| Author |
Can someone explain these BGP questions?
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| Which command allows Router A to advertise subnet 10.1.0.0/24 in BGP?
A. network 10.1.0.0
B. network 10.1.0.0 255.255.0.0
C. network 10.1.0.0 mask 255.255.0.0
D. network 10.1.0.0/16
E. network 10.1.0.0
====> I think the answer is C ( Not sure)
It seems to me that A could be true too. Since the "mask" is an optional in BGP. Am i right?
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Q2:
Given the following configuration:
router bgp 65000
neighbor 172.16.1.1 remote-as 65000
neighbor 10.1.1.2 remote-as 64500
network 192.168.1.192 mask 255.255.255.224 aggregate-address 192.168.1.0 255.255.255.0
What is the effect on Router A?
A. Router A will advertise only a route to 192.168.1.0 255.255.255.0 in BGP
B. Router A will advertise only a route to 192.168.1.192 255.255.255.224 in BGP
C. Router A always use routes learned by IBGP
D. Router A will have an IBGP connection with 172.16.1.1
E. Router A will always advertise itself as the next-hop address for BGP routes that it advertises
===> The answer is 
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Q3:
Given the following configuration:
interface serial0
no ip address
encapsulation frame-relay
interface serial0.1 point-to-point
ip address 10.5.4.1 255.255.255.0
frame-relay interface-dlci 120
interface serial0.2 point-to-point
ip address 10.5 3.1 255.255.255.0
frame-relay interface-dlci 142
router ospf 20
network 10.5.0.0 0.0.255.255 area 0
Which statement about this point-to-point configuration is not true?
A. Interfaces serial0.1 and serial0.2 will be placed in area 0
B. Adjacencies will be formed automatically with the devices connected to DLCI120 and DLCI 142 frame-relay map commands are required to complete the configuration of the subinterfaces
C. Interfaces serial0.1 and serial0.2 will not participate in a DR/BDR election
====> The answer is
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Q4:
Given the following configuration:
interface ethernet0
ip address 10.3.3.2 255.255.255.0
interface ethernet1
ip address 10.4.4.1 255.255.255.0
interface serial0
ip address 10.5.4.2 255.255.255.0
router ospf 20
network 10.3.3.2 0.0.0.0 area 0
network 10.4.4.1 0.0.0.0 area 0
network 10.5.0.0 0.0.255.255 area 0
Which statement about the functionality of line 13 is true?
A. All interfaces with an IP address that contains 10.5.x.x will be placed in area 0
B. There are 255 subnets in network 10.5.0.0
C. All networks whose IP address ends in 0.0 will be able to route traffic to network 10.5.0.0
D. Network statements use wildcard masks rather than subnet masks
===> The answer is | |
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| quote:
Originally posted by fit
Which command allows Router A to advertise subnet 10.1.0.0/24 in BGP?
A. network 10.1.0.0
B. network 10.1.0.0 255.255.0.0
C. network 10.1.0.0 mask 255.255.0.0
D. network 10.1.0.0/16
E. network 10.1.0.0
====> I think the answer is C ( Not sure)
It seems to me that A could be true too. Since the "mask" is an optional in BGP. Am i right?
The correct answer would be network 10.1.0.0 mask 255.255.255.0 which is not one of the alternatives. It is true that the mask is optional in BGP, but the default mask for 10.1.0.0 which is a class A address is 255.0.0.0.
quote:
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Q2:
Given the following configuration:
router bgp 65000
neighbor 172.16.1.1 remote-as 65000
neighbor 10.1.1.2 remote-as 64500
network 192.168.1.192 mask 255.255.255.224 aggregate-address 192.168.1.0 255.255.255.0
I assume there should be a line feed before "aggregate-address".
quote:
What is the effect on Router A?
A. Router A will advertise only a route to 192.168.1.0 255.255.255.0 in BGP
Don't you also need summary-only?
quote:
B. Router A will advertise only a route to 192.168.1.192 255.255.255.224 in BGP
C. Router A always use routes learned by IBGP
D. Router A will have an IBGP connection with 172.16.1.1
The connection will be IBGP because the AS number is the same for this router and the connected-to router.
quote:
E. Router A will always advertise itself as the next-hop address for BGP routes that it advertises
Not neccessarily. If the 192.168.1.0 network can be reached more efficiently through another router with an interface on the same segment as 10.1.1.2 then the IP address of that interface will be advertised as the next-hop. This behaviour can be overridden with the "next-hop self", but that was not done in this example.
quote:
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Q3:
Given the following configuration:
interface serial0
no ip address
encapsulation frame-relay
interface serial0.1 point-to-point
ip address 10.5.4.1 255.255.255.0
frame-relay interface-dlci 120
interface serial0.2 point-to-point
ip address 10.5 3.1 255.255.255.0
frame-relay interface-dlci 142
router ospf 20
network 10.5.0.0 0.0.255.255 area 0
Which statement about this point-to-point configuration is not true?
A. Interfaces serial0.1 and serial0.2 will be placed in area 0
This one is true.
quote:
B. Adjacencies will be formed automatically with the devices connected to DLCI120 and DLCI 142 frame-relay map commands are required to complete the configuration of the subinterfaces
C. Interfaces serial0.1 and serial0.2 will not participate in a DR/BDR election
No frame-relay map should be needed here since these are point-to-point links. For the same reason there should be no need for DR/BDRs. I would say that B is not true.
About adjacencies, is it true that the term is used only about the connection between a DR/BDR and other routers on the same multiaccess network, or is it also used about the connection between two routers on a point-to-point link?
Terje | |
| dmaftei 2001-06-20, 9:12 am |
| quote:
Originally posted by Terje
No frame-relay map should be needed here since these are point-to-point links. For the same reason there should be no need for DR/BDRs. I would say that B is not true.
When configured on point-to-point subinterfaces, OSPF works in point-to-point mode. In point-to-point mode, DR election does not occur. Therefore, C is true. Since A is also true, I'll have to agree with Terje that the correct answer is B. 
Cheers! | |
| dmaftei 2001-06-20, 9:14 am |
| quote:
Originally posted by fit
Q4:
Given the following configuration:
interface ethernet0
ip address 10.3.3.2 255.255.255.0
interface ethernet1
ip address 10.4.4.1 255.255.255.0
interface serial0
ip address 10.5.4.2 255.255.255.0
router ospf 20
network 10.3.3.2 0.0.0.0 area 0
network 10.4.4.1 0.0.0.0 area 0
network 10.5.0.0 0.0.255.255 area 0
Which statement about the functionality of line 13 is true?
A. All interfaces with an IP address that contains 10.5.x.x will be placed in area 0
B. There are 255 subnets in network 10.5.0.0
C. All networks whose IP address ends in 0.0 will be able to route traffic to network 10.5.0.0
D. Network statements use wildcard masks rather than subnet masks
A.
Cheers! | |
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| dmaftei, Terje thanks. It helps alot. |
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