Topology table all-link.

Hi all, I'm doing a lab in INE CCNP R & S workbook on GNS 3 so i don't use switch. Just simply use Router.

**On R2 Routing table : **
R2#show ip route eigrp
Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
E1 - OSPF external type 1, E2 - OSPF external type 2
i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
ia - IS-IS inter area, * - candidate default, U - per-user static route
o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
+ - replicated route, % - next hop override

Gateway of last resort is not set

  1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks

D 1.4.1.0/24 [90/20514560] via 2.4.2.4, 00:19:49, FastEthernet0/1
[90/20514560] via 1.2.1.1, 00:19:49, FastEthernet0/0
D 1.4.1.1/32 [90/20514560] via 2.4.2.4, 00:19:52, FastEthernet0/1
D 1.4.1.4/32 [90/20514560] via 1.2.1.1, 00:19:49, FastEthernet0/0
111.0.0.0/8 is variably subnetted, 7 subnets, 5 masks
D 111.111.111.0/29 [90/156160] via 1.2.1.1, 00:19:54, FastEthernet0/0
D 111.111.111.16/29 [90/156160] via 1.2.1.1, 00:19:54, FastEthernet0/0
D 111.111.111.24/30 [90/156160] via 1.2.1.1, 00:19:54, FastEthernet0/0
D 111.111.111.32/28 [90/156160] via 1.2.1.1, 00:19:54, FastEthernet0/0
D 111.111.111.64/27 [90/156160] via 1.2.1.1, 00:19:54, FastEthernet0/0

Look at the 111.111.111.0/29 route.
R2 can reach 111.111.111.0/29 using the path R2----R1 because R2-R3-R1 is not a successor.
So The path R2---R1 is put in the topology table of R2 :

R2#show ip eigrp topology
EIGRP-IPv4 Topology Table for AS(100)/ID(111.111.111.10)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status

P 111.111.111.32/28, 1 successors, FD is 156160
via 1.2.1.1 (156160/128256), FastEthernet0/0
P 1.4.1.0/24, 2 successors, FD is 20514560
via 1.2.1.1 (20514560/20512000), FastEthernet0/0
via 2.4.2.4 (20514560/20512000), FastEthernet0/1
P 1.2.1.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/0
P 111.111.111.64/27, 1 successors, FD is 156160
via 1.2.1.1 (156160/128256), FastEthernet0/0
P 1.4.1.4/32, 1 successors, FD is 20514560
via 1.2.1.1 (20514560/20512000), FastEthernet0/0
P 111.111.111.16/29, 1 successors, FD is 156160
via 1.2.1.1 (156160/128256), FastEthernet0/0
P 111.111.111.8/29, 1 successors, FD is 128256
via Connected, Loopback1
P 2.4.2.0/24, 1 successors, FD is 28160
via Connected, FastEthernet0/1
P 111.111.111.24/30, 1 successors, FD is 156160
via 1.2.1.1 (156160/128256), FastEthernet0/0
P 1.4.1.1/32, 1 successors, FD is 20514560
via 2.4.2.4 (20514560/20512000), FastEthernet0/1
P 111.111.111.0/29, 1 successors, FD is 156160
via 1.2.1.1 (156160/128256), FastEthernet0/0

The path though R2 --R3--Seriallink--R1 is not a backup path either. So it should be put in the topology-all link table.

Comments

  • Continue :
    R2#show ip eigrp topology all-links
    EIGRP-IPv4 Topology Table for AS(100)/ID(111.111.111.10)
    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
    r - reply Status, s - sia Status

    P 111.111.111.32/28, 1 successors, FD is 156160, serno 7
    via 1.2.1.1 (156160/128256), FastEthernet0/0
    P 1.4.1.0/24, 2 successors, FD is 20514560, serno 11
    via 1.2.1.1 (20514560/20512000), FastEthernet0/0
    via 2.4.2.4 (20514560/20512000), FastEthernet0/1
    P 1.2.1.0/24, 1 successors, FD is 28160, serno 1
    via Connected, FastEthernet0/0
    P 111.111.111.64/27, 1 successors, FD is 156160, serno 8
    via 1.2.1.1 (156160/128256), FastEthernet0/0
    P 1.4.1.4/32, 1 successors, FD is 20514560, serno 12
    via 1.2.1.1 (20514560/20512000), FastEthernet0/0
    P 111.111.111.16/29, 1 successors, FD is 156160, serno 5
    via 1.2.1.1 (156160/128256), FastEthernet0/0
    P 111.111.111.8/29, 1 successors, FD is 128256, serno 3
    via Connected, Loopback1
    via 1.2.1.1 (156160/128256), FastEthernet0/0
    P 2.4.2.0/24, 1 successors, FD is 28160, serno 2
    via Connected, FastEthernet0/1
    P 111.111.111.24/30, 1 successors, FD is 156160, serno 6
    via 1.2.1.1 (156160/128256), FastEthernet0/0
    P 1.4.1.1/32, 1 successors, FD is 20514560, serno 10
    via 2.4.2.4 (20514560/20512000), FastEthernet0/1
    P 111.111.111.0/29, 1 successors, FD is 156160, serno 4
    via 1.2.1.1 (156160/128256), FastEthernet0/0

    But it's not.
    When i Shutdown int f0/0 of R2.
    Now look at this :

    R2#sh ip eigrp topology all-links
    EIGRP-IPv4 Topology Table for AS(100)/ID(111.111.111.10)
    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
    r - reply Status, s - sia Status

    P 111.111.111.32/28, 1 successors, FD is 20642560, serno 22
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1
    P 1.4.1.0/24, 1 successors, FD is 20514560, serno 20
    via 2.4.2.4 (20514560/20512000), FastEthernet0/1
    P 1.2.1.0/24, 1 successors, FD is 20517120, serno 21
    via 2.4.2.4 (20517120/20514560), FastEthernet0/1
    P 111.111.111.64/27, 1 successors, FD is 20642560, serno 23
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1
    P 111.111.111.16/29, 1 successors, FD is 20642560, serno 24
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1
    P 111.111.111.8/29, 1 successors, FD is 128256, serno 3
    via Connected, Loopback1
    P 2.4.2.0/24, 1 successors, FD is 28160, serno 2
    via Connected, FastEthernet0/1
    P 111.111.111.24/30, 1 successors, FD is 20642560, serno 25
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1
    P 1.4.1.1/32, 1 successors, FD is 20514560, serno 10
    via 2.4.2.4 (20514560/20512000), FastEthernet0/1
    P 111.111.111.0/29, 1 successors, FD is 20642560, serno 26
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1

    Then i thought it's because of the metric is too high compare to the path through f0/0 metric. it can't be put in the topology table. So i turn on f0/0 and put its metric higher almost eq the metric through R2--R3--Seriallink--R1 path. But let see here.

    R2#show run | sec router
    router eigrp 100
    network 1.2.1.0 0.0.0.255
    network 2.4.2.0 0.0.0.255
    network 111.111.111.8 0.0.0.7
    offset-list 1 in 20481400 FastEthernet0/0

    R2#sh ip eigrp topology all-links
    EIGRP-IPv4 Topology Table for AS(100)/ID(111.111.111.10)
    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
    r - reply Status, s - sia Status

    P 111.111.111.32/28, 1 successors, FD is 20637560, serno 58
    via 1.2.1.1 (20637560/20609536), FastEthernet0/0
    P 1.4.1.0/24, 1 successors, FD is 20514560, serno 61
    via 2.4.2.4 (20514560/20512000), FastEthernet0/1
    via 1.2.1.1 (40995960/40993280), FastEthernet0/0
    P 1.2.1.0/24, 1 successors, FD is 28160, serno 28
    via Connected, FastEthernet0/0
    P 111.111.111.64/27, 1 successors, FD is 20637560, serno 59
    via 1.2.1.1 (20637560/20609536), FastEthernet0/0
    P 1.4.1.4/32, 1 successors, FD is 40995960, serno 60
    via 1.2.1.1 (40995960/40993280), FastEthernet0/0
    P 111.111.111.16/29, 1 successors, FD is 20637560, serno 56
    via 1.2.1.1 (20637560/20609536), FastEthernet0/0
    P 111.111.111.8/29, 1 successors, FD is 128256, serno 3
    via Connected, Loopback1
    via 1.2.1.1 (20637560/20609536), FastEthernet0/0
    P 2.4.2.0/24, 1 successors, FD is 28160, serno 2
    via Connected, FastEthernet0/1
    P 111.111.111.24/30, 1 successors, FD is 20637560, serno 57
    via 1.2.1.1 (20637560/20609536), FastEthernet0/0
    P 1.4.1.1/32, 1 successors, FD is 20514560, serno 10
    via 2.4.2.4 (20514560/20512000), FastEthernet0/1
    P 111.111.111.0/29, 1 successors, FD is 20637560, serno 55
    via 1.2.1.1 (20637560/20609536), FastEthernet0/0

    The other path is still not in the Topology all link table.

    IF I configure both path have the same metric R2'll load balancing and the path will be put in the Topology all link table.

  • Continue :

    R2(config-router)#do sh ip eigrp topology all-link
    EIGRP-IPv4 Topology Table for AS(100)/ID(111.111.111.10)
    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
    r - reply Status, s - sia Status

    P 111.111.111.32/28, 2 successors, FD is 20637560, serno 71
    via 1.2.1.1 (20642560/20614656), FastEthernet0/0
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1
    P 1.4.1.0/24, 1 successors, FD is 20514560, serno 61
    via 2.4.2.4 (20514560/20512000), FastEthernet0/1
    via 1.2.1.1 (41000960/40998400), FastEthernet0/0
    P 1.2.1.0/24, 1 successors, FD is 28160, serno 28
    via Connected, FastEthernet0/0
    P 111.111.111.64/27, 2 successors, FD is 20637560, serno 72
    via 1.2.1.1 (20642560/20614656), FastEthernet0/0
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1
    P 1.4.1.4/32, 1 successors, FD is 41000960, serno 62
    via 1.2.1.1 (41000960/40998400), FastEthernet0/0
    P 111.111.111.16/29, 2 successors, FD is 20637560, serno 69
    via 1.2.1.1 (20642560/20614656), FastEthernet0/0
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1
    P 111.111.111.8/29, 1 successors, FD is 128256, serno 3
    via Connected, Loopback1
    via 1.2.1.1 (20642560/20614656), FastEthernet0/0
    P 2.4.2.0/24, 1 successors, FD is 28160, serno 2
    via Connected, FastEthernet0/1
    P 111.111.111.24/30, 2 successors, FD is 20637560, serno 70
    via 1.2.1.1 (20642560/20614656), FastEthernet0/0
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1
    P 1.4.1.1/32, 1 successors, FD is 20514560, serno 10
    via 2.4.2.4 (20514560/20512000), FastEthernet0/1
    P 111.111.111.0/29, 2 successors, FD is 20637560, serno 68
    via 1.2.1.1 (20642560/20614656), FastEthernet0/0
    via 2.4.2.4 (20642560/20640000), FastEthernet0/1

    R2# sh ip route
    Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP
    D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area
    N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2
    E1 - OSPF external type 1, E2 - OSPF external type 2
    i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2
    ia - IS-IS inter area, * - candidate default, U - per-user static route
    o - ODR, P - periodic downloaded static route, H - NHRP, l - LISP
    + - replicated route, % - next hop override

    Gateway of last resort is not set

      1.0.0.0/8 is variably subnetted, 5 subnets, 2 masks
    

    C 1.2.1.0/24 is directly connected, FastEthernet0/0
    L 1.2.1.2/32 is directly connected, FastEthernet0/0
    D 1.4.1.0/24 [90/20514560] via 2.4.2.4, 00:00:52, FastEthernet0/1
    D 1.4.1.1/32 [90/20514560] via 2.4.2.4, 00:07:23, FastEthernet0/1
    D 1.4.1.4/32 [90/41000960] via 1.2.1.1, 00:00:52, FastEthernet0/0
    2.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
    C 2.4.2.0/24 is directly connected, FastEthernet0/1
    L 2.4.2.2/32 is directly connected, FastEthernet0/1
    111.0.0.0/8 is variably subnetted, 7 subnets, 5 masks
    D 111.111.111.0/29 [90/20642560] via 2.4.2.4, 00:00:52, FastEthernet0/1
    [90/20642560] via 1.2.1.1, 00:00:52, FastEthernet0/0

    C 111.111.111.8/29 is directly connected, Loopback1
    L 111.111.111.10/32 is directly connected, Loopback1
    D 111.111.111.16/29
    [90/20642560] via 2.4.2.4, 00:00:52, FastEthernet0/1
    [90/20642560] via 1.2.1.1, 00:00:52, FastEthernet0/0
    D 111.111.111.24/30
    [90/20642560] via 2.4.2.4, 00:00:52, FastEthernet0/1
    [90/20642560] via 1.2.1.1, 00:00:52, FastEthernet0/0
    D 111.111.111.32/28
    [90/20642560] via 2.4.2.4, 00:00:52, FastEthernet0/1
    [90/20642560] via 1.2.1.1, 00:00:52, FastEthernet0/0
    D 111.111.111.64/27
    [90/20642560] via 2.4.2.4, 00:00:52, FastEthernet0/1

    [90/20642560] via 1.2.1.1, 00:00:52, FastEthernet0/0

    if i replace the Serial link with the FE link :

    R6 has a loopback 3.3.3.3/24

    R4#show ip eigrp topology all-links
    EIGRP-IPv4 Topology Table for AS(1)/ID(4.6.0.1)
    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
    r - reply Status, s - sia Status

    P 5.6.0.0/24, 2 successors, FD is 30720, serno 11
    via 4.5.0.2 (30720/28160), FastEthernet0/0
    via 4.6.0.2 (30720/28160), FastEthernet0/1
    P 3.3.0.0/24, 1 successors, FD is 156160, serno 12
    via 4.6.0.2 (156160/128256), FastEthernet0/1
    via 4.5.0.2 (158720/156160), FastEthernet0/0
    P 4.5.0.0/24, 1 successors, FD is 28160, serno 1
    via Connected, FastEthernet0/0
    P 4.6.0.0/24, 1 successors, FD is 28160, serno 2
    via Connected, FastEthernet0/1
    it's not a B-U path but still in the topology all link table. But in the 1st senario it's not

    I tried to put the metric of the R4--R5--R6 path higher but it still in the topology table
    R4#sh ip eigrp topology all-links
    EIGRP-IPv4 Topology Table for AS(1)/ID(4.6.0.4)
    Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
    r - reply Status, s - sia Status

    P 5.6.0.0/24, 1 successors, FD is 30720, serno 7
    via 4.6.0.6 (30720/28160), FastEthernet0/1
    via 4.5.0.5 (30030720/30028032), FastEthernet0/0
    P 3.3.0.0/24, 1 successors, FD is 156160, serno 3
    via 4.6.0.6 (156160/128256), FastEthernet0/1
    via 4.5.0.5 (30158720/30156032), FastEthernet0/0
    P 4.5.0.0/24, 1 successors, FD is 28160, serno 1
    via Connected, FastEthernet0/0
    P 4.6.0.0/24, 1 successors, FD is 28160, serno 2
    via Connected, FastEthernet0/1

    Why the serial scenario didn't put the other path in ??

  • The BW and Delay of the serial interface in the scenario 1: BW 128 Kbit/sec, DLY 20000 usec,

  • I think what is happening is that, before you mess around with changing interface bandwidth/delay values...router R3 is pointing at R2 as its Successor for the 111.111.111.0/29 route. R3's metric for its direct serial connection to R1 is probably so horrible that the roundabout path to this network via R2 is better (from R3's perspective). Remember that if I'm pointing at YOU as my Successor for a route, I'm not going to advertise that route TO you (that would cause a routing loop). That would also explain why, when R2's Fast0/0 interface is up you don't see any alternative path via R3 (because R3 is USING R2 as its next-hop/Successor). But when you disable Fast0/0 on R2, then R3 has no choice but to switchover to its Serial connection...and advertise that connection back to R2.

    Hope that made sense.
    Keith

  • Thanks Sir !
    Now i finally understand !
    Have a great day ^_^

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