Group Membership Is a Set
What is a multicast group, really — and why does the whole membership picture collapse to ordinary set operations?
Open Session 01Sessions
IGMP track sessions
Queries Keep the Set Honest
Nothing in membership.py ever forgets a host on its own — so what makes a GroupTable trustworthy after a host crashes, unplugs, or roams off-link without ever calling leave()?
Snooping Reads Someone Else's Mail
IGMP is a layer-3 conversation between hosts and routers — a switch was never addressed by it. So how does a switch prune multicast traffic without breaking the layering it has no business crossing?
Open Session 03Build the Toy Querier Loop
What does one full query cycle look like end to end — router and switch together — when a host goes quiet and the forwarding set actually has to shrink because of it?
Open Session 04