IPv6 static routes look like IPv4 ones with one wrinkle: a link-local next-hop requires the exit interface. Configure routes between R1, R2, and R3 using both link-local and global next-hops, then verify with show ipv6 route.
An interface is deliberately shut on R2 and you diagnose it from R1 by climbing the OSI stack in order: confirm Layer 1, then Layer 2, then Layer 3, using the four show commands that reveal each layer's state.
Build a GRE tunnel between R1 and R3 with R2 as a transit router that has no idea the tunnel exists. Covers the Tunnel interface's source, destination, and IP, plus the underlay vs overlay distinction.
Configure PPP with CHAP on a serial link and walk the canonical debug output. One honest caveat: iol-xe nodes are Ethernet-only, so the debugs shown are Cisco's documented examples, clearly labeled as such.
Build IPv4 addressing intuition on a running router: classes, RFC 1918 private space, subnet masks and CIDR, and the show commands on R2 that explain how a device decides local versus remote.
A static route with a next-hop IP and one with an exit interface look nearly identical in the config but forward differently. This lab configures both forms for the same destination and shows what changes in ARP and the routing table.
ARP is what turns a next-hop IP into the MAC address in the frame header. Inspect R1's ARP table, generate traffic to watch dynamic entries appear, then configure a static entry and see how it differs from a learned one.
Enable IPv6 routing on R1, R2, and R3 and address them end to end: link-local, global unicast, and an EUI-64 address on R2's LAN interface so you can watch the algorithm derive a host portion from a real MAC.
One router, no networking, just the IOS XE CLI: the four modes you live in, context-sensitive help with ?, command abbreviation, and the core show commands every later lab assumes you already speak.
Configure a numbered standard ACL that denies one host and permits the rest of the LAN. Covers standard vs extended, inbound vs outbound placement, the implicit deny, and reading the match counters.
Configure single-area OSPF on R1, R2, and R3: router ospf syntax with router-id and network statements, the DR/BDR election on a broadcast segment, and end-to-end reachability across the loopbacks.
Extend VLAN 10 across the three-switch triangle: how 802.1Q trunks tag frames, why the native VLAN matters, and how VTP synchronizes VLAN configurations between switches, verified on the base topology.