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Any Questions?. Chapter 10 EIGRP. EIGRP Concepts and Operation EIGRP Configuration and Verification. Do I know this?. Go through the Quiz- 5 minutes. 1. Which of the following affect the calculation of EIGRP metrics when all possible default values are used? a. Bandwidth b. Delay
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Chapter 10 EIGRP • EIGRP Concepts and Operation • EIGRP Configuration and Verification
Do I know this? Go through the Quiz- 5 minutes
1. Which of the following affect the calculation of EIGRP metrics when all possible default values are used? a. Bandwidth b. Delay c. Load d. Reliability e. MTU f. Hop count
1. Which of the following affect the calculation of EIGRP metrics when all possible default values are used? a. Bandwidth b. Delay c. Load d. Reliability e. MTU f. Hop count Answer: A & B
2. How does EIGRP notice when a neighboring router fails? a. The failing neighbor sends a message before failing. b. The failing neighbor sends a “dying gasp” message. c. The router notices a lack of routing updates for a period of time. d. The router notices a lack of Hello messages for a period of time.
2. How does EIGRP notice when a neighboring router fails? a. The failing neighbor sends a message before failing. b. The failing neighbor sends a “dying gasp” message. c. The router notices a lack of routing updates for a period of time. d. The router notices a lack of Hello messages for a period of time. Answer: D
3. Which of the following is true about the concept of EIGRP feasible distance? a. A route’s feasible distance is the calculated metric of a feasible successor route. b. A route’s feasible distance is the calculated metric of the successor route. c. The feasible distance is the metric of a route from a neighboring router’s perspective. d. The feasible distance is the EIGRP metric associated with each possible route to reach a subnet.
3. Which of the following is true about the concept of EIGRP feasible distance? a. A route’s feasible distance is the calculated metric of a feasible successor route. b. A route’s feasible distance is the calculated metric of the successor route. c. The feasible distance is the metric of a route from a neighboring router’s perspective. d. The feasible distance is the EIGRP metric associated with each possible route to reach a subnet. Answer: B
4. Which of the following is true about the concept of EIGRP reported distance? a. A route’s reported distance is the calculated metric of a feasible successor route. b. A route’s reported distance is the calculated metric of the successor route. c. A route’s reported distance is the metric of a route from a neighboring router’s perspective. d. The reported distance is the EIGRP metric associated with each possible route to reach a subnet.
4. Which of the following is true about the concept of EIGRP reported distance? a. A route’s reported distance is the calculated metric of a feasible successor route. b. A route’s reported distance is the calculated metric of the successor route. c. A route’s reported distance is the metric of a route from a neighboring router’s perspective. d. The reported distance is the EIGRP metric associated with each possible route to reach a subnet. Answer: C
5. Which of the following network commands, following the command router eigrp 1, tells this router to start using EIGRP on interfaces whose IP addresses are 10.1.1.1, 10.1.100.1, and 10.1.120.1? a. network 10.0.0.0 b. network 10.1.1x.0 c. network 10.0.0.0 0.255.255.255 d. network 10.0.0.0 255.255.255.0
5. Which of the following network commands, following the command router eigrp 1, tells this router to start using EIGRP on interfaces whose IP addresses are 10.1.1.1, 10.1.100.1, and 10.1.120.1? a. network 10.0.0.0 b. network 10.1.1x.0 c. network 10.0.0.0 0.255.255.255 d. network 10.0.0.0 255.255.255.0 Answer: A & C
6. Routers R1 and R2 attach to the same VLAN with IP addresses 10.0.0.1 and 10.0.0.2, respectively. R1 is configured with the commands router eigrp 99 and network 10.0.0.0. Which of the following commands might be part of a working EIGRP configuration on R2 that ensures that the two routers become neighbors and exchange routes? a. network 10 b. router eigrp 98 c. network 10.0.0.2 0.0.0.0 d. network 10.0.0.0
6. Routers R1 and R2 attach to the same VLAN with IP addresses 10.0.0.1 and 10.0.0.2, respectively. R1 is configured with the commands router eigrp 99 and network 10.0.0.0. Which of the following commands might be part of a working EIGRP configuration on R2 that ensures that the two routers become neighbors and exchange routes? a. network 10 b. router eigrp 98 c. network 10.0.0.2 0.0.0.0 d. network 10.0.0.0 Answer: C &D
7. Examine the following excerpt from a router’s CLI: P 10.1.1.0/24, 1 successors, FD is 2172416 via 10.1.6.3 (2172416/28160), Serial0/1 via 10.1.4.2 (2684416/2284156), Serial0/0 via 10.1.5.4 (2684416/2165432), Serial1/0 Which of the following identifies a next-hop IP address on a feasible successor route? a. 10.1.6.3 b. 10.1.4.2 c. 10.1.5.4 d. It cannot be determined from this command output.
7. Examine the following excerpt from a router’s CLI: P 10.1.1.0/24, 1 successors, FD is 2172416 via 10.1.6.3 (2172416/28160), Serial0/1 via 10.1.4.2 (2684416/2284156), Serial0/0 via 10.1.5.4 (2684416/2165432), Serial1/0 Which of the following identifies a next-hop IP address on a feasible successor route? a. 10.1.6.3 b. 10.1.4.2 c. 10.1.5.4 d. It cannot be determined from this command output. Answer: C
8. Which of the following must occur to configure MD5 authentication for EIGRP? a. Setting the MD5 authentication key via some interface subcommand b. Configuring at least one key chain c. Defining a valid lifetime for the key d. Enabling EIGRP MD5 authentication on an interface
8. Which of the following must occur to configure MD5 authentication for EIGRP? a. Setting the MD5 authentication key via some interface subcommand b. Configuring at least one key chain c. Defining a valid lifetime for the key d. Enabling EIGRP MD5 authentication on an interface Answer: B &D
9. In the show ip route command, what code designation implies that a route was learned with EIGRP? a. E b. I c. G d. R e. P f. D
9. In the show ip route command, what code designation implies that a route was learned with EIGRP? a. E b. I c. G d. R e. P f. D Answer: F
EIGRP Concepts 1. Neighbor discovery: EIGRP routers send Hello messages to discover potential neighboring EIGRP routers and perform basic parameter checks to determine which routers should become neighbors. 2. Topology exchange: Neighbors exchange full topology updates when the neighbor relationship comes up, and then only partial updates as needed based on changes to the network topology. 3. Choosing routes: Each router analyzes its respective EIGRP topology tables, choosing the lowest-metric route to reach each subnet. Pg 380
EIGRP Neighbor • Another EIGRP using router on same subnet • Send multicast Hello • Must: • It must pass the authentication process. • It must use the same configured AS number. • The source IP address used by the neighbor’s Hello must be in the same subnet. Pg 381
EIGRP Topology • Send Update Messages to communicate topology to neighbors • Multicast to 224.0.0.10 • Full table update at startup • Partial updates when things change Pg 381-382
EIGRP Topology Pg 382
Finding Best Route • Uses a composite Metric • Combine bandwidth and delay • Can also use Load and reliability • Updates contain • Subnet number and mask • Cumulative delay • Minimum bandwidth • Router calculates bandwidth and delay on interface the update was received on • Calc new metric and compare to table • If tie, load balance up to 4 routes Pg 383
Feasible Distance and Reported Distance • Feasible Distance (FD): The metric of the best route to reach a subnet, as calculated on a router • Reported Distance (RD): The metric as calculated on a neighboring router and then reported and learned in an EIGRP Update Pg 384
Bandwidth and Delay • In order to make good decisions, bandwidth information on interfaces must be accurate Pg 385
EIGRP Convergence • EIGRP keeps topology information to make quick decisions about changes to network • Need to find loop free routes • Keeps a list of next best routes for each destination Pg 386
Successors and Feasible Successors • For Each destination EIGRP calculates • Successor –route with best metric • Metric is feasible distance • This information goes in Routing Table • EIGRP keeps backup route in mind • Feasible successor-next best route Pg 386
Successors Pg 387
Query and Reply • If no feasible successor is know, router will asks other routers • Diffusing Update Algorithm (DUAL) • Confirms there is a loop free route before putting new route in table Pg 388
Summary and Compare to OSPF Pg 389
Configuration Step 1 Enter EIGRP configuration mode, and define the EIGRP ASN by using the router eigrp as-number global command. Step 2 Configure one or more network ip-address [wildcard-mask] router subcommands. This enables EIGRP on any matched interface and causes EIGRP to advertise the connected subnet. Step 3 (Optional) Change the interface Hello and hold timers using the ip hellointerval eigrp asn time and ip hold-time eigrp asn time interface subcommands. Step 4 (Optional) Impact metric calculations by tuning bandwidth and delay using the bandwidth value and delay value interface subcommands. Step 5 (Optional) Configure EIGRP authentication. Step 6 (Optional) Configure support for multiple equal-cost routes using the maximum-paths number and variance multiplier router subcommands. Pg 389
Basic Config and verification COmmands Albuquerque#show ip route eigrp 10.0.0.0/24 is subnetted, 6 subnets D 10.1.3.0 [90/2172416] via 10.1.6.3, 00:00:47, Serial0/1 D 10.1.2.0 [90/2172416] via 10.1.4.2, 00:00:47, Serial0/0 D 10.1.5.0 [90/2681856] via 10.1.6.3, 00:00:49, Serial0/1 [90/2681856] via 10.1.4.2, 00:00:49, Serial0/0 Albuquerque#show ip eigrp neighbors IP-EIGRP neighbors for process 1 H Address Interface Hold Uptime SRTT RTO Q Seq Type (sec) (ms) Cnt Num 0 10.1.4.2 Se0/0 11 00:00:54 32 200 0 4 1 10.1.6.3 Se0/1 12 00:10:36 20 200 0 24 Albuquerque#show ip eigrp interfaces IP-EIGRP interfaces for process 1 Xmit Queue Mean Pacing Time Multicast Pending Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes Fa0/0 0 0/0 0 0/10 0 0 Se0/0 1 0/0 32 0/15 50 0 Se0/1 1 0/0 20 0/15 95 0 Albuquerque#show ip eigrp topology summary IP-EIGRP Topology Table for AS(1)/ID(10.1.6.1) Head serial 1, next serial 9 6 routes, 0 pending replies, 0 dummies IP-EIGRP(0) enabled on 3 interfaces, 2 neighbors present on 2 interfaces Quiescent interfaces: Se0/1/0 Se0/0/1 Pg 391
Metrics, Successors and Feasible Successors • We can see details about successors in the EIGRP topology Table • Routing Table • D 10.1.3.0 [90/2172416] via 10.1.6.3, 00:00:57, Serial0/1 • EIGRPT Topology • P 10.1.3.0/24, 1 successors, FD is 2172416 via 10.1.6.3 (2172416/28160), Serial0/1 Pg 392
Metrics, Successors and Feasible Successors • Routing Table • D 10.1.5.0 [90/2681856] via 10.1.4.2, 00:00:57, Serial0/0 [90/2681856] via 10.1.6.3, 00:00:57, Serial0/1 • EIGRPT Topology • 10.1.5.0/24, 2 successors, FD is 2681856 • via 10.1.4.2 (2681856/2169856), Serial0/0 • via 10.1.6.3 (2681856/2169856), Serial0/1 Pg 392
Feasible Successors • Changing the bandwidth affects the feasible successor • In EIGRP Topology • P 10.1.3.0/24, 1 successors, FD is 2172416 • via 10.1.6.3 (2172416/28160), Serial0/1 • via 10.1.4.2 (2684416/1794560), Serial0/0 Pg 394
Feasible Successors • The route to 10.1.3.0 through 10.1.6.3 (Seville) is the successor route, because the calculated metric (2,172,416), shown as the first of the two numbers in parentheses, is the best calculated metric. • The route to 10.1.3.0 through 10.1.4.2 (Yosemite) is a feasible successor route, because the neighbor’s Reported Distance (1,794,560, shown as the second number in parentheses) is lower than Albuquerque’s FD. • Although both the successor and feasible successor routes are in the EIGRP topology table, only the successor route is added to the IP routing table. Pg 395
FS and Convergence • *Mar 1 02:35:31.836: %LINK-3-UPDOWN: Interface Serial0/1, changed state to down • *Mar 1 02:35:31.852: %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor 10.1.6.3 (Serial0/1) is down: interface down • *Mar 1 02:35:31.852: DUAL: Destination 10.1.3.0/24 • *Mar 1 02:35:31.852: DUAL: Find FS for dest 10.1.3.0/24. FD is 2172416, RD is 2172416 • *Mar 1 02:35:31.856: DUAL: Removing dest 10.1.3.0/24, nexthop 10.1.6.3 • *Mar 1 02:35:31.856: DUAL: RT installed 10.1.3.0/24 via 10.1.4.2 Pg 397
EIGRP Authentication Step 1 Create an (authentication) key chain: a. Create the chain and give it a name with the key chain name global command (this also puts the user into key chain config mode). b. Create one or more key numbers using the key number command in key chain configuration mode. c. Define the authentication key’s value using the key-string value command in key configuration mode. d. (Optional) Define the lifetime (time period) for both sending and accepting this particular key. Step 2 Enable EIGRP MD5 authentication on an interface, for a particular EIGRP ASN, using the ip authentication mode eigrp asn md5 interface subcommand. Step 3 Refer to the correct key chain to be used on an interface using the ip authentication key-chain eigrp asn name-of-chain interface subcommand. Pg 397
KEYS • key chain carkeys • key 1 • key-string fred • accept-lifetime 08:00:00 Jan 11 2005 08:00:00 Feb 11 2005 • send-lifetime 08:00:00 Jan 11 2005 08:00:00 Feb 11 2005 • key 2 • key-string wilma • accept-lifetime 08:00:00 Feb 10 2005 08:00:00 Mar 11 2005 • send-lifetime 08:00:00 Feb 10 2005 08:00:00 Mar 11 2005 • interface FastEthernet0/0 • ip address 172.31.11.1 255.255.255.0 • ip authentication mode eigrp 1 md5 • ip authentication key-chain eigrp 1 carkeys Pg 398
EIGRP Max Paths and Variance • EIGRP supports multiple paths for load balancing • Default is 4 but can be set to 16 • It is unlikely to have exactly the same metric on multiple path • Use variance to change what is considered “equal” Pg 399
EIGRP Max Paths and Variance • The variance is multiplied by the current FD (the metric of the best route to reach the subnet). • Any FS routes whose calculated metric is less than or equal to the product of variance times the FD are added to the IP routing table, assuming that the maximum-paths setting allows more routes. • Routes that are neither successor nor feasible successor can never be added to the IP routing table, regardless of the variance setting. Pg 401
Tuning with Bandwidth and Delay Yosemite#show interfaces fa0/0 FastEthernet0/0 is up, line protocol is up Hardware is Gt96k FE, address is 0013.197b.5026 (bia 0013.197b.5026) Internet address is 10.1.2.252/24 MTU 1500 bytes, BW 100000 Kbit, DLY 100 usec, ! lines omitted for brevity Yosemite#configure terminal Enter configuration commands, one per line. End with CNTL/Z. Yosemite(config)#interface fa0/0 Yosemite(config-if)#delay 123 Yosemite(config-if)#^Z Yosemite#show interfaces fa0/0 FastEthernet0/0 is up, line protocol is up Hardware is Gt96k FE, address is 0013.197b.5026 (bia 0013.197b.5026) Internet address is 10.1.2.252/24 MTU 1500 bytes, BW 100000 Kbit, DLY 1230 usec, ! lines omitted for brevity Pg 395