2013 Latest Cisco 350-001 Exam Section 2: BGP (31 Questions)

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2013 Latest Cisco 350-001 Exam Section 2: BGP (31 Questions)

QUESTION NO: 1
Which of the following is are considered to be attributes of BGP routes? (Choose all that apply)
A. Origin
B. Weight
C. Local Preference
D. Community
E. Cluster List
Answer: A, C, D, E
Explanation:
Origin, Local Preference, Community, and Cluster List are all BGP attributes. ORIGIN Well-known mandatory, Type code 1 RFC 1771 LOCAL_PREF Well-Known discretionary, Type code 5 RFC 1771 COMMUNITY Optional transitive, Type 8 RFC 1997 CLUSTER_LIST Optional nontransitive, Type code 10 RFC 1966
Incorrect Answers:
B. Cisco routers do indeed use weight during the BGP route decision making process. In fact, it is the first parameter that is looked at. However, weight is a Cisco-only parameter, and is therefore not considered a BGP attribute.

QUESTION NO: 2
You are the network administrator at TestKing. You want to advertise the network 190.72.27.0/27 to an EBGP peer.
What command should you use?
A. network 190.72.27.0
B. network 190.72.27.0 mask 255.255.255.224
C. network 190.72.27.0 mask 255.255.225.240
D. network 190.72.27.0 mask 0.0.0.31.
Answer: B
Explanation:
The correct syntax is: network ip-address mask subnet-mask where
ip-address is the network address and subnet-mask is the subnet mask. In this case the network address is 190.72.27.0. The subnet mask is a 27 bit subnet mask (11111111.11111111.11111111.11100000) that equates to 255.255.255.224.
Incorrect Answers:
A. If no mask is specified, the default class mask is used. In the 190.72.27.0 case it would be a /16.
C. Here the wrong mask is used.
D. This is the inverse mask, which is normally used by OSPF when specifying the network mask, but not by BGP.

QUESTION NO: 3
The Testking BGP network consists of AS 50112 as shown in the diagram below:

Based on the physical connectivity and the IBGP peering shown, what router within the Transit AS 501112 should be setup as the route reflector and which routers should be setup as the clients based on the recommended route reflector design rules?
A. TK4 should be the route reflector with TK2 and TK5 as its clients.
B. TK2 should be the route reflector with TK5 and TK6 as its clients.

C. TK3 should be the route reflector with TK2 and TK4 as its clients.
D. TK2 should be the route reflector with TK4 and TK5 as its clients.
E. TK4 should be the route reflector with TK2 and TK3 as its clients.
F. All of the above are valid options.
Answer: B
Explanation:
Within any BGP autonomous system, every IBGP speaker must have a fully meshed peering arrangement with every other iBGP speaker. This is due to the fact that a BGP speaker will not advertise a route learned via another iBGP speaker to a third iBGP speaker. The use of route reflectors is one way to maintain connectivity throughout the AS without having a fully meshed peering arrangement. By relaxing this restriction a bit and by providing additional control, we can allow a router to advertise (reflect) iBGP learned routes to other iBGP speakers. When using route reflectors, the clients need only peer to the route reflector. In the example above, if router TK2 is configured as the route reflector, with routers TK5 and TK6 set up as clients, then 5 and 6 need only peer with TK2. In doing this, all other routers are fully meshed. No other answer choices will allow us to maintain a fully meshed iBGP configuration.

QUESTION NO: 4
Routers TK1 and TK2 are configured for BGP. Both routers reside in AS 65234. Routes
from Router TK2 show up in the BGP table on Router TK1, but not in the IP routing
table.
What could be the cause of this problem?

A. Synchronization is off.
B. The BGP peers are down.
C. BGP multi-hop is disabled on Router TK1.
D. Router TK1 is not receiving the same routes via an internal protocol.
Answer: D
Explanation:
BGP Synchronization says: “If your autonomous system is passing traffic from another AS to a third AS, BGP should not advertise a route before all routers in your AS have learned about the route via IGP.” Therefore, we can assume that synchronization is on and that the BGP routes have not yet been learned by an IGP.
Incorrect Answers:
A. If synchronization is off the routes would show up in the IP routing table on TK1.
B. If the BGP peers were down, then the routers would not be sending and receiving BGP route information to each other.
C. BGP multi-hop is only useful for EBGP peers, not IBGP peers.

QUESTION NO: 5
You have a router running BGP for the Internet connections as well as IGRP for use internally. You configure the network backdoor command on this router under the BGP process. What will this do?
A. It will change the distance of an iBGP route to 20.
B. It will change the distance of an eBGP route to 200.
C. It will change the distance of an IGRP route to 20.
D. It will not change the distance of the route.
Answer: B
Explanation:
Backdoor only makes the IGP learned route the preferred route. To specify a backdoor
route to a BGP border router that will provide better information about the network, use
the network backdoor router configuration command. To remove an address from the list,
use the no form of this command.
By definition, eBGP updates have a distance of 20 that is lower than the IGP distances.
Default distance is 120 for RIP, 100 for IGRP, 90 for EIGRP, and 110 for OSPF.
By default, BGP has the following distances, but that could be changed by the distance
command:

distance bgp external-distance internal-distance local-distance external-distance:20 internal-distance:200 local-distance:200
If we want RTA to learn about 160.10.0.0 via RTB (IGP), then we have two options:
*
Change eBGP’s external distance or IGP’s distance, which is not recommended.
*
Use BGP backdoor. BGP backdoor makes the IGP route the preferred route RTA learns 160.10.0.0 from RTB via EIGRP with distance 90, and also learns it from RTC via eBGP with distance 20. Normally eBGP is preferred, but because of the backdoor command EIGRP is preferred References:
http://www.cisco.com/en/US/products/sw/iosswrel/ps1826/products_command_summary_chapter09186a00800d9c
http://www.cisco.com/en/US/tech/tk365/tk80/technologies_tech_note09186a00800c95bb.shtml#bgpbackdoor

QUESTION NO: 6 You have two routers running BGP to two different ISP’s. You wish to influence the way that traffic comes into your network from the Internet, but your company policy prohibits the use of BGP communities. What is the best way to influence this traffic?
A. Adjust the cost of your routers.
B. Use MED values.
C. Increase the weight value on one of your routers.
D. Decrease the local preference value on one of your routers.
E. Use AS-path prepending.
F. Use Metrics.
Answer: E
Explanation:
When influencing incoming traffic from the Internet, the two most widely used methods are AS Path Prepending and Multi-Exit Discriminators (MED). AS Path prepending works by adding AS paths to certain network ranges, making them appear to the Internet to be further away than they really are. MEDs are used to advertise metrics to the neighbor AS to influence the incoming path that traffic should take to reach certain destinations. In this case, AS Path Prepending is preferred over the use of MEDs because AS path prepending information is distributed to all networks within the Internet. MEDs are only used between neighboring Autnomous Systems. Another advantage to path prepending is that the AS path information is ranked higher in the BGP decision process than the MED information. IN fact, MED information is one of the last things considered in the BGP path decision algorithm. Note: Although one method of using AS Path prepending requires the use of communities, it is not required to use communities for simply sending prepending information.
Incorrect Answers:
A, C, D, F. These are all methods for influencing traffic going out to the Internet, not coming in.
E. This would be an acceptable way to influence traffic, but would not be the best way.

QUESTION NO: 7
Your router is multi-homed to three different ISP’s for Internet access. You then configure “bgp deterministic-med” under the BGP routing process configuration of your router. What effect does this change have on your network?
A. It configures BGP to compare MEDs between different ASs.
B. It makes the default metric count the worst possible metric.
C. It makes the default metric count the best possible metric.
D. It configures BGP to reorder the entries by neighbor AS.
E. It configures BGP to reorder the entries by MED.
Answer: D
Explanation:
There is sometimes confusion between the two Border Gateway Protocol (BGP) configuration commands bgp deterministic-med and bgp always-compare-med. Enabling the bgp deterministic-med command ensures the comparison of the MED variable when choosing routes advertised by different peers in the same autonomous system. Enabling the bgp always-compare-med command ensures the comparison of the MED for paths from neighbors in different autonomous systems. The bgp always-compare-med command is useful when multiple service providers or enterprises agree on a uniform policy for setting MED. Thus, for network X, if Internet Service Provider A (ISP A) sets the MED to 10, and ISP B sets the MED to 20, both ISPs agree that ISP A has the better performing path to X. When BGP receives multiple routes to a particular destination, it lists them in the reverse order that they were received, from the newest to the oldest. BGP then compares the routes in pairs, starting with the newest entry and moving toward the oldest entry (starting at top of the list and moving down). For example, entry1 and entry2 are compared. The better of these two is then compared to entry3, and so on. The bgp always-compare-med command reorders the entries by neighbor AS.
Incorrect Answers:
A. The router would compare MEDs between different AS numbers if the “bgp always-comapre-med” was configured, not the bgp deterministic-med command. B, C. This command does not affect the default BGP metric.
E. This command reorders the entries based on AS number, not MED.
Reference:
http://www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094925.shtml

QUESTION NO: 8 Which of the following attributes are “well known” BGP attributes? (Choose all that apply)
A. Atomic-aggregate
B. MED
C. Next-hop
D. AS-path
E. Origin
F. Weight
G. Aggregator
Answer: A, C, D, E
Explanation:
The following BGP attributes are all well known: Well Known, Mandatory attributes: AS_PATH, NEXT-HOP and ORIGIN Well Known, Discretionary attributes: LOCAL_PREF and ATOMIC_AGGREGATE
Incorrect Answers:
B, E, F. The optional, transitive attributes are AGGREGATOR and COMMUNITY. The optional non-transitive attributes include MULTI_EXIT_DISC (MED, the ORIGINATOR_ID. and CLUSTER_LIST.
Reference:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/bgp.htm

QUESTION NO: 9
In BGP routing, what does the rule of synchronization mean?

A. It means that a BGP router can only advertise an iBGP-learned route provided that the route is in the only in the BGP table.
B. It means that a BGP router can only advertise an eBGP-learned route provided that the route is an IGP route in the routing table.
C. It means that a BGP router can only advertise an iBGP-learned route provided that the route is in the routing table of all its iBGP neighbors.
D. It means that a BGP router can only advertise an eBGP-learned route provided that the route is metric 0 in the BGP table.
E. It means that a BGP router can only advertise an iBGP-learned route provided that the route is an IGP route in the routing table.
Answer: E
Explanation:
The BGP rule of synchronization states that a BGP router should not advertise to external neighbors destinations learned from IBGP neighbors unless those destinations are also known via an IGP.
Incorrect Answers:
B, D. Synchronization is used to ensure that you don’t develop black holes by advertising local routes to the rest of the world, when the local routers don’t even know how to get to the route in question. That’s why synchronization with the IGP is not a concern when you either create a full iBGP mesh, or implement route reflectors, confederations, or both. Therefore, synchronization is implemented only for IBGP routes, not EBGP.
C. The route needs only be in the routing table of its own router, not every neighboring router.
Reference:
“Internet Routing Architectures” Sam Halabi page 143, Cisco Press.

QUESTION NO: 10
What is the correct sequence order that BGP routers use when determining the best route to any given destination?
A. MED, Local preference, AS-path, Weight, Origin Code
B. Origin Code, MED, Weight, AS Path, Local Preference
C. Weight, Local Preference, AS-path, Origin Code, MED
D. Weight, Local Preference, MED, AS-Path, Origin Code
E. MED, Weight, Local Preference, Origin Code, AS Path
Answer: C
Explanation: How the Best Path Algorithm Works
BGP assigns the first valid path as the current best path. It then compares the best path with the next path in list, until it reaches the end of the list of valid paths. Following is a list of rules used to determine the best path:
1.
Prefer the path with the largest WEIGHT. Note: WEIGHT is a Cisco-specific parameter, local to the router on which it’s configured.
2.
Prefer the path with the largest LOCAL_PREF.
3.
Prefer the path that was locally originated via a network or aggregate BGP subcommand, or through redistribution from an IGP. Local paths sourced by network/redistribute commands are preferred over local aggregates sourced by the aggregate-address command.
4.
Prefer the path with the shortest AS_PATH. Note the following:
5.
1. This step is skipped if bgp bestpath as-path ignore is configured.
2.
An AS_SET counts as 1, no matter how many ASs are in the set.
3.
The AS_CONFED_SEQUENCE is not included in the AS_PATH length.
4.
Prefer the path with the lowest origin type: IGP is lower than EGP, and EGP is lower than INCOMPLETE.
5.
Prefer the path with the lowest multi-exit discriminator (MED).

QUESTION NO: 11
You are setting up BGP on router TK1 and you wish to simplify the configuration file through the use of BGP peer groups. Which of the following best describes the proper use of BGP peer groups?
A. They should be used for peers with common community values
B. They should be used for peers with common inbound announcement policies
C. They should be used for peers with common outbound announcement policies
D. They should be sued to combine MED inbound policies
E. They should be used to peers with common transitive AS policies
Answer: C
Explanation:
The major benefit of specifying a BGP peer group is that it reduces the amount of system resources (CPU and memory) used in an update generation, and it also simplifies the BGP configuration. It reduces the load on system resources by allowing the routing table to be checked only once, and updates to be replicated to all peer group members instead of being done individually for each peer in the peer group. Depending on the number of peer group members, the number of prefixes in the table, and the number of prefixes advertised, this can significantly reduce the load. Cisco recommends that you group together peers with identical outbound announcement policies.

QUESTION NO: 12 Router TK1 is being configured for as both an IBGP peer to the other routers within the Testking network, and as an EBGP peer to the ISP. Select the BGP attributes that are required to be sent to these BGP neighbors from TK1:
A. AS_PATH
B. MED
C. NEXT_HOP
D. LOCAL_PREF
E. ORIGIN
F. ROUTER_ID
Answer: A, C, E

Explanation:
AS-PATH, NEXT-HOP, and ORIGIN are all well known, mandatory BGP attributes,
which is defined below:

Well known mandatory attributes
: These attributes must be recognized by all BGP speakers, and must be included in all update messages. Almost all of the attributes impacting the path decision process, described in the next section, are well known mandatory attributes.
Origin Code
The ORIGIN is a well known mandatory attribute that indicates the origin of the prefix, or rather, the way in which the prefix was injected into BGP. There are three origin codes, listed in order or preference:
1.
IGP, meaning the prefix was originated from information learned from an interior gateway protocol
2.
EGP, meaning the prefix originated from the EGP protocol, which BGP replaced
3.
INCOMPLETE, meaning the prefix originated from some unknown source
AS Path
The AS_PATH is a well-known mandatory attribute and is the list of all autonomous systems the prefixes contained in this update have passed through. The local autonomous system number is added by a BGP speaker when advertising a prefix to an eBGP peer.
Next Hop
The BGP NEXT_HOP is a well-known mandatory attribute. The Next Hop attribute is set when a BGP speaker advertises a prefix to a BGP speaker outside its local autonomous system (it may also be set when advertising routes within an AS, this will be discussed in later sections). The Next Hop attribute may also serve as a way to direct traffic to another speaker, rather than the speaker advertising the route itself.
Incorrect Answers:
B. The MUTLI_EXIT_DISC (MED) is an optional non-transitive attribute that provides a mechanism for the network administrator to convey to adjacent autonomous systems to optimal entry point in the local AS.
D. The LOCAL_PREF attribute is a well-known attribute that represents the network operator’s degree of preference for a route within the entire AS. It is not a mandatory attribute and it is not applied to all BGP updates.
F. The router ID is not a well known, mandatory BGP attribute.

QUESTION NO: 13
Assume the following routes are in the BGP routing table of router TK1.

172.16.0.0/24 172.16.1.0/24 172.16.2.0/24 172.16.3.0/24
Also assume the following commands have been configured:
router bgp 1 neighbor 10.1.1.1 remote-as 2 aggregate-address 172.16.0.0 255.255.252.0 suppress-map specific
access-list 1 permit 172.16.2.0 0.0.0.3.255 route-map specific permit 10 match ip-address 1
Which BGP routes will TK1 advertise?
A. 172.16.0.0/22
B. 172.16.0.0/22, 172.16.2.0/24, 172.16.3.0/24
C. 172.16.0.0/22, 172.16.0.0/24, 172.16.1.0/24
D. 172.16.2.0/24 and 172.16.3.0/24
E. 172.16.0.0/22 and 172.16.1.0/24
Answer: A
Explanation:
BGP allows the aggregation of specific routes into one route using the aggregate-address address mask command. Aggregation applies to routes that exist in the BGP routing table. This is in contrast to the network command, which applies to the routes that exists in IP routing table. Aggregation can be performed if at least one or more of the specific routes of the aggregate address exist in the BGP routing table. In this specific example, the router will summarize the routes into 172.16.0.0/22, as long as at least one of the more specific 172.16 assumed routes actually exist in the routing table. Normally, aggregate addresses are advertised in addition to the more specific subnets. However, in this case the suppress map will filter the more specific routes, advertising only the 172.16.0.0/22 route.

QUESTION NO: 14
A BGP router in the Testking network called P1R3 is configured as shown below:

! hostname P1R3 ! ! Output omitted ! router bgp 50001 synchronization bgp log-neighbor-changes neighbor 10.200.200.11 remote-as 50001 neighbor 10.200.200.11 update-source loopback0 neighbor 10.200.200.12 remote-as 20001 neighbor 10.200.200.12 update-source Loopback0 neighbor 10.200.200.14 remote-as 50001 neighbor 10.200.200.14 update-source Loopback0 no auto-summary
PIR3#show ip bgp summary
BGP router identifier 10.200.200.13, local As number 50001 BGP table version is 1, main routing table version 1 6 network entries using 606 bytes of memory 7 path entires using 336 bytes of memory 4 BGP path attribute entries using 240 bytes of memory 3 BGP AS-PATH entries using 72 bytes of memory 0 BGP route-map cache entries using 0 bytes of memory 0 BGP filter-list cache entries using 0 bytes of memory BGP using 1254 total bytes of memory BGP activity 6/0 prefixes, 7/2 paths, scan interval 60 secs Neighbor V AS MsgRcvd MsqSent TblVer InO OutO Up/Down State/Pfxrcd
10.200.200.11 4 50001 9 4 1 0 0 00:00: 14 6
10.200.200.12 4 50001 9 4 1 0 0 00:00: 14 6
10.200.200.14 4 50001 4 4 1 0 0 00:00: 14 0
PIR#show ip bgp
BGP table version is 1, local router: ID is 10.200.200.13 Status Codes: s suppressed, d damped, h history, * valid, > best, I – internal Origin codes: i – IGP, e – EGP, ? – incomplete Network Next Hop Metric LocPrf Weight Path
*
i10.0.0.0 10.200.200.12 0 100 0 i
*
i 10.200.200.11 0 100 0 i
*
i192.168.11.0 10.200.200.12 0 100 0 50998 50222 50223 i
*
i 10.200.200.11 0 100 0 50998 50222 50223 i
*
i192.168.12.0 10.200.200.12 0 100 0 50998 50222 50223 i
*
i 10.200.200.11 0 100 0 50998 50222 50223 i
*
i192.168.13.0 10.200.200.12 0 100 0 50998 50222 50223 i
*
i 10.200.200.11 0 100 0 50998 50222 50223 i
*
i192.168.14.0 10.200.200.11 0 100 0 50998 50222 50223 i
*
i 10.200.200.11 0 100 0 50998 50222 50223 i
PIR#show ip route
Codes: C – connected, s – static, I IGRP, R – RIP, M – mobile, B – BGP D – EIGRP, EX – EIGRP external, 0 – 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, su - IS-IS summary, L1 - IS-IS leval-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 10.0.0.0/8 is variably subnetted, 8 subnets, 2 masks o 10.200.200.11/32 [110/11] via 10.1.1.1, 00:06:38, Ethernet0/0 o 10.200.200.14/32 [110/65] via 10.1.3.4, 00:06:38, Seriall/0 o 10.200.200.12/32 [110/75] via 10.1.1.1, 00:06:38, Ethernet0/0 c 10.200.200.13/32 is directly connected, Loopback0 c 10.1.3.0/24 is directly connected, Seriall/0 o 10.1.2.0/72 [110/74] via 10.1.3.4, 00:06:38, Seriall/0 c 10.1.1.0/24 is directly connected, Ethernet0/0 c 10.1.0.0/24 [110/74] via 10.1.1.1, 00:06:38, Ethernet 0/0 Router PIR3 is running an IBGP full-mesh with its IBGP neighbors (10.200.200.11, 10.200.200.12, and 10.200.200.14). Based on the BGP configuration and the show command outputs above, why are BGP routes not being selected in the BGP table and placed into the IP routing table? A. Because the 10.200.200.11 and 10.200.200.12 neighbors are setting the Weight to 0 B. Because the 10.200.200.11 and 10.200.200.12 neighbors are setting the MED to 0 C. Because the 10.200.200.11 and 10.200.200.12 neighbors are not using next-hop-self D. Because synchronization is enabled on PIR 3 E. Because there are no routes to reach the next-hops Answer: D Explanation: A BGP router with synchronization enabled will not advertise iBGP-learned routes to other eBGP peers if it is not able to validate those routes in its IGP. Assuming that IGP has a route to iBGP-learned routes, the router will announce the iBGP routes to eBGP peers. Otherwise the router treats the route as not being synchronized with IGP and does not advertise it. Disabling synchronization using the no synchronization command under router BGP prevents BGP from validating iBGP routes in IGP. By default, synchronization is enabled on all BGP routers. QUESTION NO: 15 With regards to BGP and the administrative distance in a routed environment, which statement is correct? A. The administrative distance of all BGP routes is 20, which explains why BGP routes are preferred over any IGP (such as OSPF). B. BGP is a path vector protocol, and thus does not employ the concept of administrative distance. C. BGP dynamically adjusts its administrative distance to match that of the IGP within the AS to eliminate routing confusion. D. BGP actually employs two different administrative distance values: IBGP is 20, while EBGP is 200. E. BGP actually employs two different administrative distance values: IBGP is 200, while EBGP is 20. Answer: E Explanation: BGP employs the use of two separate administrative distances, based on the type of BGP route. (Internal or External) The table below lists the administrative distance default values of the protocols that Cisco supports: Route Source Default Distance Values Connected interface 0 Static route* 1 Enhanced Interior Gateway Routing Protocol (EIGRP) summary route 5 External Border Gateway Protocol (BGP) 20 Internal EIGRP 90 IGRP 100 OSPF 110 Intermediate System-to-Intermediate System (IS-IS) 115 Routing Information Protocol (RIP) 120 Exterior Gateway Protocol (EGP) 140 On Demand Routing (ODR) 160 External EIGRP 170 Internal BGP 200 Unknown** 255 correct Answers: A. Only external BGP routes have an AD of 20. Internal BGP routes are given a high AD to prevent these routes from overriding the routes from the IGP routing protocols, such as OSPF, EIGRP, RIP, etc. B. BGP is indeed considered a path vector routing protocol, but it does also use the concept of AD, as shown in the table above. C. The AD of BGP routes is static, with the default values shown in the table. These values can be configured to use different values, but they will still be considered static and will not change dynamically. D. BGP does indeed use two different values, but the values used are the reverse. EBGP is 20 while IBGP is 200. QUESTION NO: 16 You are configuring the Testking Internet router as a BGP peer to your ISP's router. After doing this, which BGP attributes will be carried in every BGP update (both IBGP and EBGP)? A. Origin, AS-Path, Next Hop B. Origin, local preference, AS-Path C. Router-ID, Origin, AS-Path D. Router-ID, Local-Preference, Next-Hop E. AS-Path, Local Preference, Next-Hop Answer: A Explanation: Origin, AS-PATH, and Next-Hop are all well known, mandatory BGP attributes, which is defined below: Well known mandatory attributes : These attributes must be recognized by all BGP speakers, and must be included in all update messages. Almost all of the attributes impacting the path decision process, described in the next section, are well known mandatory attributes. Origin Code The ORIGIN is a well known mandatory attribute that indicates the origin of the prefix, or rather, the way in which the prefix was injected into BGP. There are three origin codes, listed in order or preference: 1. IGP, meaning the prefix was originated from information learned from an interior gateway protocol 2. EGP, meaning the prefix originated from the EGP protocol, which BGP replaced 3. INCOMPLETE, meaning the prefix originated from some unknown source AS Path The AS_PATH is a well-known mandatory attribute and is the list of all autonomous systems the prefixes contained in this update have passed through. The local autonomous system number is added by a BGP speaker when advertising a prefix to an eBGP peer. Next Hop The BGP NEXT_HOP is a well-known mandatory attribute. The Next Hop attribute is set when a BGP speaker advertises a prefix to a BGP speaker outside its local autonomous system (it may also be set when advertising routes within an AS, this will be discussed in later sections). The Next Hop attribute may also serve as a way to direct traffic to another speaker, rather than the speaker advertising the route itself. Incorrect Answers: B, D, E. The LOCAL_PREF attribute is a well-known attribute that represents the network operator's degree of preference for a route within the entire AS. It is not a mandatory attribute that is applied to all BGP updates. C, D. The router ID is not a well known, mandatory BGP attribute. QUESTION NO: 17 The Testking BGP network has been assigned AS number 50101 as shown below: The Testking AS 50101 network is split into two AS numbers (Sub-AS 50001 and Sub-AS 50002) using Confederations without any route reflectors. Sub-AS 50001 contains 4 routers and sub-AS 50002 contains the other 3 routers. Based on this information, how many IBGP sessions are required? A. 9 IBGP sessions using Confederations with two sub-ASs where one of the sub-AS contains 4 routers and the other sub-As contains the other 3 routes. B. 11 IBGP sessions using Confederations with two sub-ASs where one of the sub-AS contains 4 routers and the other sub-As contains the other 3 routes. C. 18 IBGP sessions using Confederations with two sub-ASs where one of the sub-AS contains 4 routers and the other sub-As contains the other 3 routes. D. 21 IBGP sessions using Confederations with two sub-ASs where one of the sub-AS contains 4 routers and the other sub-As contains the other 3 routes. E. 25 IBGP sessions using Confederations with two sub-ASs where one of the sub-AS contains 4 routers and the other sub-As contains the other 3 routes. Answer: A Explanation: The advantage of confederations is that they sharply reduce the number of IBGP peering sessions. IBGP is used normally within each member AS, but a special version of EBGP known as confederations. EBGP is run between the autonomous systems. Confederations are another way of scaling IBGP. Defined in RFC 3065, this feature introduces a divide-and-conquer approach to remove the full mesh requirement. Using confederations an AS is split into multiple sub-ASs, but the network still appears as one AS to the outside world. Each sub-AS number is stripped from AS path at the confederation border. A full IBGP mesh is only required within each sub-AS, which is usually a manageable number of routers. In very large networks, you can even configure route reflection within a sub-AS. Typically private ASs are assigned for each sub-AS number. With IBGP, all routers are to be configured as a fully meshed topology. The number of connections needed for any fully meshed configuration can be found by the formula: N (N-1) 2 There are 4 Sub-AS peers in 5001 so that makes 4*3 / 2 = 6 peer sessions. Similarly, there are 3 peers in Sub-As 5002, so we have 3*2 / 2 = 3 peer sessions Therefore, the total number of peering sessions is 9(6+3). Reference: Jeff Doyle, "Routing TCP/IP" Vol. II page 287 QUESTION NO: 18 Router TK1 is used as the Testking Internet router and is configured for BGP. The Ip BGP information of this router is displayed below: TK1# show ip bgp BGP table version is 12, local router ID is 172.16.1.2 Status code: s supported, d damped, h history, * valid, > best, i -internal Origin codes: i IGP, e -EGP ? -incomplete
Network Next Hop Metric LocPrf Weight Path *> 192.168.0.0/16 172.16.1.1 0 0 50103 {50101, 50102} i
Given above information, why does the 192.168.0.0/16 prefix contain an AS-PATH of 50 103 { 50101, 50102}
A. Because AS 50101 and AS 50102 are Transit AS’s
B. Because AS 50103 is using BGP confederations with two sub-ASs (sub-AS 50101 and sub-AS 50102)
C. Because it is an aggregate route and the more specific routes have passed through AS 50101 and AS 50102
D. Because AS 50103 is using AS-Path pre-pending to influence the return traffic
E. Because AS 50103 is performing route summarization using the network 192.168.0.0. mask 255.255.0.0 command
Answer: C
Explanation:
In this example, the 192.168.0.0/16 route includes the SET {50101, 50102}. This indicates that aggregate route of 192.168.0.0 actually summarizes routes that have passed through AS 50101 and AS 50102. The AS-SET information is preserved because it becomes important in avoiding loops as it maintains an indication of where the route has been.
Incorrect Answers:
A. Transit AS numbers are displayed normally in the IP BGP table.

B. Confederations are seen as only one single AS to the rest of the Internet, so they will
not appear as an AS-SET to EBGP peers.

D. AS Path prepending is displayed normally, and if this were the case then you would
see multiple entries in a row for the same AS number.

E. Summarized routes only appear in an AS SET when the more specific routes have
passed through multiple different AS numbers.
Reference: Bassam Halabi, “Internet Routing Architectures” Cisco Press, page 359.

QUESTION NO: 19
The IP BGP information for a specific network on router TK1 is displayed below:

TK1#show ip bgp 10.254.0.0
BGP routing table entry for 10.254.0.0/24, version 8
Paths: (2 available, best #1, table
Default-IP-Routing-Table, not advertised

Advertised to non peer-group peers:

10.1.0.2 10.200.200.13 10.200.200.14
50998

172.31.1.3 from 172.31.1.3 (172.31.1.3)
Origin IGP, metric 0, localpref 100, valid, external, best
Community: 50998:1 no-export

50998

172.31.1.3 from 10.1.0.2 (10.200.200.12)
Origin IGP, metric 0, localpref 100, valid, internal

Router TK1, which is in Transit AS 50001, is not propagating the 10.254.0.0/24 prefix to its neighboring ASs. Based the “show IP BGP 10.254.0.0” output shown, determine a possible cause of this problem.
A. Because the 10.254.0.0/24 prefix is tagged with the no-export community
B. Because the best path chosen by BGP is the IBGP learned path
C. Because the best path chosen by BGP is the EBGP learned path
D. Because the 10.254.0.0/24 prefix has a MED of 0
E. Because of the EBGP split horizon rule
Answer: A
Explanation:
From the output shown above, the 10.254.0.0 route is indeed tagged with the BGP community of no-export. The Well Known BGP community of NO EXPORT means that the route can be advertised to other IBGP peers, but it is not to be passed to EBGP peers. If the BGP community of NO ADVERTISE was used instead, then this route would not be forwarded to both IBGP as well as EBGP peers.
Incorrect Answers:
B, C. Regardless of the path that the BGP route was learned, the default behavior is to forward the route to EBGP peers.
D. The metric 0 shown in the example above is the normal behavior for IBGP learned routes.
E. BGP does not use the split horizon rule. This rule applies to distance vector interior routing protocols. BGP is considered to be a path vector external routing protocol.

QUESTION NO: 20 The Testking network is using BGP for Internet routing, and part of the router configuration is shown below:
router bgp 50101
neighbor 10.1.1.1 remote-as 50102
neighbor 10.2.2.2 remote-as 50103
neighbor 10.2.2.2 route-map test2 out
neighbor 10.1.1.1 route-map test out

!
ip as-path access-list 1 permit _50104$
ip as-path access-list 2 permit .*
!
route-map test permit 10

match as-path 1

set metric 140
!
route-map test permit 20

match as-path 2
!
route-map test2 permit 10
set metric 100

Based on the configuration above, which statement is correct?
A. All prefixes originating in AS 50104 will be advertised to the 10.1.1.1 neighbor with a MED of 150.
B. All prefixes not originating in AS 50104 will be advertised to the 10.1.1.1 neighbor with a MED of 0.
C. All prefixes not originating in AS 50104 will be advertised to the 10.1.1.1 neighbor.
D. All prefixes will be advertised to the neighbor with a MED of 100.
E. All prefixes originating in AS 50104 will be advertised to the 10.2.2.2 and the 10.1.1.1 neighbor with a MED of 100.
Answer: B
Explanation:
For the 10.1.1.1 BGP peer, route-map “test” is being applied. This route map has two statement entries. The first states that all traffic originating from AS 50104 (as shown by the ” ip as-path access-list 1 permit _50104$” command statement) should have the MED set to
140. The regular expression “.*” matches everything else, so all other traffic is to be routed normally. Since the default MED value is 0, all other traffic not originating in AS will be advertised to the 10.1.1.1 peer with a MED of 0.
Incorrect Answers:
A. The MED value advertised to the 10.1.1.1 peer that originated from AS 50104 will
have the MED value set to 140, not 150.

C. All prefixes, even the one originating from AS 50104 will be advertised to the 10.1.1.1
neighbor. The only difference with traffic originating from AS 50104 is that the MED
values will be changed.
D, E. The default MED value is 0, not 100. The default local preference value is 100.

QUESTION NO: 21 Assume that a BGP router has learned prefix 63.0.0.0/8 from two different BGP neighbors. Which statement regarding the BGP route selection process and how this route will be installed is correct?
A. The update from the neighbor that has the highest weight and the highest local preference becomes the preferred path.
B. The update from the neighbor that has the shortest AS path becomes the preferred path.
C. The update from the neighbor that has the highest local preference and the highest MED becomes the preferred path.
D. The update from the neighbor that has the lowest local preference becomes the preferred path.
E. The update from the neighbor that has the highest MED becomes the preferred path.
Answer: A
Explanation:
BGP selects only one path as the best path. When the path is selected, BGP puts the selected path in its routing table and propagates the path to its neighbors. BGP uses the following criteria, in the order presented, to select a path for a destination:
1.
If the path specifies a next hop that is inaccessible, drop the update.
2.
Prefer the path with the largest weight.
3.
If the weights are the same, prefer the path with the largest local preference.
4.
If the local preferences are the same, prefer the path that was originated by BGP running on this router.
5.
If no route was originated, prefer the route that has the shortest AS_path.
6.
If all paths have the same AS_path length, prefer the path with the lowest origin type (where IGP is lower than EGP, and EGP is lower than Incomplete).
7.
If the origin codes are the same, prefer the path with the lowest MED attribute.
8.
If the paths have the same MED, prefer the external path over the internal path.
9.
If the paths are still the same, prefer the path through the closest IGP neighbor.
10.
Prefer the path with the lowest IP address, as specified by the BGP router ID.
Incorrect Answers:
B: Although this statement is correct, the weight and local preference values have a
higher precedence than the AS path length.
C, E: The lowest MED is preferred, not the highest.

D: A higher local preference is preferred over a lower one.

QUESTION NO: 22 The TestKing network is using BGP for external routing. If a BGP router has more than one route to the same IP prefix, in what order are BGP attributes examined in making a best path route selection?
A. LOCAL_PREF, MED, AS_PATH, WEIGHT, ORIGIN
C. WEIGHT, LOCAL_PREF, AS_PATH, ORIGIN, MED

E. MED, LOCAL_PREF, WEIGHT, ORIGIN, AS_PATH
Answer: C
Explanation:
BGP assigns the first valid path as the current best path. It then compares the best path with the next path in list, until it reaches the end of the list of valid paths. The following is a list of rules used to determine the best path.
1.
Prefer the path with the highest WEIGHT.
Note: WEIGHT is a Cisco-specific parameter, local to the router on which it’s configured.

2.
Prefer the path with the highest LOCAL_PREF. Note the following:

3.
Prefer the path that was locally originated via a network or aggregate BGP subcommand, or through redistribution from an IGP.
4.
Prefer the path with the shortest AS_PATH.
5.
Prefer the path with the lowest ORIGIN type: IGP is lower than EGP, and EGP is lower than INCOMPLETE.
6.
Prefer the path with the lowest multi-exit discriminator (MED). Note the following:
7.
Prefer external (eBGP) over internal (iBGP) paths. If bestpath is selected, go to Step 9 (multipath).
8.
Prefer the path with the lowest IGP metric to the BGP next hop. Continue, even if bestpath is already selected.
9.
Check if multiple paths need to be installed in the routing table for BGP Multipath. Continue, if bestpath is not selected yet.
10.
1. When both paths are external, prefer the path that was received first (the oldest one).
2.
Prefer the route coming from the BGP router with the lowest router ID. The router ID is the highest IP address on the router, with preference given to loopback addresses. It can also be set manually using the bgp router-id command.
3.
If the originator or router ID is the same for multiple paths, prefer the path with the minimum cluster list length. This will only be present in BGP route-reflector environments. It allows clients to peer with RRs or clients in other clusters. In this scenario, the client must be aware of the RR-specific BGP attribute.
4.
Prefer the path coming from the lowest neighbor address. This is the IP address used in the BGP neighbor configuration, and corresponds to the remote peer used in the TCP connection with the local router
Reference:
www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080094431.shtml

QUESTION NO: 23 The router TK1 is being configured for BGP, and the configuration will contain both IBGP and EBGP peers. Which statements regarding IBGP and EBGP neighbors are correct? (Select three)
A. BGP updates from an IBGP peer are propagated to other IBGP and EBGP peers.
B. BGP updates from an EBGP peer are propagated to other IBGP and EBGP pees.
C. IBGP peers must be directly connected. If not, the IBGP-multihop option must be configured.
be configured.
E. IBGP neighbors peering can be established using the loopback interface.
F. EBGP neighbor peering must use the physical interface address to establish peering
Answer: B, D, E
Explanation:
When a BGP router receives a BGP routing update from an EBGP neighbor, the update is propagated to all IBGP neighbors. It is important to note that the same is not true for routing updates received via an IBGP neighbor, as these updates are not passed on to all IBGP peers. This is why IBGP speakers must be configured in a full mesh. For EBGP peers, the best method is to use the directly connected interfaces as the peering IP addresses. If not, then EBGP multihop must be used. Multihop is used only in EBGP, not in IBGP. It is recommended to use the loopback interface when configuring IBGP peers, since this interface is always up. For IBGP, the peering IP address needs to only be reachable via the IGP, so they do not need to be directly connected.

QUESTION NO: 24
The TestKing network is running BGP as displayed in the diagram below:

What path will routers TestKing1 and TestKing2 take to reach the 156.36.32.0/24 network in AS 5?
A. Both will use the path through AS 1 due to TestKing1 having the shortest AS_PATH attributre.
B. TestKing1 will use the path through AS 1 and TestKing2 will use the path through AS
3.
C. Both will use the path through AS 1 due to TestKing1 having a lower LOCAL_PREF value.
D. Both TestKing1 and TestKing2 will use the path through AS 3 due to TestKing2 having a higher LOCA_PREF value.
Answer: D
Explanation:
BGP uses the following criteria, in the order presented, to select a path for a destination:
1.
If the path specifies a next hop that is inaccessible, drop the update.
2.
Prefer the path with the largest weight.
3.
If the weights are the same, prefer the path with the largest local preference.
4.
If the local preferences are the same, prefer the path that was originated by BGP running on this router.
5.
If no route was originated, prefer the route that has the shortest AS_path.
6.
If all paths have the same AS_path length, prefer the path with the lowest origin type (where IGP is lower than EGP, and EGP is lower than Incomplete).
7.
If the origin codes are the same, prefer the path with the lowest MED attribute.
8.
If the paths have the same MED, prefer the external path over the internal path.
9.
If the paths are still the same, prefer the path through the closest IGP neighbor.
10.
Prefer the path with the lowest IP address, as specified by the BGP router ID. Based on the information above, the value of the Local Preference is considered before the length of the AS Path. When comparing the Local Preference value, the higher one is preferred.

QUESTION NO: 25 Router TK 1 and TK2 are IBGP peers. Which BGP attributes are carried in all IBGP routing updates? (Select 3)
A. MED
B. Local Preference
C. Weight
D. Community
E. AS-path
F. Cost
G. Origin
Answer: B, E, G
Explanation:
There are three well-known mandatory attributes. These must be included in updates propagated to all peers (both INGP and EBGP) and includes AS-PATH, NEXT-HOP and ORIGIN. In addition to these three, all IBGP speakers must also carry the Local Preference information. The Local Preference is relevant when there is more than one path to a network outside of the current AS for instance if your network is connected to more than one ISP. Each of the routers that link to outside the AS can set a preference value for routes advertised into the AS, and this value indicates the router’s preference for these routes. Only IBGP routers share the local preference values it does not leave the AS. The higher the value the more preferable the route is so if there are multiple paths to this network the route with the highest Local Preference is chosen and all traffic destined for the network is sent this way.

QUESTION NO: 26
The TestKing network resides in AS 200 as shown in the diagram below:

A BGP router receives updates for prefix 10.0.0.0/8 sourced from AS 100 from four different BGP neighbors. TestKing1 has the Local Preference of the prefix set to 50, while the other three neighbors do nothing with Loc Pref. Neighbor TestKing2 advertises the prefix with an AS path length of 3, while all other neighbors have an AS Path length of 2. The advertisement from neighbor TestKing3 has the origin code set to E, while the other have it set to I. And Neighbor TestKing4 does nothing to any of the attributes. What statement is true?
A. Neighbor TestKing1 is the preferred path to prefix 10.0.0.0/8, since a higher local preference is better, and local preference is compared before the others.
B. Neighbor TestKing2 is the preferred path to prefix 10.0.0.0/8, since a longer AS Path is better, and AS path is compared before the others.
C. Neighbor TestKing3 is the preferred path to prefix 10.0.0.0/8, since an origin code of E is better than I, and origin code is compared before the others.
D. Neighbor TestKing4 is the preferred path to prefix 10.0.0.0/8 only after neighbor TestKing2 dies.
E. Neighbor TestKing3 is the preferred path to prefix 10.0.0.0/8 only after neighbor TestKing4 dies.
Leading the way in IT testing and certification tools, www.testking.com
– 217 –
Answer: E
Explanation:
Based on the information provided, the route for 10.0.0.0/8 will be preferred from the following routers, in order:
1.
TestKing4

2.
TestKing3

3.
TestKing2

4.
TestKing1
BGP uses the following criteria, in the order presented, to select a path for a destination:

1.
If the path specifies a next hop that is inaccessible, drop the update.

2.
Prefer the path with the largest weight.

3.
If the weights are the same, prefer the path with the largest local preference.

4.
If the local preferences are the same, prefer the path that was originated by BGP
running on this router.

5.
If no route was originated, prefer the route that has the shortest AS_path.

6.
If all paths have the same AS_path length, prefer the path with the lowest origin type

7.
If the origin codes are the same, prefer the path with the lowest MED attribute.
Incorrect Answers:
A. The default local preference value is 100, so router TestKing1 will be the last router used because its local preference was set to 50.
B. A shorter AS path is preferred over a longer one.
C. An origin code of I (Internal) is preferred over an origin code of E (External).
D. Using the information given here, router TestKing4 will be preferred over all the others, and router TestKing2 will be used only if routers TestKing4 and TestKing3 both fail.

QUESTION NO: 27
The TestKing network is using AS 200 in the following BGP network:

Router TestKing1 receives an EBGP update containing 10.0.0.0/8 sourced from AS
300. Router TestKing1 then advertises 10.0.0.0/8 to routers TestKing2 and TestKing3 via IBGP. What does router TestKing3 use as a BGP next hop to reach network 10.0.0.0/8?
A. 172.16.1.1
B. 172.16.1.2
C. 192.168.1.1
D. 192.168.1.2
E. 192.168.2.1
Answer: A
Explanation:
The EBGP next-hop attribute is the IP address that is used to reach the advertising router. For EBGP peers, the next-hop address is the IP address of the connection between the peers. For IBGP, the EBGP next-hop address is carried into the local AS, as illustrated below: Figure39-5 BGP AS-path Attribute
Figure39-6 BGP Next-Hop Attribute

Router C advertises network 172.16.1.0 with a next hop of 10.1.1.1. When Router A propagates this route within its own AS, the EBGP next-hop information is preserved. If Router B does not have routing information regarding the next hop, the route will be discarded. Therefore, it is important to have an IGP running in the AS to propagate next-hop routing information.
Incorrect Answers:
C: This would be the correct answer from router TestKing2’s perspective, as the BGP next-hop-self configuration command was used for this peer. However, the next-hop-self command was not used for the TestKing3 peer, making the regular next hop rules apply. In order for TestKing1 to advertise itself as the next hop to all IBGP peers, it would need the “next-hop-self” command configured for all peers. Reference: http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/bgp.htm

QUESTION NO: 28
The TestKing BGP network is using AS 200 as shown in the diagram below:

A router receives an EBGP update with prefix 10.0.0.0/8. This update is then
forwarded to all BGP neighbors within its AS.
Which neighbors advertise 10.0.0.0/8 with EBGP updates of their own?

A. Only router TestKing1 advertises 10.0.0.0/8 into AS 300.
B. Both router TestKing1 and router TestKing2 advertise 10.0.0.0/8 into their respective neighbor ASs.
C. Both router TestKing1 and router TestKing4 advertise 10.0.0.0/8 into their respective neighbor ASs.
D. Both router TestKing2 and router TestKing4 advertise 10.0.0.0/8 into their respective neighbor ASs.
E. Routers TestKing1, TestKing2, and TestKing4 advertise 10.0.0.0/8 into their respective neighbor ASs.
Answer: C
Explanation:
A BGP router with synchronization enabled will not advertise iBGP-learned routes to other eBGP peers if it is not able to validate those routes in its IGP. Assuming that IGP has a route to iBGP-learned routes, the router will announce the iBGP routes to eBGP peers. Otherwise the router treats the route as not being synchronized with IGP and does not advertise it. Disabling synchronization using the no synchronization command under router BGP prevents BGP from validating iBGP routes in IGP. By default, synchronization is on for all BGP routers. In this example, TestKing1 will advertise this route to its EBGP peer due to the fact that synchronization is disabled. Although synchronization is enabled on router TestKing4, it will advertise the route because it is running both OSPF and BGP, so this route will match the corresponding route within the OSPF table and be advertised.
Incorrect Answers:
A. Both TestKing1 and TestKing4 will advertise this route.
B, C, D. TestKing2 will not advertise this route. Since it is not an IBGP peer, it will not
receive the routing update in the first place so it will not be able to forward this route on
to the other AS.

QUESTION NO: 29
The TestKing1 BGP routing routes are displayed below: Based on the show ip route bgp output and the partial show run output shown, which BGP prefixes will be advertised by TestKing1 to the 10.1.1.1 neighbor?
A. 192.168.12.0/22, 192.168.16.0/24, 192.168.20.0/22, 192.168.20.0/24, 192.168.21.0/24, 192.168.22.0/22, 192.168.23.0/24, 192.168.24.0/24
B. 192.168.12.0/22, 192.168.20.0/22, 192.168.20.0/24, 192.168.21.0/24, 192.168.22.0/22, 192.168.23.0/24, 192.168.24.0/24
C. 192.168.12.0/22, 192.168.20.0/22, 192.168.20.0/24, 192.168.21.0/24, 192.168.22.0/22, 192.168.23.0/24
D. 192.168.12.0/22, 192.168.20.0/22, 192.168.20.0/24
E. 192.168.12.0/22, 192.168.20.0/22
F. All routes will be advertised, since there are no route filters in place.
Answer: A
Explanation:
When the aggregate-address command is used within BGP routing, the aggregated address is advertised, along with the more specific routes. The exception to this rule is through the use of the summary-only command. The “summary-only” keyword suppresses the more specific routes and announces only the summarized route.
Using the as-set argument creates an aggregate address with a mathematical set of autonomous systems (AS). This as-set summarizes the AS_PATH attributes of the all of the individual routes. This can be useful to avoid routing loops while aggregating routes. Again, unless the “summary-only” keyword is used with the as-set command the summary route is advertised along with the more specific routes.
In the example above, the 192.168.12.0, 192.168.13.0, 192.168.14.0, and 192.168.15.0 networks will be summarized into the only 192.168.12/22 route, which will be advertised. Along with this one route, the others will also be advertised, as well as one additional 192.168.20.0/22 route. In total, 8 different routes will be advertised.

QUESTION NO: 30
Many of the TestKing BGP routers are configured using peer groups. Which of the following correctly display the common properties of BGP peer groups?
A. Community values
B. Inbound policies
C. Outbound policies
D. MED inbound policies
E. Transitive AS policies
F. None of the above
Answer: C
Explanation:
BGP neighbors who share the same outbound policies can be grouped together in what is called a BGP peer group. Instead of configuring each neighbor with the same policy individually, Peer group allows to group the policies which can be applied to individual peer thus making efficient update calculation along with simplified configuration.
Reference:
www.cisco.com/en/US/tech/tk365/technologies_tech_note09186a0080093fb7.shtml

QUESTION NO: 31
While verifying the BGP configuration of router TestKing1, you issue the following command:
Based upon the show route-map setweight output shown above, which matching routes will be set to a weight of 200?
A. Routes that match the prefix-list named filter AND also match either the as-path filter 1 OR 2
B. Routes that match the prefix-list named filter OR also match either the as-path filter 1 AND 2
C. Routes that match the prefix-list named filter AND also match either the as-path filter 1 AND 2
D. Routes that match the prefix-list named filter OR also match either the as-path filter 1 OR 2
Answer: A
Explanation:
When the match clauses are shown on different lines, then all of the match conditions must be met. In this example, both the IP prefix list named “filter” and the AS path filter must match in order to set the weight to 200 as shown. However, in this configuration, there are two AS path filters configured, numbered 1 and 2. In this case, only one of the two filters needs to be matched. If all three of the criteria had needed to be met, then there would be three distinct lines listed under the match clauses.
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