show ip route summary
Displays a summary of the IP routing table, including route counts, protocols, and memory usage, used to quickly assess the routing table size and composition.
show ip route summaryWhen to Use This Command
- Check the total number of routes and memory consumption before adding new routes.
- Verify that a specific routing protocol (e.g., OSPF) has installed the expected number of routes.
- Troubleshoot routing table bloat or high memory usage.
- Compare route counts across different routers to ensure consistency.
Command Examples
Basic summary of routing table
show ip route summaryIP routing table name is Default-IP-Routing-Table (0x0) IP routing table maximum-paths is 32 Route entry count: 12 Number of networks: 12 Number of paths: 12 Number of paths for nexthop recursion: 0 Number of paths for load sharing: 0 Number of paths for per-packet load sharing: 0 Number of networks with paths: 12 Protocol Routes Connected 3 Static 1 OSPF 8 EIGRP 0 BGP 0 IS-IS 0 Memory bytes consumed: 3600
The output shows the routing table name and maximum paths. 'Route entry count' is the total number of routes. 'Number of networks' and 'Number of paths' are typically equal for simple topologies. The protocol breakdown shows how many routes each protocol contributed. 'Memory bytes consumed' indicates the memory used by the routing table.
Summary with many routes
show ip route summaryIP routing table name is Default-IP-Routing-Table (0x0) IP routing table maximum-paths is 32 Route entry count: 1500 Number of networks: 1500 Number of paths: 1500 Number of paths for nexthop recursion: 0 Number of paths for load sharing: 0 Number of paths for per-packet load sharing: 0 Number of networks with paths: 1500 Protocol Routes Connected 5 Static 2 OSPF 1493 EIGRP 0 BGP 0 IS-IS 0 Memory bytes consumed: 450000
This example shows a large routing table with 1500 routes, mostly from OSPF. The memory consumption is 450,000 bytes. This could indicate a router in a large OSPF domain. High memory usage may require optimization or hardware upgrade.
Understanding the Output
The 'show ip route summary' command provides a high-level overview of the IP routing table. The first line indicates the routing table name (usually Default-IP-Routing-Table). 'IP routing table maximum-paths' shows the maximum number of equal-cost paths for load balancing (default 32). 'Route entry count' is the total number of routes. 'Number of networks' and 'Number of paths' are typically identical unless there are multiple paths to the same network. The protocol breakdown lists how many routes each routing protocol has installed. 'Memory bytes consumed' is the total memory used by the routing table entries. A sudden increase in route count or memory may indicate a routing loop or misconfiguration. Normal values depend on network size; for a small enterprise, a few hundred routes is typical, while large ISPs may have hundreds of thousands.
CCNA Exam Tips
CCNA exam may ask you to identify which protocol contributed the most routes from the summary output.
Know that the 'maximum-paths' value can be changed with the 'maximum-paths' command under router configuration.
The exam might test that 'show ip route summary' does not show individual routes; use 'show ip route' for that.
Be aware that memory consumption is in bytes; a high value may indicate a need for route summarization.
Common Mistakes
Confusing 'route entry count' with 'number of networks' — they are usually the same but can differ with multiple paths.
Assuming the memory value is in kilobytes or megabytes — it is always bytes.
Forgetting that static routes and connected routes are also counted in the protocol breakdown.
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