What is BGP-EVPN for the Data Center
BGP-EVPN
Agenda
What is EVPN
What problems does VXLAN solve
What problems does BGP EVPN solve
Overview of BGP EVPN Route Types and associated use cases
The industry's Top leaders
What is E-VPN?
• Ethernet VPN (EVPN) – connect a group of customer sites using a virtual bridge.
• Treat MAC addresses as routable addresses and distribute them in BGP
• Uses Multi-protocol BGP
• Initially started as next generation L2VPN solution for service provider networks
• Evolution of EVPN
• Data center use cases
• Multi-tenancy with virtualized hosts
• Support of VXLAN and NVGRE encapsulations
• Integrated routing and bridging
• Support exchange of IP addresses and IP prefixes
• Status of EVPN
• Standardization effort – IETF L2VPN work group
• Multi-vendor support – core set of drafts co-authored by engineers from Cisco, Juniper, Alcatel-Lucent,
Verizon, ATT, Bloomberg.
• BGP MPLS based EVPN is RFC 7432 and extensions for DC is currently in draft stages.
What problems does VXLAN solve?
Customer Needs
Any workload anywhere – VLANs limited by L3 boundaries
VM Mobility
Scale above 4k Segments (VLAN limitaCon)
Secure MulC-‐tenancy
VXLAN Enables
Any Workload anywhere-‐ across Layer 3
boundaries
Seamless VM Mobility
Scale up to 16M segments
Traffic & Address IsolaCon
What problems does BGP EVPN solve for VXLAN?
• Control plane for VXLAN overlays
• Optimize/eliminate flooding of
• Unknown unicast traffic.
• Protocol messages, e.g. ARP
• Virtual machine mobility with optimal forwarding
• No hair pinning of traffic to previous location
• Active/active multi-homing with per flow load balancing
• Large scale multi-tenancy in control plane with characteristics of L3VPN
• Route filtering and constrained route distribution
• Ingress replication of multi-destination traffic
• Multicast free underlay
Advertise IP prefixes
BGP-EVPN / VXLAN Terminology
1. Layer-2 VNI
• VNI (VXLAN network identifier) carried in VXLAN packets bridged across
VTEPs (VXLAN tunnel end point) . This VNI is configured per VLAN.
2. Layer-3 VNI
• VNI carried in the VXLAN packets routed across VTEPs. This VNI is linked per Tenant VRF.
3. Anycast GW
• All L3 VTEPs are configured with same mac and same subnet for host facing SVI.
4. VRF overlay VLAN
• Every Tenant VRF will need a Vlan to be configured for VXLAN routing.
• This VLAN is configured with L3-VNI.
5. VXLAN L2 Gateway
• VTEP capable of switching VLAN->VXLAN, VXLAN->VLAN packets with in same VNI.
6. VXLAN L3 Gateway
• VTEP capable of routing packets across different VNIs.
EVPN Control Plane – Reachability Distribution
EVPN Control Plane — Host and Subnet Route Distribution
BGP Update
• Host-MAC
• Host-IP
• Internal IP Subnet
• External Prefixes
- Use MP-BGP with EVPN Address Family on leaf nodes to distribute internal
host MAC/IP addresses, subnet routes and external reachability information - MP-BGP also used to distribute IP multicast groups information
- MP-BGP enhancements to carry up to 100s of thousands of routes
with reduce convergence time
BGP EVPN Route Types
Route-Type
1
2
3
4
5
EVPN Routes
Ethernet Auto-discovery Route
MAC/IP Route
Inclusive Multicast Route
Ethernet Segment Route
IP Prefix route
Purpose
Mass withdrawal and Aliasing
Advertise host MAC and IP address
Tunnel end point discovery for setting up of replication list
Discovery of nodes in redundancy group and DF-election
Advertise IP prefixes
If you would like to know more about this subject or others, leave a comment below with you questions for the folks at Functionkey, Inc.
