Exam JN0-649 topic 1 question 8 discussion

C and D is correct BUM traffic handling is given to the overlay network by configuring VXLAN ingress-node-replication instead of multicast overlay In an EVPN-VXLAN environment, EVPN multihoming active-active mode is used instead of MC-LAG for redundant connectivity between hosts and leaf devices. In active-active mode, each of the multihomed PE device advertises a mandatory autodiscovery route per Ethernet segment as in the active-standby state. However, in the active-active state, the autodiscovery route per Ethernet segment is modified such that the active-standby bit carried in the MPLS extended community is cleared to indicate that the active-active mode is in operation.

answer will be C & D

CD If the Single-Active flag is set to 1, that means only one link associated with the Ethernet segment can be used for forwarding. If the Single-Active flag is set to 0, that means that all links associated with the Ethernet segment can be used for forwarding data (we call this active/active forwarding). Juniper QFX devices only support active/active forwarding and so this flag is always set to 0 for these devices.

Type 1 route advertisements are used for multi-homed hosts for route-withdrawels and Aliasing.

EVPN is a overlay protocol most likely not change the underlay tag. single-active represented by binary 1 or active-active represented by binary 0.

BUM Traffic Forwarding Junos devices that use MPLS encapsulation for EVPNs can only use ingress replication at this time. Ingress replication means, to flood traffic to remote PE routers, the traffic has to be replicated, once for each remote PE router. The EVPN label for this BUM traffic is learned per PE router from the route type 3, inclusive multicast Ethernet tag route. This table shows the format of the inclusive multicast Ethernet tag route. All-Active Redundancy (4) This diagram shows the format of the type 1 route, A-D route per ES. The split horizon label is advertised as part of an extended community attached to the type 1 route. The split horizon label is also called the ESI label. The extended community also indicates what type of redundancy mode is used for this given ESI: single-active represented by binary 1 or active-active represented by binary 0.

See my comments below

Single-Active Mode: When a device or a network is multi-homed to two or more PEs and when only a single PE in such redundancy group can forward traffic to/from the multi-homed device or network for a given VLAN, then such multi-homing or redundancy is referred to as "Single- Active". All-Active: When a device is multi-homed to two or more PEs and when all PEs in such redundancy group can forward traffic to/from the multi-homed device for a given VLAN, then such multi-homing or redundancy is referred to as "All-Active". If "Single-Active" flag in "ESI Label Extended Community" is set, the ES is operating in Single-Active redundancy mode. Otherwise, it is operating in All-Active redundancy mode. The Ethernet A-D per EVI route can be used for Aliasing and Backup-Path, aliasing is used for all-active mode, backup-path is for singleactive mode.

C and D is correct. QFX only support active-active forwarding so flag is always set to zero.