Hot-potato routing

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In

Internet routing between autonomous systems which are interconnected in multiple locations, hot-potato routing is the practice of passing traffic off to another autonomous system as quickly as possible, thus using their network for wide-area transit. Cold-potato routing is the opposite, where the originating autonomous system internally forwards the packet until it is as near to the destination as possible.[1][2][3]

Behaviors

Hot-potato routing (or "closest exit routing")[2] is the normal behavior generally employed by most ISPs.[1] Like a hot potato in the hand,[2] the source of the packet tries to hand it off as quickly as possible in order to minimize the burden on its network.[1]

Cold-potato routing (or "best exit routing")

NSFNET used cold-potato routing in the 90s.[2]

When a transit network with a hot-potato policy peers with a transit network employing cold-potato routing, traffic ratios between the two networks tend to be symmetric.[2]

Implementation

Routing behavior can be influenced using two

BGP communities are used to signal the cost of the route, which influences IBGP local preference.[3]

References

  1. ^ a b c d e f Subramanian, Lakshminarayanan; Padmanabhan, Venkata N.; Katz, Randy H. (2002-06-10). Geographic Properties of Internet Routing (PDF). USENIX 2002 Annual Technical Conference.
  2. ^ . Retrieved 2023-12-11.
  3. ^ . Retrieved 2023-12-12.