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Home > Archive > CCNA > July 2001 > Questions I haven't found answers to yet
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Questions I haven't found answers to yet
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| nelsons1 2001-07-14, 9:04 pm |
| I ran into a few questions that I don't have the answers for..
1. What is a SPID?
A. A SPID is a common ISDN switch type for the United States.
B. It is a series of characters used with ISDN, that identifies you to the switch at the central office.
C. It is a number that identifies the logical circuit between the source and destination device in a Frame Relay connection.
D. It is a signaling standard between the CPE device and Frame Relay switch that is responsible for managing the connection and maintaining status between the devices.
>I chose B. I ruled out A. as being the obvious wrong answer, I think D. is LMI not SPID, and I think C is DLCI.
2. Whic three pieces of CDP information about neighboring routers is displayed on your console terminal (choose three)
A. A neighboring routers hostname
B. The neighboring routers hardware platform
C. Up to one address for each protocol supported.
D. Up to two addresses for each protocol supported.
E. As many addresses as are configured for each protocol supported.
>I chose A, B, and I'm not sure about the third...maybe E??
3. Network 150.125.0.0 has the subnet mask 255.255.248.0. If an access list is applied to 150.125.8.0, with the wild card mask 0.0.7.255, which addresses will this match?
A. Only subnet 150.125.8.0
B. All subnets higher than 150.131.8.0
C. Any subnet on the network 150.125.0.0
D. Subnets 150.131.8.0 through 150.131.15.0
>I chose C, but I'm not sure..maybeB?
4. You have just entered the commands:
Router(config)#access-list 1 permit 192.50.19.0 0.0.0.255
Router(config)#interface serial0
Router(config-if)#ip access-group
Which three statements are true? (choose three)
A. This access list will not filter any network traffic going out serial 1.
B. This access list will not allow any traffic to enter the interface serial 0.
C. This access list will not filter any traffic entering the serial 0 interface.
D. This access list will only permit traffic from the network 192.50.19.0 to go out serial 0 interface.
>I didn't know which to choose, the question didnt even specify in or out when applied to the interface.
Please help.... | |
| sharky 2001-07-15, 8:34 pm |
| I am going to answer the questions from the top of my head.
1.B
2.A,B,E
3.D
4.A,C,D
 please check proper resources. | |
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| 1. Of course you are right. SPID is not used all over the world. In fact I think it is only used in North America. Anyway, it is not an ISDN switch-type.
2. I am not sure myself. When I tried this I was surprised to see that my multi-interface router with lots of IPs configured was listed with only one address, but a switch with only one IP address had this single address listed twice. The way the output is formatted and formulated makes me think that it actually intended to show me one address per protocol, and only the address of a directly connected interface. This makes sense since that is the address I would use if I wanted to further investigate my network by telneting to another device.
3. I would stick with D, but don't take my word for it. Do the math yourself!
4. An important thing to know about access-group is that the default direction is out. Only C and D makes sense to mee. Makes it difficult to choose three.
Terje | |
| Retired-Mod 2001-07-16, 11:05 am |
| CDP will show the directly connected IP address of the neighbor when using the detail addition to the sh cdp nei command.
Terje read question 4 too fast. Answer A switches the serial port on it which also makes it correct.
Retired  | |
| depamo 2001-07-16, 9:53 pm |
| A SPID is a Service Point Identifier that is given to you from your connecting telco that gives you the line. You need one for each B channel in your ISDN setup in the US or outside the US. The only thing that is differenc outside the US for (other then PRI 24-30 B channels) is the use of an NT2 device outside of the US.
Answer to 1 is B
Answer to 2 is A, B - goto
http://www.cram4exams.com/index.shtml
and try it yourself.
Answer to 3 is A - Here is the issue, you have a net mask 255.255.248.0 with an IP address of 150.125.8.0 and lastly the wildcard mask of 0.0.7.255. This means that for the access list to work, you need to write out the bits, the wildcard mask, netmask and network. According to this, everything that must match 150.125.8 because the mask only masks off the lower 11 bits and this is what you have left. since the first 11 bits going from right to left describe the host from the subnet mask (255.255.248.0) it all matches up and you specifically match this one subnet or any host within this subnet. Make sense?? Try it out.
Answer to 4 is D, if you don't tell a router which way to go with the access-group, it is assumed to be out on the applied interface. This one will allow only the network 192.50.19.0/24 and all its hosts to pass, all others will hit the implicit deny at the end of the list (at the end of every list unless you use the global pass all at the end or somewhere).
Hope that helps, if you have any more questions I could use the pratice.
Talk to you all later. | |
| depamo 2001-07-16, 10:04 pm |
| I just looked at my answer for 3 and I could barely understand it. So here it is in a little better english-
Here is the netmask and the Access List Wildcard
11111111.11111111.11111000.00000000
00000000.00000000.00000111.11111111
First on top is the netmaks of
255.255.248.0
and below the access list wildcard of
0.0.7.255
They match up pretty good, so good that the only thing that could be a wild card is the host portion of the ip address!! This is represented by a 1 in the access list wildcard which is the same as saying, if you have a one in that place in the wild card mask, I don't care what it is, it matches. If a bit has a zero in the wild card mask, then it is the same as saying it must match. So you have to match the network portion exactly which is 150.125.8.0 -
Hopefully that makes more sense.
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| quote:
You need one for each B channel in your ISDN setup in the US or outside the US
For all I know SPIDs are used in other places of the world than the US, but I never use SPID when configuring ISDN in my country (Norway). Everything I know about SPIDs are from the books.
quote:
The only thing that is differenc outside the US for (other then PRI 24-30 B channels) is the use of an NT2 device outside of the US.
You don't always need NT2 outside US, but why would you never use it in the US? I know it is common for the NT1 to be built into the device (eg. router) which precludes other simultaneous uses of the same ISDN line and voids the need (or use) for an NT2. But is there any reason you could not install a separate NT1 in the US? In that case you would have an S interface and could in theory connect any ordinary non-U ISDN device, including an NT2.
quote:
Originally posted by Retired-Mod
Terje read question 4 too fast. Answer A switches the serial port on it which also makes it correct.
You are right! I should learn to read. Not only all those letters, but the numbers too.
Terje | |
| dmaftei 2001-07-17, 4:45 am |
| quote:
Originally posted by depamo
Hopefully that makes more sense.
So, what you're saying is that the answer for question 3 is D, right? | |
| dmaftei 2001-07-17, 4:53 am |
| quote:
Originally posted by depamo
Answer to 4 is D, if you don't tell a router which way to go with the access-group, it is assumed to be out on the applied interface. This one will allow only the network 192.50.19.0/24 and all its hosts to pass, all others will hit the implicit deny at the end of the list (at the end of every list unless you use the global pass all at the end or somewhere).
The answer to question 4 is A, C and D. You can find an explanation --> here <--. | |
| nelsons1 2001-07-17, 10:43 am |
| Thanks for the help guys...Didn't see those questions on the test but I understand it better now. | |
| doctorcisco 2001-07-17, 6:15 pm |
| quote:
Originally posted by nelsons1
I ran into a few questions that I don't have the answers for..
1. What is a SPID?
Minor correction to previous answer ... Service *Profile* Identifier. They double as the phone number for the 2 B channels. They are so named because they are not merely the phone numbers, but have information attached about which kinds of service the circuit provides the user. Perhaps the most common example is that the SPID profile on the switch tells the switch whether the circuit is data-only, or both data and voice (you also have to think about the video and other services ISDN was designed to provide, but we don't think about too much in the WAN world.)
quote:
2. Whic three pieces of CDP information about neighboring routers is displayed on your console terminal (choose three)
A. A neighboring routers hostname
B. The neighboring routers hardware platform
C. Up to one address for each protocol supported.
D. Up to two addresses for each protocol supported.
E. As many addresses as are configured for each protocol supported.
As Terje said, sh cdp neigh *det* gives you the IP address of the neighbor's interface on the shared link, in addition to A and B that sh cdp neigh will give you. C is a badly worded though technically correct answer; I don't think you'll get an IPX or Appletalk address no matter what.
quote:
3. Network 150.125.0.0 has the subnet mask 255.255.248.0. If an access list is applied to 150.125.8.0, with the wild card mask 0.0.7.255, which addresses will this match?
A. Only subnet 150.125.8.0
B. All subnets higher than 150.131.8.0
C. Any subnet on the network 150.125.0.0
D. Subnets 150.131.8.0 through 150.131.15.0
>I chose C, but I'm not sure..maybeB?
The answer is A, *IF* you assume that the mask on 150.125.8.0 is also 255.255.248.0.
However, if you're using VLSM (as almost all IP networks do), knowing the mask for 150.125.0.0/21 tells you NOTHING about the mask for 150.125.8.0. So if you assume that 150.125.8.0 - 150.125.15.0 are 24-bit masks, as they certainly CAN be in a VLSM environment, D could also be correct. The author of the question displays some ignorance here.
The best way to learn from this bad question is to understand that this ACL will match everything in the address space 150.125.8.0 - 150.125.15.255, regardless of how this address space is subnetted. ACL's don't care about subnet masks; they don't even LOOK at subnet masks. All traffic with these addresses will match the list.
HTH,
doctorcisco | |
| dmaftei 2001-07-17, 6:45 pm |
| With all due respect for the good ol' doctor, I disagree to some extent...
quote:
Originally posted by doctorcisco
The answer is A, *IF* you assume that the mask on 150.125.8.0 is also 255.255.248.0.
First, with the data given in the question (specifically wild card mask 0.0.7.255), the answer can never be A. You need a 0.0.0.255 wildcard mask to hit A.
quote:
However, if you're using VLSM (as almost all IP networks do), knowing the mask for 150.125.0.0/21 tells you NOTHING about the mask for 150.125.8.0.
In agreement here.
quote:
So if you assume that 150.125.8.0 - 150.125.15.0 are 24-bit masks, as they certainly CAN be in a VLSM environment, D could also be correct. The author of the question displays some ignorance here.
This is the only real problem I see with this question: the assumption that 150.125.8.0 through 150.125.15.0 are 24-bit masked.
quote:
The best way to learn from this bad question...
Actually, I think this is a very good question. The extra information (Network 150.125.0.0 has the subnet mask 255.255.248.0) really forces you to think about it, and tests your ability to find and use the good info when mixed with useless info.
quote:
... is to understand that this ACL will match everything in the address space 150.125.8.0 - 150.125.15.255, regardless of how this address space is subnetted. ACL's don't care about subnet masks; they don't even LOOK at subnet masks. All traffic with these addresses will match the list.
Total agreement here.
Cheers! | |
| laceywa 2001-07-17, 8:21 pm |
| What have you people been reading or studying to come out with answers that does not even make sense. Here are the correct answers.
1. B
2. A, B, E (not sure on E, but when you think about subinterface it makes sense)
3. D (remember bracket)
4. B, C, D (it said to chose three and A talks about S1 not S0. | |
| dmaftei 2001-07-18, 5:21 am |
| quote:
Originally posted by laceywa
What have you people been reading or studying to come out with answers that does not even make sense. Here are the correct answers.
Lucky us you showed up with the "correct" answers... [grin]
quote:
4. B, C, D (it said to chose three and A talks about S1 not S0.
Question 4 is Which three statements are true? (choose three). Choice A is true: since the access list is not applied to serial 1, it follows that "this access list will not filter traffic going out serial 1". Soo... do you take another shot at which one of B, C and D is false?
And, btw, with this type of questions ("which is true" or "which is false"), you have to look for the truth value of the choises, even if those choices are completely unrelated to the statements preceding the question. For example:
Question 1: access-list 1 deny any is applied to interface serial 0 both inbound and outbound. Which of the following are true (choose two)?
A. all traffic through serial 0 will be blocked.
B. telnet traffic through serial 0 will be allowed.
C. ftp traffic through serial 0 will be allowed.
D. given that the human population is constantly increasing, and that the total amount of common sense on Earth remains constant, it follows that the amount of common sense per capita is constantly decreasing.
Choice A is obviously true, and choices B and C are obviously false. Choice D is true (albeit not obvious), therefore you will have to choose D, even if it has nothing to do with access list 1 and serial 0.
Catch the drift?!  | |
| laceywa 2001-07-18, 5:21 pm |
| Thanks for keeping me straight. | |
| Retired-Mod 2001-07-18, 5:40 pm |
| Yep Terje,
I actually have an old 2503 in the US that does require an external NT1 and I'm sure there are many others that have similar experiences.
Yankee
PS. I knew ya knew that other question but I got a kick out of pointing it out anyway | |
| chunder 2001-07-18, 5:52 pm |
| ok. way back to the first post... question #3:quote:
3. Network 150.125.0.0 has the subnet mask 255.255.248.0. If an access list is applied to 150.125.8.0, with the wild card mask 0.0.7.255, which addresses will this match?
A. Only subnet 150.125.8.0
B. All subnets higher than 150.131.8.0
C. Any subnet on the network 150.125.0.0
D. Subnets 150.131.8.0 through 150.131.15.0
is the question worded properly? look at the network in the question: 150.125.0.0 and then the subnets mentioned in D: 150.131.8.0 through 150.131.15.0. i mean, if this is what the author of the question really intended for it to read then the answer is NOT D, is it? so, based on the little knowledge i have of wildcards (which i think is my weakest area) then i want to agree with depamo and the doctor... however, when the docotor brings up VLSM i want to say "CCNA is not concerned about Variable Length Subnet Masks for the test". would that be a correct statement? and the only thing i can find on VLSM in Lammle's book is a brief description in the glossary. and i can't find it in the Cisco ICND book. however, there's a little more than a blurb in ExamCram about it but it appears to more of a "gee-whiz" than scripture.
if there was an answer of 150.125.8.0 - 150.125.15.0 i'd pick that. people mention it but it's not an option.
also, the class of IP in question is class B. default mask is 16 bit which already makes the 15.131.x.x completely different.
am i confused? i need someone to shed some light.
thanx. | |
| depamo 2001-07-18, 6:13 pm |
| 4. You have just entered the commands:
Router(config)#access-list 1 permit 192.50.19.0 0.0.0.255
Router(config)#interface serial0
Router(config-if)#ip access-group
Which three statements are true? (choose three)
A. This access list will not filter any network traffic going out serial 1.
B. This access list will not allow any traffic to enter the interface serial 0.
C. This access list will not filter any traffic entering the serial 0 interface.
D. This access list will only permit traffic from the network 192.50.19.0 to go out serial 0 interface.
OK, there was some question to my answer of D I read it way too fast so here is some explination--
Remeber, you have only the information that is given, right now you have only one access list on the outbound 'process' on serial interface 0.
A - Is right, as far as you know the access list will not effect serial 1, only serial 0, I missed the 1 in the question.
B - Is wrong, all traffic will come into Serial 0 with these settings, you have only effected outboud traffic (pretend you are inside the router when you use inbound and outbound)
C - Is right, this access list will not effect 'entering' traffic or inbound traffic because it is effecting Serial 0 as an outbound interface only.
D - Is right, this access list will only permit traffic from the network 192.50.19.0 to go out the Serial 0 interface.
As I said, missed a couple of remarks and some awkward words were used, hope that it didn't confuse you.
Also the Answer to the wild card from 3 that I had to restate for clarity was correct as A.
Two main things to remeber here, the question and the possible answers. They want to know which networks are effected, without writing it out in binary, this would be very difficult. The subnet mask will give you information as to where the wildcard starts and the subnet stops. When building an access list, this is very important when deciding who get access to which networks and TCP/UDP ports. In the end, the subnet mask is not considered but you should understand how this is working once implemented. One more bit to the left with the subnet mask and you have a very different outcome then keeping it the same and by not changing anything in the access list. Because of this reason, you should always be aware of your networks, subnetmasks, and wildcards. Seen this mistake too many times in the past and the router will not care one way or the other, the subroutine will still compare in the same method.
Thanks for the catch everyone, I stand corrected on 4, that was an obvious error on my part. Will be sure not to make mistakes on future questions.
Later and good luck to everyone. | |
| dmaftei 2001-07-18, 7:28 pm |
| quote:
Originally posted by laceywa
Thanks for keeping me straight.
You're most welcome! Lucky me (this time) I talked only about question 4, because with question 3 I was way off base. See below... | |
| dmaftei 2001-07-18, 7:31 pm |
| quote:
Originally posted by doctorcisco
The answer is A, *IF* you assume that the mask on 150.125.8.0 is also 255.255.248.0.
doctorcisco (and depamo) were right after all. Thanks, chunder, for showing me the 131s. I must have been stuck on stupid for the last two days. Sheesh... | |
| chunder 2001-07-18, 8:21 pm |
| ok. cool that i understood it and you're welcome D. it was just a little oversight and i still love you (in that idolistic stalker way) | |
| depamo 2001-07-19, 3:01 pm |
| I am going to be taking 503 in one week, I needed the beating, the answer I gave was obviously wrong (serial 1 vs serial 0) and it is exactly what Cisco will do on the exam to make sure that after 5 days without sleep and working at the same time, you are paying attention during an exam.
So, hats off and if you are testing, this is what you will be dealing with so open your eyes, don't jump to conclusions, and take your time. |
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