Shrimp Co. is opening remote offices in Milwaukee and New Orleans. Implement multi-area OSPF for scalable routing and configure GRE tunnels to connect all locations over the internet.

Tip: Individual topology files are available in the diagrams folder on my Github

• Use the following area assignments:
  • Area 0: Core (SEA MDF routers and DSWs)
  • Area 1: Milwaukee site
  • Area 2: Minneapolis site

Include the loopbacks and GRE tunnel interfaces in the appropriate areas.

router ospf 1
 network 10.255.1.0 0.0.0.255 area 0.0.0.0
 network 172.20.25.0 0.0.0.255 area 0.0.0.0
 network 172.16.0.0 0.0.255.255 area 1
 network 172.18.0.0 0.0.255.255 area 2

• Create point-to-point GRE tunnels over the public internet (using Eth3 on MDF routers)
• Terminate tunnels between sea-mdf-r1 ⇆ mke-at-r1 and sea-mdf-r2 ⇆ msp-at-r1
• Assign tunnel IPs from 192.168.100.0/30
• Tunnel interfaces should be included in OSPF

interface Tunnel1
 ip address 192.168.100.1 255.255.255.252
 tunnel source Ethernet3
 tunnel destination [Remote IP]

Repeat on each router with appropriate local/remote IPs.

Configure route summarization on ABRs (sea-mdf-r1 and sea-mdf-r2) to reduce OSPF LSAs:

router ospf 1
 area 1 range 10.2.0.0 255.255.0.0
 area 2 range 10.3.0.0 255.255.0.0

• Implement MLAG between sea-mdf-dsw1 and dsw2
• Create Port-Channel1 for MLAG peer link, and Port-Channel10 for downstream access switches
• Use consistent LACP and VLAN settings
• MLAG ID: 10

interface Port-Channel1
 description MLAG Peer Link
 switchport
 switchport mode trunk
 mlag peer-link

interface Ethernet3
 channel-group 1 mode active

mlag configuration
 domain-id shrimp-co
 local-interface Vlan4094
 peer-address 10.1.1.2
 peer-link Port-Channel1

Configure corresponding access switches with Port-Channel10 to both DSWs.

show ip ospf neighbor
show ip route ospf
show interfaces tunnel1

show mlag
show mlag interfaces

ping 172.16.25.67
traceroute 172.18.25.100
dig seamart.com