Interdomain Routing and the
Border Gateway Protocol (BGP)—
What does it all mean?
What about Logical Connectivity?
Actually, IP addresses Identify Interfaces
How Are Forwarding Tables Populated to implement Routing?
Routers Talking to
Routers
(The “control plane”)
Architecture of Dynamic Routing
"Topology information is flooded within..."
Happy Packets: The Internet Does Not Exist Only to Populated Routing Tables
Autonomous Routing Domains Don’t Always Need BGP or an ASN
ASNs Can Be “Shared” (RFC 2270)
Attributes are Used to Select Best Routes
Shorter Doesn’t Always Mean Shorter
Shedding Inbound Traffic with ASPATH Padding Hack
Padding May Not Shut Off All Traffic
COMMUNITY Attribute to the Rescue!
Hot Potato Routing: Go for the Closest Egress Point
Getting Burned by the Hot Potato
Cold Potato Routing with
MEDs
(Multi-Exit Discriminator Attribute)
Policies Can Interact
Strangely
(“Route Pinning” Example)
Separate dynamic and static semantics
An instance of the Stable Paths Problem (SPP)
A Solution to a Stable Paths Problem
An SPP may have multiple solutions
Multiple solutions can
result in
“Route Triggering”
SURPRISE : Beware of Backup Policies
Distributed algorithms to solve SPP?
SPVP wanders around assignment space
Modeling assignment to variable X
SPP Solvability is NP-complete
A sufficient condition for sanity
Titles of Some Recent Internet Drafts
Selected Bibliography on Routing