Trying to debug and get what I want out of OSPF.
- robbat2, 2014/09/13

Goals:
------
Ensure traffic for a given src/dst pair flows via the highest bandwidth link;
despite local addressing.

The addresses are going to be on the hosts, this is not routing traffic for
other systems behind the hosts. Would also like it to be dynamic, so that some
of the service IPs can move around and always get the optimal bandwidth path.

Network diagram:
----------------
+-----------+
|    NET1   |
+-----------+
 |  |  |  |
 H1~H3 H2~H4
 |  |  |  |
+-----------+
|    NET2   |
+-----------+

4 hosts: H1..H4

4 areas:
NET1(0.0.0.0) - 1Mbit, 10.77.0.0/16 (eth0)
NET2(0.1.0.0) - 10Mbit 10.1.0.0/16 (eth1)
H1/H3(0.2.13.0) xconnect - 40Mbit, 10.2.13.0/24 (eth2)
H2/H4(0.2.24.0) xconnect - 40Mbit, 10.2.24.0/24 (eth2)

(speed scaled down for test purpose, the real network is 1/10/40Gbit).

Configuration (common):
-----------------------
interface eth0
 bandwidth 1000
 ip ospf cost 10000
exit
interface eth1
 bandwidth 10000
 ip ospf cost 1000
exit
interface eth2
 bandwidth 40000
 ip ospf cost 250
exit
router ospf
 auto-cost reference-bandwidth 1
 no network 10.1.0.0/16 area 0.1.0.0
 no network 10.2.13.0/24 area 0.2.13.0
 no network 10.2.24.0/24 area 0.2.24.0
 no network 10.77.0.0/16 area 0.77.0.0
 no network 172.30.1.0/24 area 172.30.1.0
 no network 172.30.2.0/24 area 172.30.2.0
 no network 172.30.3.0/24 area 172.30.3.0
 no network 172.30.4.0/24 area 172.30.4.0
 network 10.1.0.0/16 area 0
 network 10.2.13.0/24 area 0
 network 10.2.24.0/24 area 0
 network 10.77.0.0/16 area 0
 network 172.30.1.0/24 area 0
 network 172.30.2.0/24 area 0
 network 172.30.3.0/24 area 0
 network 172.30.4.0/24 area 0
exit

Configuration (unique per host):
--------------------------------
router ospf
 router-id 10.77.0.11 # H1
 router-id 10.77.0.12 # H2
 router-id 10.77.0.13 # H3
 router-id 10.77.0.13 # H4
exit
interface lo
 address 172.30.1.11/32 # H1
 address 172.30.2.12/32 # H2
 address 172.30.3.13/32 # H3
 address 172.30.4.14/32 # H4
exit
interface eth0
 address 10.77.0.11/16 # H1
 address 10.77.0.12/16 # H2
 address 10.77.0.13/16 # H3
 address 10.77.0.14/16 # H4
exit
interface eth1
 address 10.1.0.11/16 # H1
 address 10.1.0.12/16 # H2
 address 10.1.0.13/16 # H3
 address 10.1.0.14/16 # H4
exit
interface eth2
 address 10.2.13.11/24 # H1
 address 10.2.24.12/24 # H2
 address 10.2.13.13/24 # H3
 address 10.2.24.14/24 # H4
exit

Desired results:
----------------
10.77.0.11 -> 10.77.0.13
should route via xconnect

10.77.0.11 -> 10.77.0.14
should route via NET2:H4

10.77.0.11 -> 10.2.24.12
should route via NET2:H2

10.77.0.11 -> 10.2.24.14
should route via NET2:H4

172.30.1.11 -> 172.30.2.12
should route via NET2:H2

172.30.1.11 -> 172.30.3.13
should route via xconnect

Results:
--------
(on H1)
# ip route get 10.77.0.13 from 10.77.0.11
10.77.0.13 from 10.77.0.11 dev eth0

# ip route get 10.77.0.14 from 10.77.0.11
10.77.0.14 from 10.77.0.11 dev eth0

# ip route get 10.2.24.14 from 10.77.0.11
10.2.24.14 from 10.77.0.11 via 10.77.0.12 dev eth0

# ip route get 172.30.2.12 from 172.30.1.11
172.30.2.12 from 172.30.1.11 via 10.77.0.12 dev eth0

# ip route get 172.30.2.12 from 172.30.1.11
172.30.2.12 from 172.30.1.11 via 10.77.0.12 dev eth0

Notes on testcase environment
-----------------------------
The testcase environment is running on libvirt, with the links constrained to
the described 1/10/40Mbit speeds.