On the use of Trial and Error Traffic Engineering techniques in the Internet

The Border Gateway Protocol governs the overall routing in the Internet. With the time, it has been overloaded with functions which is was not initially designed for. The main example is Traffic Engineering. Internet Service Providers need to adjust the traffic on their peerings and in absence of a better alternative, use Trial and Error techniques based on manipulating the Autonomous System Path attribute in Border Gateway Protocol (BGP-4) updates. This paper shows sequences of BGP4 updates where the use of Trial and Error Traffic Engineering techniques have led to instability and the countermeasures used to minimise their impact impact. The analysis methods presented also partially reveal the way Internet Service Providers use AS_PATH Prepending.