show ip eigrp traffic
Displays EIGRP packet statistics including sent/received counts for each packet type, used to verify EIGRP neighbor communication and troubleshoot packet loss or authentication issues.
show ip eigrp trafficWhen to Use This Command
- Verify EIGRP hello packets are being exchanged between neighbors after configuration
- Troubleshoot EIGRP neighbor adjacency failures by checking for packet drops or authentication errors
- Monitor EIGRP traffic volume to identify potential network issues or misconfigurations
- Confirm EIGRP route updates are being sent and received correctly
Command Examples
Basic EIGRP traffic statistics
show ip eigrp trafficIP-EIGRP Traffic Statistics for AS 100 Hellos sent/received: 1500/1498 Updates sent/received: 25/23 Queries sent/received: 2/2 Replies sent/received: 2/2 Acks sent/received: 27/25 Input queue high water mark: 2, 0 drops SIA-Queries sent/received: 0/0 SIA-Replies sent/received: 0/0 Hello process ID: 123 PDM process ID: 456 IP Socket queue: 0/2000 (current/max) Hello Timer: 5 secs
This output shows EIGRP packet counters for AS 100. 'Hellos sent/received' indicates neighbor discovery health; numbers should be roughly equal. 'Updates sent/received' shows route exchange activity. 'Queries' and 'Replies' indicate convergence events. 'Acks' are acknowledgments for reliable packets. 'Input queue high water mark' and 'drops' indicate congestion; zero drops is ideal. 'SIA' counters show stuck-in-active events (should be zero). 'Hello Timer' shows the configured hello interval.
EIGRP traffic with authentication errors
show ip eigrp trafficIP-EIGRP Traffic Statistics for AS 100 Hellos sent/received: 500/498 Updates sent/received: 10/8 Queries sent/received: 1/1 Replies sent/received: 1/1 Acks sent/received: 11/9 Input queue high water mark: 5, 3 drops SIA-Queries sent/received: 0/0 SIA-Replies sent/received: 0/0 Authentication type errors: 2 Authentication key errors: 1 Hello process ID: 123 PDM process ID: 456 IP Socket queue: 0/2000 (current/max) Hello Timer: 5 secs
This output shows authentication errors: 'Authentication type errors: 2' and 'Authentication key errors: 1'. These indicate mismatched authentication configuration between neighbors. The input queue drops (3) may also be related to authentication failures. This helps pinpoint why EIGRP neighbors are not forming.
Understanding the Output
The 'show ip eigrp traffic' command provides a snapshot of EIGRP packet activity for a specific autonomous system. The 'Hellos sent/received' counters should be roughly equal; a significant disparity may indicate a one-way communication issue. 'Updates' reflect route changes; a high number could indicate flapping routes. 'Queries' and 'Replies' are used during convergence; excessive queries may suggest network instability. 'Acks' should correlate with updates and queries. The 'Input queue high water mark' shows the peak queue depth; persistent high values with 'drops' indicate congestion or slow processing. 'SIA' counters should be zero; non-zero values indicate stuck-in-active conditions. Authentication error counters appear only when EIGRP authentication is configured; any non-zero value indicates a problem. The 'Hello Timer' shows the configured hello interval (default 5 seconds for most interfaces).
CCNA Exam Tips
CCNA exam tip: Know that 'show ip eigrp traffic' is used to verify EIGRP neighbor communication; if Hellos are not incrementing, check interface and network statements.
CCNA exam tip: Understand that 'drops' in the input queue indicate that the router is overwhelmed; this can cause neighbor flapping.
CCNA exam tip: Remember that authentication errors are displayed in this command; non-zero values mean EIGRP authentication is misconfigured.
CCNA exam tip: Be aware that SIA counters should be zero; non-zero values indicate a stuck-in-active condition, often due to a lost query or reply.
Common Mistakes
Mistake 1: Assuming that if Hellos are sent, the neighbor is fully adjacent; Hellos only indicate neighbor discovery, not full adjacency (must also see routes).
Mistake 2: Ignoring input queue drops; even a few drops can cause neighbor flapping and should be investigated.
Mistake 3: Forgetting to specify the AS number if multiple EIGRP processes exist; use 'show ip eigrp 100 traffic' to filter.
Related Commands
show ip eigrp interfaces
Displays detailed information about interfaces on which EIGRP is enabled, including neighbor status, pending routes, and interface statistics, used to verify EIGRP adjacency and interface participation.
show ip eigrp neighbors
Displays the neighbor table for EIGRP, showing all directly connected EIGRP routers and their status, used to verify EIGRP adjacencies and troubleshoot neighbor relationships.
show ip eigrp topology
Displays the EIGRP topology table, showing all learned routes and their feasible successors, used to verify EIGRP convergence and path selection.
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