CCNP Routing Study Guide- P15

Chia sẻ: Cong Thanh | Ngày: | Loại File: PDF | Số trang:30

Thêm vào BST

Báo xấu

88
lượt xem 20
download

Download Vui lòng tải xuống để xem tài liệu đầy đủ

CCNP Routing Study Guide- P15:T his book is intended to help you continue on your exciting new path toward obtaining your CCNP and CCIE certification. Before reading this book, it is important to have at least read the Sybex CCNA: Cisco Certified Network Associate Study Guide, Second Edition. You can take the CCNP tests in any order, but you should have passed the CCNA exam before pursuing your CCNP.

Chủ đề:

Bình luận(0) Đăng nhập để gửi bình luận!

Lưu

Nội dung Text: CCNP Routing Study Guide- P15

Route Maps 385 where routemail is an arbitrary name chosen for the route map, 10 is the route map sequence number, and the sequence number is 10 by default, unless another number is specified. We will now set the criteria for the first match clause: match ip address 101 where 101 is the access list that the match clause is checking traffic against. We will now use the set clause to specify the next-hop address of traffic satisfying the match clause: set ip next-hop 172.16.2.2 where 172.16.2.2 is the IP address of the next-hop router. Finally, we need to specify where to send traffic if the match condition is not met: route-map routemail permit 20 set ip next-hop 172.16.1.2 where 20 is the sequence number and 172.16.1.2 is the next-hop router. RouterA will now send all SMTP traffic over the 56Kbps link to RouterC and all other traffic over the 1.544Mbps link to RouterB, as shown in Figure 10.13. FIGURE 10.13 Policy routing configuration for example 1 ISP A RouterB 172.16.1.2/24 WWW, FTP, etc. Company A RouterA 1.544Mbps link s0 172.16.1.1/24 Internet 172.16.2.1/24 s1 56Kbps link ISP B RouterC SMTP 172.16.2.2/24 access-list 101 permit tcp any any eq 25 ! route-map routemail permit 10 match ip address 101 set ip next-hop 172.16.2.2 ! route-map routemail permit 20 set ip next-hop 172.16.1.2 Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
386 Chapter 10 Route Optimization Policy Routing Subnets As another example, consider the following scenario. Company A has the same ISP connections as in the previous example. Inside Company A, we have two VLANs, the Engineering VLAN (172.16.3.0/24) and the Account- ing VLAN (172.16.4.0/24), as illustrated in Figure 10.14. Our goal is to direct traffic from the Engineering VLAN (172.16.3.0/24) out the 1.544Mbps link (interface s0) and to direct traffic from the Accounting VLAN (172.16.4.0/24) out the 56Kbps link (interface s1). FIGURE 10.14 Policy routing example 2 Company A ISP A Engineering VLAN RouterB 172.16.1.2/24 RouterA e0 1.544Mbps link 172.16.3.1/24 s0 172.16.1.1/24 Internet 172.16.4.1/24 172.16.2.1/24 e1 s1 56Kbps link ISP B RouterC Accounting VLAN 172.16.2.2/24 First, we need to create our access lists, specifying the conditions we’re looking for, that is, whether a packet was sourced from the Engineering or Accounting VLAN: access-list 1 permit 172.16.3.0 0.0.0.255 access-list 2 permit 172.16.4.0 0.0.0.255 Next, we need to create our route map and specify the match and set parameters. In this example, we will use the name “routevlan”: route-map routevlan permit 10 match ip address 1 set interface serial0 ! Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Route Maps 387 route-map routevlan permit 20 match ip address 2 set interface serial1 The Accounting users will now have their Internet traffic directed to ISP B, while the Engineering users will have their Internet traffic directed to ISP A, as shown in Figure 10.15. FIGURE 10.15 Policy routing configuration for example 2 ISP A Engineering VLAN Company A RouterB 172.16.1.2/24 RouterA 1.544Mbps link e0 s0 172.16.3.1/24 172.16.1.1/24 Internet 172.16.4.1/24 172.16.2.1/24 e1 s1 56Kbps link ISP B RouterC Accounting VLAN 172.16.2.2/24 access-list 1 permit 172.16.3.0 0.0.0.255 access-list 2 permit 172.16.4.0 0.0.0.255 ! route-map routevlan permit 10 match ip address 1 set interface serial0 ! route-map routevlan permit 20 match ip address 2 set interface serial1 Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
388 Chapter 10 Route Optimization Summary In this chapter, we discussed how to take networks running different routing protocols and allow them to exchange routing information, through a process called route redistribution. One of the challenges of route redistri- bution is that many routing protocols use different metrics. To overcome this challenge, we set default metrics for various routing protocols. After exam- ining several redistribution examples, we reviewed commands for verifying and troubleshooting route redistribution. We explored various advanced route-manipulation techniques including setting metrics on a protocol-by-protocol basis and setting metrics for spe- cific routes. We introduced the distribute-list feature as a tool for fil- tering the receiving or advertising of routes, and we showed the virtual interface Null0 to be an efficient way of discarding packets destined for spec- ified networks. We also detailed how to redistribute static and connected routes. Finally, we introduced the powerful features of route maps. We used the route map components, match and set clauses, in examples where we routed traffic based on the source network and Layer 4 information (TCP port numbers). Key Terms Before taking the exam, make sure you are familiar with the following terms: hop count metric Null0 route redistribution Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Written Lab 389 Written Lab Write the configuration for the RouterA, such that HTTP traffic is directed to RouterC, and all other traffic is directed to RouterB, as shown in the following graphic: RouterB 172.16.2.1 Telnet, FTP, etc. RouterA T1 Internet T3 HTTP RouterC 172.16.1.1 Solution The first step is to create an access list that specifies the traffic we are inter- ested in, which in this case is HTTP traffic. By default, HTTP uses TCP port 80. Therefore, our access list would be access-list 101 permit tcp any any eq 80 Next, we need to create a route map. In this exercise, we will name it “routeweb”: route-map routeweb permit 10 We’ll now set the criteria for the first match clause: match ip address 101 Next, we will use the set clause to specify the next-hop address of traffic satisfying the match clause: set ip next-hop 172.16.1.1 Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
390 Chapter 10 Route Optimization Finally, we need to specify where to send traffic if the match condition is not met: route-map routeweb permit 20 set ip next-hop 172.16.2.1 RouterA will now send all HTTP traffic over the T3 link to RouterC and all other traffic over the T1 link to RouterB. Hands-on Lab A dd a distribute-list command to RouterA, such that RouterB can see network 1.1.1.0/24 in its routing table, but not network 2.2.2.0/24, as shown in the following graphic: Lo0 1.1.1.1/24 RouterA RIP RouterB s0 s0 3.3.3.1/24 3.3.3.2/24 Lo1 2.2.2.2/24 Solution RouterA and RouterB should have their s0 interfaces interconnected with a serial crossover cable. We will arbitrarily designate RouterB as the DCE side and RouterA as the DTE side. First, we create an access list on RouterA that specifies which networks we want to be advertised: access-list 1 permit 1.0.0.0 0.255.255.255 Next, we use the distribute-list command to permit only the net- work specified in the access list: router rip distribute–list 1 out Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Hands-on Lab 391 Following are possible configurations for RouterA and RouterB: RouterA ! version 11.2 ! hostname RouterA ! interface Loopback0 ip address 1.1.1.1 255.255.255.0 ! interface Loopback1 ip address 2.2.2.2 255.255.255.0 ! interface Serial0 ip address 3.3.3.1 255.255.255.0 ! router rip distribute-list 1 out network 1.0.0.0 network 2.0.0.0 network 3.0.0.0 ! access-list 1 permit 1.0.0.0 0.255.255.255 ! no ip classless ! line con 0 line aux 0 line vtp 0 4 login ! end Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
392 Chapter 10 Route Optimization RouterB ! version 11.2 ! hostname RouterB ! interface Serial0 ip address 3.3.3.1 255.255.255.0 clockrate 56000 ! router rip network 3.0.0.0 ! no ip classless ! line con 0 line aux 0 line vtp 0 4 login ! end Issuing the show ip route command on RouterB reveals that RouterB has entries for networks 1.1.1.0 and 3.3.3.0 but not for network 2.2.2.0. Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Review Questions 393 Review Questions 1. Which of the following is the metric used by RIP? A. Ticks B. Bandwidth C. Delay D. Hop count 2. Which of the following is the network address and subnet mask of the default route? A. 127.0.0.1 255.255.255.255 B. 0.0.0.0 0.0.0.0 C. 255.255.255.255 0.0.0.0 D. 255.255.255.255 255.255.255.255 3. What are the two clauses used by route maps? A. metric B. match C. access D. set 4. Which of the following are Cisco proprietary protocols? (Choose all that apply.) A. RIP B. IGRP C. OSPF D. EIGRP Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
394 Chapter 10 Route Optimization 5. Which of the following are metric components of IGRP? (Choose all that apply.) A. Delay B. Hops C. Bandwidth D. Ticks 6. What number would we assign to the load component of an EIGRP metric to indicate that a link was approximately 10 percent loaded? A. 10 B. 1 C. 2.5 D. 25 7. What is the default MTU size metric component for an Ethernet interface? A. 1500 bytes B. 1518 bytes C. 64 bytes D. 4000 bytes 8. What is the most desirable value for the reliability metric component? A. 255 B. 0 C. 1 D. 100 Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Review Questions 395 9. Which of the following protocols share similar metrics? A. RIP and OSPF B. IGRP and EIGRP C. BGP and RTMP D. NLSP and RIP 10. What command, under the router eigrp 10 command, would you enter to set the default metric for EIGRP to use, regardless of which protocol was being distributed into the EIGRP process? A. redistribute eigrp metric 56 10 255 1 1500 B. default-metric 56 10 255 1 1500 C. metric 10 D. default metric 10 11. Given the access list access-list 1 permit 10.0.0.0 0.255.255.255, what command would allow only network 10.0.0.0/8 to be added to a router’s routing table? A. access-list 1 in B. distribute-list 1 out C. distribute-list 1 in D. distribute 1 out 12. What happens to packets that are forwarded to the Null0 interface? A. The packets are sent to the gateway of last resort. B. The packets are policy-routed. C. The packets are marked as discard eligible. D. The packets are discarded. Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
396 Chapter 10 Route Optimization 13. Which of the following commands will display the default redistribu- tion metric for a protocol? A. show ip route B. trace C. show ip protocols D. debug ip route 14. Which of the following commands will redistribute manually config- ured routes into a specified routing process? A. redistribute connected B. redistribute static C. redistribute default D. redistribute local 15. If a local interface is not part of a routing process, what command may be used to inject its route into a routing process? A. redistribute connected B. redistribute static C. redistribute default D. redistribute local 16. Which of the following are possible applications of route maps? (Choose all that apply.) A. Load sharing B. Directing different traffic types over different links C. Route redistribution D. Traffic prioritization Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Review Questions 397 17. Given the command route-map routemail permit 20, what does 20 represent? A. The sequence number of the route map B. The access list number being used C. The TCP port number being routed D. The percent of bandwidth to be allocated 18. In order for IGRP and EIGRP to automatically redistribute routes into each other, what must be true? A. They must be advertising subnets of the same major network. B. They must have the same process ID (the same Autonomous System). C. They must be in different areas. D. They must both be in totally stubby areas. 19. What command could you use to view RIP updates as they occur? A. show ip protocols B. show ip route C. show ip rip D. debug ip rip 20. What does the command distribute-list 2 out do? A. It prevents or permits the routes specified in access-list 2 from being added to the local routing table. B. It prevents or permits the routes specified in access-list 2 from being advertised. C. It redirects the routes specified in access-list 2 to the Null0 interface. D. It redistributes routes specified in access-list 2 to all routing protocols. Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
398 Chapter 10 Route Optimization Answers to Review Questions 1. D. RIP considers only the number of routers (hops) to be traversed en route to a destination network. 2. B. Cisco uses 0.0.0.0 0.0.0.0 to indicate a default route in a static routing statement. 3. B and D. Route maps have two primary components, a match clause and a set clause. The function of the match clause is to specify the traffic that is to be policy routed. The purpose of the set clause is to manipulate the routing of traffic by adjusting such parameters as next- hop address. 4. B and D. IGRP and EIGRP are similar in that they use the same met- ric components, and they are both Cisco proprietary. 5. A and C. The metric components of IGRP are bandwidth, delay, reli- ability, load, and MTU size. 6. D. The values for load range from 1 through 255, where 1 is unloaded and 255 is completely loaded. A 10 percent load may be cal- culated by multiplying 255 by .1, which equals 25.5. Since we need to specify load in terms of an integer, we choose 25. 7. A. Even though the maximum MTU size for Ethernet is 1518 bytes, the default MTU value used in the metric calculation for an Ethernet interface is 1500 bytes. 8. A. Reliability values range from 1 through 255, where 1 is com- pletely unreliable and 255 is completely reliable. 9. B. Both IGRP and EIGRP use bandwidth, delay, reliability, load, and MTU size as their metric components. 10. B. The command default-metric 56 10 255 1 1500 can be used to specify the metric to be used for any route being redistributed into EIGRP. This may not be optimal if you want to specify different met- rics for different protocols. Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Answers to Review Questions 399 11. C. The in parameter on a distribute-list command specifies routes to be added to a router’s routing table. The out parameter specifies routes to be advertised from a router. 12. D. The Null0 interface is a virtual interface, which is sometimes referred to as a bit bucket. Packets sent to the Null0 interface are dis- carded. Since a static route requires less processing than an access list, a route to Null0 is sometimes preferable to an access list denying a par- ticular host or network. 13. C. The show ip protocols command will display such information as redistribution parameters. 14. B. The redistribute static command redistributes routes that have been manually configured. 15. A. The redistribute connected command redistributes routes of networks that are connected directly to the local router. These routes may or may not be a part of a routing process. 16. A, B, C, and D. Route maps, which use a combination of match and set clauses, can be used for all of the listed applications. 17. A. The 20 is the sequence number of the route map. The sequence numbers of the route map determine in what order the match and set clauses will be evaluated. 18. B. If IGRP and EIGRP processes are both running on the same router, and they both have the same process ID, then their routes will automatically be redistributed into each other. 19. D. The debug ip rip command can be used to view the contents of RIP updates as they occur. 20. B. The out parameter of the distribute-list command deals with advertising routes, while the in parameter deals with adding routes to the local routing table. Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Appendix Practice Exam A Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
1. How is a BGP session established between two routers? A. Telnet B. TCP (SYN, ACK, SYN) C. UDP (SYN, ACK, SYN) D. IPX SAP 2. Which of the following is true concerning a stub area? A. It does not receive summary Link State Advertisements. B. It does not receive Type 5 LSAs. C. It is configured with the IOS command area stub area-id. D. Only the ABR needs to be configured as stubby. 3. Which two of the following would you use to avoid creating a full- mesh BGP network? A. Confederations B. Route maps C. Prefix lists D. Route reflectors 4. Which of the following are used by EIGRP to send queries to other EIGRP neighbors? A. Broadcasts B. Multicasts C. ACKs D. Unicasts Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Practice Exam 403 5. Which of the following is the IOS command to clear all dynamic IP routes from a router's routing table? A. clear ip route * B. clear ip route 0.0.0.0 C. clear ip route all D. clear ip route 127.0.0.1 6. When should BGP be used? (Choose all that apply.) A. When multi-homing B. When connecting multiple ISPs C. When connecting routers within the same AS D. When configuring backup links 7. What route/subnet mask combination indicates a default route? A. 127.0.0.1 255.255.255.255 B. 255.255.255.255 255.255.255.255 C. 0.0.0.0 255.255.255.255 D. 0.0.0.0 0.0.0.0 8. Which Cisco layer is responsible for breaking up collision domains? A. Core B. Backbone C. Distribution D. Access Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
404 Appendix A Practice Exam 9. What does the IOS command show ip ospf virtual-links do? A. It shows the router link states. B. It shows the network link states. C. It shows the status of a router’s virtual links. D. It shows the virtual memory that a router is using to maintain its link state database. 10. What does the command redistribute static do? A. It makes dynamically learned routes permanent. B. It takes manually configured routes and redistributes them into a specified routing protocol. C. It takes routes from directly connected interfaces and redistributes them into a specified routing protocol. D. It causes the same metric to be used for a routing protocol, regard- less of which routing protocol it is being redistributed into. 11. Which syntax used with the clear ip bgp command is used to iden- tify that the command is to affect inbound or outbound triggered updates? A. open in B. soft C. triggered inbound D. triggered outbound 12. What is the default administrative distance of EIGRP? A. 0 B. 1 C. 90 D. 100 E. 110 Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com
Practice Exam 405 13. If an external AS is not receiving updates from your AS, which of the following show commands can be used to troubleshoot this? (Choose all that apply.) A. show ip bgp events B. show ip bgp neighbor C. show ip bgp all D. show ip bgp 14. If you wanted to summarize networks 172.16.100.0/24 and 172.16.106.0/24, which network and mask would you use? A. 172.16.0.0/24 B. 172.16.100.0/20 C. 172.16.106.0/20 D. 172.16.96.0/20 15. Which of the following statements are true? (Choose all that apply.) A. Every OSPF network must have an Area 0. B. A router with one or more interfaces in Area 0 is said to be a back- bone router. C. If an IGRP routing process connects to a multi-area OSPF net- work, the router through which it enters the OSPF network is called an ABR. D. An ASBR separates two or more OSPF areas. 16. If you wanted to reduce bandwidth usage, which Cisco IOS features could you use? (Choose all that apply.) A. Access lists B. Snapshot routing C. Compression of WANs D. TTL E. DDR F. Incremental updates Copyright ©2001 SYBEX , Inc., Alameda, CA www.sybex.com