11-07-2017 01:49 PM - edited 03-08-2019 12:39 PM
Hi,
I'm trying to understand why I can't see secondary path in one of following case scenarios:
a)fa0/0-> delay 100, variance 1:
P 10.10.3.0/24, 1 successors, FD is 158720 via 172.16.3.3 (158720/156160), FastEthernet1/1 via 172.16.1.2 (179200/128256), FastEthernet0/0 R1#sh ip route 10.10.3.0 Routing entry for 10.10.3.0/24 Known via "eigrp 100", distance 90, metric 158720, type internal Redistributing via eigrp 100 Last update from 172.16.3.3 on FastEthernet1/1, 00:01:34 ago Routing Descriptor Blocks: * 172.16.3.3, from 172.16.3.3, 00:01:34 ago, via FastEthernet1/1 Route metric is 158720, traffic share count is 1 Total delay is 5200 microseconds, minimum bandwidth is 100000 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops 2 R1#
b)fa0/0->no delay, variance 1:
P 10.10.3.0/24, 1 successors, FD is 156160 via 172.16.1.2 (156160/128256), FastEthernet0/0 R1#sh ip route 10.10.3.0 Routing entry for 10.10.3.0/24 Known via "eigrp 100", distance 90, metric 156160, type internal Redistributing via eigrp 100 Last update from 172.16.1.2 on FastEthernet0/0, 00:00:30 ago Routing Descriptor Blocks: * 172.16.1.2, from 172.16.1.2, 00:00:30 ago, via FastEthernet0/0 Route metric is 156160, traffic share count is 1 Total delay is 5100 microseconds, minimum bandwidth is 100000 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops 1 R1#
c)fa0/0-> delay 100, variance 2:
P 10.10.3.0/24, 2 successors, FD is 179200 via 172.16.1.2 (179200/128256), FastEthernet0/0 via 172.16.3.3 (158720/156160), FastEthernet1/1 R1#sh ip route 10.10.3.0 Routing entry for 10.10.3.0/24 Known via "eigrp 100", distance 90, metric 158720, type internal Redistributing via eigrp 100 Last update from 172.16.3.3 on FastEthernet1/1, 00:01:54 ago Routing Descriptor Blocks: 172.16.3.3, from 172.16.3.3, 00:01:54 ago, via FastEthernet1/1 Route metric is 158720, traffic share count is 80 Total delay is 5200 microseconds, minimum bandwidth is 100000 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops 2 * 172.16.1.2, from 172.16.1.2, 00:01:54 ago, via FastEthernet0/0 Route metric is 179200, traffic share count is 71 Total delay is 6000 microseconds, minimum bandwidth is 100000 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops 1 R1#
d)fa0/0->no delay, variance 2:
P 10.10.3.0/24, 2 successors, FD is 156160, serno 121 via 172.16.1.2 (156160/128256), FastEthernet0/0 via 172.16.3.3 (158720/156160), FastEthernet1/1 R1#sh ip route 10.10.3.0 Routing entry for 10.10.3.0/24 Known via "eigrp 100", distance 90, metric 156160, type internal Redistributing via eigrp 100 Last update from 172.16.3.3 on FastEthernet1/1, 00:00:46 ago Routing Descriptor Blocks: 172.16.3.3, from 172.16.3.3, 00:00:46 ago, via FastEthernet1/1 Route metric is 158720, traffic share count is 59 Total delay is 5200 microseconds, minimum bandwidth is 100000 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops 2 * 172.16.1.2, from 172.16.1.2, 00:00:46 ago, via FastEthernet0/0 Route metric is 156160, traffic share count is 60 Total delay is 5100 microseconds, minimum bandwidth is 100000 Kbit Reliability 255/255, minimum MTU 1500 bytes Loading 1/255, Hops 1 R1#
In a scenario A I see two available paths in topology table and one of them is successor, why I can't see the same number of paths in scenario B?
IMO I should see also the path available via Fa1/1 (172.16.3.3) with a metric: 158720/156160 and 1 successor over Fa0/0.
Thanks
Solved! Go to Solution.
11-11-2017 02:45 PM
I found the error is a bug. When I changed IOS version the second route is not taken to topology table:
R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#router eigrp 100 R1(config-router)#no variance ... *Nov 11 23:22:38.043: DUAL: Find FS for dest 10.10.3.0/24. FD is 156160, RD is 156160 *Nov 11 23:22:38.043: DUAL: 172.16.1.2 metric 156160/128256 *Nov 11 23:22:38.043: DUAL: 172.16.3.3 metric 158720/156160 found Dmin is 156160 *Nov 11 23:22:38.043: DUAL: RT installed 10.10.3.0/24 via 172.16.1.2 ... R1(config-router)#va R1(config-router)#variance 2 R1(config-router)# .. *Nov 11 23:24:37.723: DUAL: Find FS for dest 10.10.3.0/24. FD is 156160, RD is 156160 *Nov 11 23:24:37.727: DUAL: 172.16.1.2 metric 156160/128256 *Nov 11 23:24:37.727: DUAL: 172.16.3.3 metric 158720/156160 found Dmin is 156160 *Nov 11 23:24:37.727: DUAL: RT installed 10.10.3.0/24 via 172.16.1.2
11-07-2017 01:58 PM
ok, I found the reason, with 'all-links' I can see both:
R1#sh ip eigrp topo all-links ... P 10.10.3.0/24, 1 successors, FD is 156160, serno 140 via 172.16.1.2 (156160/128256), FastEthernet0/0 via 172.16.3.3 (158720/156160), FastEthernet1/1
Weird I don't need this parameter for scenario A .
11-07-2017 02:20 PM
eh, I found the reason: feasibility condition, sorry for spam but I didn't know how to remove posts
11-07-2017 02:36 PM
11-07-2017 11:48 PM - edited 11-08-2017 03:35 AM
It's basically scenario B again:
R1#sh ip eigrp topology EIGRP-IPv4 Topology Table for AS(100)/ID(10.10.1.1) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status ... P 10.10.3.0/24, 1 successors, FD is 156160 via 172.16.1.2 (156160/128256), FastEthernet0/0 R1#
R1#sh ip eigrp topology all-links EIGRP-IPv4 Topology Table for AS(100)/ID(10.10.1.1) Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply, r - reply Status, s - sia Status ... P 10.10.3.0/24, 1 successors, FD is 156160, serno 153 via 172.16.1.2 (156160/128256), FastEthernet0/0 via 172.16.3.3 (158720/156160), FastEthernet1/1 R1#
So, by the definition FD(156160) of 172.16.1.2 is not higher than RD(156160) of 172.16.3.3. They are the same and it's clear why I can't see path via 172.16.3.3. Not sure why I can see two with 'variance 2':
R1(config)#router ei R1(config)#router eigrp 100 R1(config-router)#va R1(config-router)#variance 2 R1(config-router)# ... *Nov 7 16:52:45.930: EIGRP-IPv4(100): Find FS for dest 10.10.3.0/24. FD is 156160, RD is 156160 on tid 0 *Nov 7 16:52:4 R1(config-router)#5.930: EIGRP-IPv4(100): 172.16.1.2 metric 156160/128256 *Nov 7 16:52:45.930: EIGRP-IPv4(100): 172.16.3.3 metric 158720/156160 found Dmin is 156160 *Nov 7 16:52:45.930: DUAL: AS(100) RT installed 10.10.3.0/24 via 172.16.1.2 *Nov 7 16:52:45.930: DUAL: AS(100) RT installed 10.10.3.0/24 via 172.16.3.3 *Nov 7 16:52:45.930: DUAL: AS(100) Send update about 10.10.3.0/24. Reason: new if on tid 0 R1(config-router)#
R1(config-router)#no variance R1(config-router)# ... *Nov 7 16:55:46.526: EIGRP-IPv4(100): Find FS for dest 10.10.3.0/24. FD is 156160, RD is 156160 on tid 0 *Nov 7 16:55:46.526: EIGRP-IPv4(100): 172.16.1.2 metric 156160/128256 *Nov 7 16:55:46.526: EIGRP-IPv4(100): 172.16.3.3 metric 158720/156160 found Dmin is 156160 *Nov 7 16:55:4 R1(config-router)#6.526: DUAL: AS(100) RT installed 10.10.3.0/24 via 172.16.1.2 *Nov 7 16:55:46.526: DUAL: AS(100) Send update about 10.10.3.0/24. Reason: lost if on tid 0 R1(config-router)#
It looks like the variance is taken into feasible condition check:
variance 1:
172.16.1.2 metric 156160/128256 <- installed
172.16.3.3 metric 158720/156160 found Dmin is 156160 <- removed (expected)
variance 2:
172.16.1.2 metric 156160/128256 <- installed
172.16.3.3 metric 158720/156160 found Dmin is 156160 <- installed (why?)
11-11-2017 02:45 PM
I found the error is a bug. When I changed IOS version the second route is not taken to topology table:
R1#conf t Enter configuration commands, one per line. End with CNTL/Z. R1(config)#router eigrp 100 R1(config-router)#no variance ... *Nov 11 23:22:38.043: DUAL: Find FS for dest 10.10.3.0/24. FD is 156160, RD is 156160 *Nov 11 23:22:38.043: DUAL: 172.16.1.2 metric 156160/128256 *Nov 11 23:22:38.043: DUAL: 172.16.3.3 metric 158720/156160 found Dmin is 156160 *Nov 11 23:22:38.043: DUAL: RT installed 10.10.3.0/24 via 172.16.1.2 ... R1(config-router)#va R1(config-router)#variance 2 R1(config-router)# .. *Nov 11 23:24:37.723: DUAL: Find FS for dest 10.10.3.0/24. FD is 156160, RD is 156160 *Nov 11 23:24:37.727: DUAL: 172.16.1.2 metric 156160/128256 *Nov 11 23:24:37.727: DUAL: 172.16.3.3 metric 158720/156160 found Dmin is 156160 *Nov 11 23:24:37.727: DUAL: RT installed 10.10.3.0/24 via 172.16.1.2
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