# lab02-OSPF-CLOS ### Task Underlay. OSPF Set up OSPF in the underlay network to establish IP connectivity between all network devices • Document the following: ⁠◦ Implementation plan ⁠◦ IP addressing scheme ⁠◦ Network topology diagram ⁠◦ Device configurations (if applied manually or via automation) • Verify IP reachability between all devices within the OSPF domain ### Network diagram ![stand-plan](https://content.gitbook.com/content/t770ZYQYIfz1HzwklrwS/blobs/Bft5mGn1Ec0MSN1YKwPO/stand-plan.png) The lab is built using the following role-based device mapping host- linux, leaf - frr, spine - arista ### Underlay IP Address Allocation • Underlay addressing follows the format 10.x.y.z, where: ⁠◦ x = Data Center ID ⁠◦ y = Spine switch ID ⁠◦ z = Sequential host address per leaf connection • Host addressing uses the 172.16.x.z/24 format, where: ⁠◦ x = Leaf switch ID ⁠◦ z = Sequential host address ⁠◦ Each leaf switch uses .1 as its own IP in the corresponding subnet • Loopback addressing uses 192.168.a.b/32, where: ⁠◦ a = 1 for spine switches ⁠◦ a = 2 for leaf switches ⁠◦ b = Spine or leaf ID (assigned sequentially) • IPv6 addressing uses fd00::\[IPv4] Interconnect ipv4 ipv6 | Device A | Interface A | IPv4 A | IPv6 A | Device B | Interface B | IPv4 B | IPv6 B | | -------- | ----------- | ------------- | -------------------- | -------- | ----------- | ------------- | -------------------- | | Spine-1 | Eth1 | 10.1.1.0/31 | fd00::10:1:1:0/127 | Leaf-1 | Eth8 | 10.1.1.1/31 | fd00::10:1:1:1/127 | | Spine-1 | Eth2 | 10.1.1.2/31 | fd00::10:1:1:2/127 | Leaf-2 | Eth8 | 10.1.1.3/31 | fd00::10:1:1:3/127 | | Spine-1 | Eth3 | 10.1.1.4/31 | fd00::10:1:1:4/127 | Leaf-3 | Eth8 | 10.1.1.5/31 | fd00::10:1:1:5/127 | | Spine-2 | Eth2 | 10.1.2.0/31 | fd00::10:2:1:0/127 | Leaf-1 | Eth9 | 10.1.2.1/31 | fd00::10:2:1:1/127 | | Spine-2 | Eth2 | 10.1.2.2/31 | fd00::10:2:1:2/127 | Leaf-2 | Eth9 | 10.1.2.3/31 | fd00::10:2:1:3/127 | | Spine-2 | Eth3 | 10.1.2.4/31 | fd00::10:2:1:4/127 | Leaf-3 | Eth9 | 10.1.2.5/31 | fd00::10:2:1:5/127 | | Host-1 | Eth1 | 172.16.1.2/24 | fd00::172:16:1:2/116 | Leaf-1 | Eth1 | 172.16.1.1/24 | fd00::172:16:1:1/116 | | Host-2 | Eth1 | 172.16.2.2/24 | fd00::172:16:2:2/116 | Leaf-2 | Eth1 | 172.16.2.1/24 | fd00::172:16:2:1/116 | | Host-3 | Eth1 | 172.16.3.2/24 | fd00::172:16:3:2/116 | Leaf-3 | Eth1 | 172.16.3.1/24 | fd00::172:16:3:1/116 | | Host-4 | Eth1 | 172.16.4.2/24 | fd00::172:16:4:2/116 | Leaf-3 | Eth2 | 172.16.4.1/24 | fd00::172:16:4:1/116 | loopback | Device | Loopback ipv4 | loopback ipv6 | | ------- | ------------- | ----------------- | | Spine-1 | 192.168.1.1 | fd00::192:168:1:1 | | Spine-2 | 192.168.1.2 | fd00::192:168:1:2 | | Leaf-1 | 192.168.2.1 | fd00::192:168:2:1 | | Leaf-2 | 192.168.2.2 | fd00::192:168:2:2 | | Leaf-3 | 192.168.2.2 | fd00::192:168:2:3 | {% hint style="info" %} Since task doesn't contain instructions for host IP addressing, and both leaf and spine nodes are implemented as routers, host IPs are assigned from separate subnets prior to overlay configuration. This ensures basic connectivity while keeping underlay and overlay roles clearly separated. {% endhint %} Once the overlay is deployed, we’ll place all hosts into a single subnet to emulate Layer 2 connectivity. ### Launching a lab in the Netlab **Netlab Usage Notes:** To enable **BFD** in FRR, you need to **manually activate the daemon** in the default image, since Netlab does not officially declare BFD support for FRR devices. Edit the following file: `/usr/local/lib/python3.10/dist-packages/netsim/templates/provider/clab/frr/daemons.j2` and add: `bfdd=yes` Similarly, if you want to use other **protocols** without declaring Netlab modules, you can enable the desired daemons directly in the same file. **Lab Notes:** For **OSPF**, enable **authentication** on leaf–spine links using clear-text passwords (`spine1`, `spine2`). {% hint style="info" %} Clear-text is used because Netlab does not support MD5 authentication for FRR. Since authentication here serves mainly as a safeguard against misconfiguration, using plain text is acceptable. {% endhint %} Enable **BFD** on interfaces. {% hint style="info" %} While the timers may appear overly conservative, in practice it's best to avoid values below **500 ms** on virtual devices. This ensures stability without compromising responsiveness. {% endhint %} File [Topology](https://github.com/aeangel/otus-DC-net/blob/main/lab02/topology.yml) For quick reference, here’s the inline listing:
topology.yml ```yml --- provider: clab module: [ ospf ] nodes: s1: device: eos id: 1 loopback: ipv4: 192.168.1.1/32 ipv6: fd00::192:168:1:1/128 s2: device: eos id: 2 loopback: ipv4: 192.168.1.2/32 ipv6: fd00::192:168:1:2/128 l1: device: frr id: 3 loopback: ipv4: 192.168.2.1/32 ipv6: fd00::192:168:2:1/128 l2: device: frr id: 4 loopback: ipv4: 192.168.2.2/32 ipv6: fd00::192:168:2:2/128 l3: device: frr id: 5 loopback: ipv4: 192.168.2.3/32 ipv6: fd00::192:168:2:3/128 h1: device: linux h2: device: linux h3: device: linux h4: device: linux links: #spine1-leaf1,2,3 - interfaces: - node: s1 ifname: eth1 ipv4: 10.1.1.0 ipv6: fd00::10:1:1:0 ospf: password: 'spine1' bfd: true - node: l1 ifname: eth8 ipv4: 10.1.1.1 ipv6: fd00::10:1:1:1 ospf: password: 'spine1' bfd: true prefix: ipv4: 10.1.1.0/31 ipv6: fd00::10:1:1:0/127 - interfaces: - node: s1 ifname: eth2 ipv4: 10.1.1.2 ipv6: fd00::10:1:1:2 ospf: password: 'spine1' bfd: true - node: l2 ifname: eth8 ipv4: 10.1.1.3 ipv6: fd00::10:1:1:3 ospf: password: 'spine1' bfd: true prefix: ipv4: 10.1.1.2/31 ipv6: fd00::10:1:1:2/127 - interfaces: - node: s1 ifname: eth3 ipv4: 10.1.1.4 ipv6: fd00::10:1:1:4 ospf: password: 'spine1' bfd: true - node: l3 ifname: eth8 ipv4: 10.1.1.5 ipv6: fd00::10:1:1:5 ospf: password: 'spine1' bfd: true prefix: ipv4: 10.1.1.4/31 ipv6: fd00::10:1:1:4/127 #spine2-leaf1,2,3 - interfaces: - node: s2 ifname: eth1 ipv4: 10.1.2.0 ipv6: fd00::10:1:2:0 ospf: password: 'spine2' bfd: true - node: l1 ifname: eth9 ipv4: 10.1.2.1 ipv6: fd00::10:1:2:1 ospf: password: 'spine2' bfd: true prefix: ipv4: 10.1.2.0/31 ipv6: fd00::10:1:2:0/127 - interfaces: - node: s2 ifname: eth2 ipv4: 10.1.2.2 ipv6: fd00::10:1:2:2 ospf: password: 'spine2' bfd: true - node: l2 ifname: eth9 ipv4: 10.1.2.3 ipv6: fd00::10:1:2:3 ospf: password: 'spine2' bfd: true prefix: ipv4: 10.1.2.2/31 ipv6: fd00::10:1:2:2/127 - interfaces: - node: s2 ifname: eth3 ipv4: 10.1.2.4 ipv6: fd00::10:1:2:4 ospf: password: 'spine2' bfd: true - node: l3 ifname: eth9 ipv4: 10.1.2.5 ipv6: fd00::10:1:2:5 ospf: password: 'spine2' bfd: true prefix: ipv4: 10.1.2.4/31 ipv6: fd00::10:1:2:4/127 #host1 - interfaces: - node: h1 ifname: eth1 ipv4: 172.16.1.2 ipv6: fd00::172:16:1:2 - node: l1 ifname: eth1 ipv4: 172.16.1.1 ipv6: fd00::172:16:1:1 ospf: false prefix: ipv4: 172.16.1.0/24 ipv6: fd00::172:16:1:0/116 #host2 - interfaces: - node: h2 ifname: eth1 ipv4: 172.16.2.2 ipv6: fd00::172:16:2:2 - node: l2 ifname: eth1 ipv4: 172.16.2.1 ipv6: fd00::172:16:2:1 ospf: false prefix: ipv4: 172.16.2.0/24 ipv6: fd00::172:16:1:0/116 #host3 - interfaces: - node: h3 ifname: eth1 ipv4: 172.16.3.2 ipv6: fd00::172:16:3:2 - node: l3 ifname: eth1 ipv4: 172.16.3.1 ipv6: fd00::172:16:3:1 ospf: false prefix: ipv4: 172.16.3.0/24 ipv6: fd00::172:16:3:0/116 #host4 - interfaces: - node: h4 ifname: eth1 ipv4: 172.16.4.2 ipv6: fd00::172:16:4:2 - node: l3 ifname: eth2 ipv4: 172.16.4.1 ipv6: fd00::172:16:4:1 ospf: false prefix: ipv4: 172.16.4.0/24 ipv6: fd00::172:16:4:0/116 ```
### Validating
spine-1 ```txt s1#show ip ro VRF: default Gateway of last resort is not set C 10.1.1.0/31 directly connected, Ethernet1 C 10.1.1.2/31 directly connected, Ethernet2 C 10.1.1.4/31 directly connected, Ethernet3 O 10.1.2.0/31 [110/20] via 10.1.1.1, Ethernet1 O 10.1.2.2/31 [110/20] via 10.1.1.3, Ethernet2 O 10.1.2.4/31 [110/20] via 10.1.1.5, Ethernet3 C 192.168.1.1/32 directly connected, Loopback0 O 192.168.1.2/32 [110/30] via 10.1.1.1, Ethernet1 via 10.1.1.3, Ethernet2 via 10.1.1.5, Ethernet3 O 192.168.2.1/32 [110/10] via 10.1.1.1, Ethernet1 O 192.168.2.2/32 [110/10] via 10.1.1.3, Ethernet2 O 192.168.2.3/32 [110/10] via 10.1.1.5, Ethernet3 s1#show ipv6 ro VRF: default O3 fd00::10:1:1:1/128 [110/10] via fe80::a8c1:abff:fe9a:849, Ethernet1 C fd00::10:1:1:0/127 [0/0] via Ethernet1, directly connected O3 fd00::10:1:1:3/128 [110/10] via fe80::a8c1:abff:fef1:7cc4, Ethernet2 C fd00::10:1:1:2/127 [0/0] via Ethernet2, directly connected O3 fd00::10:1:1:5/128 [110/10] via fe80::a8c1:abff:feef:e7a2, Ethernet3 C fd00::10:1:1:4/127 [0/0] via Ethernet3, directly connected O3 fd00::10:1:2:1/128 [110/10] via fe80::a8c1:abff:fe9a:849, Ethernet1 O3 fd00::10:1:2:0/127 [110/20] via fe80::a8c1:abff:fe9a:849, Ethernet1 O3 fd00::10:1:2:3/128 [110/10] via fe80::a8c1:abff:fef1:7cc4, Ethernet2 O3 fd00::10:1:2:2/127 [110/20] via fe80::a8c1:abff:fef1:7cc4, Ethernet2 O3 fd00::10:1:2:5/128 [110/10] via fe80::a8c1:abff:feef:e7a2, Ethernet3 O3 fd00::10:1:2:4/127 [110/20] via fe80::a8c1:abff:feef:e7a2, Ethernet3 C fd00::192:168:1:1/128 [0/0] via Loopback0, directly connected O3 fd00::192:168:1:2/128 [110/30] via fe80::a8c1:abff:fe9a:849, Ethernet1 via fe80::a8c1:abff:fef1:7cc4, Ethernet2 via fe80::a8c1:abff:feef:e7a2, Ethernet3 O3 fd00::192:168:2:1/128 [110/10] via fe80::a8c1:abff:fe9a:849, Ethernet1 O3 fd00::192:168:2:2/128 [110/10] via fe80::a8c1:abff:fef1:7cc4, Ethernet2 O3 fd00::192:168:2:3/128 [110/10] via fe80::a8c1:abff:feef:e7a2, Ethernet3 s1#show bfd peers VRF name: default ----------------- DstAddr MyDisc YourDisc Interface/Transport Type LastUp LastDown LastDiag State -------------- ---------------- ---------------- ------------------------- ------------ -------------------- -------------- ------------------- ----- 10.1.1.1 4036363286 3063445977 Ethernet1(1129) normal 08/20/25 22:21 NA No Diagnostic Up 10.1.1.3 1231824312 1715554816 Ethernet2(1131) normal 08/20/25 22:21 NA No Diagnostic Up 10.1.1.5 2599637788 1867128317 Ethernet3(1133) normal 08/20/25 22:21 NA No Diagnostic Up DstAddr MyDisc YourDisc Interface/Transport Type LastUp LastDown LastDiag State ------------------------------- ---------------- --------------- ------------------------- ------------ -------------------- -------------- ------------------- ----- fe80::a8c1:abff:fe9a:849 4221965281 365649942 Ethernet1(1129) normal 08/20/25 22:21 NA No Diagnostic Up fe80::a8c1:abff:feef:e7a2 1006718991 365649942 Ethernet3(1133) normal 08/20/25 22:21 NA No Diagnostic Up fe80::a8c1:abff:fef1:7cc4 216279368 503132544 Ethernet2(1131) normal 08/20/25 22:21 NA No Diagnostic Up ```
spine-2 ```txt s2#show ip ro VRF: default Gateway of last resort is not set O 10.1.1.0/31 [110/20] via 10.1.2.1, Ethernet1 O 10.1.1.2/31 [110/20] via 10.1.2.3, Ethernet2 O 10.1.1.4/31 [110/20] via 10.1.2.5, Ethernet3 C 10.1.2.0/31 directly connected, Ethernet1 C 10.1.2.2/31 directly connected, Ethernet2 C 10.1.2.4/31 directly connected, Ethernet3 O 192.168.1.1/32 [110/30] via 10.1.2.1, Ethernet1 via 10.1.2.3, Ethernet2 via 10.1.2.5, Ethernet3 C 192.168.1.2/32 directly connected, Loopback0 O 192.168.2.1/32 [110/10] via 10.1.2.1, Ethernet1 O 192.168.2.2/32 [110/10] via 10.1.2.3, Ethernet2 O 192.168.2.3/32 [110/10] via 10.1.2.5, Ethernet3 s2#show ipv6 ro VRF: default Displaying 17 of 23 IPv6 routing table entries O3 fd00::10:1:1:1/128 [110/10] via fe80::a8c1:abff:fe45:5487, Ethernet1 O3 fd00::10:1:1:0/127 [110/20] via fe80::a8c1:abff:fe45:5487, Ethernet1 O3 fd00::10:1:1:3/128 [110/10] via fe80::a8c1:abff:feab:149e, Ethernet2 O3 fd00::10:1:1:2/127 [110/20] via fe80::a8c1:abff:feab:149e, Ethernet2 O3 fd00::10:1:1:5/128 [110/10] via fe80::a8c1:abff:fe2a:bc56, Ethernet3 O3 fd00::10:1:1:4/127 [110/20] via fe80::a8c1:abff:fe2a:bc56, Ethernet3 O3 fd00::10:1:2:1/128 [110/10] via fe80::a8c1:abff:fe45:5487, Ethernet1 C fd00::10:1:2:0/127 [0/0] via Ethernet1, directly connected O3 fd00::10:1:2:3/128 [110/10] via fe80::a8c1:abff:feab:149e, Ethernet2 C fd00::10:1:2:2/127 [0/0] via Ethernet2, directly connected O3 fd00::10:1:2:5/128 [110/10] via fe80::a8c1:abff:fe2a:bc56, Ethernet3 C fd00::10:1:2:4/127 [0/0] via Ethernet3, directly connected O3 fd00::192:168:1:1/128 [110/30] via fe80::a8c1:abff:fe45:5487, Ethernet1 via fe80::a8c1:abff:feab:149e, Ethernet2 via fe80::a8c1:abff:fe2a:bc56, Ethernet3 C fd00::192:168:1:2/128 [0/0] via Loopback0, directly connected O3 fd00::192:168:2:1/128 [110/10] via fe80::a8c1:abff:fe45:5487, Ethernet1 O3 fd00::192:168:2:2/128 [110/10] via fe80::a8c1:abff:feab:149e, Ethernet2 O3 fd00::192:168:2:3/128 [110/10] via fe80::a8c1:abff:fe2a:bc56, Ethernet3 s2#show bfd peers VRF name: default ----------------- DstAddr MyDisc YourDisc Interface/Transport Type LastUp LastDown LastDiag State -------------- ---------------- ---------------- ------------------------- ------------ -------------------- -------------- ------------------- ----- 10.1.2.1 1038882734 1867128317 Ethernet1(1140) normal 08/20/25 22:21 NA No Diagnostic Up 10.1.2.3 476357661 2044274492 Ethernet2(1144) normal 08/20/25 22:21 NA No Diagnostic Up 10.1.2.5 2107959149 3063445977 Ethernet3(1146) normal 08/20/25 22:21 NA No Diagnostic Up DstAddr MyDisc YourDisc Interface/Transport Type LastUp LastDown LastDiag State ------------------------------- ---------------- ---------------- ------------------------- ------------ -------------------- -------------- ------------------- ----- fe80::a8c1:abff:fe2a:bc56 755184907 3120229879 Ethernet3(1146) normal 08/20/25 22:21 NA No Diagnostic Up fe80::a8c1:abff:fe45:5487 2205458108 3120229879 Ethernet1(1140) normal 08/20/25 22:21 NA No Diagnostic Up fe80::a8c1:abff:feab:149e 1370192998 1612082641 Ethernet2(1144) normal 08/20/25 22:21 NA No Diagnostic Up ```
#### Verify ping reachability to all device loopbacks from leaf-1.
leaf-1 pings ```txt l1# ping 192.168.2.2 PING 192.168.2.2 (192.168.2.2): 56 data bytes 64 bytes from 192.168.2.2: seq=0 ttl=63 time=0.813 ms 64 bytes from 192.168.2.2: seq=1 ttl=63 time=0.961 ms 64 bytes from 192.168.2.2: seq=2 ttl=63 time=0.964 ms 64 bytes from 192.168.2.2: seq=3 ttl=63 time=0.932 ms ^C --- 192.168.2.2 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 0.813/0.917/0.964 ms l1# ping 192.168.2.3 PING 192.168.2.3 (192.168.2.3): 56 data bytes 64 bytes from 192.168.2.3: seq=0 ttl=63 time=1.186 ms 64 bytes from 192.168.2.3: seq=1 ttl=63 time=1.043 ms 64 bytes from 192.168.2.3: seq=2 ttl=63 time=1.222 ms 64 bytes from 192.168.2.3: seq=3 ttl=63 time=1.048 ms ^C --- 192.168.2.3 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 1.043/1.124/1.222 ms l1# ping 192.168.1.1 PING 192.168.1.1 (192.168.1.1): 56 data bytes 64 bytes from 192.168.1.1: seq=0 ttl=64 time=0.145 ms 64 bytes from 192.168.1.1: seq=1 ttl=64 time=0.118 ms 64 bytes from 192.168.1.1: seq=2 ttl=64 time=0.099 ms 64 bytes from 192.168.1.1: seq=3 ttl=64 time=0.098 ms ^C --- 192.168.1.1 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 0.098/0.115/0.145 ms l1# ping 192.168.1.2 PING 192.168.1.2 (192.168.1.2): 56 data bytes 64 bytes from 192.168.1.2: seq=0 ttl=64 time=0.102 ms 64 bytes from 192.168.1.2: seq=1 ttl=64 time=0.101 ms 64 bytes from 192.168.1.2: seq=2 ttl=64 time=0.101 ms 64 bytes from 192.168.1.2: seq=3 ttl=64 time=0.112 ms ^C --- 192.168.1.2 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 0.101/0.104/0.112 ms l1# ping ipv6 fd00::192:168:2:2 PING fd00::192:168:2:2 (fd00::192:168:2:2): 56 data bytes 64 bytes from fd00::192:168:2:2: seq=0 ttl=63 time=1.543 ms 64 bytes from fd00::192:168:2:2: seq=1 ttl=63 time=0.781 ms 64 bytes from fd00::192:168:2:2: seq=2 ttl=63 time=1.588 ms ^C --- fd00::192:168:2:2 ping statistics --- 3 packets transmitted, 3 packets received, 0% packet loss round-trip min/avg/max = 0.781/1.304/1.588 ms l1# ping ipv6 fd00::192:168:2:3 PING fd00::192:168:2:3 (fd00::192:168:2:3): 56 data bytes 64 bytes from fd00::192:168:2:3: seq=0 ttl=63 time=1.360 ms 64 bytes from fd00::192:168:2:3: seq=1 ttl=63 time=0.760 ms 64 bytes from fd00::192:168:2:3: seq=2 ttl=63 time=0.913 ms ^C --- fd00::192:168:2:3 ping statistics --- 3 packets transmitted, 3 packets received, 0% packet loss round-trip min/avg/max = 0.760/1.011/1.360 ms l1# ping ipv6 fd00::192:168:1:1 PING fd00::192:168:1:1 (fd00::192:168:1:1): 56 data bytes 64 bytes from fd00::192:168:1:1: seq=0 ttl=64 time=0.096 ms 64 bytes from fd00::192:168:1:1: seq=1 ttl=64 time=0.149 ms 64 bytes from fd00::192:168:1:1: seq=2 ttl=64 time=0.101 ms ^C --- fd00::192:168:1:1 ping statistics --- 3 packets transmitted, 3 packets received, 0% packet loss round-trip min/avg/max = 0.096/0.115/0.149 ms l1# ping ipv6 fd00::192:168:1:2 PING fd00::192:168:1:2 (fd00::192:168:1:2): 56 data bytes 64 bytes from fd00::192:168:1:2: seq=0 ttl=64 time=0.111 ms 64 bytes from fd00::192:168:1:2: seq=1 ttl=64 time=0.128 ms 64 bytes from fd00::192:168:1:2: seq=2 ttl=64 time=0.116 ms 64 bytes from fd00::192:168:1:2: seq=3 ttl=64 time=0.097 ms ^C --- fd00::192:168:1:2 ping statistics --- 4 packets transmitted, 4 packets received, 0% packet loss round-trip min/avg/max = 0.097/0.113/0.128 ms ```
Device configuration files: [Spine-1](https://github.com/aeangel/otus-DC-net/blob/main/lab02/s1.conf) [Spine-2](https://github.com/aeangel/otus-DC-net/blob/main/lab02/s2.conf) [Leaf-1](https://github.com/aeangel/otus-DC-net/blob/main/lab02/l1.conf) [Leaf-2](https://github.com/aeangel/otus-DC-net/blob/main/lab02/l2.conf) [Leaf-3](https://github.com/aeangel/otus-DC-net/blob/main/lab02/l3.conf)