
Topology 1

- VPC001 routes:

- CSR routes:
Network Next Hop Metric LocPrf Weight Path
* 10.0.0.0/16 169.254.100.45 200 0 64512 i
*> 169.254.201.57 100 0 64512 i
*m 10.11.64.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 10.11.65.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 10.11.66.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*> 169.254.0.0/30 0.0.0.0 0 32768 ?
*> 169.254.0.4/30 0.0.0.0 0 32768 ?
*> 169.254.100.44/30
0.0.0.0 0 32768 ?
*> 169.254.201.56/30
0.0.0.0 0 32768 ?
*> 172.31.0.0/28 0.0.0.0 0 32768 ?
*> 172.31.0.128/28 172.31.0.1 0 32768 ?
Metric 100 comes from:
advertised_route_priority = 100
Topology 2

- VPC001:
- CSR:
Network Next Hop Metric LocPrf Weight Path
* 10.0.0.0/16 169.254.100.45 200 0 64512 i
*> 169.254.201.57 100 0 64512 i
* 10.11.64.0/24 169.254.129.1 333 0 64514 ?
*m 169.254.0.1 100 0 64514 ?
*> 169.254.0.5 100 0 64514 ?
* 10.11.65.0/24 169.254.129.1 333 0 64514 ?
*m 169.254.0.1 100 0 64514 ?
*> 169.254.0.5 100 0 64514 ?
* 10.11.66.0/24 169.254.129.1 333 0 64514 ?
*m 169.254.0.1 100 0 64514 ?
*> 169.254.0.5 100 0 64514 ?
*> 169.254.0.0/30 0.0.0.0 0 32768 ?
*> 169.254.0.4/30 0.0.0.0 0 32768 ?
*> 169.254.100.44/30
0.0.0.0 0 32768 ?
*> 169.254.129.0/30 0.0.0.0 0 32768 ?
*> 169.254.129.4/30 0.0.0.0 0 32768 ?
*> 169.254.201.56/30
0.0.0.0 0 32768 ?
*> 172.31.0.0/28 0.0.0.0 0 32768 ?
*> 172.31.0.128/28 172.31.0.1 0 32768 ?
- CSR RIB:
S* 0.0.0.0/0 [1/0] via 172.31.0.1, GigabitEthernet1
10.0.0.0/8 is variably subnetted, 4 subnets, 2 masks
B 10.0.0.0/16 [20/100] via 169.254.201.57, 06:57:24
B 10.11.64.0/24 [20/100] via 169.254.0.5, 00:02:15
[20/100] via 169.254.0.1, 00:02:15
B 10.11.65.0/24 [20/100] via 169.254.0.5, 00:02:15
[20/100] via 169.254.0.1, 00:02:15
B 10.11.66.0/24 [20/100] via 169.254.0.5, 00:02:15
[20/100] via 169.254.0.1, 00:02:15
169.254.0.0/16 is variably subnetted, 12 subnets, 2 masks
C 169.254.0.0/30 is directly connected, Tunnel10
L 169.254.0.2/32 is directly connected, Tunnel10
C 169.254.0.4/30 is directly connected, Tunnel11
L 169.254.0.6/32 is directly connected, Tunnel11
C 169.254.100.44/30 is directly connected, Tunnel2
L 169.254.100.46/32 is directly connected, Tunnel2
C 169.254.129.0/30 is directly connected, Tunnel20
L 169.254.129.2/32 is directly connected, Tunnel20
C 169.254.129.4/30 is directly connected, Tunnel21
L 169.254.129.6/32 is directly connected, Tunnel21
C 169.254.201.56/30 is directly connected, Tunnel1
L 169.254.201.58/32 is directly connected, Tunnel1
172.31.0.0/16 is variably subnetted, 3 subnets, 2 masks
C 172.31.0.0/28 is directly connected, GigabitEthernet1
L 172.31.0.13/32 is directly connected, GigabitEthernet1
S 172.31.0.128/28 [1/0] via 172.31.0.1
Topology 3
routing_mode = "REGIONAL"
CSR:
*> 10.0.0.0/16 169.254.100.45 100 0 64512 i
* 169.254.201.57 200 0 64512 i
*> 10.11.64.0/24 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
*> 10.11.65.0/24 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
*> 10.11.66.0/24 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
*> 169.254.0.0/30 0.0.0.0 0 32768 ?
*> 169.254.0.4/30 0.0.0.0 0 32768 ?
*> 169.254.100.44/30
0.0.0.0 0 32768 ?
*> 169.254.129.0/30 0.0.0.0 0 32768 ?
*> 169.254.129.4/30 0.0.0.0 0 32768 ?
*> 169.254.201.56/30
0.0.0.0 0 32768 ?
*> 172.31.0.0/28 0.0.0.0 0 32768 ?
*> 172.31.0.128/28 172.31.0.1 0 32768 ?
Subnetworks 10.11.64-66 are on us-east1. Adding a new subnet to vpc001 but located in us-central1:
*> 10.0.0.0/16 169.254.100.45 100 0 64512 i
* 169.254.201.57 200 0 64512 i
*> 10.11.64.0/24 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
*> 10.11.65.0/24 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
*> 10.11.66.0/24 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
*> 100.64.0.0/24 169.254.129.1 100 0 64514 ?
*> 169.254.0.0/30 0.0.0.0 0 32768 ?
*> 169.254.0.4/30 0.0.0.0 0 32768 ?
*> 169.254.100.44/30
0.0.0.0 0 32768 ?
*> 169.254.129.0/30 0.0.0.0 0 32768 ?
*> 169.254.129.4/30 0.0.0.0 0 32768 ?
*> 169.254.201.56/30
0.0.0.0 0 32768 ?
*> 172.31.0.0/28 0.0.0.0 0 32768 ?
*> 172.31.0.128/28 172.31.0.1 0 32768 ?
100.64.0.0/24 is advertised from central gateway.
Topology 4

Default Config:
- vpc001 routes:

- vpc002 routes:

Network Next Hop Metric LocPrf Weight Path
* 10.0.0.0/16 169.254.100.45 200 0 64512 i
*> 169.254.201.57 100 0 64512 i
*m 10.11.64.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 10.11.65.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 10.11.66.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*> 169.254.0.0/30 0.0.0.0 0 32768 ?
*> 169.254.0.4/30 0.0.0.0 0 32768 ?
*> 169.254.100.44/30
0.0.0.0 0 32768 ?
*> 169.254.201.56/30
0.0.0.0 0 32768 ?
*> 172.31.0.0/28 0.0.0.0 0 32768 ?
*> 172.31.0.128/28 172.31.0.1 0 32768 ?
Import/Export:
- vpc001:

- vpc002

- CSR
Network Next Hop Metric LocPrf Weight Path
* 10.0.0.0/16 169.254.100.45 200 0 64512 i
*> 169.254.201.57 100 0 64512 i
*m 10.11.64.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 10.11.65.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 10.11.66.0/24 169.254.0.5 100 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*> 169.254.0.0/30 0.0.0.0 0 32768 ?
*> 169.254.0.4/30 0.0.0.0 0 32768 ?
*> 169.254.100.44/30
0.0.0.0 0 32768 ?
*> 169.254.201.56/30
0.0.0.0 0 32768 ?
*> 172.31.0.0/28 0.0.0.0 0 32768 ?
*> 172.31.0.128/28 172.31.0.1 0 32768 ?
Topology 5

*> 10.0.0.0/16 169.254.100.45 100 0 64512 i
* 169.254.201.57 200 0 64512 i
* 10.11.64.0/24 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
* 10.11.65.0/24 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
* 10.11.66.0/24 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
*m 10.12.64.0/24 169.254.3.5 100 0 64514 ?
*> 169.254.3.1 100 0 64514 ?
* 169.254.4.5 333 0 64514 ?
* 169.254.4.1 333 0 64514 ?
*m 10.12.65.0/24 169.254.3.5 100 0 64514 ?
*> 169.254.3.1 100 0 64514 ?
* 169.254.4.5 333 0 64514 ?
* 169.254.4.1 333 0 64514 ?
*m 10.12.66.0/24 169.254.3.5 100 0 64514 ?
*> 169.254.3.1 100 0 64514 ?
* 169.254.4.5 333 0 64514 ?
CSR1000v RIB:
S* 0.0.0.0/0 [1/0] via 172.31.0.1, GigabitEthernet1
10.0.0.0/8 is variably subnetted, 7 subnets, 2 masks
B 10.0.0.0/16 [20/100] via 169.254.100.45, 01:27:49
B 10.11.64.0/24 [20/100] via 169.254.0.5, 01:28:10
[20/100] via 169.254.0.1, 01:28:10
B 10.11.65.0/24 [20/100] via 169.254.0.5, 01:28:10
[20/100] via 169.254.0.1, 01:28:10
B 10.11.66.0/24 [20/100] via 169.254.0.5, 01:28:10
[20/100] via 169.254.0.1, 01:28:10
B 10.12.64.0/24 [20/100] via 169.254.3.5, 00:12:47
[20/100] via 169.254.3.1, 00:12:47
B 10.12.65.0/24 [20/100] via 169.254.3.5, 00:12:47
[20/100] via 169.254.3.1, 00:12:47
B 10.12.66.0/24 [20/100] via 169.254.3.5, 00:12:47
[20/100] via 169.254.3.1, 00:12:47
100.0.0.0/24 is subnetted, 1 subnets
B 100.64.0.0 [20/100] via 169.254.2.1, 00:03:01
Using the same AS vpc001 and vpc002 does not exchange routes. If we change vpc002 CR to a different AS (64515):
- vpc002 rt:

- vpc001 rt:

Topology 6

- vpc001 rt:

Topology 7


Topology 8

- CSR rt:
* 10.11.64.0/24 169.254.2.5 333 0 64514 ?
* 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
* 10.11.65.0/24 169.254.2.5 333 0 64514 ?
* 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
* 10.11.66.0/24 169.254.2.5 333 0 64514 ?
* 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
* 10.12.64.0/24 169.254.4.1 333 0 64514 ?
*> 169.254.3.1 100 0 64514 ?
* 169.254.4.5 333 0 64514 ?
*m 169.254.3.5 100 0 64514 ?
* 10.12.65.0/24 169.254.4.1 333 0 64514 ?
*> 169.254.3.1 100 0 64514 ?
* 169.254.4.5 333 0 64514 ?
*m 169.254.3.5 100 0 64514 ?
* 10.12.66.0/24 169.254.4.1 333 0 64514 ?
*> 169.254.3.1 100 0 64514 ?
* 169.254.4.5 333 0 64514 ?
*m 169.254.3.5 100 0 64514 ?
* 100.64.0.0/24 169.254.2.5 333 0 64514 ?
* 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
* 100.64.8.0/21 169.254.2.5 333 0 64514 ?
* 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
* 100.64.16.0/21 169.254.2.5 333 0 64514 ?
* 169.254.2.1 333 0 64514 ?
*> 169.254.0.1 100 0 64514 ?
*m 169.254.0.5 100 0 64514 ?
- CSR RIB:
B 10.11.64.0/24 [20/100] via 169.254.0.5, 00:13:49
[20/100] via 169.254.0.1, 00:13:49
B 10.11.65.0/24 [20/100] via 169.254.0.5, 00:13:49
[20/100] via 169.254.0.1, 00:13:49
B 10.11.66.0/24 [20/100] via 169.254.0.5, 00:13:49
[20/100] via 169.254.0.1, 00:13:49
B 10.12.64.0/24 [20/100] via 169.254.3.5, 00:13:49
[20/100] via 169.254.3.1, 00:13:49
B 10.12.65.0/24 [20/100] via 169.254.3.5, 00:13:49
[20/100] via 169.254.3.1, 00:13:49
B 10.12.66.0/24 [20/100] via 169.254.3.5, 00:13:49
[20/100] via 169.254.3.1, 00:13:49
100.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
B 100.64.0.0/24 [20/100] via 169.254.0.5, 00:13:49
[20/100] via 169.254.0.1, 00:13:49
B 100.64.8.0/21 [20/100] via 169.254.0.5, 00:13:49
[20/100] via 169.254.0.1, 00:13:49
B 100.64.16.0/21 [20/100] via 169.254.0.5, 00:13:49
[20/100] via 169.254.0.1, 00:13:49
- VPC001 rt:

References
https://cloud.google.com/vpc/docs/using-routes#gcloud
https://cloud.google.com/network-connectivity/docs/router/support/troubleshooting