A network that does not fall Four lessons that make a network survive faults and grow: STP and what stops loops, gateway redundancy with HSRP and VRRP, IPv6 from addressing to operation, and BGP, which joins the whole internet.
Lessons 0 Overview Four lessons that make a network survive faults and grow: STP and what stops loops, gateway redundancy with HSRP and VRRP, IPv6 from addressing to operation, and BGP, which joins the whole internet. 1 Backup links without loops: STP and EtherChannel Why a company puts two links between every pair of switches, why that extra link can bring the whole network down in seconds, how the spanning tree protocol stops the loop, and how EtherChannel bundles several cables into one faster link. 2 A gateway that never dies: HSRP, VRRP and DHCP relay Every device knows one gateway. What happens if the router holding it fails? Here you learn how two routers share one virtual address, how a DHCP request reaches a server on another network, and why you need DHCP snooping. 3 IPv6 in practice: the plan, automatic addresses and dual stack In the foundation you saw what an IPv6 address looks like. Now you run it: how to split a /48 across your sites, how a device gets its own address with SLAAC, why there is no ARP and no broadcast, how IPv4 and IPv6 live together, and the security mistakes everyone makes. 4 BGP: how the world's networks agree on the road The internet is tens of thousands of independent networks, each an autonomous system (AS). Here you see how each AS announces its addresses, how BGP picks the road by policy rather than speed, how a company connects to two providers, how one BGP mistake took big companies down, and what RPKI is. 5 Wrap-up and resources The takeaways and glossary of this track.