GIRO - Geographically Informed Inter-Domain Routing

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GIRO - Geographically Informed Inter-Domain
Routing
Ricardo Oliveira Mohit Lad Beichuan
Zhang Lixia Zhang UCLA
UCLA Univ. of Arizona UCLA
Adding Geographical Information

• Current BGP route selection is suboptimal
• BGP uses policy based routing (i.e. customer
  route preferred over provider route)
• Internet topology becomes more densely
  connected?multiple routes satistfy policy
  constraints, a router needs to pick one.
• BGP lacks the necessary information to make the
  best selection, as shown in the example.

AS6461 has a peer-to-peer relation with AS577 and
AS3561. The min-AS-hop route through Chicago
travels a distance over 3,500 miles, the
alternative route through Seattle is aobut 700
miles.

• GIRO the basic Idea
• Use geographical location and distance
  information to improve route selection while
  adhering to routing policies
• Each border router is configured with its
  geo-location information (latitude/longitude),
  and attach information to BGP updates as a new
  attribute
• Example The AS path A B C goes through three
  ASes via egress and ingress routers of each AS
• Each router can derive its distance to the
  destination prefix from the geo-location
  information carried in the routes, and use this
  distance information to replace the min-AS-hop
  count in the route selection

Adding geographic information to route
announcement.
Evaluation

• Simulation Setup
• Used RocketFuel derived topology with 67 ISPs and
  668 AS level links
• Path selection based on no-valley policy, with
  preference of route in decreasing order of
  customer, peer and provider.
• To simulate BGP routes, we used hop count as a
  tie-break
• For GIRO routes, we replace the hop count
  tie-break with route geographic distance using
  ?124 miles ( 1ms latency)

GIRO route decision process Changes introduced
by GIRO are in bold text, the rest is the same as
in BGP decision process.

• GIRO paths are shorter
• For over 70 of the paths, GIRO paths have
  shorter distance than BGP
• For about 20 of the paths the length reduction
  is 40 or higher

GIRO path length reduction compared to BGP routes.

• Summary
• GIRO incorporates geographic location
  information into routing updates to assist best
  route selection
• By taking advantage of geographical distance
  information, GIRO can select paths of shortest
  physical distance
• within the constraints of routing policies.
• As ongoing work, we plan to incorporate
  geographic location information into IP address
  structure to improve
• routing scalability through aggregation.