Hi,
I have a situation where a E1 route is being overriden by a E2 route.
The E1 route is entering the area from a mpls superbackbone and the
E2 from an ASBR in the same area. According to what I know an E1
route should always win from a E2 route.. I feel that I am going
to learn something here.
R5 is connected to SW2 and R4.
On SW2 the following is done:
!
ip route 12.12.12.12 255.255.255.255 Null0
!
router ospf 100
router-id 0.0.0.8
log-adjacency-changes
redistribute static subnets
network 155.1.58.8 0.0.0.0 area 0
!
On R4 the following is done:
!
router ospf 100 vrf TEST
router-id 0.0.0.4
log-adjacency-changes
redistribute bgp 100 subnets
network 155.1.45.4 0.0.0.0 area 0
!
router bgp 100
no synchronization
bgp log-neighbor-changes
neighbor 6.6.6.6 remote-as 100
neighbor 6.6.6.6 update-source Loopback10
neighbor 204.12.1.254 remote-as 54
no auto-summary
!
address-family vpnv4
neighbor 6.6.6.6 activate
neighbor 6.6.6.6 send-community extended
exit-address-family
!
address-family ipv4 vrf TEST
no synchronization
exit-address-family
!
On R5 the following is done:
!
router ospf 100
router-id 0.0.0.5
log-adjacency-changes
network 155.1.45.5 0.0.0.0 area 0
network 155.1.58.5 0.0.0.0 area 0
Rack1R5#
Some relevant show commands:
Rack1R5#show ip route ospf 100
12.0.0.0/32 is subnetted, 1 subnets
O E2 12.12.12.12 [110/20] via 155.1.58.8, 05:41:13, FastEthernet0/0
Rack1R5#
Rack1R5#show ip ospf database external 12.12.12.12
OSPF Router with ID (0.0.0.5) (Process ID 100)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 1494
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 12.12.12.12 (External Network Number )
Advertising Router: 0.0.0.8
LS Seq Number: 8000000B
Checksum: 0x79E4
Length: 36
Network Mask: /32
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 0
Rack1R5#
Rack1R5#show ip ospf database router 0.0.0.8
OSPF Router with ID (0.0.0.5) (Process ID 100)
Router Link States (Area 0)
Routing Bit Set on this LSA
LS age: 1533
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 0.0.0.8
Advertising Router: 0.0.0.8
LS Seq Number: 80000024
Checksum: 0xDF9B
Length: 36
AS Boundary Router
Number of Links: 1
Link connected to: a Transit Network
(Link ID) Designated Router address: 155.1.58.5
(Link Data) Router Interface address: 155.1.58.8
Number of TOS metrics: 0
TOS 0 Metrics: 200
Rack1R5#
Now if I remove the static route on SW2:
Rack1SW2(config)#no ip route 12.12.12.12 255.255.255.255 Null0
And ask R5 what external route it has we see that only after
the static from SW2 has been removed R5 will accept the E1
route since the E2 route is no longer available:
Rack1R5#show ip ospf database external
OSPF Router with ID (0.0.0.5) (Process ID 100)
Type-5 AS External Link States
Routing Bit Set on this LSA
LS age: 55
Options: (No TOS-capability, DC)
LS Type: AS External Link
Link State ID: 12.12.12.12 (External Network Number )
Advertising Router: 0.0.0.4
LS Seq Number: 80000001
Checksum: 0xF046
Length: 36
Network Mask: /32
Metric Type: 2 (Larger than any link state path)
TOS: 0
Metric: 20
Forward Address: 0.0.0.0
External Route Tag: 3489661028
Rack1R5#
Rack1R5#show ip ospf database router 0.0.0.4
OSPF Router with ID (0.0.0.5) (Process ID 100)
Router Link States (Area 0)
Routing Bit Set on this LSA
LS age: 820
Options: (No TOS-capability, DC)
LS Type: Router Links
Link State ID: 0.0.0.4
Advertising Router: 0.0.0.4
LS Seq Number: 80000016
Checksum: 0xAB3C
Length: 48
Area Border Router
AS Boundary Router
Number of Links: 2
Link connected to: another Router (point-to-point)
(Link ID) Neighboring Router ID: 0.0.0.5
(Link Data) Router Interface address: 155.1.45.4
Number of TOS metrics: 0
TOS 0 Metrics: 64
Link connected to: a Stub Network
(Link ID) Network/subnet number: 155.1.45.0
(Link Data) Network Mask: 255.255.255.0
Number of TOS metrics: 0
TOS 0 Metrics: 64
Rack1R5#
Your analysis/help is appreciated.
Regards
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Received on Thu Apr 11 2013 - 23:03:29 ART
This archive was generated by hypermail 2.2.0 : Wed May 01 2013 - 06:47:40 ART