CIS 185 CCNP ROUTE EIGRP Part 1

CIS 185 CCNP ROUTE EIGRP Part 1
Rick Graziani Cabrillo College Last Updated: Fall 2011

EIGRP Part 1 Review Neighbor Adjacencies and EIGRP Reliability
EIGRP Metric DUAL Basic EIGRP Configuration Passive-Interfaces Summarization Default Route

Materials Book: Implementing Cisco IP Routing (ROUTE) Foundation Learning Guide: Foundation learning for the ROUTE Exam By Diane Teare Book ISBN-10: ISBN-13: eBook ISBN-10: ISBN-13:

Review

What do we remember about EIGRP?
What type of protocol is EIGRP? Distance Vector What are the default metrics used by EIGRP? Bandwidth (slowest) and Delay (cumulative) What are the optional metrics? Reliability and Load Note: Book also state MTU but it is not a metric. What algorithm is used to determine best path? DUAL (Diffusing Update Algorithm)

Review of EIGRP from CCNA
Enhanced Interior Gateway Routing Protocol (EIGRP) Released in 1992 with Cisco IOS Software Release 9.21. Enhancement of Cisco’s: Interior Gateway Routing Protocol (IGRP). Both are Cisco proprietary, operate only on: Cisco routers Protocol Dependent Modules (PDM) EIGRP supports several routed protocols independently. Ex: IPv4 and IPv6 Reliable Transport Protocol (RTP) RTP sends uses both reliable and unreliable transport Reliable ACK is returned EIGRP Queries, Updates and Replies Unreliable No ACK EIGRP Hellos, and ACKs Neighbor Discovery and Recovery Identify neighbors Recognize when neighbor is down Diffusing Update Algorithm (DUAL) Process for analyzing list of available paths, selecting best paths, and feasible fail-over routes,

RTP and EIGRP Packet Types
What transport layer protocol does EIGRP use? Reliable Transport Protocol (RTP) Why doesn’t EIGRP use UDP or TCP? Reliable Transport Protocol (RTP) Delivery and reception of EIGRP packets. Cannot use the services of UDP or TCP IPX and AppleTalk do not use protocols from the TCP/IP protocol suite. RTP includes both reliable delivery and unreliable delivery of EIGRP packets: Reliable RTP requires an acknowledgment (like TCP). Unreliable RTP does not require an acknowledgment (like UDP). RTP can send packets either as a unicast or a multicast ( ).

Protocol-Dependent Modules
EIGRP uses protocol-dependent modules (PDM). to route different protocols, including: IP, Internetwork Packet Exchange (IPX) AppleTalk, PDMs are responsible for the specific routing tasks for each network layer protocol. Example The IP-EIGRP module is responsible for: Sending and receiving EIGRP packets that are encapsulated in IP. Using DUAL to build and maintain the IP routing table. EIGRP uses protocol-dependent modules (PDM). to route different protocols, including: IPv4 IPv6 Internetwork Packet Exchange (IPX) AppleTalk

EIGRP Packet Frame Header Frame Payload CRC IP Header Protocol Number
EIGRP Message On a LAN, the EIGRP packet is encapsulated in an Ethernet frame with a destination multicast MAC address: E A The destination IP address is set to the multicast and the EIGRP protocol field is 88. The EIGRP header identifies the type of EIGRP packet and autonomous system number. The EIGRP message consists of the Type / Length / Value (TLV).

EIGRP Header

EIGRP Packet

EIGRP Packet Types – Hello Packet
What are Hello packets used for by EIGRP to: Discover neighbors (sometimes called neighborships) Form adjacencies with those neighbors What is the multicast address? Hint: ? Are these sent as reliable or unreliable deliver? Unreliable delivery – No ACKs returned Hello packets are used by EIGRP to: Discover neighbors Form adjacencies with those neighbors EIGRP hello packets: multicasts unreliable delivery Before any EIGRP packets can be exchanged between routers, EIGRP must first discover its neighbors. EIGRP routers discover neighbors and establish adjacencies with neighbor routers using the hello packet.

Hello Protocol NBMA Link that are All other serial interfaces and LANs
Most networks, EIGRP hello packets are sent every 5 seconds. On multipoint nonbroadcast multiaccess (NBMA) networks such as X.25, Frame Relay, and ATM interfaces with access links of T1 (1.544 Mbps) or slower, hellos are unicast every 60 seconds. An EIGRP router assumes that as long as it is receiving hello packets from a neighbor, the neighbor and its routes remain viable.

Hello Protocol Default hold time - 3 times the hello interval
NBMA Link that are All other serial interfaces and LANs Default hold time - 3 times the hello interval If the hold time expires: EIGRP declares the route as down DUAL searches for a new path in the topology table or by sending out queries. It is NOT automatically adjusted if Hello Interval is modified. Hold time - maximum time the router should wait to receive the next hello before declaring that neighbor as unreachable. Default hold time - 3 times the hello interval, 15 seconds on most networks 180 seconds on low-speed NBMA networks If the hold time expires: EIGRP declares the route as down DUAL searches for a new path in the topology table or by sending out queries. More later.

EIGRP Packet Types – Update and Acknowledgement Packets
EIGRP uses triggered updates Update Packets – Reliable Delivery Acknowledgment (ACK) Packets – Unreliable Delivery Sent when reliable delivery is used (update, query, and reply packets). Update Packets Contains only the routing information needed (a change occurs) Sent only to those routers that require it. Uses reliable delivery. Multicast when sent to multiple routers Unicast when sent to a single router Acknowledgment (ACK) Packets Sent when reliable delivery is used (update, query, and reply packets). Sent as an unreliable unicast. EIGRP uses the terms partial and bounded when referring to its update packets. EIGRP sends its updates only when the metric for a route changes. Partial - update only includes information about the route changes. Bounded - propagation of partial updates sent only to those routers that are affected by the change. This minimizes the bandwidth required to send EIGRP packets.

EIGRP Packet Types – Query and Reply Packets
Queries and replies use reliable delivery (Ack returned). Used by DUAL when searching for networks and other tasks. Used by DUAL when searching for networks and other tasks. Queries and replies use reliable delivery. To keep this example simple, acknowledgments were omitted in the graphic. All neighbors must send a reply regardless of whether they have a route to the downed network. Queries can use multicast or unicast, whereas replies are always sent as unicast. DUAL is discussed in a later section. Queries and replies packets are discussed in more detail in CCNP.

DUAL: An Introduction J. J. Garcia-Luna-Aceves
Diffusing Update Algorithm (DUAL) is the convergence algorithm used by EIGRP. First proposed by E. W. Dijkstra and C. S. Scholten. The most prominent work with DUAL has been done by J. J. Garcia-Luna-Aceves. Routing loops, even temporary ones, can be extremely detrimental to network performance. Distance vector routing protocols such as RIP prevent routing loops with hold-down timers and split horizon. Although EIGRP uses both of these techniques, it uses them somewhat differently; the primary way that EIGRP prevents routing loops is with the DUAL algorithm.

DUAL: An Introduction (More later!)
R2: Checks Topology table for Feasible Successor. If no FS… X Or holdtime expires 1. A directly connected network on R2 goes down. R2 sends an EIGRP update message to its neighbors indicating the network is down . 2. R1 and R3 return an EIGRP acknowledgment indicating that they have received the update from R2. 3. R2 does not have an EIGRP backup route known as a feasible successor. (more later.) So, R2 sends an EIGRP query to its neighbors asking them whether they have a route to this downed network. 4. R1 and R3 return an EIGRP acknowledgment indicating that they have received the query from R2 5. R1 and R3 send an EIGRP reply message in response to the query sent by R2. In this case, the reply would state that the router does not have a route to this network. 6. R2 returns an acknowledgment indicating that it received the reply. Diffusing Update Algorithm (DUAL) is the convergence algorithm used by EIGRP. First proposed by E. W. Dijkstra and C. S. Scholten. The most prominent work with DUAL has been done by J. J. Garcia-Luna-Aceves. Distance vector routing protocols such as RIP prevent routing loops with hold-down timers and split horizon. Although EIGRP uses both of these techniques, it uses them somewhat differently; the primary way that EIGRP prevents routing loops is with the DUAL algorithm. .

Summary - RTP Packet Types
Hellos – Identifies neighbors Used by the neighbor discovery and recovery process. Multicast Unreliable delivery Acknowledgements (ACK) – Acknowledges receipt Hello packets with no data Unicast Updates – Advertises routes Transmitted only when necessary Unicast when sent to a specific router Multicast when sent to multiple routers Reliable delivery Queries – Ask about a route (DUAL) Multicast or Unicast Queries and Replies – Ask about a route and answer a query (DUAL) Replies: Unicast

Administrative Distance
We will discuss Administrative Distance in more detail in a later chapter. Later in this chapter, you learn how to configure EIGRP summary routes. Routes manually summarized. When compared to other interior gateway protocols (IGP), EIGRP is the most preferred by the Cisco IOS software because it has the lowest AD. Later in this chapter, you learn how to configure EIGRP summary routes. Routes redistributed into EIGRP.

Neighbor Adjacencies and EIGRP Reliability

Configuring Hello Intervals and Hold Times
Router(config-if)# ip hello-interval eigrp as-number seconds Router(config-if)# ip hold-time eigrp as-number seconds Configurable on a per-interface basis, NOT per neighbor (LANs) Does not have to match with other EIGRP routers to establish adjacencies. Hello intervals and hold times are configurable on a per-interface basis and do not have to match with other EIGRP routers to establish adjacencies. We will see later, OSPF’s Hello and other timers do need to match. The seconds value for both hello and holdtime intervals can range from 1 to 65,535 If you change the hello interval, make sure that you also change the hold time to a value equal to or greater than the hello interval. Otherwise, neighbor adjacency will go down after the hold time expires and before the next hello interval.

Neighbor Table Contents
SRTT (Smooth Round Trip Timer) and RTO (Retransmit Interval) are used by RTP to manage reliable EIGRP packets. SRTT indicates how long it takes for this neighbor to respond to reliable packets. RTO indicates how long to wait before retransmitting if no ACK is received. R1# show ip eigrp neighbors IP-EIGRP neighbors for process 100 H Address Interface Hold Uptime SRTT RTO Q Seq (sec) (ms) Cnt Num Se0/0/ :07: R1# Neighbor’s IP address Queue count should always be zero otherwise there’s congestion on the link. The sequence number of the last update, query, or reply packet that was received from this neighbor. Amount of time since this neighbor was added to the neighbor table. Lists the order in which a peering session was established with the specified neighbor, starting with 0. H (handle)— Internal number used by the Cisco IOS. Order in which a neighboring (peering) session was established Starts with 0. Address—The neighbor’s IP address. Interface—The outgoing interface on this router receiving hello packets for the neighbor. Hold Time—The maximum time, in seconds, that the router waits to hear from the neighbor without receiving anything from a neighbor before considering the link unavailable. Originally, had to be a hello packet, but in current Cisco IOS any EIGRP packet received after the first hello from that neighbor resets the timer. Uptime—Time, in HH:MM:SS since the router first heard from this neighbor. Local interface receiving EIGRP Hello packets. Seconds remaining before declaring neighbor down. The current hold time and is reset to the maximum hold time whenever a Hello packet is received.

Start Neighbor Table Contents Stop Smooth Round Trip Timer (SRTT)—The average number of milliseconds it takes for an EIGRP packet to be sent to this neighbor and for the local router to receive an acknowledgment of that packet. Used to determine the retransmit interval, a.k.a. retransmit timeout (RTO). RTO—The amount of time, in milliseconds, that the router waits for an acknowledgment before retransmitting a reliable packet from the retransmission queue to a neighbor. Start Stop No ACK Returned

Start Stop EIGRP Reliability RTO—The amount of time, in milliseconds, that the router waits for an acknowledgment before retransmitting a reliable packet from the retransmission queue to a neighbor. Updates, queries and replies are sent reliably. A sequence number is assigned and an explicit ACK is returned for each sequence number. No ACK Returned 16 x RTO < Hold Timer If the RTO expires before and ACK is received, EIGRP retransmits another copy of the packet. A maximum of 16 times OR until the hold time expires then the Neighbor is declared down. When a neighbor is declared down: The adjacency is removed All networks reached through that neighbor are removed from the routing table. 180 second hold time on low-speed NBMA links can be a long time to wait. Retransmission occurs after each RTO timer expires. After 16 attempts the neighbor is declared down. This is less time than waiting for the hold time to expire.

EIGRP Reliability Update101 Update100 No ACK Received
(in queue) No ACK Received Multicast Flow Timer expires Potential problem on multiaccess (Frame Relay, Ethernet) media where multiple neighbors reside. The next reliable multicast packet cannot be sent until all peers have Acknowledged the previous multicast packet. If one or more neighbors are slow to respond it adversely affects all peers. When a neighbor is slow to respond to multicasts or does not acknowledge the multicast, the router will retransmit the packet as a unicast. This allows reliable multicasts to continue and speeds up convergence without waiting for peers on lower speed links. Multicast flow timer - Determines how long a router should wait for an ACK to be received before switching from multicast to unicast. Calculation is based on RTO and SRTT (Cisco proprietary) R3# 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 Se0/ / / Se0/ / / R3#

R3# show ip eigrp neighbors detail IP-EIGRP neighbors for process 1 H Address Interface Hold Uptime SRTT RTO Q Seq Type (sec) (ms) Cnt Num Se0/ :03: Version 12.3/1.2, Retrans: 2, Retries: 0 Se0/ :04: Version 12.3/1.2, Retrans: 1, Retries: 0 Se0/ :09: Version 12.3/1.2, Retrans: 0, Retries: 0 Se0/ :10: R3# The show ip eigrp interfaces detail command displays a router's EIGRP Hello timer setting for each enabled interface.

Initial Route Discovery
B Updated Updated EIGRP Neighbor Table EIGRP Neighbor Table Hello, I am Router A. Is anyone there? Hello, I am Router B. Updated Here is all my routing information. I’m using split horizon. Updated EIGRP Topology Table EIGRP Topology Table Thanks for the information! That is very nice of you. Successor Successor Here is all my routing information. I’m also using split horizon. Updated Updated IP Routing Table IP Routing Table Thanks for the information! We’ve reached convergence.

Example: EIGRP Tables Router C’s tables:
The network shown illustrates router C’s EIGRP tables. Routers A and B have established a neighbor relationship with router C. Both routers A and B have paths to network /24, among many others that are not shown. Router A has an EIGRP metric of 1000 for /24, so router A advertises /24 to router C with a metric of Router C installs the route to /24 via router A in its EIGRP topology table with an advertised distance of 1000. Router B has network /24 with a metric of 1500 in its IP routing table, so router B advertises /24 to router C with an advertised distance of Router C places the route to /24 network via router B in the EIGRP topology table with an advertised distance of 1500. Router C has two entries to reach /24 in its topology table. The EIGRP metric for router C to reach both routers A and B is This cost (1000) is added to the respective advertised distance from each router, resulting in the feasible distances from router C to reach network /24 shown in the figure. Router C chooses the least-cost feasible distance, which is 2000, via router A, and installs it in the IP routing table as the best route to reach /24. The EIGRP metric in the routing table is equal to the feasible distance from the EIGRP topology table. Router A is the successor for the route to /24.

Router-ID Router(config)# router eigrp as
Router(config-router)# router-id ip-address EIGRP Router ID is an IP address used to uniquely identify an EIGRP router. 1. Use the IP address configured with the EIGRP router-id command. 2. Highest IP address of any of its loopback interfaces. 3. Highest active IP address of any of its physical interfaces.

Forming Neighbor Adjacencies
The following are the most common causes of problems with EIGRP neighbor relationships: Unidirectional link Uncommon subnet, primary, and secondary address mismatch Mismatched masks K value mismatches Mismatched AS numbers Stuck in active Layer 2 problem Access list denying multicast packets Manual change (summary router, metric change, route filter) Does NOT prevent neighbor relationships Hello and Hold timer setting mismatch Duplicate router IDs IP MTU mismatch

The Metric

EIGRP Message

EIGRP Message - TLVs

TLV 0x0001 - EIGRP Parameters
K values are used to calculate the EIGRP metric. The Hold Time advertised by a neighbor is the maximum time a router should wait for any valid EIGRP message sent by that neighbor before declaring it dead.

TLV 0x0002 - Internal IP Routes
Delay: Sum of delays in units of 10 microseconds from source to destination. Bandwidth: Lowest configured bandwidth on any interface along the route. Prefix length: Specifies the number of network bits in the subnet mask. Destination: The destination address of the route.

TLV 0x0003 - External IP Routes
Fields used to track external source of route. Same fields contained in the Internal IP route TLV (0x0002). IP external routes are routes which are imported into EIGRP through redistribution of a default route or other routing protocols.

Metric By default, K1 and K3 are set to 1, and K2, K4, and K5 are set to 0. The result is that only the bandwidth and delay values are used in the computation of the default composite metric. Reliability and Load are optional metrics. MTU is NOT a metric, never has been, never will be.

Metric The K values on R1 are set to the default.
R1# show ip protocols Routing Protocol is “eigrp 1” Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0 <output omitted> K1 K2 K3 K4 K5 The K values on R1 are set to the default. Changing these values to other than the default is not recommended unless the network administrator has a very good reason to do so. Cisco recommends that these values are not modified.

Metric: Displaying Interface Values
SanJose2> show interface s0/0 Serial0/0 is up, line protocol is up Hardware is QUICC Serial Description: Out to Westasman Internet address is /30 MTU 1500 bytes, BW 1544 Kbit, DLY usec, rely 255/255, load 246/255 <output omitted> EIGRP bandwidth uses the minimum bandwidth link represented in 107 divided by the kilobits per second. Show interfaces displays bandwidth in kilobits per second. EIGRP delay value is the sum of delays in tens of microseconds multiplied by 256. Show interfaces displays delay in microseconds.

Metric Calculation For a review and examples of how the EIGRP metric is calculate read Chapter 2 EIGRP, “EIGRP Metric Calculation” or review my CIS 82 PowerPoint presentations on EIGRP.

IP EIGRP Neighbor Table IP EIGRP Topology Table
EIGRP Operations EIGRP selects primary (successor) and backup (feasible successor) routes and injects those into the topology table. The primary (successor) routes are then moved to the routing table. IP EIGRP Neighbor Table Neighbor IP Address Local router exit interface to neighbor List of directly connected adjacent EIGRP neighbor routers and the local interface to exit to reach it. IP EIGRP Topology Table Destination 1 FD / AD via each neighbor List of all routes learned from each EIGRP neighbor and identifies successor routes and feasible successor routes. When a router discovers a new neighbor, an update is sent to and received from its new neighbor populating the topology table (containing destinations advertised by all neighbors) The topology table: Updated when a directly connected route or interface changes or when a neighboring router reports a change to a route Entry for a destination exists in either active or passive state: Passive state: router is not performing a recomputation Active state: router is performing a recomputation Recomputation occurs when the destination has no feasible successors (initiated by sending a query packet to each of the neighboring routers IP Routing Table Destination 1 Best route List of the best (successor) routes from the EIGRP topology table and other routing processes.

Example: EIGRP Tables The network shown illustrates router C’s EIGRP tables. Routers A and B have established a neighbor relationship with router C. Both routers A and B have paths to network /24, among many others that are not shown. Router A has an EIGRP metric of 1000 for /24, so router A advertises /24 to router C with a metric of Router C installs the route to /24 via router A in its EIGRP topology table with an advertised distance of 1000. Router B has network /24 with a metric of 1500 in its IP routing table, so router B advertises /24 to router C with an advertised distance of Router C places the route to /24 network via router B in the EIGRP topology table with an advertised distance of 1500. Router C has two entries to reach /24 in its topology table. The EIGRP metric for router C to reach both routers A and B is This cost (1000) is added to the respective advertised distance from each router, resulting in the feasible distances from router C to reach network /24 shown in the figure. Router C chooses the least-cost feasible distance, which is 2000, via router A, and installs it in the IP routing table as the best route to reach /24. The EIGRP metric in the routing table is equal to the feasible distance from the EIGRP topology table. Router A is the successor for the route to /24.

DUAL Concepts Diffusing Update Algorithm is the algorithm used by EIGRP. Determines: best loop-free path loop-free backup paths (which can be used immediately) DUAL also provides the following: Fast convergence Minimum bandwidth usage with bounded updates DUAL uses several terms that are discussed in more detail throughout this section: Successor Feasible distance Feasible successor Reported distance or advertised distance Feasible condition or feasibility condition

Successors and Feasible Successors
Feasible distance (FD) is the minimum distance (metric) along a path to a destination network. Reported distance (RD or AD) is the distance (metric) towards a destination as advertised by an upstream neighbor. Reported distance is the distance reported in the queries, the replies and the updates. A neighbor meets the feasible condition (FC) if the reported distance by the neighbor is less than the current feasible distance (FD) of this router. "If a neighbors metric is less than mine, then I know the neighbor doesn't have a loop going through me." A feasible successor is a neighbor whose reported distance (RD) is less than the current feasible distance (FD). Feasible successor is one who meets the feasible condition (FC). Your route (metric) to the network (RD to me) must be LESS than my current route (my total metric) to that same network. If your route (metric) to the network (RD to me) is LESS than my current route (my total metric), I will include you as a FEASIBLE SUCCESSOR. If your route (metric) to the network (RD to me) is MORE than my current route (my total metric), I will NOT include you as a FEASIBLE SUCCESSOR.

Example 1: Best Path (Successor)? Feasible Successor?
RD = 6,000,000 Which router is the successor? R2 FD = 6,500,000 Network X S0/0 R1 S0/1 FD = 3,500,000 R3 RD = 3,000,000 FD = RD + additional Delay of serial link between R1 and neighbor. (This could also be due the slowest bandwidth.)

Example 1 Successor Is R2 a feasible successor?
RD = 6,000,000 Is R2 a feasible successor? R2 FD = 6,500,000 Network X S0/0 R1 S0/1 FD = 3,500,000 Successor R3 RD = 3,000,000 FD of 3,500,000 is the metric for network X in the routing table for R1.

NOT a Feasible Successor
Example 1 NOT a Feasible Successor RD = 6,000,000 R2 FD = 6,500,000 Network X S0/0 R1 S0/1 FD = 3,500,000 Successor R3 RD = 3,000,000 RD of R2 is greater than FD through R3. Does not meet FC. No FS.

Example 1 RX NOT a Feasible Successor RD = 6,000,000 R2 Network X S0/0 R1 S0/1 Successor R3 RD = 3,000,000 Maybe R2’s path to Network X includes R1 - Loop

Example 1 NOT a Feasible Successor RD = 6,000,000 R2 Network X RX S0/0 R1 S0/1 Successor R3 RD = 3,000,000 Or maybe R2’s does have a valid path to Network X. But R1 can’t tell because the distance vector update only gives it distance and direction.

Example 2: Best Path (Successor)? Feasible Successor?
RD = 4,000,000 R2 FD = 5,500,000 Network X S0/0 R1 S0/1 FD = 4,500,000 Successor R3 RD = 3,000,000 FD = RD + additional Delay of serial link between R1 and neighbor. (This could also be due the slowest bandwidth.)

Example 2 Feasible Successor Successor
RD = 4,000,000 R2 FD = 5,500,000 Network X S0/0 R1 S0/1 FD = 4,500,000 Successor R3 RD = 3,000,000 RD of R2 is less than (or equal to) the FD through R3. Meets FC, there is no loop back through R1. Is a FS.

Query and Reply Packets
RtrD Queries RtrB Replies RtrE RtrA X RtrF RtrC RtrG Looking for new route If there are no Feasible Successors, the router must ask neighbors for help in hope of finding a new, loop-free path to the destination. Neighbor routers are compelled to reply to this query. If a neighbor has a route, it will reply with information about the successor(s). If not, the neighbor notifies the sender that it doesn’t have a route to the destination either.

Step 1 /24 A (1) (1) B D (2) (2) (1) C E (1) The topology

X Successor Feasible Successor (AD is less than FD) Step 2 A B D C E
/24 A (1) X (1) B D (2) (2) (1) C E (1) Successor Feasible Successor (AD is less than FD)

Step 3 /24 A Unusable (1) Successor still via Router A Unreachable B D Q (2) (2) (1) Successor still via Router B C E (1) Unusable Router D: Sets the metric to network /24 as unreachable (–1 is unreachable). No FS (Feasible Successor) in the topology table, so the route changes from the passive state to the Active state. Active state: Router sends out queries to neighboring routers looking for a new successor. Sends a query to Routers C and E for an alternative path to network /24. Marks Routers C and E as having a query pending (q). Router E: DUAL marks the path to network /24 through Router D as Unusable. Router C: DUAL marks the path to network /24 through Router D as Unusable.

Step 4 /24 A Unusable (1) Successor still via Router A B D (2) (2) (1) R Successor still via Router B C Q E (1) Unusable Router D: DUAL receives a reply from Router C indicating no change to the path to /24 DUAL removes the query pending flag from Router C. DUAL stays Active on network /24, awaiting a reply from Router E to its query (q). Router E: there is no FS to network /24, because the AD from Router C (3) is not less than the original FD (also 3). DUAL generates a query to Router C. DUAL marks Router C as query pending (q). Router C: DUAL marks the path to network /24 through Router E as Unusable.

Step 5 /24 A (1) Successor still via Router A B D (2) (2) (1) Converged Successor still via Router B C E R (1) Router D: DUAL stays active on network /24, awaiting a reply from Router E (q). Router E: DUAL receives a reply from Router C indicating no change. It removes the query flag from Router C. It calculates a new FD and installs a new successor route in the topology table. It changes the route to network /24 from Active to Passive (converged).

Step 6 R Router D: DUAL receives a reply from Router E.
/24 A (1) Converged Successor still via Router A B D (2) (2) (1) Converged R Successor still via Router B C E (1) Router D: DUAL receives a reply from Router E. It removes the query flag from Router E. It calculates a new FD. It installs new successor routes in the topology table. Two routes (through Routers C and E) have the same FD, and both are marked as successors. It changes the route to network /24 from Active to Passive (converged).

Step 7 /24 A (1) Successor still via Router A B D (2) (2) (1) Successor still via Router B C E (1) Router D: Two successor routes are in the topology table for network /24. Both successor routes are listed in the routing table, and equal-cost load balancing is in effect. The network is stable and converged. Successor No Feasible Successors

Basic EIGRP Configuration

Our Topology

Preconfigs Configured on all routers. R1(config)# no ip domain lookup
R1(config)# line con 0 R1(config-line)# exec-timeout 0 0 R1(config-line)# logging synchronous Configured on all routers.

R1 interface FastEthernet0/0 ip address ! interface Serial0/0 bandwidth 1544 ip address clock rate 64000 interface Serial0/1 ip address Bandwidth of 1,424 Kbps (1,424,000 bps) between R3 and R4 on bottom link 1544 configured on all serial links just in case.

R2 interface FastEthernet0/0 ip address 192.168.20.1 255.255.255.0 !
interface Serial0/0 bandwidth 1544 ip address interface Serial0/1 ip address clock rate 64000

interface Serial0/0 bandwidth 1544 ip address clockrate 64000 interface Serial0/1 ip address interface Serial0/2 ip address interface Serial0/3 bandwidth 1424 ip address

interface Serial0/0 bandwidth 1544 ip address interface FastEthernet0/1 ip address interface Serial0/1 bandwidth 1424 ip address

Configuring EIGRP – R1 R1(config)# router eigrp 1 R1(config-router)# network R1(config-router)# network R1(config-router)# network Wildcard masks – Specifically tells EIGRP which interfaces to be enabled on. If subnet mask is used IOS may convert it for the running-config. Let’s do R2, R3 and R4 serial interfaces with wildcard masks…

Configuring EIGRP R2(config)# router eigrp 1
R2(config-router)# network R2(config-router)# network R2(config-router)# network R3(config)# router eigrp 1 R3(config-router)# network R3(config-router)# network R3(config-router)# network R3(config-router)# network R3(config-router)# network R4(config)# router eigrp 1 R4(config-router)# network R4(config-router)# network R4(config-router)# network

Outputs Why does R3 prefer the top link to 172.16.0.0?
R3# show ip route C /24 is directly connected, FastEthernet0/0 D /24 [90/ ] via , 00:02:47, Serial0/0 D /16 [90/ ] via , 00:02:39, Serial0/2 D /24 [90/ ] via , 00:17:22, Serial0/1 /30 is subnetted, 5 subnets C is directly connected, Serial0/1 C is directly connected, Serial0/2 D [90/ ] via , 00:02:57, Serial0/0 [90/ ] via , 00:02:57, Serial0/1 C is directly connected, Serial0/0 C is directly connected, Serial0/3 Why does R3 prefer the top link to ? It is 1,544 kbps link compared to 1,424 kbps link below What do you notice about the network? How many paths? R3 has equal cost paths to /30

Outputs Does R3 see R4 as a neighbor on both links? Yes
R3# show ip eigrp neighbors IP-EIGRP neighbors for process 1 H Address Interface Hold Uptime SRTT RTO Q Seq Type (sec) (ms) Cnt Num Se0/ :17: Se0/ :17: Se0/ :23: Se0/ :24: R3# Does R3 see R4 as a neighbor on both links? Yes

Outputs Some other commands… R3# show ip eigrp neighbors detail
IP-EIGRP neighbors for process 1 H Address Interface Hold Uptime SRTT RTO Q Seq Type (sec) (ms) Cnt Num Se0/ :03: Version 12.3/1.2, Retrans: 2, Retries: 0 Se0/ :04: Version 12.3/1.2, Retrans: 1, Retries: 0 Se0/ :09: Version 12.3/1.2, Retrans: 0, Retries: 0 Se0/ :10: R3# Some other commands…

Outputs R3# 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 Se0/ / / Se0/ / / Se0/ / / Se0/ / / R3#

What are these telling us?
R3# show ip protocols Routing Protocol is "eigrp 1" Outgoing update filter list for all interfaces is not set Incoming update filter list for all interfaces is not set Default networks flagged in outgoing updates Default networks accepted from incoming updates EIGRP metric weight K1=1, K2=0, K3=1, K4=0, K5=0 EIGRP maximum hopcount 100 EIGRP maximum metric variance 1 Redistributing: eigrp 1 Automatic network summarization is in effect Maximum path: 4 Routing for Networks: /30 /30 /30 /30 Routing Information Sources: Gateway Distance Last Update :03:03 :03:03 :03:11 :03:03 Distance: internal 90 external 170 What are these telling us? K values Variance, later Directly connected networks Neighbors

Feasible distance: if this router was the successor.
Outputs R3# show ip eigrp topology <output omitted> P /30, 2 successors, FD is via ( / ), Serial0/1 via ( / ), Serial0/0 P /16, 1 successors, FD is via ( /28160), Serial0/2 via ( /28160), Serial0/3 Reported Distance is less than Feasible distance Feasible distance successor feasible successor Feasible distance: if this router was the successor.

Outputs Why does R3 show a third entry for 10.0.0.0/30?
R3# show ip eigrp topology all-links P /30, 2 successors, FD is , serno 13 via ( / ), Serial0/1 via ( / ), Serial0/0 via ( / ), Serial0/3 successor successor non-feasible successor Why does R3 show a third entry for /30? Why is R4 a non-feasible successor? Reported distance > Feasible distance There is a loop via the lower (1424kps) link!!!

Passive Interfaces

Passive Interfaces Two ways to prevent EIGRP from speaking sending EIGRP messages on an interface. 1. Enable EIGRP on the interface using the EIGRP network command and use the the passive-interface command. Does NOT send any EIGRP messages on the interface. No Hellos, thus no neighbor adjacency Prefix (interface subnet) is still advertised on other interfaces 2. Do NOT enable EIGRP on the interface, Advertise about the connected route using route redistribution using the redistribute connected configuration command. More complicated Less popular

Passive Interfaces R1# show ip eigrp inter IP-EIGRP interfaces for process 1 Xmit Queue Mean Pacing Time Multicast Pending Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes Se0/ / / Se0/ / / Fa0/ / / The show ip eigrp interfaces command displays working interfaces on which EIGRP has been enabled, but omits passive interfaces. A failure of the interface, or making the interface passive, would omit the interface from the output of this command.

Passive Interfaces No longer a neighbor. Must include network command.
R1(config)# router eigrp 1 R1(config-router)# passive-interface fa 0/0 R1# show ip eigrp inter IP-EIGRP interfaces for process 1 Xmit Queue Mean Pacing Time Multicast Pending Interface Peers Un/Reliable SRTT Un/Reliable Flow Timer Routes Se0/ / / Se0/ / / R1# R1(config-router)# network No longer a neighbor. Must include network command.

Passive Interfaces Verifying R1# show ip protocols
<output omitted> Routing for Networks: /30 /30 Passive Interface(s): FastEthernet0/0 Verifying

Passive Interfaces R4(config)# router eigrp 1
R4(config-router)# passive-interface default R4(config-router)# no passive-interface ser 0/0 R4(config-router)# no passive-interface ser 0/1 R4# show ip protocols <output omitted> Routing for Networks: /30 /30 Passive Interface(s): FastEthernet0/0 FastEthernet0/1

Summarization

Summarization Benefits: Smaller routing tables Reduces Query scope:
EIGRP Query stops at a router which has a summary route that includes the subnet listed in the Query, but not the specific route listed in the Query EIGRP supports summarization on any router in the network Trade-offs: Can cause suboptimal routing Packets destined for inaccessible destinations will flow to the summarizing router before being discarded Note: If a packet matches two routes in the routing table, the best match will be the route with the longest-bit-match, the route with the longer prefix-length (subnet mask).

EIGRP Summarization – Odds and Ends
Any EIGRP router can summarize routes. OSPF: Summarization can only take place on the ABRs and ASBRs. The summary route's metric is based on the lowest metric route upon which the summary route is based. The summary route will use a metric equal to the metric of the lowest metric subordinate route. Manual summarization creates a Null0 summary on the router doing the summarization. R3(config)# interface serial 0/0/1 R3(config-if)# ip summary-address eigrp R3# show ip route <output omitted> D /22 is a summary, 00:00:06, Null0 Creates a Null0 summary route

The Null0 Summary Route R1# show ip route /24 is variably subnetted, 3 subnets, 2 masks D /24 is a summary, 00:45:09, Null0 C /30 is directly connected, Serial0/0/1 D /30 [90/ ] via , 00:44:56, S0/0/1 /16 is variably subnetted, 4 subnets, 3 masks D /16 is a summary, 00:46:10, Null0 C /24 is directly connected, FastEthernet0/0 D /24 [90/ ] via , 00:45:09, S0/0/0 C /30 is directly connected, Serial0/0/0 D /24 [90/ ] via , 00:44:55, Serial0/0/1 EIGRP automatically includes a Null0 summary route as a child route whenever both of the following conditions exist: There is at least one subnet that was learned via EIGRP. Automatic summarization is enabled. (By default with EIGRP) What if R1 received a packet: It would be discarded – never looking for a supernet or default route Regardless of ip classless or no ip classless command Helps prevent any routing loops between the edge and ISP routers. EIGRP automatically includes a Null0 summary route as a child route whenever both of the following conditions exist: There is at least one subnet that was learned via EIGRP. Automatic summarization is enabled. (By default with EIGRP) R1 will discard any packets that match the parent /16 classful network but do not match one of the child routes /24, /24, or /24. For example, a packet to would be discarded. This Null0 summary route is a child route that will match any possible packets of the parent route that do not match another child route. This is regardless of ip classless or no ip classless command. Therefore denying the use of any supernet or default route.

Disabling Automatic Summarization
/16 R3# show ip route /24 is variably subnetted, 3 subnets, 2 masks D /24 is a summary, 01:08:35, Null0 C /30 is directly connected, Serial0/0/0 C /30 is directly connected, Serial0/0/1 D /16 [90/ ] via , 01:08:30, Serial0/0/0 C /24 is directly connected, FastEthernet0/0 Like RIP, EIGRP automatically summarizes at major network boundaries using the default auto-summary command. Like RIP, EIGRP automatically summarizes at major network boundaries using the default auto-summary command.

/16 /16 R3# show ip route /24 is variably subnetted, 3 subnets, 2 masks D /24 is a summary, 01:08:35, Null0 C /30 is directly connected, Serial0/0/0 C /30 is directly connected, Serial0/0/1 D /16 [90/ ] via , 01:08:30, Serial0/0/0 C /24 is directly connected, FastEthernet0/0 Both R1 and R2 automatically summarized those subnets to the /16 classful boundary when sending EIGRP update packets to R3. The result is that R3 has one route to /16 through R1. R1 is the successor because of the difference in bandwidth. Both R1 and R2 automatically summarizing. R1 is the successor because of the difference in bandwidth.

/16 R3# show ip route <output omitted> D /16 [90/ ] via , 01:08:30, Serial0/0/0 Is this the best route for all subnets? No, suboptimal routing may occur. R3 will route all packets destined for through R1. Solution? Need R1 and R2 to send individual subnets. R1 and R2 must stop automatically summarizing /16. You can quickly see that this route is not optimal. R3 will route all packets destined for through R1. Across a very slow link to R2 (64 Kbps). Need R1 and R2 to send individual routes for each of the /16 subnets. In other words, R1 and R2 must stop automatically summarizing /16.

R1(config)# router eigrp 1 R1(config-router)# no auto-summary %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor (Serial0/0/0) is resync: summary configured %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor (Serial0/0/0) is down: peer restarted %DUAL-5-NBRCHANGE: IP-EIGRP(0) 1: Neighbor (Serial0/0/0) is up: new adjacency <output omitted> R2(config)# router eigrp 1 R2(config-router)# no auto-summary R3(config)# router eigrp 1 R3(config-router)# no auto-summary Automatic summarization can be disabled with the no auto-summary. The router configuration command eigrp log-neighborchanges is on by default on some IOS implementations. If on, you will see output similar to that shown for R1. Automatic summarization can be disabled with the no auto-summary. The router configuration command eigrp log-neighborchanges is on by default on some IOS implementations. .

R1# show ip route /30 is subnetted, 2 subnets C is directly connected, Serial0/0/1 D [90/ ] via , 00:16:55, S0/0/1 /16 is variably subnetted, 3 subnets, 2 masks C /24 is directly connected, FastEthernet0/0 D /24 [90/ ] via , 00:16:53, S0/0/1 C /30 is directly connected, Serial0/0/0 D /24 [90/ ] via , 00:16:52, Serial0/0/1 R1 no more Null0 summary routes: D /24 is a summary, 00:45:09, Null0 D /16 is a summary, 00:46:10, Null0 What does this mean? This means any packets for their parent networks that do not match a child route, the routing table will check supernet and default routes. Unless no ip classess is used R1 no more Null0 summary routes: D /24 is a summary, 00:45:09, Null0 D /16 is a summary, 00:46:10, Null0 This mean any packets for their parent networks that do not match a child route, the routing table will check supernet and default routes. Unless no ip classess is used

R2# show ip route /30 is subnetted, 2 subnets D [90/ ] via , 00:15:44, S0/0/1 C is directly connected, Serial0/0/1 /16 is variably subnetted, 3 subnets, 2 masks D /24 [90/ ] via , 00:15:44, S0/0/1 C /24 is directly connected, FastEthernet0/0 C /30 is directly connected, Serial0/0/0 /30 is subnetted, 1 subnets C is directly connected, Loopback1 D /24 [90/ ] via , 00:15:44, S0/0/1 R2 no more Null0 summary routes : D /24 is a summary, 00:00:15, Null0 D /16 is a summary, 00:00:15, Null0 R2 no more Null0 summary routes : D /24 is a summary, 00:00:15, Null0 D /16 is a summary, 00:00:15, Null0

Shouldn’t the best path only be through R1 with the 1544-Mbps link?
/16 R3# show ip route /30 is subnetted, 2 subnets C is directly connected, Serial0/0/0 C is directly connected, Serial0/0/1 /16 is variably subnetted, 3 subnets, 2 masks D /24 [90/ ] via , 00:00:11, S0/0/0 D /24 [90/ ] via , 00:00:12, S0/0/1 D /30 [90/ ] via , 00:00:12, S0/0/0 [90/ ] via , 00:00:12, S0/0/1 C /24 is directly connected, FastEthernet0/0 /16 Without automatic summarization, R3’s routing table now includes the three subnets: /24, /24, and /24. Why does R3’s routing table now have two equal-cost paths to /24? Shouldn’t the best path only be through R1 with the 1544-Mbps link? Why does R3’s routing table now have two equal-cost paths to /24? Shouldn’t the best path only be through R1 with the 1544-Mbps link?

/16 /16 R3# show ip route <output omitted> D /30 [90/ ] via , 00:00:12, S0/0/0 [90/ ] via , 00:00:12, S0/0/1 The slowest link is the 64-Kbps link that contains the /30 network. The 1544-Mbps link and the 1024-Kbps link are irrelevant in the calculation as far as the bandwidth metric is concerned. The slowest link is the 64-Kbps link

Manual Summarization EIGRP can be configured to summarize routes, whether or not automatic summarization (auto-summary) is enabled. Modified topology. EIGRP can be configured to summarize routes, whether or not automatic summarization (auto-summary) is enabled. Modified topology.

Manual Summarization Add two more networks to R3.
R3(config)# interface loopback 2 R3(config-if)# ip address R3(config-if)# interface loopback 3 R3(config-if)# ip address R3(config-if)# router eigrp 1 R3(config-router)# network R3(config-router)# network Add two more networks to R3. With the appropriate network commands R3 will propagate these networks to other routers. Add two more networks to R3. Configure EIGRP network statements.

Manual Summarization /24, /24, /24 /24, /24, /24 Only pertinent routes shown R1# show ip route D /24 [90/ ] via , 02:07:38, S0/0/1 D /24 [90/ ] via , 00:00:34, S0/0/1 D /24 [90/ ] via , 00:00:18, S0/0/1 R2# show ip route D /24 [90/ ] via , 02:08:50, S0/0/1 D /24 [90/ ] via , 00:01:46, S0/0/1 D /24 [90/ ] via , 00:01:30, S0/0/1 R1 and R2 routing tables show these additional networks in their routing tables. Instead of sending three separate networks, R3 can summarize the /24, /24, and /24 networks as a single route. Instead of sending three separate networks, R3 can summarize the /24, /24, and /24 networks as a single route.

Determining the Summary EIGRP Route
1. Write out the networks that you want to summarize in binary. 2. Find the matching bits. Count the number of leftmost matching bits, which in this example is 22. This number becomes your subnet mask for the summarized route: /22 or 3. To find the network address for summarization, copy the matching 22 bits and add all 0 bits to the end to make 32 bits. The result is the summary network address and mask for /22 1. Write out the networks that you want to summarize in binary. 2. Find the matching bits. Count the number of leftmost matching bits, which in this example is 22. This number becomes your subnet mask for the summarized route: /22 or 3. To find the network address for summarization, copy the matching 22 bits and add all 0 bits to the end to make 32 bits. The result is the summary network address and mask for /22

Configure EIGRP Manual Summarization
/22 /22 Router(config-if)# ip summary-address eigrp as-number network-address subnet-mask R3(config)# interface serial 0/0/0 R3(config-if)# ip summary-address eigrp R3(config)# interface serial 0/0/1 Because R3 has two EIGRP neighbors, the EIGRP manual summarization in configured on both Serial 0/0/0 and Serial 0/0/1. R3# show ip route <output omitted> D /22 is a summary, 00:00:06, Null0 Creates a Null0 summary route Because R3 has two EIGRP neighbors, the EIGRP manual summarization in configured on both Serial 0/0/0 and Serial 0/0/1.

Verify EIGRP Manual Summarization
/22 /22 R1# show ip route <output omitted> D /22 [90/ ] via , 00:01:11, Serial0/0/1 R2# show ip route D /22 [90/ ] via , 00:00:23, Serial0/0/1 Summary routes lessen the number of total routes in routing tables, which makes the routing table lookup process more efficient. Summary routes also require less bandwidth utilization for the routing updates because a single route can be sent rather than multiple individual routes. Fewer number of total routes in routing tables Faster routing table lookup process more efficient. Summary routes also require less bandwidth and memory Single route can be sent rather than multiple individual routes. NOTE: The minimum metric of specified routes is used as the metric of the summary route.

Default Route

Redistribute default static route in EIGRP updates
EIGRP Default Route Default Route The ISP router in our topology does not physically exist. By using a loopback interface, we can simulate a connection to another router. R2(config)# ip route loopback 1 R2(config)# router eigrp 1 R2(config-router)# redistribute static Using a static route to /0 as a default route is not routing protocol dependent. The “quad zero” static default route can be used with any currently supported routing protocols. EIGRP requires the use of the redistribute static command to include this static default route with its EIGRP routing updates. Unlike RIP and OSPF, EIGRP does not propagate a by default. Two ways to propagate a static default route in EIGRP: Redistribute static Network command redistribute static will redistribute all static routes by default.

Redistribute default static route in EIGRP updates
EIGRP Default Route Default Route Only static default route shown, other output omitted. R1# show ip route Gateway of last resort is to network D*EX /0 [170/ ] via , 00:02:14, S0/0/1 D: This static route was learned from an EIGRP routing update. *: The route is a candidate for a default route. EX: The route is an external EIGRP route, in this case a static route outside of the EIGRP routing domain. 170: This is the AD of an external EIGRP route. In the routing tables for R1 and R3, notice the routing source and AD for the new static default route. D: This static route was learned from an EIGRP routing update. *: The route is a candidate for a default route. EX: The route is an external EIGRP route, in this case a static route outside of the EIGRP routing domain. 170: This is the AD of an external EIGRP route.

EIGRP Default Route Default Route R2(config)# ip route loopback 1 R2(config)# router eigrp 1 R2(config-router)# network Using a static route to /0 as a default route is not routing protocol dependent. The “quad zero” static default route can be used with any currently supported routing protocols. EIGRP requires the use of the redistribute static command to include this static default route with its EIGRP routing updates. The network command will propagate a default route as a result of the static default route.

EIGRP Default-network
Redistribute default static route in EIGRP updates Default Route There is another method to propagate a default route in EIGRP, using the ip default-network command. More information on this command can be found at this site: There is another method to propagate a default route in EIGRP, using the ip default-network command.

EIGRP Default- network
R2(config)# ip default-network R2(config)# router eigrp 1 R2(config-router)# network R2(config-router)# network R2(config-router)# network Using a static route to /0 as a default route is not routing protocol dependent. The “quad zero” static default route can be used with any currently supported routing protocols. EIGRP requires the use of the redistribute static command to include this static default route with its EIGRP routing updates. ip default-network network-number network-number - Network of last-resort gateway that will be announced to all other routers. R2’s routing table: will be shown as the “gateway of last resort” This network is propagated in EIGRP as a “gateway of last resort” If a subnet is specified IOS will install a static route in the running-config

A few commands…

show ip eigrp traffic R1# show ip eigrp traffic IP-EIGRP Traffic Statistics for AS 100 Hellos sent/received: 338/166 Updates sent/received: 7/7 Queries sent/received: 0/0 Replies sent/received: 0/0 Acks sent/received: 2/2 SIA-Queries sent/received: 0/0 SIA-Replies sent/received: 0/0 Hello Process ID: 228 PDM Process ID: 226 IP Socket queue: 0/2000/1/0 (current/max/highest/drops) Eigrp input queue: 0/2000/1/0 (current/max/highest/drops) R1# Displays the number of various EIGRP packets sent and received

debug ip eigrp traffic Displays the types of EIGRP packets sent and received by the router on which this command is executed. See example in Chapter 2 for a detailed explanation of this output. R2# debug eigrp packets *Jul 26 10:51:24.051: EIGRP: Sending HELLO on Serial0/0/0 *Jul 26 10:51:24.051: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 *Jul 26 10:51:24.111: EIGRP: Sending HELLO on FastEthernet0/0 *Jul 26 10:51:24.111: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 *Jul 26 10:51:26.667: EIGRP: Received HELLO on Serial0/0/0 nbr *Jul 26 10:51:26.667: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/re ly 0/0 *Jul 26 10:51:28.451: EIGRP: Sending HELLO on FastEthernet0/0 *Jul 26 10:51:28.451: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 *Jul 26 10:51:29.027: EIGRP: Sending HELLO on Serial0/0/0 *Jul 26 10:51:29.027: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 *Jul 26 10:51:31.383: EIGRP: Received HELLO on Serial0/0/0 nbr *Jul 26 10:51:31.383: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/re *Jul 26 10:51:33.339: EIGRP: Sending HELLO on FastEthernet0/0 *Jul 26 10:51:33.339: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 *Jul 26 10:51:33.511: EIGRP: Sending HELLO on Serial0/0/0 *Jul 26 10:51:33.511: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 *Jul 26 10:51:36.347: EIGRP: Received HELLO on Serial0/0/0 nbr *Jul 26 10:51:36.347: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 peerQ un/re *Jul 26 10:51:37.847: EIGRP: Sending HELLO on Serial0/0/0 *Jul 26 10:51:37.847: AS 100, Flags 0x0, Seq 0/0 idbQ 0/0 iidbQ un/rely 0/0 *Jul 26 10:51:37.899: EIGRP: Sending HELLO on FastEthernet0/0

debug ip eigrp Displays general debugging information.
See example in Chapter 2 for a detailed explanation of this output.

That’s all for tonight, good night!

CIS 185 CCNP ROUTE EIGRP Part 1
Rick Graziani Cabrillo College Last Updated: Fall 2010

CIS 185 CCNP ROUTE EIGRP Part 1

Similar presentations

Presentation on theme: "CIS 185 CCNP ROUTE EIGRP Part 1"— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

CIS 185 CCNP ROUTE EIGRP Part 1

Similar presentations

Presentation on theme: "CIS 185 CCNP ROUTE EIGRP Part 1"— Presentation transcript:

Similar presentations

About project

Feedback