do is allocate the individual ports of the cards to different STRs so it's the full line card or nothing so like if you have a sip spot card you cannot say that this particular sip is going to that SDR it's going to the full full line card okay so I want to say here that 0 3 star 0 4 & 7 are going to be allocated to that particular card now next main difference we're going to see is that anytime you make a configuration change it doesn't automatically apply in iOS X R so if I hit ctrl Z or if I hit end it's going to say do I actually want to apply these changes or essentially do I want to commit the changes so I could have manually typed commit which would have saved or since I type end I can type yes that's going to do the same thing as is running the commit so now it's going to reboot these cards and then assign them to the second X R here okay basically this is the console that's going to the second PRP that's in that chassis so before that it said that this distributed route processor node is not ready for active login this is because it was the backup PRP for the first one so if you wanted multiple routers in the chassis but also redundancy you would need the primary processor the backup and then for the other SDR is likewise you we need a pair of of PRP s where each router that you want redundancy for Str I believe it just has to be PRP - yeah yeah it's a little bit a little bit different in the hard way oh yeah yeah yeah elliegator bases bay location pretty sure right yeah okay so eventually once it boots then it's allowed me to to log in here so the the problem with this though really the platform is not meant to be rebooted to begin with so like if you power it off and power it back on it literally takes about 45 minutes for the platform to fully to fully boot so I'm going to leave this alone and then go to a different rack that I have it has the cards that are fully booted here okay so these ones now when I connect to the console it's just going to look like a physically separate router so this is the normal global configuration mode depending on what particular user that I'm logged in as I may or may not have access to the admin mode in this case I'm so you can I say Who am I know let's say shoe run I am logged in as the user name xr2 they are the root user but specifically for this particular logical router so they don't have access to to allocate what are the different line cards this would normally be like your your admin operator but you don't want them changing the the physical configuration of how the other shelf is actually set up now is kind of a side note of this when you're using the equipment in the lab if you accidentally delete the config this local user is going to go away and the easiest way to delete the config is from global config is to say commit replace basically this says take whatever changes that I made in global config and then overwrite them to whatever the config' is so if i say yes now it's essentially deleting everything this is the same as saying write erase and reload except I don't have to reboot all the line cards okay now when I show run basically nothing is going to be in the other running config okay this is fine but the issue is now if I exit out of the console there's no local user that is allowed to login to this this SDR so typically what you would have is is in a real design it's normally going to be through triple-a that you have some user that you're talking to like tak X R radius with to do the the authentication but if I were to log in here as the the admin user in my case it's X R admin and go to admin mode this command here it says triple-a authentication login remote local this means for other SDRs in the chest you chassis we're in the shelf system they can use these logins here in order to get locally to their consoles for anyone who is not basically the the owner SDR where the owner SDR is like the the main one where you're doing all the configuration from any time that you log in from this you would have to add the at admin after the username so user name is XR admin at admin so now I'm logged in as the as the root system which is different than just a local username for that for that particular SDR so now I could make a change like if I were to say username X r2 password Cisco and then commit this change now when I log out now the user is is recreated so I can get back to them now when you're using the the rental recs if you do this and accidentally lock yourself out you're not going to have access to this user because this is the one that our scripting system uses like to just to manage reset the racks what you can do though is when you log in through regular telnet you're going to get a menu that shows up to connect to the consoles of the different routers but there's also this option to do password recovery basically this is a script that's going to go in and then add that particular username back in so if you do lock yourself out I set it up so that you can do automatic recovery for it that would be a problem yeah yeah okay so if you do commit replace don't worry about it you can always you can always revert it without having to like submit a support ticket or anything like that but I the the scripting system the way that we designed it is that normally it will have the local user name in there and then there's a banner that says like use this default login in order to get there otherwise you're not going to log in without that that root system login question so if so physically like if we were to look at the chassis and let me let me pull up a picture of it here it's still one chassis right it's yet it's so it's it's one physical chassis but then inside of it there's there's two PRPs and then for line cards so they're sharing the same backplane but from our interface they look like they look like different physical routers yes yeah so they're like the sonnet interfaces those are cabled back-to-back between the routers basically yeah it doesn't affect the rest of the config so the only thing it does is just log in and adds the user and then logs out so you can get you can get back into it so I'm not sure where the pictures yeah okay so this is what the chassis looks like that so these are that these are the four port gig cards or now is that the that's the PRP these are these are the management ports and then the the console on the aux port so basically you have two separate console cables one to one and one to the other then once you configure this the second one is in SDR they're treated as independent routers by default they're all part of the same router so the second one normally is going to be a backup of the first card that if the first card goes down then the second one is going to take over for it so it's like non-stop forwarding like stateful switch over does it automatically this one here so the first one is in slot zero second one there is in slot 1 these are the clocking cards and then this this one I think I know so this those are the OSI 40 aides right there so if we look at the like the full config of the first one this is the only thing you need to do just to specify what the other virtual routers are but the key is that this 0 3 this is the PRP you can't allocate a new router without a physical route processor to be able to handle it ok so when we're not in admin mode if I were to look at the show diag summary they're only going to see the specific hardware that is dedicated to them so this first router XR one is consider the owner SDR it's the default one and I have cards 0 1 & 6 allocated to it so like when I share YP interface brief it's only going to show those particular cards ok the management interfaces these are part of the PRP they're normal Ethernet links like that you use for telnet or SSH into the box then these are the the 4 port gig cards and then the the packet over SONET link same thing is going to be true on the the other one when we show IP interface brief this command is not authorized this is is anybody wouldn't know why this error came up here I created the user but I didn't authorize them to run the exact process so what I needed to do was under the username I had to put them in the proper group ok the group is I want them in the root group for that particular logical routers route - LR so now I would have to go in through admin again XR admin at admin and say let's show run so username X r2 is in the group root ok so this is going to be the the most privileged user of the of the logical router of the SDR then these other ones are sub users that can run show commands but can't make changes and then you can also define your own groups this would be like if you wanted to do tax like command authorization and create different groups to say these particularly users can run these show commands but not other ones then you have the option to to do that here not to the SDR yeah so root system is under only the admin mode yeah well the the what it may be referring to is to turn the software package on so we'll look at the config of NetFlow but if we go back to the admin mode the other thing that you would want to do here is if you look at the show install activex this tells you what software packages the individual line cards are running so typically the only the only case that you would not activate every single package on every single card is if you don't have enough resources on the card so in in this particular case basically the cards have maximum memory as does the PRP so it's not really going to make a difference but if I was not running multicast then there's really no reason for me to turn this feature on because I might be introducing multi gasps bugs possibly with other features and you kind of like isolate the the software from from different components of it but in this case if we look at it says that there's the owner SDR which is the first PRP which is node 0 0 CPU 0 basically everything is turned on here and I want to say I want to say that NetFlow would be under die eggs I'm not a hundred percent sure management so install the other one that you would want to look at here is show installed in active this would be for some reason you downloaded the software but didn't turn it on the specific line card and what could be a common mistake of this so you you download the all the software like through TFTP to the to the admin mode then you have to actually install it which is to say install and then whatever the whatever the particular file is you would say install activate and then whatever the package is normally it's going to show up here but in this case everything is already running so it doesn't show it but once you install it if you don't actually commit your changes then it discards them when you exit out of admin mode so you would have to say install commit once it's once it's actually fully done so the idea behind this is that you can do the software upgrade in service without having to like schedule a maintenance window then if something goes wrong it's not actually activated until you you do the final commit once your once you're done with it but if you see for some reason you're working on one of these platforms in a command is missing let you type MPLS LDP and it says unrecognized command it would mean that that particular software package is not activated on the card and it could get a little bit finicky because I could theoretically say that MPLS is activated on this card but not on this card when you selectively do the install I could say install it just on node 0 1 and not on 0 6 but assuming you want all features everywhere you just activate every single package on every single card I'm sorry probably not because in the lab exam I doubt that they're going to give you admin access to the individual SDR yeah yeah but just from a from a practical point of view if you're doing a new install for this and you see that it doesn't run the feature that you need then that's what you need to look at is in the admin mode is the actual package on ok beyond that there's not really much that you need to do in the admin mode now you do like the initial install like if you're going from regular iOS to XR that would be done under the admin mode then defining the SDR s and then activating the the packages just exit that just leaves leaves admin mode yeah if I exit now it should have said I'm not sure if I made any changes here but it would have said that the user was XR admin which is the one that's under root system so like you said this particular group is not under the SDR because that's authorization for the admin mode how do I log into the admin mode so you you just come in through the console or through like SSH if you're on the owner STR which is this one I would just type the username you're not gonna have access to this yeah so then from here if I say admin since I'm in root system it allows me to do that okay from the non owner sdrs you would have to login as whatever the the admin username is and then at admin okay from here then you could go to admin mode but and it's doing this the same thing it's just that I'm connecting from the non the non owner SD are okay but then the in the within the scope of the LAV exam you're not going to have to worry about that just just a kind of side note if you are doing new installs of this that you need to make sure that from the admin mode everything is set up correctly first and the line cards are allocated to however you want to divide the the chassis or the the shelf system okay the next thing that's going to be different from the from the regular like exec mode or the global config mode when we look at show run and actually let me revert this back to its defaults I'm going to say commit replace so that's deleting all the config and if we now look at the show run there's basically nothing in the initial configuration where when we look at regular iOS if I were to say on any of the regular platforms even when you don't have things like IP addresses assigned or other features here like we're doing that when you trunking at least you're going to see the physical interfaces and some of the default values but in the case of iOS X are they're essentially is no default configuration for anything so anything that you want to implement you're turning all of those features on so if I look at the show IP interface brief the cards are allocated to the router but they're not actually configured yet that's why they don't show up in the the initial config a lot of the other features that you would normally take for granted like CDP for example is not on by default so what you may want to do is turn CDP on then at the actual line cards also turn CDP on then I could figure out what's going on in the actual physical topology so if you globally turn on CDP doesn't turn on correct so and some features you'll see like this where you have to just turn the feature on to start then you go under the specific interface config different sub configuration mode and then actually enable the feature on a per port basis okay so now these changes that I made turning CDP on and then enabling it on the link it's not in the yet the active running config so if we look at the show run you'll see that nothing is actually changed yet if we look at the show config these are my uncommitted changes basically means that their configuration changes I made but they didn't actually apply yet to the running config so this is going to be most useful when you're making a config change and then you try to commit it and it says for some reason one of your commands failed so if you say show config you're going to know just what are those particular changes that I tried to make for that individual commit so now if I want to apply this I have two options I can either type commit or I could type exit or end and then it's going to ask me do you want to commit these changes before exiting here so now the changes are made if we look at the show run now we see that CDP is on those particular links and it's on globally okay also I want to add a host name here just so I can tell them apart I'll say this is X r1 and I'll add that user name in there just enough to keep using the admin logon also user name XR one password is Cisco and the group is route - LR on the other router I'm going to do the same thing except the interface numbering is going to be a little bit different you so on X are two different hostname and then these are different port numbers oops once you get used to it it's actually a lot better than iOS and a lot of in a lot of different ways AAS ours in the CRS No okay so right now you can see there's there's not that much config that I've added just turn CDP on now see DPR on the links I also have this this username to make sure I don't lock myself out if we show CDP neighbors I have the the other XR which is connected back to back so if we look at the wiring that's talking about these two ports here then also on the the packet over SONET interface it should be running they really for that the SONET links there's there's nothing fancy about this they're just regular serial interfaces except they're much higher speed than you would have like your WIC one T or which u T on the the regular routers so if I were to say like show interphase POS zero seven zero zero its bandwidth is two-and-a-half gigs so its OC 48 the encapsulation is is hdl-c now the CRC is normally going to be 32 bits normally you wouldn't change this it's that on a higher speed links you need to need a larger error check otherwise you could miss some of the errors in the frames and then they would get discarded so basically every single frame that comes in the card is doing the error check to make sure that the transmission was fine but beyond this it's going to behave just like a normal serial interface so if we look at the the config of it right now the only thing that's running there is is CDP and let's say that we have just a basic back to back configuration between them so we have XR 1 to XR 2 this side is POS 0 6 0 0 this is POS 0 7 0 0 ok we'll say the IP subnet is just going to be the 10 network / 24 we'll say this guy is dot 1 this guy is to okay so at the link level a lot of the syntax is very similar to regular iOS where I could say like the IP address is 1000 1/24 I could also be a little bit more specific of this it does give you some backwards compatibility from the regular iOS syntax where the the full completion of the syntax would be the ipv4 address and then what's a nice shortcut you can just say slash 24 or / 31 whatever you have now when I show config in the running config it's still going to show up is the dotted decimal format but configuration wise is a little bit easier just to enter it this way then to figure out all your whatever your weird like discontinuous masks are so if I end it's going to ask me do I want to commit yes I do on the other one I could just say commit that's going to do it manually out for me okay so now I should just have basic connectivity to the other side which I do so really nothing too complicated about this config just the link is up it doesn't have to be running CDP this is just for you know check that the port is working then it's running IP version 4 if we want it to run ipv6 the syntax is going to be similar so on the interface we'll say the ipv6 address and then whatever address we want to use same thing on the other side yes as soon as you turn an address on it turns the routing process on globally right correct for regular iOS if you're running ipv6 routing you need to say ipv6 unicast - routing ok because the default is already IP routing for version 4 for version 4 version 6 you have to turn it on ok this can be kind of confusing because it allows you to configure addresses it even allows you to configure routing protocols but the process doesn't initialize until you say ipv6 unicast - routing but in iOS X are you don't have to do that as soon as you turn an address on then it's going to start the routing process g6 address okay so now I should be able to ping the other end with ipv6 which I can okay now what we want to do the verification there's a fundamental change in in the hierarchy of how the verification syntax works in XR versus regular iOS and once you get used to it it makes more sense the way that the commands are ordered so instead of saying show IP route or show IP v6 route some of these will be in there for backwards compatibility but things like show IP BGP you don't want to use the normal hierarchy of the iOS syntax instead what I'm saying is that I want to check the routing table what's the particular address family identifier and the sub address family identifier like am I talking about the ipv4 multicast routing table or am I talking about just the ipv4 unicast routing table so show route ipv4 would then be the equivalent of show IP route okay likewise for v6 this would be show route ipv6 like show route ipv6 show route ipv6 connected show ipv6 route rip whatever the particular protocols are show route is going to show I believe this is going to show just a global ipv4 table which it does okay also when we get into bgp especially with MPLS it can't get kind of confusing what the order the syntax is where on the routers we would say something like show IP bgp evpn be for unicast all or VPN be for all you could also say show bgp VPN be for unicast 4xr this is going to be similar to that second syntax so show BGP what's the main address family identifier which is VPN what's the sub address family unicast in this case then what's the particular route distinguisher or what's the particular vrf this is how we're going to check an customers table for bgp likewise if we had VRS configured we would say show route what's the vrf then inside what in the vrf what's the AFI and what's the SAF iso show route vrf all ipv4 multicast this would be for like our VPN multicast routing inside the the layer 3 VPN so this does take a little bit getting used to but once you get familiar with it it makes a little bit more sense how the structure is is listed okay the other thing next that is a major difference is how the configs are committed and then how they are saved locally on the other box so in regular iOS normally you just have two configs you have your running config and you have your startup config in the case of XR there's no difference between the running config and the startup config there's only the config is whatever the active configuration is but every time you do a commit as a protection mechanism the router is going to save all of those individual differences or basically config dips or commit diffs for you so if you say show config show config commit I can list what are the different changes that have been made so this is going to go back quite a while where they have individual numbers that correspond to them you can also give them a label which is like a just a description that you want to use so I could say like set the label to bgp enabled so then i know if something is wrong and i need to remove that config i can roll back to whatever the one is is previous to that so if we look at XR one the previous changes I made were like to to put the to put CDP on that was one commit the next commit was to add that user then I added ipv4 addresses and committed so each of these are going to be listed individually so if I were to say show config commit show me the last show config commit changes show me the last three changes that were made now it doesn't list them individually of these three which happened during which commit if you wanted to do that you have to list the specific identifiers or I could say show me the changes that happen since whatever that particular number is yeah when you so let's let's make a minor change let's like add a loopback address let's say the address is 1 1 1 1/32 when I commit I could say that the label is loopback so now when I show config commit list that was my loopback so now if I want to roll that back I can use the description as opposed to the number okay but it's automatically going to do this for you you don't have to do anything else in order for it to keep the the backups of the config commit label commit label and then whatever the name was in a regular iOS you can do this but it's under a separate feature so if we go to the regular iOS documentation this is going to be under I want to say network management No configuration replace and rollback this is the and let's just look at their example this is the archived config command so you can do this in regular iOS every time you make a change every time you write the config it's going to save it in the archive and then you can roll those individual changes back this is also useful if you want to do command accounting but you don't have tac-x setup so every time the user makes changes if I want to keep it keep a list of what are those actual changes that they're making that's what the archive is going to do so let's look at this like let's say like on router one if I were to say turn the archive on and I want to do the archive for the config changes I'm not a hundred percent sure so let's see I want to say notify syslog that would generate a log message every time someone makes a change and then let's say record no logging enable the I'm sorry the maximum I think it's going to just depend on the platform so default length is 100 I'm assuming this means 100 in shirt entries not like 100 bytes or 100 and lines so now when I exit assuming that logging is on you can see it generated it's this log message that my user which I'm can I'm on the console it made this particular change so you can do it now you can say of archive and Figg let's configure replace actually that's what it's going to do it so this is going to allow you to rollback based on whatever changes that you made so you can do it it's it's not as intuitive as xrs is because XR does this automatically every time that you make a commit it's going to show up in the commit list and then you can like I said you can show these individually you could show the combinations of them or if you were to accidentally say commit replace which deletes everything because I didn't make any changes I could now say roll back my config the last one commit okay so this always undoes whatever the last change that you made is here the other thing that's useful is that if you're making a change live outside of a change control window that you could say to commit the config but then to commit confirmed and how many minutes do I have or seconds like let's say 180 seconds that after I make the commit so let's say I create like a look back one commit confirm 30 you are exiting after okay I need to stay I need to stay in global config now so what we should see is that in 30 seconds it's going to say where your change is okay if not if you don't answer me then I'm going to roll back the config so the idea behind this is that if I make the change and then I lock myself out with the new change this is automatically going to revert back to whatever the one that I had before in iOS kind of the best thing that you can do for this is to say like reload and five if I screw it up then just reboot the box and yeah I don't know what happened or you could say test crash make it look it wasn't your fault that the router reloaded so let's say it says your changes there's a trial and a firm say show Ron let's see if it has the loopback so removed it it automatically rolled it back because I didn't say that I wanted to confirm the commit so that's kind of a nice feature about just the general interface of X are some of the other things that are different is that when you run the different show commands there's different Linux utilities like tail or egress that you could use for for searching and doing regular expression work some of these if I were to say like show run include IP address or let's say ipv4 address in this particular version it doesn't allow you to do multiple pipes if I were to say like show run include IP address or interface doesn't support this so you would have to you would have to put it through grep and then use the regex in text for that I'm not really that great with Linux syntax but you can do it here so if you were to say show run and then use the utility grep so this would be basically the same as saying show run now I need to say then expression ipv4 address so this is the same as saying show run include because I didn't add a regular expression here but what is also nice about this is that assuming when we show install activex and hopefully they would do this for you in the exam hopefully the documentation is installed so you can have man pages man command let's say utility EGH rep and let's see if they have an example at the end so as you can see you can get really really complex with this it's really useful when your your configs are really large like if this is a PE router that is servicing literally hundreds of customers you may have crazy BGP and crazy vrf config that just saying show run is going to take way too long to try to parse through whatever you're trying to look for in our case within the scope of the lab exam the config is not going to get that big so you don't necessarily need to use these but if you're if you're already good with with UNIX and Linux syntax then a lot of these utilities are already there this type of stuff is going to be documented under if we go to so let me start back at the main documentation page let's say products iOS iOS X our config guides we're running 3:9 this is going to be under I want to say system monitoring or system management I should say so this one upgrading that's going to be now that's 3.8 let me go to 3.9 but you can see there's not as many topic domains as compared to regular iOS so before you get to the lab just open all of these in different tabs and then you know click around and to see what particular topics are located where most of them are pretty self-explanatory like routing is obviously going to be a GP BGP stuff but then like under MPLS this is just where LDP and traffic engineering are the things that are like l2 l3 VPN that's going to be under Virtual Private Networks okay questions up to this point okay let's see now another thing that it is going to help you with when you go to commit the config is that if you make an error let's say that we configure loopback to has the address 1 1 1 1/32 I already have another interface that has that configured this one extra this is an exception this allowed me to override it but let's say let's say it's like a blatant syntax error or we could do that most of them and you guys are going to be seeing a lot of commit fails this week as I'm going through this so we'll have plenty of examples of when I'm screwing up the the syntax here but let's say like this so let's turn BGP on and let's say like for a neighbor 1000 to address family ipv4 unicast it should tell me here that I didn't actually enable ipv6 or ipv4 unicast routing on to the BGP process first so now when we say show config fail it tells you what the specific error message is sometimes these are not very descriptive where it just says that your commit did not work but most of the time it's going to tell you what the actual problem is so for this neighbor I tried to run this command but the address family has not been initialized this means that globally under the BGP process I needed to turn address family ipv4 unicast on what you could also do is to say commit best effort which says take the portions of my changes that were not errors and put those into the config then the ones that got rejected just leave those out and those are going to go under the show config fail so this was rejected but it should have put BG it should have turned VG beyond and it should have at least specified the neighbour so this is useful when when you look at show config if you have tons and tons of changes you want to apply some of those but then go back and fix the problems afterwards you don't have to completely abort which says don't commit my changes and then start from scratch okay this is also going to be useful if you're doing let's say like l3 VPN configures you can piece-by-piece put your config together on one of them like let's say we have a vrf named a that has address family ipv4 unicast with the import route target of 101 the export route target of 102 so whatever my policy is once I'm done with this I can show config and then basically copy this whole thing out make whatever changes I need for the other X are like in notepad and then apply that all all at once but again if you don't want to make the changes you can just abort and then that's going to go back to to exec so like I said as we go through the different features we're going to go through the comparisons of all of the configs like how do we configure OSPF on regular iOS versus XR is 2 is BGP but just as kind of a general overview the things you have to remember is that every change that you make you have to commit if you want to remove that then you can roll back the changes and then when you're looking at the especially when you're looking at the routing table because if you're looking at like a vrf table versus the global table it can get very frustrating when you're trying to figure out like why is this route not showing up and it's because you're looking at the wrong table like I'm looking at this particular customer not the not the global table or vice versa yeah the same would be true with other verifications like if I do a ping and I say ping 1000 - that's talking about the global table as opposed to whatever particular virtual routing and forwarding instance like would be for an individual customer questions yes pretty much no there-there are going to be so the question was you do need to enable default features like SEF or like IP routing most the time when you turn a feature on it's going to do whatever else behind the scenes that you need to do that there are going to be some exceptions for that one of them would be like if we're doing MPLS traffic engineering you also need to turn it LDP on even if you're not using LDP for labeling you can end up in some weird situations where your config looks good but then the router doesn't actually forward traffic and those are going to be kind of more minor caveats that we're going to talk about when we get to those particular features

Channel: INEtraining

Views: 67,505

Keywords: CCIE, cisco, ine, brain mcgahan, routing, switching

Id: -sGBfFgxIPM

Length: 57min 12sec (3432 seconds)

Published: Thu Jun 28 2012