IPNL: A NAT-Extended Internet Architecture Francis & Gummadi Riku Honkanen

NAT basics Network Address Translation Pros –Expands IPv4 address space –Isolates private network address space from global address space Cons –Unaddressable hosts –Complicates scalable network operation

IP Next Layer major attributes Infrastructure reuse –Changes only to hosts & NAT boxes FQDN Utilization –Fully qualified domain name as the main identifier Extended IP address space Isolated site addressing –Global addresses do not show in internal site routing

IPv4  IPNL

IPNL example

IPNL address MRIP = Middle Realm IP address –globally unique IP address of a frontdoor RN = Realm Number –Realm number assigned by a frontdoor or a site EHIP = End Host IP –private IP address inside a realm

IPNL Header Format Separate local and global header Global header is not used for local packets Global header must be attached if FQDN header is attached

Connection states In the beginning host knows –Own FQDN –Own EHIP –Destination FQDN Session initiation by DNS lookup Random ID (RID) for each connection Maintained variables for each global connection –“next-hop” value –List of MRIPs for the destination –List of MRIP+RN combinations for the destination –Latest MRIP+RN combination used

Seminar theme related ID/Locator split –FQDN mainly identifier but also locator –IPNL address mainly locator but also short- term identifier Might work together with HIP IPNL addresses can change dynamically during the connection while FQDN stays the same Multi-homing by isolated site addressing

Conclusions Strengths –Extends IPv4 addressing effectively –Good scalability –Support for dynamic address changes and multi-homing Question marks –Neighbor pinging –Hijack resistance mechanisms