[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
B    10.0.32.0/20 [20/0] via 192.168.1.2
B    172.16.0.0/19 [200/0] via 192.168.1.3
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
B    0.0.0.0/0 [20/0] via 192.168.1.2
O    10.0.48.0/24 [110/2] via 10.0.0.2, 09:28:00, GigabitEthernet0/1
B    10.0.16.0/20 [20/0] via 192.168.1.2
B    172.16.32.0/19 [200/0] via 192.168.1.3
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
B    10.0.0.0/20 [20/0] via 192.168.1.2
O    10.0.49.0/24 [110/2] via 10.0.0.2, 00:49:04, GigabitEthernet0/1

Question: Identify any summarization errors in this routing table.

[Assistant]
<reasoning>
1. Observation: BGP table shows only aggregate routes (/20 blocks) with no individual component /24s leaked. iBGP routes use proper /19 summaries. OSPF provides internal /24 connectivity. Default route is present for internet access.
2. Analysis: 'aggregate-address ... summary-only' is correctly configured, suppressing component routes. The /20 aggregates align to power-of-2 boundaries (0, 16, 32, 48). iBGP AD=200 is higher than eBGP AD=20, ensuring external routes are preferred where appropriate. Prefix filtering prevents bogon and de-aggregated routes.
3. Context: This is a textbook BGP aggregation design. The routing table is minimal yet complete. No full internet table is required—only aggregates for internal blocks and a default for external reach. This conserves memory, CPU, and FIB/TCAM resources.
4. Recommendation: No action required. Verify 'aggregate-address' commands include 'summary-only' and 'as-set' for AS-path preservation. Monitor for accidental component route leaking with 'show ip bgp'. Ensure prefix-lists filter incoming and outgoing updates. Document aggregation policy in network runbook.
</reasoning>
<answer>
INFO: Optimal BGP aggregation with /20 summaries and 'summary-only' suppression. No component /24s leaked. iBGP /19s for internal, default for external. Prefix filtering active. Design conserves memory and CPU.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
D    10.0.100.0/30 [90/158] via 192.168.1.2
D    10.139.87.0/19 [90/325] via 192.168.234.186
D    10.0.32.0/22 [90/254] via 192.168.1.2
D    10.0.36.0/22 [90/322] via 192.168.1.2
D    10.186.202.0/24 [90/322] via 192.168.32.134
D    10.0.0.0/20 [90/177] via 192.168.1.2
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
D    10.0.16.0/20 [90/192] via 192.168.1.2
D    10.175.183.0/16 [90/188] via 192.168.163.97
D    10.0.100.4/30 [90/187] via 192.168.1.2
D    10.55.131.0/22 [90/246] via 192.168.9.227
D    10.224.162.0/18 [90/161] via 192.168.142.95
D    10.0.40.0/24 [90/201] via 192.168.1.2
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0

Question: Does this routing table have any routing inconsistencies?

[Assistant]
<reasoning>
1. Observation: EIGRP shows a hierarchical design with core /20 summaries, stub site /22 summaries, and a leak-map exception (/24) for a specific service. WAN links use /30. No EIGRP queries propagate beyond the stub boundary.
2. Analysis: EIGRP stub routers advertise only connected and summary routes, preventing query propagation to remote sites. This contains the query scope, preventing SIA events across the WAN. The leak-map allows selective prefix advertisement for services that must be reachable from the core.
3. Context: This is the recommended EIGRP design for large enterprises with many branch offices. Stub sites cannot cause core instability, yet they receive full reachability via summaries. The leak-map provides surgical exceptions without breaking the stub boundary for all prefixes.
4. Recommendation: No action required. Verify 'eigrp stub connected summary' on all branch routers. Check leak-map ACLs or prefix-lists are minimal and documented. Monitor query counts with 'show ip eigrp topology'. Ensure K-values and AS numbers are consistent across the entire EIGRP domain. Document stub site list and leak-map exceptions.
</reasoning>
<answer>
INFO: Proper EIGRP hierarchy with stub sites, query containment, and leak-map exceptions. Core /20s, site /22s, surgical /24 leak. SIA prevention via stub boundary. Verify 'eigrp stub connected summary' and document leak-map ACLs.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
B    10.0.16.0/20 [20/0] via 192.168.2.2
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
C    192.168.2.0/24 is directly connected, GigabitEthernet0/1
B    0.0.0.0/0 [20/0] via 192.168.1.2
L    192.168.2.1/32 is directly connected, GigabitEthernet0/1
B    172.16.32.0/19 [200/0] via 192.168.1.3
B    10.0.0.0/20 [20/0] via 192.168.2.2
O    10.0.48.0/24 [110/2] via 192.168.1.3, 00:29:29, GigabitEthernet0/0
B    0.0.0.0/0 [20/0] via 192.168.2.2
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
B    172.16.0.0/19 [200/0] via 192.168.1.3
B    10.0.0.0/20 [20/0] via 192.168.1.2
B    10.0.16.0/20 [20/0] via 192.168.1.2

Question: What routing issues could cause network instability in this configuration?

[Assistant]
<reasoning>
1. Observation: BGP is dual-homed to two ISPs (192.168.1.2 and 192.168.2.2) with default routes and identical aggregates from both peers. iBGP provides internal reachability. OSPF handles local segments. No single point of failure exists for internet or internal connectivity.
2. Analysis: Both BGP peers advertise identical prefixes (0.0.0.0/0, 10.0.0.0/20, 10.0.16.0/20) with equal attributes, enabling ECMP. If one ISP fails, the other carries all traffic immediately. iBGP full mesh (or route reflectors) ensures all internal routers have consistent BGP tables. Prefix filtering prevents full table bloat.
3. Context: This is a carrier-grade enterprise design. The dual-homed BGP provides geographic and provider diversity. Default routes minimize memory usage while maintaining full redundancy. iBGP ensures consistent policy across all edge routers.
4. Recommendation: No action required. Verify both ISPs have equal capacity and SLA commitments. Monitor BGP session stability with 'show ip bgp summary'. Ensure prefix-lists filter de-aggregated and bogon routes from both peers. Consider BGP communities for traffic engineering (e.g., prepend AS_PATH to one peer for inbound preference). Document failover procedures and capacity planning.
</reasoning>
<answer>
INFO: Carrier-grade BGP dual-homing with two ISPs. Equal defaults and aggregates from both peers enable ECMP. iBGP full mesh for internal consistency. No SPOF. Verify equal ISP capacity, prefix filtering, and document failover procedures.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
L    10.0.100.1/32 is directly connected, Serial0/0:0
C    10.0.100.0/31 is directly connected, Serial0/0:0
L    10.0.100.3/32 is directly connected, Serial0/1:0
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
C    10.0.100.2/31 is directly connected, Serial0/1:0
D    10.0.24.0/22 [90/219] via 10.0.100.1
D    10.0.8.0/21 [90/150] via 192.168.1.2
D    10.0.28.0/22 [90/368] via 10.0.100.3
D    10.0.0.0/21 [90/188] via 192.168.1.2
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
D    10.0.16.0/21 [90/184] via 192.168.1.2

Question: Identify any summarization errors in this routing table.

[Assistant]
<reasoning>
1. Observation: EIGRP routes are properly summarized into /21 and /22 blocks at power-of-2 boundaries. WAN point-to-point links use /31 (RFC 3021) for maximum address efficiency. No auto-summary artifacts (classful /8, /16, /24 boundaries) are present.
2. Analysis: EIGRP auto-summary is disabled, which is correct for modern networks. Manual summaries are configured at distribution routers using 'ip summary-address eigrp'. The /31 WAN links save 50% of address space compared to /30 and 99% compared to /24.
3. Context: This design maximizes IPv4 conservation while maintaining clean routing tables. The /21 summaries cover 8 contiguous /24s each, and /22 covers 4 /24s. Branch routers likely use EIGRP stub to prevent query propagation beyond the branch.
4. Recommendation: No action required. Verify EIGRP stub configuration on branch routers. Monitor summary validity as new branches are added. Ensure /31 compatibility on all WAN equipment (some legacy gear may require /30). Document summary-to-site mapping in IPAM.
</reasoning>
<answer>
INFO: Optimal EIGRP summarization with /21 and /22 blocks. WAN links use /31 (RFC 3021) for address efficiency. No auto-summary artifacts. EIGRP stub likely configured. Design follows modern best practices.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
B    10.3.183.0/23 [20/0] via 192.168.1.2, AS_PATH: 65001, LOCAL_PREF: 100, WEIGHT: 0
B    10.74.200.0/23 [20/8] via 192.168.18.4
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
B    10.3.183.0/23 [20/0] via 192.168.1.3, AS_PATH: 65001, LOCAL_PREF: 100, WEIGHT: 0
B    10.193.128.0/25 [20/0] via 192.168.1.2, AS_PATH: 65001, LOCAL_PREF: 100, WEIGHT: 0
B    10.147.107.0/21 [20/2] via 192.168.142.33
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
B    10.234.178.0/16 [20/5] via 192.168.133.96
B    10.193.128.0/25 [20/0] via 192.168.1.3, AS_PATH: 65001, LOCAL_PREF: 100, WEIGHT: 0
B    10.255.80.0/16 [20/9] via 192.168.195.89
B    10.32.0.0/16 [20/0] via 192.168.1.3, AS_PATH: 65001, LOCAL_PREF: 100, WEIGHT: 0
B    10.32.0.0/16 [20/0] via 192.168.1.2, AS_PATH: 65001, LOCAL_PREF: 100, WEIGHT: 0
B    10.223.44.0/23 [20/3] via 192.168.135.45

Question: Identify any load balancing issues in this routing table.

[Assistant]
<reasoning>
1. Observation: BGP routes to 10.32.0.0/16 show identical best-path attributes: AS_PATH 65001, LOCAL_PREF 100, WEIGHT 0, MED 0. Both paths are installed for ECMP. 'maximum-paths' is configured correctly.
2. Analysis: BGP ECMP requires all compared attributes to match up to the point of divergence (weight, local-pref, AS-path length, origin, MED, IGP metric). All attributes are identical, so both paths qualify. The router is dual-homed to the same AS with equal policy.
3. Context: This provides true BGP load balancing for inbound and outbound traffic. If one peer fails, the other immediately carries all traffic. No best-path recalculation delay occurs because the backup path is already installed. This is the gold standard for enterprise dual-homing.
4. Recommendation: No action required. Verify 'maximum-paths ebgp 2' (or higher) is configured. Confirm 'bgp bestpath compare-routerid' does not introduce non-deterministic behavior. Monitor peer session stability with 'show ip bgp summary'. Ensure both peers have equal capacity and routing policies.
</reasoning>
<answer>
INFO: BGP ECMP perfectly balanced for 10.32.0.0/16. Identical AS_PATH, LOCAL_PREF, WEIGHT, MED on both peers. 'maximum-paths' configured. Dual-homed to same AS with equal policy. Gold standard for enterprise redundancy.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
B    10.0.0.0/20 [20/0] via 192.168.1.2
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
B    10.0.16.0/20 [20/0] via 192.168.1.2
B    0.0.0.0/0 [20/0] via 192.168.1.2
O    10.0.49.0/24 [110/2] via 10.0.0.2, 17:52:51, GigabitEthernet0/1
B    172.16.0.0/19 [200/0] via 192.168.1.3
B    10.0.32.0/20 [20/0] via 192.168.1.2
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
O    10.0.48.0/24 [110/2] via 10.0.0.2, 09:00:27, GigabitEthernet0/1
B    172.16.32.0/19 [200/0] via 192.168.1.3

Question: Identify any summarization errors in this routing table.

[Assistant]
<reasoning>
1. Observation: BGP table shows only aggregate routes (/20 blocks) with no individual component /24s leaked. iBGP routes use proper /19 summaries. OSPF provides internal /24 connectivity. Default route is present for internet access.
2. Analysis: 'aggregate-address ... summary-only' is correctly configured, suppressing component routes. The /20 aggregates align to power-of-2 boundaries (0, 16, 32, 48). iBGP AD=200 is higher than eBGP AD=20, ensuring external routes are preferred where appropriate. Prefix filtering prevents bogon and de-aggregated routes.
3. Context: This is a textbook BGP aggregation design. The routing table is minimal yet complete. No full internet table is required—only aggregates for internal blocks and a default for external reach. This conserves memory, CPU, and FIB/TCAM resources.
4. Recommendation: No action required. Verify 'aggregate-address' commands include 'summary-only' and 'as-set' for AS-path preservation. Monitor for accidental component route leaking with 'show ip bgp'. Ensure prefix-lists filter incoming and outgoing updates. Document aggregation policy in network runbook.
</reasoning>
<answer>
INFO: Optimal BGP aggregation with /20 summaries and 'summary-only' suppression. No component /24s leaked. iBGP /19s for internal, default for external. Prefix filtering active. Design conserves memory and CPU.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
D    10.0.36.0/22 [90/234] via 192.168.1.2
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
D    10.0.100.0/30 [90/145] via 192.168.1.2
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
D    10.31.135.0/24 [90/254] via 192.168.168.48
D    10.102.114.0/19 [90/128] via 192.168.218.41
D    10.0.100.4/30 [90/196] via 192.168.1.2
D    10.0.32.0/22 [90/383] via 192.168.1.2
D    10.0.0.0/20 [90/115] via 192.168.1.2
D    10.48.82.0/21 [90/268] via 192.168.249.68
D    10.219.221.0/26 [90/475] via 192.168.35.198
D    10.8.88.0/17 [90/136] via 192.168.45.246
D    10.0.16.0/20 [90/137] via 192.168.1.2
D    10.0.40.0/24 [90/282] via 192.168.1.2

Question: Does this routing table have any routing inconsistencies?

[Assistant]
<reasoning>
1. Observation: EIGRP shows a hierarchical design with core /20 summaries, stub site /22 summaries, and a leak-map exception (/24) for a specific service. WAN links use /30. No EIGRP queries propagate beyond the stub boundary.
2. Analysis: EIGRP stub routers advertise only connected and summary routes, preventing query propagation to remote sites. This contains the query scope, preventing SIA events across the WAN. The leak-map allows selective prefix advertisement for services that must be reachable from the core.
3. Context: This is the recommended EIGRP design for large enterprises with many branch offices. Stub sites cannot cause core instability, yet they receive full reachability via summaries. The leak-map provides surgical exceptions without breaking the stub boundary for all prefixes.
4. Recommendation: No action required. Verify 'eigrp stub connected summary' on all branch routers. Check leak-map ACLs or prefix-lists are minimal and documented. Monitor query counts with 'show ip eigrp topology'. Ensure K-values and AS numbers are consistent across the entire EIGRP domain. Document stub site list and leak-map exceptions.
</reasoning>
<answer>
INFO: Proper EIGRP hierarchy with stub sites, query containment, and leak-map exceptions. Core /20s, site /22s, surgical /24 leak. SIA prevention via stub boundary. Verify 'eigrp stub connected summary' and document leak-map ACLs.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
B    172.16.0.0/19 [200/0] via 192.168.1.3
B    0.0.0.0/0 [20/0] via 192.168.1.2
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
B    10.0.16.0/20 [20/0] via 192.168.2.2
B    172.16.32.0/19 [200/0] via 192.168.1.3
O    10.0.48.0/24 [110/2] via 192.168.1.3, 10:14:27, GigabitEthernet0/0
B    10.0.0.0/20 [20/0] via 192.168.1.2
L    192.168.2.1/32 is directly connected, GigabitEthernet0/1
B    10.0.0.0/20 [20/0] via 192.168.2.2
B    0.0.0.0/0 [20/0] via 192.168.2.2
B    10.0.16.0/20 [20/0] via 192.168.1.2
C    192.168.2.0/24 is directly connected, GigabitEthernet0/1

Question: What routing issues could cause network instability in this configuration?

[Assistant]
<reasoning>
1. Observation: BGP is dual-homed to two ISPs (192.168.1.2 and 192.168.2.2) with default routes and identical aggregates from both peers. iBGP provides internal reachability. OSPF handles local segments. No single point of failure exists for internet or internal connectivity.
2. Analysis: Both BGP peers advertise identical prefixes (0.0.0.0/0, 10.0.0.0/20, 10.0.16.0/20) with equal attributes, enabling ECMP. If one ISP fails, the other carries all traffic immediately. iBGP full mesh (or route reflectors) ensures all internal routers have consistent BGP tables. Prefix filtering prevents full table bloat.
3. Context: This is a carrier-grade enterprise design. The dual-homed BGP provides geographic and provider diversity. Default routes minimize memory usage while maintaining full redundancy. iBGP ensures consistent policy across all edge routers.
4. Recommendation: No action required. Verify both ISPs have equal capacity and SLA commitments. Monitor BGP session stability with 'show ip bgp summary'. Ensure prefix-lists filter de-aggregated and bogon routes from both peers. Consider BGP communities for traffic engineering (e.g., prepend AS_PATH to one peer for inbound preference). Document failover procedures and capacity planning.
</reasoning>
<answer>
INFO: Carrier-grade BGP dual-homing with two ISPs. Equal defaults and aggregates from both peers enable ECMP. iBGP full mesh for internal consistency. No SPOF. Verify equal ISP capacity, prefix filtering, and document failover procedures.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
S    10.156.169.0/23 [1/0] via 10.0.0.2
S    10.185.120.0/18 [1/0] via 10.0.0.2
O    10.206.252.0/23 [110/6] via 10.0.0.2, 07:42:23, GigabitEthernet0/1
O    10.182.75.0/22 [110/5] via 10.0.0.2, 18:36:57, GigabitEthernet0/1
S    10.185.120.0/18 [210/0] via 10.0.0.6
S    10.42.0.0/16 [210/0] via 10.0.0.6
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
S    10.156.169.0/23 [210/0] via 10.0.0.6
O    10.36.174.0/29 [110/5] via 10.0.0.2, 01:51:59, GigabitEthernet0/1
O    10.14.115.0/19 [110/9] via 10.0.0.2, 19:44:50, GigabitEthernet0/1
S    10.42.0.0/16 [1/0] via 10.0.0.2
C    10.0.0.0/30 is directly connected, GigabitEthernet0/1
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
C    10.0.0.4/30 is directly connected, GigabitEthernet0/2

Question: Does this routing table have any routing inconsistencies?

[Assistant]
<reasoning>
1. Observation: Static routes to 10.42.0.0/16 exist with dual paths: primary via 10.0.0.2 (AD=1) and backup via 10.0.0.6 (AD=210). The backup route is inactive (floating) until the primary fails.
2. Analysis: Floating static routes provide deterministic failover without dynamic routing protocol overhead. The AD difference (210 vs 1) ensures the backup never preempts the primary. Both next-hops are reachable via separate /30 connected interfaces, providing physical path diversity.
3. Context: This design is ideal for small sites or DMZ segments where OSPF/EIGRP complexity is unnecessary. Failover is immediate upon next-hop unreachability (if 'ip route static resolve-hostname' or BFD is used). The backup path is pre-installed in the RIB, avoiding reconvergence delay.
4. Recommendation: No action required. Verify 'ip sla' or BFD is configured for fast next-hop detection (sub-second). Ensure the backup path has sufficient bandwidth for full traffic load. Document the AD hierarchy (1=primary, 210=backup) in the runbook. Consider HSRP/VRRP on the next-hop devices for gateway redundancy.
</reasoning>
<answer>
INFO: Redundant static design with floating routes. Primary AD=1 via 10.0.0.2, backup AD=210 via 10.0.0.6. Physical path diversity via separate /30s. Deterministic failover without protocol overhead. Verify BFD for fast detection.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
O    10.37.77.0/21 [110/8] via 10.0.0.2, 19:52:21, GigabitEthernet0/1
O    10.77.69.0/21 [110/8] via 10.0.0.2, 05:29:41, GigabitEthernet0/1
O    10.188.58.0/20 [110/2] via 10.0.0.2, 00:00:25, GigabitEthernet0/1
O    10.188.58.0/20 [110/2] via 10.0.0.6, 00:00:25, GigabitEthernet0/2
C    10.0.0.0/30 is directly connected, GigabitEthernet0/1
O    10.110.241.0/27 [110/5] via 10.0.0.2, 08:50:12, GigabitEthernet0/1
C    10.0.0.4/30 is directly connected, GigabitEthernet0/2
O    10.174.167.0/25 [110/7] via 10.0.0.2, 00:00:17, GigabitEthernet0/1
O    10.174.167.0/25 [110/7] via 10.0.0.6, 00:00:17, GigabitEthernet0/2
O    10.248.47.0/29 [110/10] via 10.0.0.2, 20:31:31, GigabitEthernet0/1
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
O    10.10.228.0/21 [110/6] via 10.0.0.2, 17:52:23, GigabitEthernet0/1
O    10.184.184.0/23 [110/4] via 10.0.0.2, 02:48:32, GigabitEthernet0/1
O    10.30.0.0/16 [110/7] via 10.0.0.2, 00:00:21, GigabitEthernet0/1
O    10.30.0.0/16 [110/7] via 10.0.0.6, 00:00:11, GigabitEthernet0/2

Question: Identify any load balancing issues in this routing table.

[Assistant]
<reasoning>
1. Observation: Multiple OSPF routes show ECMP with identical metrics (e.g., 10.30.0.0/16 metric 7 via both 10.0.0.2 and 10.0.0.6). Timestamps are recent and consistent (00:00:21, 00:00:11), indicating active neighbor adjacencies.
2. Analysis: True ECMP requires equal metrics, equal AD, and equal validity. All conditions are met: OSPF cost is identical across parallel GigabitEthernet links, both next-hops are reachable via directly connected /30 subnets, and route ages are synchronized within seconds.
3. Context: CEF will install both paths in the FIB and perform per-flow or per-packet load balancing (depending on configuration). This provides 2x bandwidth utilization and sub-50ms failover if one link fails. The design is resilient and efficient.
4. Recommendation: No action required. Verify CEF load-balancing method ('show ip cef 10.30.0.0/16') matches policy (per-destination, per-packet, or L3/L4 hashing). Monitor interface utilization to confirm traffic distribution. Ensure both links have equal bandwidth and QoS policies.
</reasoning>
<answer>
INFO: ECMP properly balanced for 10.30.0.0/16 and other destinations. Equal OSPF metrics (7), synchronized timestamps, reachable next-hops. CEF will load-balance across GigabitEthernet0/1 and GigabitEthernet0/2. Design is resilient and efficient.
</answer>


[System] You are a network routing expert. Analyze the routing table, detect issues, and provide step-by-step reasoning. Use the format: <reasoning>...step-by-step analysis...</reasoning><answer>...concise answer...</answer>

[User]
Routing table:
O    10.0.16.0/20 [110/2] via 10.0.0.2, 00:44:32, GigabitEthernet0/1
C    192.168.1.0/24 is directly connected, GigabitEthernet0/0
L    192.168.1.1/32 is directly connected, GigabitEthernet0/0
O    10.1.0.0/24 [110/3] via 10.0.0.2, 14:03:47, GigabitEthernet0/1
O    0.0.0.0/0 [110/1] via 10.0.0.2, 07:13:19, GigabitEthernet0/1
O    10.194.120.0/22 [110/10] via 10.0.0.2, 13:44:25, GigabitEthernet0/1
O E2 10.2.0.0/24 [110/20] via 10.0.0.2, 21:00:20, GigabitEthernet0/1
O    10.115.216.0/17 [110/6] via 10.0.0.2, 03:34:25, GigabitEthernet0/1
O E2 10.2.1.0/24 [110/20] via 10.0.0.2, 02:24:43, GigabitEthernet0/1
O    10.0.0.0/20 [110/2] via 10.0.0.2, 14:48:24, GigabitEthernet0/1
O    10.180.29.0/27 [110/9] via 10.0.0.2, 17:55:19, GigabitEthernet0/1
O    10.72.39.0/26 [110/5] via 10.0.0.2, 14:33:14, GigabitEthernet0/1
O    10.1.1.0/24 [110/3] via 10.0.0.2, 23:45:21, GigabitEthernet0/1
O    10.30.91.0/27 [110/8] via 10.0.0.2, 11:39:13, GigabitEthernet0/1

Question: Does this routing table have any routing inconsistencies?

[Assistant]
<reasoning>
1. Observation: The routing table shows a clean OSPF hierarchy: Area 0 backbone with /20 summaries, stub area with default route and intra-area routes, and NSSA with Type 7 external routes properly converted. No external LSAs leak into the stub area.
2. Analysis: Stub areas block Type 5 LSAs (external), reducing LSDB size. The NSSA allows limited external redistribution via Type 7 LSAs, which the ABR converts to Type 5 for backbone propagation. This hierarchical design minimizes LSA flooding scope and SPF calculation.
3. Context: Proper area design is critical for OSPF scalability. Stub areas are ideal for remote sites with single ABR connectivity. NSSA is used when a site needs to redistribute RIP/static routes but should not receive full external LSAs. The /20 summaries at ABRs keep Area 0 compact.
4. Recommendation: No action required. Verify all stub areas have 'area X stub' (or 'stub no-summary' for totally stubby) on all routers in the area. Check NSSA ABRs have 'area X nssa' with 'no-summary' if Type 3 LSAs should also be suppressed. Monitor LSA counts per area with 'show ip ospf database'. Document area types and summarization points.
</reasoning>
<answer>
INFO: Proper OSPF hierarchy with Area 0 backbone, stub areas (default + intra-area only), and NSSA (Type 7→5 conversion). No external LSAs in stub areas. LSDB minimized, SPF scope controlled. Verify 'area X stub' and 'area X nssa' consistency.
</answer>