Verifying Eigrp Operation

This section describes how to verity EIGRP operation.

Verifying EIGRP Operation

show ¡p eigrp neighbors • Displays the neighbors router# discovered by IP EIGRP

show ip eigrp topology • Displays the IP EIGRP topology table router#

show ip route eigrp • Displays current EIGRP entries - in the routing table router#

show ip protocols • Displays the parameters and

- current state of the active router# routing protocol process show ip eigrp traffic • Displays the number of IP EIGRP

packets sent and received

002, CiscoSystems, Inc. All rights reserved. Cisco CCIE Prep v1.0—Module 6-63

The show commands can be used to verify EIGRP operation.

Table 5-1: show Commands

Command

Description

show ip eigrp neighbors

Displays neighbors discovered by EIGRP

show ip eigrp topology

Displays the EIGRP topology table. This command shows the topology table, the active or passive state of routes, the number of successors, and the FD to the destination.

show ip route eigrp

Displays the current EIGRP entries in the routing table

show ip protocols

Displays the parameters and current state of the active routing protocol process. This command shows the EIGRP AS number. It also displays filtering and redistribution numbers, as well as neighbors and distance information.

show ip eigrp traffic

Displays the number of EIGRP packets sent and received. This command displays statistics on hello, updates, queries, replies, and acknowledgments.

Verifying EIGRP Operation (Cont.)

router#

debug eigrp packets

• Displays all types of EIGRP packets, both sent and received

router#

debug eigrp neighbors

• Displays the EIGRP neighbor

router#

interaction

debug ip eigrp

• Displays advertisements and changes EIGRP makes to the routing table

router#

debug ip eigrp summary

• Displays a brief report of the EIGRP routing activity

© 2002, CiscoSystems, Inc. All rights reserved.

Cisco CCIE Prep v1.0—Module 6-64

These debug commands can be used to verify EIGRP operation.

Table 5-2: debug Commands

Command

Description

debug eigrp packets

Displays the types of EIGRP packets sent and received. A maximum of 11 packet types can be selected for individual or group display.

debug eigrp neighbors

Displays the neighbors discovered by EIGRP and the contents of the hello packets

debug ip eigrp

Displays EIGRP packets that are sent and received

debug ip eigrp summary

Displays a summarized version of EIGRP activity. It also displays filtering and redistribution numbers, as well as neighbors and distance information.

show ip eigrp neighbors Command

This can be one of the most useful commands when verifying the operational status of EIGRP. The show ip eigrp neighbors command will show the status of all EIGRP neighbors. The neighbor should be "up" for as long as EIGRP has been running on the link. EIGRP will form a neighbor with all routers on the same subnet, and in the same AS. EIGRP will not form a neighbor with mismatched k values; but a neighbor can be formed with mismatched hellos and dead timers. A neighbor with a short uptime is a clear indication of a problem. Another important field is the queue count. This field indicates the number of packets waiting to be transmitted to that neighbor. This value should be 0 or a number under 20. Consistent Q values in the range of 60 or greater are considered high. A high Smooth Round Trip Timer (SRTT) number can mean the packet is experiencing some type of delay on the link.

Rl# show ip eigrp neighbors

IP-EIGRP neighbors for process 2001

H Address

Interface Hold Uptime (sec)

SRTT RTO Q Seq

Cnt Num

SeO.l

136 05:48:23 36 1302 0 15

Se0.1

131 05:48:24 40 1302 0 17

■ Handle (H): A Cisco IOS internal number used to identify a neighbor. Do not confuse this with hop count.

■ Neighbor Address: This is the adjacent neighbor's IP address. A neighbor should be formed between every router on that subnet running EIGRP in a common AS.

■ Interface: The interface that is reporting the neighbor.

■ HoldTime: This is the amount of time, which counts down, that EIGRP waits for a 'hello' before tearing down the neighbor.

■ Uptime: States how long the neighbor has been up. This number should be up for as long as the link has been up.

■ SRRT: The number of milliseconds it takes for an EIGRP packet to be sent to this neighbor, and for the local router to receive an acknowledgement, hence, a round trip timer. If this number equals zero, a packet has never made a successful round trip.

■ Retransmission TimeOut (RTO): The amount of time, in milliseconds, that the EIGRP waits before re-transmitting a packet from the retransmission queue to a neighbor.

■ Queue count (Q): The number of packets waiting in the queue to be sent out to this neighbor. This value should be 0 or a very low number. A high queue count indicates that data is having trouble getting through.

■ Sequence Number (Seq-Num): Sequence number of the last update, query, or reply that was received from this neighbor. If this number equals zero, it indicates that no reliable packets have ever been received from the neighbor, another clear indication of a problem.

This command lists the EIGRP topology table discussed earlier. The table lists all routes that EIGRP is aware of and whether EIGRP is actively processing information on that route. Under most normal conditions, the routes should all be in a passive state, no EIGRP processes are running for that route. If the routes are active, this could indicate the Stuck In Active (SIA) state, which will be discussed in more detail in an upcoming section. The show ip eigrp topology command can also be extended to show information about an individual route or subnet. This information will include all relevant information about the route, including all of show ip eigrp topology Command its metrics and successors, as well as how the route was learned. This example illustrates the use of show ip eigrp topology followed by the extended version of the command.

Rl# show ip eigrp topology

IP-EIGRP Topology Table for process 2001

Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - Reply status

P 172.16.5.0/24, 1 successors, FD is 23394560

via 172.16.1.5 (23394560/2 816 00), SerialO.l P 172.16.6.0/24, 1 successors, FD is 23394560

via 172.16.1.6 (23394560/2 816 00), Serial0.1 P 172.16.1.0/24, 1 successors, FD is 23368960

via Connected, Serial0.1 P 172.16.2.0/24, 1 successors, FD is 281600 via Connected, Ethernet1

R1# show ip eigrp topology 2001 172.16.5.0 255.255.255.0

IP-EIGRP topology entry for 172.16.5.0/24

State is Passive, Query origin flag is 1, 1 Successor(s), FD is 23394560 Routing Descriptor Blocks:

172.16.1.5 (Serial0.1), from 172.16.1.5, Send flag is 0x0

Composite metric is (23394560/281600), Route is Internal Vector metric:

Minimum bandwidth is 112 Kbit

Total delay is 21000 microseconds

Reliability is 254/255

Load is 1/255

Minimum MTU is 1500

Hop count is 1

The fields to note in this output are as follows:

■ P - Passive, no EIGRP computation is being performed. This is the ideal state.

■ A - Active, EIGRP computations are "actively" being performed for this destination. Routes constantly appearing in an active state, indicates a neighbor or query problem. Both are symptoms of the SIA problem.

■ U - Update, an update packet was sent to this destination.

■ Q - Query, a query packet was sent to this destination.

■ R - Reply, a reply packet was sent to this destination.

■ Route information - IP address of the route or network, its subnet mask, and the successor, or next hop to that network, or the feasible successor.

■ FD - Feasible distance to the destination network.

■ Send Flag - The type of packets that need to be sent for the entry are indicated by the send flag.

0x0 - If there are packets tha need to be sent in relation to this entry, this indicates the type of packet.

0x3 - The router has received a query for this network and needs to send a unicast reply. route is active and a multicast query should be sent. route has changed and a multicast update should be sent.

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