Pings didn’t work while in Router A inverse-arp correctly showed 192.168.2.1 behind the proper serial interface and using dlci 50. The explanation is very simple: if the two peers are in different L3 subnets they will not be directly connected and so the peer is unreachable.

To me the “most likely clause” implies those assumptions:
1. basic frame-relay configuration (simple “encapsulation frame-relay” statement inside an interface, no manual mapping)
2. since a mask is not specified in the question I would use the classful one, a /24

So, given that two IP addresses on two different subnets would not be seen as directly connected in the routing table, the IP address configured in Router A should fall in the network 192.168.2.0/24, the same of RouterB.
That’s why my answer woud be “D. incorrect IP address”

Nonetheless I think the question is very ambiguous (or, better, totally wrong), since some pieces are definitely missing. I hope it is a wrong transcription or it has been corrected in the real exams by now.

Following, some meaningful outputs of my lab:
!
! RouterA
!
RouterA#show running-config
! many lines omitted
!
interface Serial0/0/0
description toWAN
ip address 192.168.1.1 255.255.255.0
encapsulation frame-relay
!
! many lines omitted

RouterA# show frame-relay lmi
LMI Statistics for interface Serial0/0/0 (Frame Relay DTE) LMI TYPE = CISCO
Invalid Unnumbered info 0 Invalid Prot Disc 0
Invalid dummy Call Ref 0 Invalid Msg Type 0
Invalid Status Message 0 Invalid Lock Shift 0
Invalid Information ID 0 Invalid Report IE Len 0
Invalid Report Request 0 Invalid Keep IE Len 0
Num Status Enq. Sent 28 Num Status msgs Rcvd 27
Num Update Status Rcvd 0 Num Status Timeouts 16

RouterA# show frame-relay pvc

PVC Statistics for interface Serial0/0/0 (Frame Relay DTE)
DLCI = 50, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0

input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155

RouterA# show frame-relay map
Serial0/0/0 (up): ip 192.168.2.1 dlci 50, dynamic,
broadcast,
CISCO, status defined, active

RouterA#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route

Gateway of last resort is not set

C 192.168.1.0/24 is directly connected, Serial0/0/0

!
! ROUTER B
!

RouterB#show running-config
! many lines omitted
!
interface Serial0/0/0
description toWAN
ip address 192.168.2.1 255.255.255.0
encapsulation frame-relay
!
! many lines omitted

RouterB#show frame-relay lmi
LMI Statistics for interface Serial0/0/0 (Frame Relay DTE) LMI TYPE = CISCO
Invalid Unnumbered info 0 Invalid Prot Disc 0
Invalid dummy Call Ref 0 Invalid Msg Type 0
Invalid Status Message 0 Invalid Lock Shift 0
Invalid Information ID 0 Invalid Report IE Len 0
Invalid Report Request 0 Invalid Keep IE Len 0
Num Status Enq. Sent 154 Num Status msgs Rcvd 153
Num Update Status Rcvd 0 Num Status Timeouts 16

RouterB#show frame-relay pvc

PVC Statistics for interface Serial0/0/0 (Frame Relay DTE)
DLCI = 75, DLCI USAGE = LOCAL, PVC STATUS = ACTIVE, INTERFACE = Serial0/0/0

input pkts 14055 output pkts 32795 in bytes 1096228
out bytes 6216155 dropped pkts 0 in FECN pkts 0
in BECN pkts 0 out FECN pkts 0 out BECN pkts 0
in DE pkts 0 out DE pkts 0
out bcast pkts 32795 out bcast bytes 6216155

RouterB#show frame-relay map
Serial0/0/0 (up): ip 192.168.1.1 dlci 75, dynamic,
broadcast,
CISCO, status defined, active

RouterB#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route

Gateway of last resort is not set

C 192.168.2.0/24 is directly connected, Serial0/0/0

!
! TEST 1
!

RouterA#ping 192.168.2.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.2.1, timeout is 2 seconds:
…..
Success rate is 0 percent (0/5)

!
! TEST 2
!
! Config changes to make the two class C subnets in the same supernet
!
RouterA#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
RouterA(config)#interface serial 0/0/0
RouterA(config-if)#ip address 192.168.1.1 255.255.0.0
RouterA(config-if)#end
RouterA#
%SYS-5-CONFIG_I: Configured from console by console

RouterA#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route

Gateway of last resort is not set

C 192.168.0.0/16 is directly connected, Serial0/0/0

RouterB#configure terminal
Enter configuration commands, one per line. End with CNTL/Z.
RouterB(config)#interface serial 0/0/0
RouterB(config-if)#ip address 192.168.2.1 255.255.0.0
RouterB(config-if)#end
RouterB#
%SYS-5-CONFIG_I: Configured from console by console

RouterB#show ip route
Codes: C – connected, S – static, I – IGRP, R – RIP, M – mobile, B – BGP
D – EIGRP, EX – EIGRP external, O – OSPF, IA – OSPF inter area
N1 – OSPF NSSA external type 1, N2 – OSPF NSSA external type 2
E1 – OSPF external type 1, E2 – OSPF external type 2, E – EGP
i – IS-IS, L1 – IS-IS level-1, L2 – IS-IS level-2, ia – IS-IS inter area
* – candidate default, U – per-user static route, o – ODR
P – periodic downloaded static route

Gateway of last resort is not set

C 192.168.0.0/16 is directly connected, Serial0/0/0

!
! TEST 2
!
RouterA#ping 192.168.2.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.2.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 12/20/27 ms

2. We are looking at the network from Router A end so its does not matter what router B has or does not have we cannot tell. Even the question says so.#

Answer:
Mr Net Admin can see that the DLCI map is correct as he is aware of the IP on the remote side as shown in the question.

Local DLCI (Router –> FR switch) is mapped to remote IP destination.

Thus, IP is correct, DLCI map is OK. irrespective of hub and spoke or 1 – 1 connection. Therefore we are sure of this because we have evidence that its correct.

The question is can the bandwidth or LMI type be the problem.

Bandwidth issues will most likely cause congestion and not loss of connection.

Yes, LMI type can cause problems and is a ””likely”” cause since we don’t have evidence that it’s not we can’t eliminate it.

ANSWER is B.

so what is really the correct answer for q7? is it incorrect ip or incorrect map?
thanks.

VTP Sim, EIGRP and ACL 2

Also, I saw a few question about frame relay I havent seen before – be careful

What surprises me is that if frame-relay map statement is correctly configured in both routers, the ping between them works even if one router has ip address 192.168.1.1 and the other router has ip address 10.1.1.1 (so this means the routers are in totally separate subnets, and there is no router in between, just the frame relay switch).

The configuration is like this:
R1# sho run int s0/0
Building configuration…

Current configuration : 176 bytes
!
interface Serial0/0
ip address 192.168.1.1 255.255.255.0
encapsulation frame-relay IETF
clock rate 2000000
frame-relay map ip 10.1.1.1 50
frame-relay lmi-type ansi
end

R2#sho run int s0/0
Building configuration…

Current configuration : 176 bytes
!
interface Serial0/0
ip address 10.1.1.1 255.255.255.0
encapsulation frame-relay IETF
clock rate 2000000
frame-relay map ip 192.168.1.1 75
frame-relay lmi-type ansi
end

Now try to ping:

R1#ping 10.1.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.1.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/6/12 ms
R1#

R2#ping 192.168.1.1

Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.1.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 1/2/4 ms
R2#

Surprise!!! so the ping works even if there is no router to route between the two subnets, but only the frame relay switch. I cannot explain this, however based on this I would now agree that :C. incorrect map statement” is the correct answer.

1 ARP
2 proxy ARP
3* Inverse ARP
4 something like: frame relay inverse map
5 something else…

* – my mark

Please, can someone explain the answer to the question number 4?

B. They require a unique subnet within a routing domain. —– Is right
But the other answer is not sure.

http://certificationpath.com/view/640-816-s/questions/what-are-two-characteristics-of-frame-relay-pointtopoint-subinterfacesy-a-composite-solution-q24436

the Answer is C, why?

the question didnt specify which 1 is Router A and which is Router B, so that is where the trick is!!

Assume that left Router is Router A, then apply that map statement, you will find that that statement is correct and if you try to ping the ping will reach to the other router and the reply will depend on the config of the that other Router.

Then Again, Assume that the Right router is Router A the you will find that, the map ip statement is incorect and with that statement the ping will never reach to the other Router.

So come to the Question, it state that:-

Router A is unable to reach Router B ….. …….

that means the Right is Router A and from that map statement it can not reach left Router which is Router B.

Can anyone give me some info

thanks

http://class10e.com/Cisco/in-the-frame-relay-network-which-ip-address-would-be-assigned-to-the-interfaces-with-point-to-point-pvcs/

The problem can be an incorrect map statement on Router B. RouterA can reach RouterB, but without a correct map statement on RouterB, the reply can’t make the way back.

So I guess is answer C

So for me I go with D (incorrect IP address)

|| Question 7 ||
I have information that all interfaces that participate in Frame Relay should be in the same network subnet.
But now in Q7 they are not in the same network. And map statement needs remote ip and local DLCI.

I think at now the problem can be clear with Subnet mask specifiying.

DO you think we should answer this question in exam.

|| Question 7 ||
I have information that all interfaces that participate in Frame Relay should be in the same network subnet.
But now in Q7 they are not in the same network. And map statement needs remote ip and local DLCI.

I think at now the problem can be clear with Subnet mask specifiying.

DO you think we should answer this question in exam.

our perspective is Router A (as is the one is being stated as having no access to Router B) IF we assume that Router A is the one to the left!!:

1) assuming a mask /22 (instead of /24)

map is ok:

to go to 192.168.2.1 you need to use DLCI 50

2)if mask is /24 (what we usually assume from that kind of ip) they won’t be able to connect because they are in different subnets.

3) If “output” (that’s a lousy output, no command will give you that “output) for the map is wrong it should be “75″ instead of “50″ then, answer C will be the way to go.

Anyway, if that’s the real question/graphic, Cisco made another big mistake there…

1) wrong (or waaay misleading) ip scheme
2) wrong map statement
3) no labels on routers

I hope we won’t find that kind of question in an exam because who wants to pay for an exam with that many mistakes?

If they are on different subnet, they can’t communicate.

The map statement is also wrong, but…

DLCI number misconfiguration is an L2 issue, different IP subnet is an L3 issue.

The question states that RA can’t “reach” RB, which kind of tells me that it is a L3 issue.

My other problem with this question is that what if the 0 subnet is not enabled? That means the IP address is a network address, 1 more reason why I think the answer is D, even though SEKAR and most 9tut ppl say C is the correct. Any thoughts?

The correct answer is D.

You can set GNS3 to run exactly like the diagram in the picture complete with frame-relay switch. If you configure it like the question’s example it won’t work. But if you use 192.168.1.11 instead of 192.168.2.1 then it works. It doesn’t matter which one is Router A and Router B, it still won’t work without the IP addresses configured correctly. I know the subnet mask isn’t stated but because this is the case your only option is to go with a classful mask, which is protocol for any question that doesn’t explicitly state the mask, with that said it also forces you to recognize classful boundaries, which is a bonus evaluation for the question.

thanxx :)

For me, the answer is D – incorrect IP address.

All interfaces in a network should belong to the same network address in a frame-relay multipoint or point-to-point configurations. Local DLCI should always be mapped to the remote interface IP address (Statically or Dynamically). This is a layer 2 protocol. The mapping is correct as shown in the table above but still connectivity failed due to suspected incorrect ip address. This is a more valid reason why connectivity fails.

Subnet mask is not given in the problem but both are class C addresses which has a default SM of /24.

Thanks in adv!!

1) configured both router with the ip add in the question and assigned 16 bit mask. I could ping successfully

2) I changed mask to 24 bit( now both router in different subnet), RouterA cant reach RouterB(I assume this is because RouterA detected the network different)

3)Configured a frame relay map with wrong dlci on RouterB( wrong frame map statement). RouterA can reach RouterB, but RouterB cant reach RouterA)

)Configured a frame relay map with wrong ip and correct dlci on RouterB( wrong frame map statement). RouterA can reach RouterB, but RouterB cant reach RouterA)

4) Configured RouterB with different LMI type, Router A still can reach RouterB but RouterB couldnt reply back, because different lmi type caused line protocol down.

5)Configured RouterA with different LMI type, line protocol went down, now RouterA cant reach RouterB

So its possible that wrong LMI type on Router A or both interfaces are on different subnets

I issued “show frame-relay map” command on both scenarios and observed the following output.

MULTIPOINT, IP’s are on the same subnet.

R1#show frame-relay map

Serial0/0 (up): ip 192.168.5.2 dlci 503(0x1F7,0x7C70), static, broadcast, CISCO, status defined, active

POINT TO POINT, IP’s are on different subnet.

R1#show frame-relay map
Serial0/0.503 (up): point-to-point dlci, dlci 503(0x1F7,0x7C70), broadcast status defined, active

Comparing these two outputs are telling me that if I see a DLCI number and and IP address in the output, then we have multipoint configuration.
Maybe this is why we can say that the ip’s are on the same subnet (even though there is no information in the question regarding what the subnet mask is).

Now, the output in the question is telling me that if you want to get to remote IP 192.168.2.1, use local DLCI 50, so this output show the result of “show frame-relay map” issued on Router A, and it indicates Multipoint configuration.

If router A (192.168.1.1) pings router B (192.168.2.1), router B gets the ICMP echo message, this direction works.
But then, router B needs to send echo-reply back to A. If there is a mapping problem on router B (if they did not map remote ip 192.168.1.1 to local DLCI 75) then Icmp-echo would not be able to get back to router A. Then router A would say he can’t reach router B. (Again, router A would not be able to know if he made it to Router B, unless he gets a reply from router B).
So, there must be a mapping configuration issue on router B. Therefore, I would choose “C. Incorrect map statement” as the answer.