Potential Impacts of Four-Byte AS Numbers in Partial Deployment

—Inter-domain routing is suffering from the lack of identifiers for the rapidly growing number of Autonomous Systems (AS), and therefore the 4-byte AS number has been proposed along with the transition scenario. In a partial deployment environment, 4-byte-enabled Border Gateway Protocol (BGP) speakers have to exchange AS path vector with the old, 2-byte-only ones, via some way of translation and tunneling. The latter does not recognize and will possible lose the information about the 4-byte AS numbers. In this paper, we present a comprehensive analysis in order to identify the potential risks in deploying 4-byte AS numbers. It is found that 1) the loss of the AS4 PATH attributes will disable loop detection and lead to persistent oscillation in certain configuration; 2) AS PATH-based match and COMMUNITY-based control may be ambiguously applied, and result in policy violations. Typical examples analyzed in real experiments validate these findings. Furthermore, AS path translation ad...

• Type: Conference
• Year: 2007
• Where: ICON
• Authors: Yuncheng Zhu, Junxiu Lu, Maoke Chen
• Keywords: 4-byte As Numbers, Border Gateway Protocol, Computer Networks, ICON 2007, Partial Deployment Environment