IDR WG6PE-Alt

draft-manral-idr-mpls-explicit-null-00.txtVishwas Manral, IPInfusion

Manoj Dutta, IPInfusionIETF 71, Philadelphia, PA, USA

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)

Typical topology

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

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

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

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.

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)

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.

Feedback?