1. Translation Spot Negotiation in IPv4/IPv6-Coexist Mesh draft-cui-softwire-pet-03 Yong Cui, Mingwei Xu, Peng Wu Jianping Wu, Xing Li, Chris Metz

2. Challenges of translation Basic IPv4-IPv6 transition techniques – Tunnel for IPv4-over-IPv6/IPv6-over-IPv4 traversing – Translation for IPv4-IPv6 inter-connection But translation has technical challenges – Scalability: IPv4 addr consuming/mapping maintenance – Application layer translation – Operation complexity: per-packet/from IP to app layer – Lack of efficient NAT46 mechanism – Refer to RFC4966 for more details – Inherent properties due to the principle of translation

3. Tunnel for translation spot “transfer” Naturally, translation happens on IP border Use a tunnel to transfer the translation to other spot – Tunnel for traversing between translation spot and IP border – Choose translation spot flexibly Translator with better hardware capability; traffic less- aggregated; support ALG or not; etc. IPvX Backbone IPvX Edge IPvY Internet BR AFBR Xlate IP Border Translation Spot IPvX Backbone IPvX Edge IPvY Internet BR IPvY-over-IPvX Tunnel AFBR Xlate AFBR TE Xlate TE IP Border Translation Spot

4. Real Problem in IPv4/IPv6-coexist mesh Mesh Scenario – Exists in CERNET2 Communications – E-IP over I-IP traversing(RFC5565) – Inter-connection between E-IP & I-IP (the scope of this draft) Translation spot – AFBR (IP-border) – BR (non IP-border) E-IP Internet I-IP Backbone I-IP Internet E-IP Client Net I-IP Client Net I-IP Client Net I-IP Client Net E-IP Client Net E-IP Client Net BR AFBR

5. Solution Softwire tunnel(RFC 5565) to transfer translation spot – E-IP over I-IP routing(RFC 5549) required for translation Translation spot negotiation using BGP on AFBRs/BRs – BGP already supported by AFBR/BR in mesh scenario – Protocol extensions: A new BGP Attribute "Translation Information Attribute" with 4 TLVs, to Decide translation spot Deliver translation context