Zach Thomas

Network Engineer

Skill: Routing

  • Aruba CX – OSPF – Basics

    Category: Networking

    Skills: OSPF, Routing, 

    Equipment: Aruba CX Virtual Switches, Virtual PC’s, Eve-Ng

    Objective

    • Learn the basics of OSPF routing
    • Configure OSPF on 4 seperate Layer 3 switches

    Topology

    Image.png

    Devices

    • 4 x Aruba CX Switches (Virutal)
    • 4 x Virtual PCs

    Steps

    1. Setup your lab enviroment based on the topology above
    2. Turn on all nodes
      • If using EVEng (Click “More Actions” on the side and “Start all nodes”
    3. You will need to confiugre each switch
      • Hostname
      • Interface IP
      • Enable interfsces
    4. Configure OSPF Routing
    5. Test Pinging different PCs
    6. Explorer useful commands

    Configure Switches Hostname & Interface IP Addresses

    sw1

    switch(config)# hostname sw1

sw1(config)# int 1/1/1
sw1(config-if)# ip address 192.168.1.1/24

sw1(config-if)# int 1/1/2
sw1(config-if)# ip address 10.0.12.1/30

sw1(config-if)# int 1/1/3
sw1(config-if)# ip address 10.0.14.1/30

sw1(config-if)# int 1/1/1-1/1/3
sw1(config-if-<1/1/1-1/1/3>)# no shutdown

    sw2

    switch(config)# hostname sw2

sw2(config)# int 1/1/1
sw2(config-if)# ip address 192.168.2.1/24

sw2(config-if)# int 1/1/2
sw2(config-if)# ip address 10.0.12.2/30

sw2(config-if)# int 1/1/3
sw2(config-if)# ip address 10.0.23.1/30

sw2(config-if)# int 1/1/1-1/1/3
sw2(config-if-<1/1/1-1/1/3>)# no shutdown

    sw3

    switch(config)# hostname sw3

sw3(config)# int 1/1/1
sw3(config-if)# ip address 192.168.3.1/24

sw3(config-if)# int 1/1/2
sw3(config-if)# ip address 10.0.43.2/30

sw3(config-if)# int 1/1/3
sw3(config-if)# ip address 10.0.23.2/30

sw3(config-if)# int 1/1/1-1/1/3
sw3(config-if-<1/1/1-1/1/3>)# no shutdown

    sw4

    switch(config)# hostname sw3

sw4(config)# int 1/1/1
sw4(config-if)# ip address 192.168.4.1/24

sw4(config-if)# int 1/1/2
sw4(config-if)# ip address 10.0.43.1/30

sw4(config-if)# int 1/1/3
sw4(config-if)# ip address 10.0.14.2/30

sw4(config-if)# int 1/1/1-1/1/3
sw4(config-if-<1/1/1-1/1/3>)# no shutdown

    Configure Virtual PCs Hostname & Interface IP Addresses

    vpc1

    VPCS> set pcname vpc1

vpc1> ip 192.168.1.2/24 192.168.1.1
         IP ADDRESS     DEFAULT GATEWAY

    vpc2

    VPCS> set pcname vpc2

vpc2> ip 192.168.2.2/24 192.168.2.1
         IP ADDRESS     DEFAULT GATEWAY

    vpc3

    VPCS> set pcname vpc3

vpc3> ip 192.168.3.2/24 192.168.3.1
         IP ADDRESS     DEFAULT GATEWAY

    vpc4

    VPCS> set pcname vpc4

vpc4> ip 192.168.4.2/24 192.168.4.1
         IP ADDRESS     DEFAULT GATEWAY

    Configure OSPF

    • We will set the OSPF proccess id as 1
    • We will set the Router-ID to the following (this can be anything it is not an IP address)
      • sw1 = 1.1.1.1
      • sw2 = 2.2.2.2
      • sw3 = 3.3.3.3
      • sw4 = 4.4.4.4
    • we will setup area 0 (This is the backbone)

    sw1

    sw1(config-ospf-1)# router ospf 1
sw1(config-ospf-1)# router-id 1.1.1.1

sw1(config-ospf-1)# int 1/1/1-1/1/3
sw1(config-if-<1/1/1-1/1/3>)# ip ospf 1 area 0
OSPF Area is not configured.
Do you want to create (y/n)? y

    sw2

    sw2(config)# router ospf 1
sw2(config-ospf-1)# router-id 2.2.2.2

sw2(config-ospf-1)# int 1/1/1-1/1/3
sw2(config-if-<1/1/1-1/1/3>)# ip ospf 1 area 0
OSPF Area is not configured.
Do you want to create (y/n)? y

    sw3

    sw3(config)# router ospf 1
sw3(config-ospf-1)# router-id 3.3.3.3

sw3(config-ospf-1)# int 1/1/1-1/1/3
sw3(config-if-<1/1/1-1/1/3>)# ip ospf 1 area 0
OSPF Area is not configured.
Do you want to create (y/n)? y

    sw4

    sw4(config)# router ospf 1
sw4(config-ospf-1)# router-id 4.4.4.4

sw4(config-ospf-1)# int 1/1/1-1/1/3
sw4(config-if-<1/1/1-1/1/3>)# ip ospf 1 area 0
OSPF Area is not configured.
Do you want to create (y/n)? y

    Activities

    • From vp1 ping vpc3 (192.168.3.2)
      • Was it sucessful?
    • use the command sh ip route You should see several routes
      • Routes with orgin/Type is OSPF routes
    Image.png
    • Anoher good command is sh ip ospf neighbors
    Image.png
    • Here you will see DR and BDR
      • DR = Designated Router
        • Acts as the hub for LSAs on that network
        • Chosen by highest priority (default is 1, 0-255)
      • BDR = Backup Designated Router
        • Takes over if the DR goes down

    Common Commands for OSPF

    • router ospf <process id>
    • router-id <0.0.0.0>
    • ip ospf <process id> area <area number - Usually 0>
    • sh ip routed
    • sh ip ospf neighbors 
    • sh ip ospf interface
    • sh interface brief Less common for ospf

    Common issues

    • Wrong subnet mask at one end
    • Duplicate IP on a segment
    • Wrong netowrk at one end of a segment