Network Fundamentals Final Exam Review

alright see you guys out final next week so I figured we're going to do in lab today is we're just going to go over the final exam I have three types of style techniques of going over this final exam one is we did a Jeopardy the other one we're going to do it who wants to be a millionaire and the last one I took some frequently asked questions from last year's final exam and brought them in here so you guys can see what the final exam is going to look like I'll be posting on Cisco tonight one practice final it'll be until tomorrow at midnight and then the next day Thursday I'll be posting another version of that I believe there are three practice finals on Cisco's website so I'll be posting all three of them the third one will be posted this weekend it make sure you guys take them ask questions if you have any the way we're going to do this we're just going to go around the classroom I will pick on Brian Brian you'll pick your first question and then after we work it out we'll go to the next one hey guys so Brian County which one you want your categories are up top and then the difficulty quote-unquote are somewhere up on the board so troubles for 100 now call me Bob if you want if a routing issue would occur in your internet work what device should you examine to isolate this error so which one would you look at first if you have a routing issue it is a 100 level course so don't let it uh mislead you what do you think Brian really all supposed to I'll give him a chance and if he passes in it's up to the rest of the class to answer this evans over here it's not the bit to answer it don't overthink the question if you're having a routing issue what device will you look at there you go it is a 100 level course so 100 points alright let's go back to the home and see good commands 400 my hands for a hundred you're getting nothing for it what information can be gathered by using the command ipconfig yeah so it's the host configuration by the way that command only works in doss if you try it in Linux or even iOS 10 you have to use the command if config yep so interface configures what they're saying which is sort of smart because hopefully by now you realize your network interface card doesn't have to have an IP address you could be using like Apple talk or IP X or even ipv6 correct so using IP command is sort of like very biased to the IP protocol which is very common all right Evan I'll go if config 200 he's bold give him a hard time mister I pick a hundred level question a technician is asked to secure the privileged exec mode of a switch by requiring a password which type of password required the log so I required this login and D considered the most secure so you're trying to lock down the privileged exec mode it doesn't matter if it's a switch router or whatever as long as you realize you're locking down the privileged exec mode and it's got to be the most quote/unquote secure enable secret would be the best one yep which prompt would you issue this command from global configuration yes yep right and for 200 what information could be gathered by using the command netstat this is from chapter 4 transport layer what did chapter 4 handle in the course what was the transport layer all about segments but we're still on Brett right now until throws off to the class I encourage you guys use this command if you started noticing your internet connections being sluggish for your computers being sluggish but I gave you the command net stat - and and I think the end just does it in numerical order you can do net stat - all and that will display a list of all what this way ah I wouldn't go that far as much as Brian again find out why don't you do that hold the window key typing the letter R so I hit the letter R then type in CMD hit enter and type in net stat see what it gives you and you can even do the dash n if you wanted a numerical water doesn't matter all the act of what active connections what are those calls yeah and you can actually see UDP connections as well but yes all the active connections taken from your computer that's what's important know that these are all different connections that you have going either out or coming in to your computer Michael troubles for to wear my add a PC cannot connect to any remote website ping its default gateway or pay a printer that is fully functional on the local network segment which action will verify the TCP / IP stack is functioning correctly on this computer get the loop back which is what address that's zero that one so you ping the loop back to test the protocol stack to see if it's functioning back to you Brian trebles for three host a and b are unable to communicate with each other what is the reason for this so we have a diagram remember do not make any assumptions since go deliberately threw you off because you might want to say well that router should be a switch and that's not the case they wanted it this way the other thing I wanted to make point to you is you on your final exam it is multiple choice right now I'm just testing your general knowledge going back out there and grabbing it like I said I'm doing three different methods here so work with what you're given so Brian which how do you going to accomplish this tell me I'll do it up on the board so everybody else can see it okay so he wants to verify the seats are on the same subnet but be careful tell me what needs to be on the same subnet for them to work this host eight host B need to be on the same subnet using this logical topology no this routers has three networks as this way in one network here one one network there so host a host B do not need to be on the same network but what does need to be on the same network the Gateway for each network right so this interfaces be on the same network is that so if I look at host a the way I can verify that is that my IP address is one ninety two dot one sixty eight dot two hundred dot 130 slash twenty six that's the last twenty six two telling me put all your attention on the fourth octet right guys let's take that one thirty and convert it into decimal it gives me a one twenty eight and a dead marker see a 128 flip 64 32 16 8 4 2 1 right and then my subnet mask is just 1 1 followed by a couple zeros clever slash 26 which I'm all good with because this is telling me my subnet host bits are to the right subnet bits are to the left correct so I know just to be a host address cool let's check out what the gateway address is we have a dot 128 that's a 1 here in a 0 there then all zeros what's wrong with a gateway address why what is the gateway address when you have all zeros in the host part so I assigned and this is a noob first time learning this stuff typically they assign the they try to sign the gateway the network address because I think in the routers represent a network so they get the network address no device gets a network address or host address right there's our broadcast address we good about that and no two devices on the same network and have the same host address so let's look at host be 65 that's a and it is a slash 26 that's what 65 looks like in binary let's see what the Gateway address was 64 so it looks like host B and host day was set up by the same noob and that is they gave them both the network address and that would not work right so the network address was given to the Gateway which is not feasible the router cannot ping the route so the router cannot ping the router that is directly connected to the serial interface what should the technician do what the hell am i doing you guys get to pick your own choice where we are Ian luckily address dressing for 200 which statement is true about layer 3 addresses are they physical addresses what do I mean by physical addresses they are literally burned into the rom of a network interface card so they're signed by the manufacturer be are they used in routing decisions okay what about C are they only used on local networks sort of B and C sort of conflict with each other right so if you're going to do one or the other you get that memory checked out what about D they are they are altered each time a packet crosses a router do we change IP addresses other paths from pakka from router router no what does get changed from router to router or from host to host or device to device the physical address right the frame so B is the right choice B was the correct choice I just want to eliminate the other possibilities yes you some cards will actually print out a label on there the manufacturer parental label and put it on there the way you can find out your MAC address is go to dust type an IP config space forward slash all and you'll get your physical address will has it on the back of yep yep the reason why is they use that MAC address is the SSID number Evon whew finally somebody what's david by which subnet mask will allow for 1020 hosts per subnet on the IP network 10.0.0.0 let me erase this what formula you're going to be using the answer that question to some power so to the bits they're going to be able to accommodate so Q raised to what power is going to be able to accommodate now everybody's always going to the calculator you should at least tell me what to raise to aid us because you won't be able to use this on the exam 256 right to raise today's 256 so to raise to 9 is going to be what 512 because just double 256 so then to raise to 10 would be 1024 which would be the money so 10 host bits so it would be a slash / 22 or what are we going to do for some of the masks because I didn't ask your prefix so this is what we have we have a ten so we have two over here and then we'll X are two zeros over here so one two three four five six one two three four five six seven eight so I have 10 zeros right because that's those 10 are representing so this should be 252 because this is 3-month 255 minus 3 is just a shortcut to doing that because all want to give me 255 right and this is a two and this is a one so just invert them so my subnet mask be 255 dot 255 dot 255 dot 255 through one extra 255 there but I tend to do that Brett mill the road kind of guy huh yeah I can't talk into the 400 what type of cable is shown here and when would a technician use this cable straight-through do you really need to look at the pin layout for these can you just look at the 568a and also see there's a 568 over here and if there's too fuss if both ends have the same pin layout then they are a how would I make this a crossover exactly just swap the orange and the green right so make the three of green white and make the six a green and then make the one a green orange way and make the two in orange right those the only colors you switch around everything else stays the same so make one and a and the other one a B all right Michael shrubs kind of talking a 500 too late you got this one solve this one before so the router cannot ping the route of the router that is directly connected to the serial interface what's wrong so this is what they've issued so they typed in int s 0 / 0 / 0 typed in clock right 56,000 by the way you know this to be the DCE now right because the clock rates set up then they typed a no shut good down and remembered everything except for what command did they forget to put it in fact the ping command actually needs that which is what investing an IP address all right Brian can I talk into troubles for 500 all right let's kill that column hosi is able to ping the loopback but is unable to communicate with host a and host B what is likely the problem so C cannot talk to a and B see has an IP address of 172 dot 1630 1.90 slash 27 I believe you're the first person started this one off and if you're having routing issues what's the very first if I should go to any time you have problems like this folks escalate I see a hub nothing I can do about that correct hubs are dummies whatever they get they get to send out to everybody else correct so then I go up to my router I look at my router and I'm given the following configuration information work with what you have 172 dot 1630 1.93 this is the biggest complaint I have with these exams because they give you everything in the real world you have to do the detective and find out what to look for knowing what commands to type and when to type them in there here they're saying yeah well if they gave you this information it must be important correct so let's look at this once every 2.16 dot 3193 slash 28 any flags going off to you folks yeah this is a slash 27/28 and more for them to calculate the network address correctly they better have the same subnet mask so you run down to the trouble thing and they did say the loopback was successful so letting you know the protocol stack is correct it's just they didn't configure the PC correctly if it's just a waste to assume there's other hosts on the network not allows for scalability so then I can add other devices on here instead of because remember the router isn't going to be in that room this could just be somebody's office and this is going to be in the wiring closet the telecom room so this just might be a person's office they let they'd like to add a lot to those diagrams just to make it yeah exactly of everything else so they can go out of your way Ian you're next can't talk in the 500 500 you realize if you get the hard ones out here when you're on the exam I mean how do you measure difficulty I just look at the exam questions maybe put them at the 500 level who knows one must a router serial interface be configured with the clock rate the N we've already discussed that so you're seeing if I'm building those questions in here and there yeah those are pricks I'm not that way I love you guys too much I'm going to be straightforward I've been honest with you guys all semester long what I change now Evan yeah we can I like that pansies a technician wants to store a backup copy of the saved configuration on a TFTP server at one ninety two dot one sixty eight dot 3.2 before reloading the iOS what should the technician type by the way this question is on the exam I like that I like the copy start why did you say start and not run because you wanted to copy the configuration upon startup well it says the saved configuration altered oh yeah and where is the startup configuration file stored up in the well if you saved it in yeah it has to be it's got to be saved because it's not saved unless you do it right the startup is the saved configuration and we just call it a start-up because that's what they boot it up from right hence it's got to be an nvram non-volatile good so you did copy start what's the last part you're getting really carried away there you don't have to worry about USB not in this one same way we're here oh well then you're just going to copy so just type in TFTP at the end of the command yeah I'm guessing the okay if you're going to put the IP address at the end of the command stop and think about this for a second could there are other services be running on this end device like FTP or whatever the case may be so you should be actually doing the TFTP to let them know that's the service you want to initiate and then maybe you'd be greeted with a prompt that'll ask for the IP address which is what will happen so if you just type in copy start up - config I just do copy start because it's the only follow-up the beginning with that then TFTP then you'll be presented with a question where's the tf2b server located it does it have to be a local IP address can it be a remote address as long as your router has connection to that site then yes absolutely then they're going to ask you for the name of it and now you just call it r1 start if you will because that's the name of the router that we're dealing with all right it is on the exam it just might be a slightly different hey I talked you guys into that there we go yeah a question like this is on the exam maybe not asked this way I always love these these Cisco questions what table accurately associates the RF what does RFC stand for request for comments it's how we've actually made the 802 11 feedback so the I Triple E is created this huge journals upon journals for feedbacks from you guys so requests for comments and this particular one in 1918 somebody said wouldn't it be great if we had all private addresses for the land so that we can reuse some of these addresses over and over and that's what this particular RFC 18 1918 is all about do you really need to know that no just asking you what are the private IP addresses let's see if you guys can answer these Brep let's answer by Oh process eliminations well can we rule out can we rule out a why do you say yes the silver males to one-ninety 2.16 you're saying that's not the correct subnet mask I like it because the private address because what he's saying is in a class a the private address is in this range right like 1.2.3 in this octet is a private address correct I like that so you ruled this out because of this being a 255 there correct like it what else can you rule out can you rule out be what do you guys think why do I hate be ironically Class B is wrong Class B starts at 170 2.16 correct so that rules out a and B now what about C can we rule out C is this a Class C private address 192 dot 168 it's a Class B private beginning if you will one ninety two dot sixteen is a class a private these look good so far does this represent a class C's subnet mask for a private address block you ruled out that one for that same logic so this one's good using the same logic that you applied what about this one well this one's tricky we're going to pause over that what about this one is this look like a class a network part ten host parts second third fourth octet this one's looking pretty sexy let's compare C to D what makes C and D different well right there that 240 is wrong correct I roll out D B and a and I'm stuck with C and that I have to worry about this 240 here remember Class B goes from 170 to 1600 all the way up to 170 2.31 dot 255 dot 255 correct sixteen 231 isn't that like 16 host away well when you look at this one four bits 128 plus 64 plus 32 plus 16 gives me 244 bits to raise to four gives you 16 16 networks right for Class B so that's the subnet mask that is correct did you have to know that to raise to4 to answer this question no because you could have ruled it out with this one over here everybody's good with that so be or sorry C would be the correct choice Michael OSI for 500 what you said let's see all the 500 questions I told you they're going to be on the exam we got about an hour left of class we got two more reviews to go through we'll laugh at you if you get it wrong this question isn't on the exam you and it takes what's OS I stand for wait wait is it on this one see there's four variations I can assign you guys and I haven't decided which one I'm going to give you guys whether it's the first second third to the fourth I think the first one is on but the fourth one I don't think it's on what do you think the O stands for describe the status of that door over there open system interconnected it's just why is it open one day you can do whatever you want with it but it's not owned by any company so it's free for any company to look at this model and play along nicely hence the interconnect that all these layers are interconnected together so when you decide to build an interface card you agree to make sure it's compliant with layer two it's going to work with a driver and that person who developed a driver is going to agree that it's going to understand layer three addressing right and it works its way up the stack so system is just a set of rules so as an open set of rules that tell you how the layers connect together how the communication process is upheld any takers for 500 Brian which one you want I'm sorry for 400 yeah I think we should be focusing on the OSI because that's a big chunk of the class other than addressing what type of network is maintained if a server takes no dedicated role in the network that's like a classroom where there is no dedicated teacher we all sit around in the circle there we go peer to peer what's the other type of model that we have that we've learned chapter three what's that chapter three is a throwback client/server you and the difference between the two as it's saved in this question the server takes no dedicated role and a client server that's the only thing a server does is hand out resources clients have to do what they make the request right okay a question like that is on the exam but it might be slipped clients every model in take yeah VC is communicating with another PC on a remote network the two networks are connected by three routers which command will help to identify the path between the host be careful now show IP route will only display the routing table of a particular router that's not what they're asking here they're asking you the path in which the packet will travel as it arrives to the other host tracer out there you go or trace our to you depending on what and by the way you can run trace RT for sorry traceroute from the iOS just like you run the ping Evan OSI 300 which OSI layer addressing is required to route packets between two networks that question keeps on coming up and up and up network layer or layer three right either whether interchanged this leads to a really good question we will just call them the network way refer to layer three it's not like you're saving any bread you want to know why because you look at the top and you know there's seven layers and you can say it's somewhere in the middle like layer three right whereas knowing the names like what is the first layer with the layer seven application application presentation session transport network data link and physical where you can just say layer seven six five four three two one yeah but I think it's just I know do it transport in the other ones better get to know them by Wednesday right all right I know you did that one right potluck for 400 nobody wants to finish off commands a little lonely old 300 how many usable house addresses may be assigned when using 128 dot 107 dot 0 dot 0 network address with a subnet mask of 255 dot 255 dot to forty eight dot zero which information you care most about this or that so I met mask got to 48 and at zero to 48 looks like this right it should be a 128 plus 64 is 192 plus 32 gives me to 24 plus what 16 gives me 240 plus 8 gives me 248 followed by one two three four five six seven eight zero is correct now we're talking about range usable host addresses so I know that the very first address I'll draw this on red it's got to go between I don't care what's over here so I'm just going to put little X's because I can't change that correct but it's going to be all zeros to this point except for a one right there correct then I give myself one to many zeros 1 2 3 4 5 6 7 good and then it's going to go all the way up to all ones and a zero there correct because all ones would be the broadcast address and all zeroes would be the network address so since I'm splitting the third octet I got a look at the third octet luckily they gave me all zeroes correct and third octet so this would look like zeros here so it better be 128 dot 107 dot 0.14 the first usable and then the last usable better be meet converting this so that's a seven dot 2:54 let's see how what we did oh they're honest total usable how many usable so I gave you the usable range made it more than in fact I think I gave you an exam question by accident the way to get that one is 1 2 3 4 5 6 7 8 9 10 11 oops consider it a freebie you've got a little zealous there Michael don't worry we got a couple 100's left for you have you want fellas which service is used when the nslookup command is issued on the computer and once again you could probably just type that community and go to das type it nslookup followed by a question mark if in doubt personally I would just look at NS and realize that those two letters mean something I need to know what those are where else did we see two letters well I was actually at three letters but had the NS in it especially when we're configuring our computers I always told you guys not to bother with this because we're not going out on the Internet or not using blank networks over closed DNS DNS the domain name so when you're looking up to convert an domain name to an IP address chapter 3 Brian stay away from the 100's I don't want you to hurt Ian's feelings what happens when a host station receives a frame that contains its own MAC address and destination there you go remove the layer to information to reveal layer three to reveal the IP address figure all right whoa don't be changing my lifestyle around like that I don't know what I'm going to do what can the user do from the command prompt router config dashed line what type of interface will it configure which would be a virtual interface yes so vty very good what else could it configure nice special cable aqua color what is it what what what interface console you got it they say a physical but it should be console or line interfaces yep stop picking your nails and look at the screen you know okay Evan what's up which two actions could be taken by a router if a specific match is not made to a router in this routing table there's two so a packet comes in looks for the destination Network address or calculates the network mix our destination network address looks at its routing table and has two choices if you get somebody's mail in your mailbox and it's not addressed to you so you could drop it but what's the other thing could you do especially if it's your mail if your neighbor if it's your neighbors mail yeah default route so just pass it on there you go so default route or drop the packet those the two by the way might be on the exam might not be servers that no he's saving us from network congestion because those packets are roaming all around which is the question I was going to get into what else would a router do as each pack is passed through it what field will it reduce so that when it reaches the zero the message will self-destruct so we don't get time to live and the packet header is reduced that is always a good thing because otherwise we have packets from 1980 still roaming around the internet which would be dragging our bandwidth down so get easier guys which ipv4 address represents a valid host address for a subnet ouch this question is always a pain in the butt well they're all slash 28 right so first thing I'm going to do is just set up this one two three four five six seven eight right for once this is my slash 28 this is my subnet mask we go with that next thing out of all those octet switch one am I just going to be converting to decimal why can't it be C or D all right the way you can tell that it's the only thing you're looking at is the fourth octet right so if you look at 32 a 32 is a 0 0 a 1 then all zeros so it can't be that one because that's a network out address but you look at 0 that's all zeros and here's where the line is drawn so that's a negative so let's look at 79 of 79 is a 1 in the 64 can't be a 1 into 32 right can't be a 1 in there but then it's all ones afterwards which we can assign hence 1:13 which would be be correct you guys see how I got that how many times I've had to do all this binary crap I'll bring paper for you guys yeah so B is the answer B in binary right we were just on you Ellen right I thought we were on you Brett for two doesn't matter does it really guys it's not like anybody's getting actually individual credit here it's figure to give somebody a choice but models being shown you know all you see is four layers TCP / IP Final Jeopardy or bonus round what OSI layers represent the network access layer you have physical and data link what uh layers represent the application layer application presentation and session there you go so it was TCP / IP model we took it up to the next level Michael you take the potluck for 200 yes you do and I know our design project a network designer needs to select a device to provide collision-free connections to 40 hosts on the land what type intermediary device should we put up on this local area network collision-free as always a convenient way to screw it up for my students are trying to memorize this on that it is not a hub yeah so it's not a hub it's gonna be a it's gonna be a local area network remember as you switch switch Brian looks like everybody gets 100 level course class question what's OSI layer does IP rely on to determine whether packets have been lost and to request retransmission networks are used to pass packets from router to router to get to its destination in fact it says what does the IP rely on hence you tell me network the IP is part of the network layer so that should have been a given within the question if you will transport n can handle this one boy what does your network yeah yeah it's just system software's there's like there's the iOS or the OS eyes you get social system software for Cisco devices so it's the internet work operating system what is the effect of using the copy running-config startup that's your second time getting one of these commands wait why are you why would you be copying are you copying both or you're copying one from the other so what is the effect of using copy running-config to start up your copying they're running so you're basically saving the configuration right I'll put that one for you and it was a hard choice and network technician is trying to determine the correct IP address configuration for the first host on the network with the given information 192 dot 168 sorry 100 dot 30 what can we tell what are we going to do here we want the first IP address well we got the subnet mask one-one-one right / 28 now we just need to do what let's look at that 30 see what looks like a binary this dirty look like in binary correct a 16 in there 24 28 30 oh good so this is where the line is drawn we know all ones we'll give me the broadcast address so all zeroes would give me the network address so the first usable would look like this which would be what 17 because 16 plus 1 and that would go all the way up to there's one but 30s being used so 29 would be the last usable the next you know because I believe we got them all what's that that's another one we'll get there Oh where's it at who doesn't guys buy your lottery ticket last week I know you guys think you can't what you gotta be kidding me so I've been corrupting a minor all this time that's better what does IP rely on to ash or reliability anybody will take it we'll make these open up riot TCP absolutely nothing it's unreliable yeah but the question is it's got to rely on something because it's unreliable layer three ICMP ICMP what was that used to work well protocol that was like a that's a ping command UDP well that's the counter to TCP so either it's going to be a or C so TCP is what gives us reliable transmission love it what does TCP use to reliably transfer data how do they accomplish reliability what's that it's whoa whoa whoa wait a minute what does TCP used to reliably transfer data yeah sure you want to call couch he was just kidding it is it yeah biggest thing is sequence numbers and acknowledgments acknowledgments are letting you know that what it did receive or what expects to receive next right that was expectation acknowledgement what does hierarchical ipv4 addressing provide 32bit host addresses members a 32-bit system we can rule out a because that's what MAC addresses what about D chapter five stuff it's like rip we haven't even learned any of that stuff really what about see at least one address per person you guys have smartphone tablets laptop Xbox Playstation yeah so you getting the idea that no two devices can have the same IP address right so hunts no person can be given an IP address maybe a network address but not an IP address all right so B would be the choice it's 32 bit unique host address what is a characteristic of csma/cd see multiple devices can transmit simultaneously that's true but explain why it's not a be careful though I want to rule out see in a minute but that's why I'm asking you to explain a all devices listen I can hear all communication pull the audience a lot of people think it's a many people think it's B we can rule out B because we're talking about csma/cd which ring topology uses tokens so let's totally against each other you don't have any collisions when use tokens it's like those with the microphones love talk what about D a device must have priority in the queue to transmit its QoS so we're stuck between a and C and csma/cd devices are not allowed to transmit simultaneously because if they do they're going to get collisions because CSMA stands for carrier sense multiple access so you have this common medium with multiple different devices are going to be accessing it correct and water for them to actually send data they have to check to see if there's anything on the wire if there's nothing on the wire they're allowed to transmit exactly because multiple devices are not allowed to transmit simultaneously and point-to-point you're allowed to because once sending the other ones receiving button CSMA you're not allowed to so to me I guess a would be the one because when you are transmitting aren't they listening for that carrier sometimes they can hear everybody and what they're sending if you will they choose not to listen why why are they choose not to listen because their MAC address does not match the frame MAC address correct hence they just choose to throw it away exactly once you change the rules your company is using 178 doubt 15.6 t 4.1 all the way up to 95 to 54 for host addresses what's the network address and the subnet mask to identify this guess what you get to do again that's right this time you're not given the subnet mask so in order for me to accomplish this I'm going to take the octet that met our different right so 78 7 8 or say 15 and 15 I'm saying but 64 95 or not so let me convert the 64 into binary I get a 0 1 0 0 0 0 0 0 and then 1 I get a 0 0 0 0 0 0 0 1 my upper limit is 95 95 looks like this one two three four five six seven eight because I know 32 and 64 would give me 96 so the number right before 96 is 95 when I note 254 it's one two three four five six seven eight there's my complete rage everybody's good about that start on the left you work your way over to the far right until you find pairs that are binary pairs that are not matching zero and zero match right go to the next one one and one are the same correct go to the next one zero and zero the same correct go to the next one zero and one are not the same I drop my line why must these be the same there's some that right there are some that address so my subnet mask is all this then correct so what is my network address my network address must be 64.0 so I look for 64.0 so it looks like it's between B and D now I have a slash 18 or slash 19 17 18 19 right because this is the third octet so my choice would be D most of the problems we have done so far it's me going back to binary and once your problems on the final exam is going to be addressing plus a little OSI stuff what is the data link layer responsible ironically another OSI question you'll be doing that tomorrow offer your final lab that's that if that counts so what's the responsibility for the data link layer see ya control media access for placement of frames on the media so anytime we ever talked about that we were at chapter 7 what is true about ARP I believe this exam is on your sorry this question is on your exam or some variation of it coming rule out a I was not designed to find the destination IP address correct what about C ARP tables are stored in NVRAM what is the only thing we've learned that was stored in nvram start up ARP is actually stored in RAM so if you want to restart your computer to lose your ARP table and what is the ARP table used for mapping IP addresses to physical addresses correct that's why we don't want a storm in NVRAM because logical addresses can change all the time so what about B or D uses proxy MAC address for source and destination during transit between routes will we mean by proxy what's your definition of a proxy if I say I'm going to have somebody vote for me because I can't be there the vote we would call that a proxy voter correct so it's somebody that's representing you that is not you correct but they're going to sort of go the way you wanted to so they're going to act like you is that okay so when did that ever happened when I wanted to communicate with a device outside by network when I went to go reframe that packet so here I am a host I am the sender now I'm going to talk to somebody outside my network what's the very first thing I had to do before I can build the frame I had to determine whether or not this packet belongs to my network or it's destined to go outside my network correct so I found the destination network address and said oh this is not the same network address that I have hence what MAC address do I put in the frame to be able to send the packet out the gateways the router but is that router the actual destination device the final destination device so isn't that router sort of acting like a proxy to get to there you have to go through me almost like I know a friend who knows a friend who knows a friend so you're sort of acting as a proxy for that end person and instead of saying I know somebody knows somebody knows somebody what do you say to your friends I know somebody right not that that person needs to know somebody and that person needs to know somebody that person needs to know somebody I just know somebody so proxy Mac is when your host puts the default gateways MAC address in for the frame and passes on to the router not knowing that the router is that person or not and what that rod will do is check its routing table and maybe it knows how to get to that destination device maybe it doesn't so maybe it passes on to another router hence that other router will act as a proxy for this router I know somebody who knows somebody who knows somebody good about that I can rule out D because the source MAC address doesn't stay the same during transmission so whether you guys knew that or not you can use the process of elimination to eliminate all those because the only thing that stays the same as packets are being transmitted is what address the IP addresses and why do the IP addresses stay the same so the packet can make its way back right why our MAC address is changing all the time because we're going from device the device from local to local to local right that's why we call it local delivery so B is the best choice what type of address is to 15.1 92.1 77.1 sixty dot slash 27 right host address and valid broadcast can we eliminate B yeah because they all fit between 0 to 255 correct so we're saying slash 27 here's my subnet mask 0 sorry 1 1 then all zeros afterwards now I got to see what 160 looks like correct what's that broadcast is usually a odd number you're correct very good like it so now we're stuck between a and C so we eliminate D because broadcast is an odd number we have an even number here I say hell let's just figure it out we have a one here a 0 here a 1 there that's 160 correct then I have all zeros afterwards all zeroes in the host part make up the network hence yeah because remember these are the subnets so it'd be choice C yet again back to that old binary stuff how do you determine the default gateway for a host device I like drawing pictures when it comes to this first choice says nearest Ethernet switch interface on the same so what they're saying is you have a PC connected to a switch this interface is going to be the default gateway for the PC just a switch act like a gateway no so as out of the question be near a serial router interface on the land of the router so that means I must have a router and that must be connected to another router using a serial and they're asking me is that interface going to be the Gateway for this PC now nearest Ethernet interface on the next hop router here's the next hop router here's that interface is that Ethernet interface going to be the Gateway for this PC hence the nearest Ethernet interface router on the same subnet as the hosts so Dee seems to be logical what range of dynamically assigned port addresses are used by the client apps I don't like this answer or mentally it is B but there is a better answer and so what I'm going to ask you guys is what are the three categories when it comes to port addresses I'll start you off starts with zero what's the end of the next range so we're in the beginning the next range so the first fringe which we call the well-known ports go from 0 to 1023 next range goes from ten twenty four to forty nine thousand 151 what do they call those they are not dynamic like they want to tell you they are they call them registered ports and then forty nine thousand one hundred fifty two all the way up to 65535 becoming dynamic ports technically this question is sort of right because you're allowed to sign anything after 1024 as being dynamic but we are trying to move to that three model three category C so B is the answer they want you to pick there is a better one make sure you guys do know your well-known dynamic and your registers or well-known registers and dynamic Oh Evan you answered this question the last time what does the command copy TFTP running config Gil he's over 2 so it takes a backup file and puts it into the running memory so copies from tf2 pizzeria so choice a very good how many broadcast amines are created by a switch I can ask this question four different ways let's do this one how many broadcast mains are created by a switch what is another name for a broadcast domain a network how many networks is a switch create which doesn't great networks right routers do correct so it's going to say 1 by default since all ports are part of the same network all right what if I say this how many broadcast domains are created by a hub that's variation number 2 same answer because hubs and switches aren't breaking networks up right what if I say how many collision domains this is variation number three how many collision domains are created by switches one per port very good what if I say how many HUS are how many brought new how many collision domains are created by hubs it's one giant collision domain the more collision domains you have the less chances you're gonna have collisions ironically yeah which is correct regarding a 568 cable 568a pin 1 and 2 what colors are they blue orange green or brown green green B is what orange what are the following can you not use a straight-through cable for PC to switch straight through a crossover you guys connect the PC to switch let's type of cable straight through router Ethernet to a switch what type of cable connecting just similar devices straight through router console to PC network interface card use a console cable million-dollar question when using that what type of address must be assigned to the interface closest to the ISP so let's say this is the ISP what type of IP address do I sign this interface what does not stand for close network address translation what does that mean private to public what side this whereas we're dealing with private addresses I want the PC and the switch right this sides going to deal with public this is the public side what type of address would you assign this side of the router public host why not a public network IP address very good going back to we learn privates are eliminated so we're stuck with a and C and a is the best choice all right top 20 questions that students got wrong in the past from Cisco's finals by the way the questions have changed somewhat what they still pretty consistent question 9 some variation is going to be dealing with this what three characteristics of csma/cd choose three of them so let's go big fans when it comes to picking more than one answer correct let's see what can we rule out it uses a token system to avoid collisions Sesma does not avoid collisions right data is transmitted only when the data signal is present it's actually the opposite right if the data signal is present is going to shut up in weight astern so we eliminate that now I got four and I got to pick three out of the four so now I get the question 75% correct devices can be configured with a higher transmission priority to see us I may care about that what service does care about that when it comes to prioritization quality of service QoS so we limited those and now we're left with the top three a B and C let's check see if a is correct it monitors the media for presence of a data signal yeah so we just got something down here after detecting a collision host can resume transmission after random timer has expired a jam signal is used to ensure that all hosts are aware that a collision has occurred yeah you're going to make sure that everybody's up on page two that after you set the jamming signal we set we called a random timer the jitter timer so that devices can then go back without recreating a collision so a B and C are the three options that I would pick we're sort of the exhibit the host was disconnected from switch - that was over here brought over to switch one which combination of IP address subnet mask and default gateway should be assigned to the host to allow a fully functional Network so here you are given this information okay so which one e we can eliminate EB cuz it's completely out of their the way eliminate is he said 196 what should the default gateway be what's that a 10.10.5.3 five correct because we're here remember it's always the closest ethernet side correct here we are unfortunately that eliminates e but I'm still stuck with FDC B and a and the other ones that can eliminate number yep so let's look at it we have a slash twenty seven a slash twenty seven is dot two to four correct 128 plus 64 plus 32 so now I eliminate it a C and E so I'm stuck with B C or F correct what else can I do now wait a minute B D and F well B and E have a dot 37 for the IP address but F has a dot 63 well remember the subnet mask we have three ones than all zeros correct what's a 63 oops you have all ones right what's all ones in the host part so f is out of the question now we're with B and D sorry B and E now we're really up with B and D so we got 37 and 32 well let's take a look with 32 looks like ah you're making assumption that every time a router is always configured to last usable in this case it's not take a look at what 32 represents when I took my CCNA exam for this course I didn't bother go into that process of elimination you guys are going to the first thing I did through it right to binary all the time I mean 90% of the damn exam is some kind of binary variation right I limited through these I realized that 32 is the network address 60 there was a broadcast address then I went and eliminate the subnet masks and then I went to the process of looking at the default gateways so this answer should be what be 37 - it's the only host address look at it through binary guys which two factors can be determined by looking at this topology for collision domains are they being presented in this logical topology five how many collision domains are represented by a switch one per port one two three correct how many collision domain is represented by a hub 1 1 2 3 4 so a is a good one one logical network is represented is that true now one network here to go one network there correct to broadcast domains that represented we set another name for broadcast is network we have two networks those are my two three networks are needed now because I'll have us to three logical address ranges are required no once again all I have is two so collision domains of broadcast domains I don't know why my students in the past have gotten this question wrong they issued the showrunning configuration command to show you what's active on the router and you see that the interface FA 0 / 0 or the fastethernet 0/0 has an IP address of 10.1.1.1 with a subnet mask of 255 dot 255 dot 255 dot 0 the question then asks a user wants to access the internet from PC a part of the running configuration of the router is shown what default gateway IP address should be configured they always want to give it 10.1.1.10 54:1 is the only time you give a switch an IP address ya management purposes switch doesn't handle routing traffic so it should be 10.1.1.1 so a should be the only choice some of them would have answered the serial connector but as you guys found on the other questions it's this side of the router correct examine the graphic which current configuration host so what's with the current configuration host day in the clerical office failed and was replaced although a ping for the loopback was successful the replacement computer cannot access the company's network so replace to a with the new computer here at the new configuration for a with proxy ARP disabled on FA 0/0 of the router what is the likely cause of the problem some time ask because this is last 26th and the rest of most last 27 correct one importantly this last 27 up there as well by the way could you even know if the network failed network card failed is there any way any information provided to rule that out pin yourself exactly could you determine that the cables were unplugged you got to pick yourself again so yeah either you're there so you can't make those assumptions so make sure when you guys answer those you look at it with what was given to you it's part of the exhibit hos day sends a frame to host seal with a destination MAC address CC the MAC address for host C is not in the Mac cab of the switch how we'll switch one handle the frame translation frame comes in to switch one checks its MAC table so CC is not in there what's the next step let's see switch one will drop the frame yes or no I'm not sure we'll come back to that one beasts which one will forward the frame to host see why not so I can't forward it very good switch one will flood the frames out of all ports can we rule that one out we could what why can we eliminate that okay that's good so it doesn't rule out this part though it forwards out of all the ports except the one the packet came in on or the frame came in on is that all right even where it's going to do a broadcast or even when the packet was a broadcast packet it's not going to send it back the person just got them sending it to it right that would be stupid it's like me talking to you guys and I'll talk to myself the same time well Nick what do you think the answer is all right so see is eliminated and B is a limited now we're stuck with a and D I like D because it handles what we just stopped talking about but why would you guys want to say that the frame is dropped this is where I want to argue with you when did we learn about friends being dropped that's a packet and you can't find a route once again that's a packet packets are dropped frames don't want I mean switches don't want to drop frames the only time a switch will ever drop it is when it first receives a frame and it cannot find its MAC address then it does a broadcast it does an ARP request send it out all the other ports except when it came in on an ass is there anybody who has this MAC address if there is nobody on that network with that MAC address then it'll drop it but it first has to flood all the other ports except the one that it came in on that see if there's anybody out there just turned on their computer with that MAC address before it can discard ok no different a router discard in your packet before it can discard it's got to check its routing table correct so I choose the last one and by the way switch to would then say I know about that MAC address because I'm going to act as a proxy to that device so then switch one opacity switch to switch to would look at its physical table and say oh yeah that's FA 0/10 user types in the enable command which tasks can be performed at this can you configure a device from the privileged exec mode can you configure individual interfaces from this mode can you configure terminal lines from this mode hence show and debug remember I was only telling you guys hold the control key at the letter Z type and show IP interface brief or show IP route or ping or trace route or anything of the nature so D is the choice I believe this is the fifth time we saw this question but it's on here because I got it wrong on my final exam and I got it wrong because just like I did poorly on my SATs I don't tend to read things clearly so I will read it out to you guys look at the picture a network technician has made several changes to r1 since the configuration has last been safe where are these configurations being stored at right now running very good the modified configuration did not produce the desired changes hence the running configuration he's not happy with the technician wants to store a backup copy of the saved configuration on a TFTP server before reloading it which action will cause the unmodified data to be saved on the TFTP server B I had the pat you on the back I just for some reason did not put the on and unmodified because throughout the whole damn question it's the modified to modify the modified and the last part of the question thank you for making this a reading course Cisco which action will cause the unmodified data so right off the bat you can eliminate a and C because they're dealing with running config now how do we eliminate D because the next part is about the IP address and three dot 254 is our one and it needs to go to the TFTP server so do a better job in reading that I will and the answer is B because it says unmodified I think this is the last question refer to the exhibit at which OSI layer is a serial interface 0 / 0 / 1 experiencing problems says show interface 0 / 0 / 1 it says the serial 1 is up so somebody turned it on but line protocol is down layer one that's what I thought well it's I need layer to this no why would you say layer two well because it's but it's protocol remember we have up and up right so it's turned on so that means the physical interface is working later ones physical layer - it's about the protocols and it says line protocol is down so we're talking about like CSMA or point to point or something to the effect correct what about layer three congruent layer three so so far I like layer two why can I roll out layer three does a serial connection need a layer three IP address one good point what about layer four whereas layer four used it notice you're in the router router doesn't care about transport layer stuff this is port addresses if it was a firewall maybe but who cares about port addresses the end devices right not I mean by port addresses I'm not talking about the ports the physical ports ironically has poured named but I'm talking about the end devices because the port addresses identify the service that's going to fulfill the request and the clients application that makes the request right so be careful you can eliminate almost every choice by the information they gave you layer one is eliminated because it is up that means they turned it on so the interface is okay layer 3 can be eliminate the serial connection you really don't need a layer 3 address layer 4 can be eliminated because routers don't handle that unless it has firewalls turned on Oh question 50 by the way your final exam is all multiple choice and it is 50 questions what do we have here and network administrator's troubleshooting a link that is down between r1 and r2 what type of cable should be connecting r1 and r2 what type of cable should be connecting r1 and r2 through Fast Ethernet you can see FA 0 / 0 @ fa 0 / 1 just use the Seri ok better bandwidth maybe to connect I started to correct the problem which wire pairs need to be switched on one of the Ethernet cable so it should be a crossover cable and which ones do we need to switch what's that let's look at pin 1 and I started pair 1 and pair two pair 1 is this blue stuff does the blue need to change at all so you limited anything with pair 1 in it ok so now we eliminate a and B what about C pair 2 what have we learned where you guys are checking for crossover cables if it's green white on one side and orange white on the other side for pin 1 then it's going to be a crossover assuming everything else is the same I mean correctly wired so I like pair 2 and pair 3 I should be switching the green stuff with the orange stuff right what about D pair two pair for the Brown never change now we didn't care about the brown so para what two or three so I would definitely choose C on your exam might ask you what is the paid configuration for crossover so just make sure you guys know one two three what six any questions Wednesday 8 o'clock for your class if you're watching at home your exam is Monday 6 p.m. to 9 p.m. so bring dinner Monday that is what December 10th and you guys are December 12th any other questions I got three minutes two minutes what is the blue and said you can make you nope you don't need them they're just there for future use the other thing that could be used for absorbing interference some are use them to put power over ethernet so if you have a device that can be powered up by like a camera or whatever through ethernet then you can use those pins to some electricity anything else guys everybody's good tomorrow your final lab facing 11 weapons now we're going to do that tomorrow in class

Channel: Nicholas Andre

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Id: -y9AGPFk0qU

Length: 84min 50sec (5090 seconds)

Published: Tue Dec 04 2012