1. IDR WG 6PE-Alt draft-manral-idr-mpls-explicit-null-00.txt Vishwas Manral, IPInfusion Manoj Dutta, IPInfusion IETF 71, Philadelphia, PA, USA

2. What is 6PE-Alt IPv6 Migration approach enabled by MPLS Very lightweight mechanism to inter-connect IPv6 islands over MPLS-enabled IPv4 clouds IPv6/IPv4 Provider Edge router connected to an MPLS cloud Inter Provider scenarios (Options A, B and C) still use basic EBGP with no changes used. No changes to any protocol required (so document will be informational)

3. Typical topology +------------+ |site A CE|---+ +----------------------+ +------------+ | | | +---------------+ |_| 6PE-Alt-+ |__ | CE | | | IPv4 MPLS core | | site C | +------------+ | | | +---------------+ |site B CE|---+ +----------------------+ +------------+ IPv6 islands IPv4 cloud IPv6 island

4. Typical topology

5. 6PE Adds a new AFI/ SAFI combination to BGP Each route is attached to a label and exchanged Use of the label is: - Allows PHP - IPv4 Explicit NULL label used in the last Hop Additional advantages - Allows load balancing at the P routers - One IPv6 lookup can be prevented

6. 6PE Adds a new AFI/ SAFI combination to BGP Each route is attached to a label and exchanged Use of the label is: - Allows PHP - IPv4 Explicit NULL label used in the last Hop Additional advantages - Allows load balancing at the P routers - One IPv6 lookup can be prevented

7. 6PE Adds a new AFI/ SAFI combination to BGP Each route is attached to a label and exchanged Use of the label is: - Allows PHP - IPv4 Explicit NULL label used in the last Hop Additional advantages - Allows load balancing at the P routers - One IPv6 lookup can be prevented

8. 6PE RFC4798 gives the reason to have 2 labels: The use of a second level label allows PHP on the IPv4 LSR upstream of the egress 6PE router, without any IPv6 capabilities/upgrades on the penultimate router; this is because it still transmits MPLS packets even after the PHP (instead of having to transmit IPv6 packets and encapsulate them appropriately). Also, an existing IPv4-signaled LSP that is using "IPv4 Explicit NULL label" over the last hop could not be used to carry IPv6 with a single label since the "IPv4 Explicit NULL label" cannot be used to carry native IPv6 traffic while it could be used to carry labeled IPv6 traffic.

9. 6PE-Alt No extensions required for any protocol No new AFI/ SAFI pair used Use of the IPv6 Explicit NULL label as (VPN label) inner label Changes required - Allows load balancing by intelligently using combination of IPv4 Explicit NULL and IPv6 Explicit NULL labels - Ask IANA for another set of Explicit NULL labels (this would help in load balancing in all cases – not just 6PE-Alt)

10. 6PE-Alt Advantages - No additional signaling required - Memory saving of 8 bytes for every route - Lookup considerably better as it is based on - Simpler/ better usage of tables in the hardware - Any router having BGP IPv6 support can become a 6PE router - Same functionality as 6PE in the data plane - No different Inter Provider related changes (affecting EBGP) like 6PE Lot of feedback on v6ops and IDR lists - Lighter weight approach and can be used along with 6PE.

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