| 1: | What is the most important difference between BGP-4 and earlier versions of BGP?
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| 2: | What two problems was CIDR developed to alleviate?
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| 3: | What is the difference between classful and classless IP routers?
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| 4: | What is the difference between classful and classless IP routing protocols?
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| 5: | Given the addresses 172.17.208.0/23, 172.17.210.0/23, 172.17.212.0/23, and 172.17.214.0/23, summarize the addresses with a single aggregate, using the longest possible address mask.
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| 6: | What is an address prefix?
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| 7: | The routing table in Example 2-16 is taken from a classless router. To what next-hop address does the router forward packets with each of the following destination addresses?
172.20.3.5
172.20.1.67
172.21.255.254
172.16.50.50
172.16.0.224
172.16.51.50
172.17.40.1
172.17.41.1
172.30.1.1
Example 2-16 The Routing Table for Review Question 7
Stratford#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
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, * - candidate default
Gateway of last resort is not set
172.20.0.0 is variably subnetted, 6 subnets, 2 masks
D 172.20.0.0 255.255.0.0 [90/409600] via 172.20.5.2, 00:01:50, Ethernet0
D 172.20.2.0 255.255.255.0
[90/409600] via 172.20.6.2, 00:01:50, Ethernet1
D 172.20.3.0 255.255.255.0
[90/5401600] via 172.20.6.2, 00:01:50, Ethernet1
C 172.20.5.0 255.255.255.0 is directly connected, Ethernet0
C 172.20.6.0 255.255.255.0 is directly connected, Ethernet1
C 172.20.7.0 255.255.255.0 is directly connected, Ethernet2
172.16.0.0 is variably subnetted, 3 subnets, 2 masks
D 172.16.50.0 255.255.255.0
[90/409600] via 172.20.6.2, 00:01:50, Ethernet1
D 172.16.0.0 255.255.255.0
[90/460800] via 172.20.6.2, 00:01:51, Ethernet1
D 172.16.0.0 255.255.0.0 [90/409600] via 172.20.7.2, 00:01:51, Ethernet2
172.17.0.0 is subnetted (mask is 255.255.255.0), 1 subnets
D 172.17.40.0 [90/2841600] via 172.20.7.2, 00:01:52, Ethernet2
D 172.16.0.0 (mask is 255.240.0.0) [90/409600] via 172.20.5.2, 00:01:52, Ethernet0
Stratford#
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| 8: | Explain how summarization helps hide network instabilities.
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| 9: | Explain how summarization can cause asymmetric traffic patterns.
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| 10: | Is asymmetric traffic undesirable?
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| 11: | What is a NAP?
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| 12: | What is a route server?
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| 13: | What is a provider-independent address space, and why can it be advantageous to have one?
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| 14: | Why can it be a problem to have a /21 provider-independent address space?
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| 15: | What is a routing policy?
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| 16: | What is the underlying protocol that BGP uses to reliably connect to its neighbors?
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| 17: | What are the four BGP message types, and how is each one used?
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| 18: | In what state or states can BGP peers exchange Update messages?
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| 19: | What is NLRI?
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| 20: | What is a path attribute?
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| 21: | What are the four categories of BGP path attributes?
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| 22: | What is the purpose of the AS_PATH attribute?
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| 23: | What are the different types of AS_PATH?
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| 24: | What is the purpose of the NEXT_HOP attribute?
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| 25: | What is the purpose of the LOCAL_PREF attribute?
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| 26: | What is the purpose of the MULTI_EXIT_DISC attribute?
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| 27: | What attribute or attributes are useful if a BGP speaker originates an aggregate route?
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| 28: | What is a BGP administrative weight?
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| 29: | Given an EBGP route and an IBGP route to the same destination, which route will a BGP router prefer?
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| 30: | A router has two IBGP routes to the same destination. Path A has a LOCAL_PREF of 300 and three AS numbers in the AS_PATH. Path B has a LOCAL_PREF of 200 and two AS numbers in the AS_PATH. Assuming no other differences, which path will the router choose?
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| 31: | What is route dampening?
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| 32: | Define the penalty, suppress limit, reuse limit, and half-life as they apply to route dampening.
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| 33: | What is IGP synchronization, and why is it important?
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| 34: | Under what circumstances can you safely disable IGP synchronization?
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| 35: | What is a BGP peer group?
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| 36: | What is a BGP community?
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| 37: | What is a route reflector? What is a route reflection client? What is a route reflection cluster?
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| 38: | What is the purpose of the ORIGINATOR_ID and the CLUSTER_LIST path attributes?
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| 39: | What is a BGP confederation?
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| 40: | Can route reflectors be used within confederations?
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| 41: | What is the purpose of the next-hop-self function? Are there any reasonable alternatives to using this function?
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