SCION

Question 1

Intra ISD Path Exploration

Answer 1

Beaconing:

• Core ASes initiate PCBs (Path-segment construction beacons) to traverse to lower ASes
• Each PCB represents a path from core to current AS
• PCBs are secured through origin auth. and MACs

Question 2

Intra ISD Path registration

Answer 2

up path: AS selects path segments to announce as up-path segments for local hosts, registered at local path server
- AS selects path segments to announce as down-path segments for others, uploaded to core path server in Core AS

Question 3

Path lookup (remote ISD)

Answer 3

• host queries RAINS server for address of H -> H:
• host contacts local path server to query path segments for -> up-path, core-path, down-path segments

remote ISD

• if local path server has down-path not cached ask core path server
• if core path server has down-path not cached ask remote core path server
• eventually local host gets up, core and down-path

Question 4

Interface Identifiers

Answer 4

Each AS assigns integer number to each interface that connects to neighboring AS.
Use internal routing protocol to connect between ingress and egress SCION border router

Question 5

Hop field MAC verification

Answer 5

based on local AS secret key

over timestamp, flags, Exp Time, Ingress, Egress, hop field of previous AS)

Question 6

Core AS duties

Answer 6

• manage and distribute ISDs TRC
• Issue certs for all AS inside ISD
• provide connectivity to neighboring ISD

Question 7

Low Latency connectivity

Answer 7

SCION can choose preferred path depending on application. Use low latency, low bandwith path for certain applications

Question 8

Low Earth Orbit Satellite Network

Answer 8

Idea: use low orbit satellite to provide connectivity.
Problem: many satellites needed to provide full connectivity
SCION can integrate satellite network

Question 9

control plane

Answer 9

deals with network topology and makes routing decisions. Responsible to discover paths, deal with route establishment, failures and policing.

Question 10

data plane

Answer 10

responsible for packet forwarding that end hosts have injected into network. packets are forwarded based on routes established in the control plane.