1. EVPN BUM Procedures Update
We live in a connected world and the foundation for these connections is the network.
Broadband Internet traffic is doubling each and every year (according to IDC) [or] Internet traffic worldwide will grow three-fold by the year (Internet Trends, Mary Meeker (KCPB)
Today we have 2.5 billion Internet users in the world – roughly one-third of the Earth’s population. In the next decade, the number of Internet users will double to 5 billion (Mary Meeker, KPCB)
That means that two-thirds of the world will be connected by 2023.
When you add in the big trends of cloud, mobility, video and security, the combined rate of acceleration is placing unprecedented demands on the network.
[Optional stats/factoids]
100 hours of video uploaded every single minute to YouTube (YouTube)
Mobile video traffic exceeded 50 percent for the first time in (Cisco VNI)
Mobile network connection speeds more than doubled in (Cisco VNI)
In 2012, a fourth-generation (4G) connection generated 19 times more traffic on average than a non-4G connection. Although 4G connections represent only 0.9 percent of mobile connections today, they already account for 14 percent of mobile data traffic. (Cisco VNI)
[NOTE: Consider finding alternate source for above stats to avoid siting Cisco]
As you just described (refer to pain points from previous slide), you are living in this world and feeling the pressure every day.
Pradeep Sindhu founded Juniper 17 years ago on the belief that we should solve technology problems that matter most to our customers and that make a difference in the world. He recognized the importance of the network and the impact it would have on our world.
Our mission is simple, but powerful; to connect everything and empower everyone.
In today’s connected world, this mission is more relevant than ever.
Here at Juniper we are focused on helping alleviate those pain points through our portfolio of high performance networking products.
[T] And we do this by listening to our customers and helping them address their challenges and capitalize on their opportunities.
Jeffrey Zhang, Wen Lin Jorge Rabadan, Keyur Patel IETF 93, Prague

2. EVPN BUM Procedures
RFC 7432 (EVPN) refers to RFC 7117 (VPLS Multicast) for quite some EVPN BUM procedures
RFC 7432 mentions selective tree for Ingress Replication and refer to RFC 7117
The same could apply to P2MP tunnels
RFC 7432 refers to RFC 7117 for P2MP inclusive tree
RFC 7117 includes inter-as segmentation procedures
With complicated and VPLS-specific rules for inclusive tree
RFC 6514 (MVPN) has slightly different procedures for inter-as inclusive trees
Good to adopt MVPN instead of VPLS procedures for inter-as inclusive trees
RFC 7524 (Inter-area segmentation) covers MVPN and VPLS
Goals of this draft: clarifications/updates/extensions for EVPN BUM procedures
New EVPN route types for selective tree
Updated inter-as segmentation procedure for EVPN
Extending inter-area segmentation to cover EVPN and support inter/intra-region

3. Selective Tree Only need to define S-PMSI and Leaf A-D routes for EVPN
All existing procedures in RFC 7117 apply
An S-PMSI route announces that an ingress PE intends to send certain multicast flow on a specific tunnel (vs. the inclusive tunnel)
An egress PE that needs to receive the traffic joins the specific tunnel
By sending mLDP label mapping or PIM join for the tunnel, or,
By letting ingress know explicitly about itself via Leaf A-D routes
This is called leaf-tracking
Needed for Ingress Replication, RSVP-TE P2MP tunnel, or BIER transportation
A Leaf A-D route is specifically in response to a particular PMSI route
The same concept is also used for tunnel segmentation
Even for inclusive tree

4. Motivations for tunnel segmentation
Segmentation may be necessary for Inter-AS/provider deployments
One AS/provider may use mLDP while the other uses RSVP-TE P2MP
Even if RSVP-TE P2MP can be used in both AS/providers, tunnel signaling may have to be restricted to individual AS/providers and not across
Technical or administrative reasons
Segmentation may be desired in certain situations
Even if it’s not absolutely necessary
Examples:
Different areas using different tunnel types
Tunnel aggregation in smaller areas for better congruency
Smaller per-area BIER sub-domains (hence shorter BitString)
Same tunnel type in multiple AS/areas but limit the Leaf A-D routes to single AS/area
IR in multiple AS/areas but limit replication to single AS/area and let ASBRs/ABRs relay the replication

5. Leaf Tracking & Fan-out for Ingress Replication
PE1
PE1
PE1 tracks one downstream ABR1
ABR1 tracks two downstream ABR3 & 5
ABR3 tracks two egress PEs
ABR5 tracks one egress PE
Reduced control plane overhead
on ingress PEs
ABR1
ABR2
ABR1
ABR2
ABR3
ABR3
ABR4
ABR6
ABR4
ABR6
ABR5
ABR5
PE1 sends one copy
ABR1 sends two copies to ABR3 & 5
ABR3 sends two copies to PE2 & 3
ABR5 sends one copy to PE4
Reduced bandwidth usage and
replication burden
PE2
PE3
PE4
PE2
PE3
PE4
w/o segmentation
w/ segmentation
PE1 tracks three egress PEs
PE1 sends three copies

6. Tunnel Segmentation Procedures
Segmentation points are ASBRs/ABRs
RFC 6513/6514: MVPN Inter-AS segmentation
RFC 7117: VPLS Inter-AS segmentation
RFC 7524 (Seamless MPLS Multicast for MVPN/VPLS): Inter-Area Segmentation
When an ASBR/ABR re-advertises a PMSI/IMR A-D route:
It changes the PTA to specify a new tunnel for the downstream segment
ASBR and EVPN ABR: changes BGP next hop to its own address
MVPN/VPLS ABR: changes S-NH-EC to specify its own address
Segmented Next Hop Extended Community
A downstream ASBR/ABR/PE joins that tunnel segment
PIM join or mLDP label mapping, or
Leaf A-D routes towards the upstream ASBR/ABR
Either the BGP next hop or specified in S-NH-EC of corresponding PMSI/IMR A-D route
The upstream ASBR/ABR further joins its upstream tunnel segment
And stitches the upstream segment to the downstream segment in forwarding path

7. Inter-Area IR Segmentation Example
PE1
ABR3: L200 -> (L100, base LSP to PE2)
(L110, base LSP to PE3)
ABR6: L210 -> (L120, base LSP to PE4)
Label 300
NH/S-NH-EC: PE1
ABR1: L300 -> (L200, base LSP to ABR3)
(L210, base LSP to ABR6)
ABR1
ABR2
PE1: (S,G) -> (L300, base LSP to ABR1)
NH/S-NH-EC: ABR1
NH/S-NH-EC: ABR2
Label 200
Label 210
ABR3
ABR4
ABR6
NH/S-NH-EC: ABR3
NH/S-NH-EC: ABR4
PMSI A-D to all RR clients
Dashed lines for those
not preferred by receivers
ABR5
NH/S-NH-EC: ABR5
NH/S-NH-EC: ABR6
Label 100
Label 110
Leaf A-D
To upstream ABR/PE
specified in NH or S-NH-EC
of PMSI A-D
Label 120
PE2
PE3
PE4

8. Inter-Area Segmentation Extensions
Inter-area  Inter-region
While RFC 7524 is based on areas, the area/ABR can be replaced by region/RBR
A region can be a subset of an area, defined by a BGP peer group
A region can even be an entire AS plus its external link
Inter-region  intra-region
With inter-region, a RBR changes next hop and tunnel type/id when it re- advertise a PMSI/IMR route into other regions, and stitches the segments in different regions together
With intra-region, a RBR could do the same even when it re-advertise into the same region, and stitches the segments together
Use cases include assisted Ingress Replication and Virtual Hub and Spoke

9. Inter-AS Inclusive Tunnel Segmentation
VPLS requires that only one ASBR re-advertises a VPLS A-D route into an AS
That requires complicated and VPLS-specific election procedures that do not apply to EVPN
This document proposes for EVPN to follow generic MVPN inter-as segmentation procedures
Any ASBR can re-advertise IMR routes into its AS, and the egress PEs or downstream ASBRs will accept traffic from their own choice of upstream ASBR – as in the selective tree case and inter-area case
ASBRs could also consume and aggregate individual per-PE IMR routes into per-AS IMR routes that they originate
This achieves better scaling and backwards compatibility

10. Summary and Next Steps Clarified/Updated/Extended EVPN BUM procedures
New route types for selective tree
Updated inter-as inclusive tunnel segmentation
Extended inter/intra-region segmentation
Next steps
Seek and address comments from the community
Add more details
Current revision focuses on discussing the ideas and concepts
Will seek WG adoption afterwards