BGP-EVPN Flashcards
What is BGP?
Border gateway protocol
What is EVPN?
Ethernet VPN (EVPN) is a standards-based BGP control plane to advertise MAC addresses, MAC and IP bindings and IP Prefixes.
What are the three main functions of EVPN?
1) Advertise MAC addresses
2) MAC and IP bindings
3) IP prefixes
What is the main reason to use EVPN?
Controls/minimizes mac/ip address flooding which scales best in a network with multiple leaf routers.
In BGP, what is an RD (route distinguisher)?
It identifies routes belong to a VRF.
In BGP, what is a RT (route target)?
It defines which prefixes are imported and exported between bgp peers.
What is VXLAN?
It is a layer 2 in a layer 3 overlay tunnel. It’s an ethernet/IP and UDP tunnel using udp port 4789.
What are two ways VXLAN utilizes mac/ip learning?
1) flood and learn
2) bgp evpn
In BGP, what is an address family?
Allows multi-protcol (MP-BGP) behavior to be defined over a single BGP peering. It carries this information to its’ peers.
What are examples of address families?
1) IPv4 unicast and multicast
2) IPv6 unicast and multicast
3) VPNv4
4) CLNP (connection-less network protocol)
What information is carried in the EVPN address family?
1) Host MAC
2) Host IP
3) Network
4) VRF
5) VTEP
What is the purpose of the underlay network?
It provides reachability information to reach the VTEP (routing).
What is the purpose of the overlay network?
It distributes end host information (mac/ip) - which vtep is the end host behind.
What is the advantage of using EVPN BGP over data plane/control plane learning?
It supports integrated routing and bridging.
True or false: VNIs can be used as layer 3 and layer 2.
True
What is a layer 2 VNI?
Used for bridging, and used for the same LAN segment.
What is a layer 3 VNI?
Used for routing when traffic has to leave a layer 2 VNI.
In BGP EVPN, what is IRB (integrated routing and bridging)?
This allows VTEPS in a VXLAN network to foward both layer 2 and layer 3 traffic.
True or false: In BGP EVPN, traffic between different subnets are forwarded through the VXLAN gateways.
True
What are two types of IRB (integrated routing and bridging)?
1) Assymmetric
2) Symmetric
What is required to enable vxlan bridging and routing?
Configuring a VTI (virtual tunnel interface), such as the configuration command: interface vxlan1
What is Direct VXLAN Routing?
Direct VXLAN routing with VXLAN enabled addresses this issue by configuring each VTEP with all VLANs. This allows packets to be VXLAN-bridged to a local VTEP and routed to remote VTEPs.
What are the 3 main evpn route types?
1) Route type 2 - MAC to IP mapping to end hosts. L2
2) Route type 3 - Needs to receive BUM traffic from a VNI
3) Route type 5 - VRF to IP prefix. L3
What is symmetric IRB (integrated routing and bridging)?
1) Both local and remote vteps perform routing.
2) Routing is over a layer 3 VNI.
3) Bridging only happens on the vlan between the vtep and tenant.
What is asymmetric IRB (integrated routing and bridging)?
1) Only ingress vtep performs routing.
2) Once routing is performed, packets are bridged over a layer 2 VNI to the remote vtep.
3) The remote vtep deencapsulates the packets, and they are bridge to the final destination.
What is a BGP community?
A BGP community is an optional, transitive BGP attribute that is recognized and passed to other BGP peers. You might see a BGP community as a tag attached to the BGP routes exchanged between two BGP peers.
True or false: EVPN is considered the control plane.
True
True or false: Vxlan is considered the data plane.
True
What are the 2 VRFs used in BGP-EVPN?
1) IP VRF
2) MAC VRF
How is IP VRF used?
To build L3 overlay networks.
How is MAC VRF used?
Signifies a broadcase domain, used to build L2 overlay networks.
What are the two types of VNIs?
1) Layer 2 VNI
2) Layer 3 VNI
What are layer 2 VNIs used for?
L2VNI is used to create MAC-VRF
What are layer 3 VNIs used for?
L3 VNI used for IP-VRF sometimes we call it Tenant-VRF
