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JN0-649 Exam - Question 8


Which two statements are correct about the deployment of EVPN-VXLAN on QFX Series devices? (Choose two.)

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Correct Answer: CD

Junos OS supports ingress replication for BUM traffic forwarding, which means that to flood traffic to remote PE routers, the traffic must be replicated once for each remote PE router. Additionally, in an EVPN-VXLAN environment, Type 1 route advertisements always have the single-active flag set to 0. This indicates that all links associated with the Ethernet segment can be used for forwarding data, thus enabling active-active forwarding. Juniper QFX devices only support this active-active forwarding mode.

Discussion

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CiscoTestOptions: CD
Nov 28, 2022

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.

Jafet0990Options: CD
Dec 5, 2023

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.

JoeSunOptions: CD
Dec 23, 2022

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.

penguin02007Options: CD
Dec 6, 2022

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

mohdemaOptions: BC
Dec 6, 2022

See my comments below

mohdema
Dec 8, 2022

Answer is actually CD I mistyped

somanyquestionsOptions: CD
Oct 19, 2023

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

mohdema
Dec 6, 2022

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.

mohdema
Dec 6, 2022

The bit in the active-standby flag field in the ESI label extended community is used for signaling the active-standby mode (bit set).

mohdema
Dec 6, 2022

In active-standby mode, the designated forwarder (DF) advertises the autodiscovery route per Ethernet segment with an ESI MPLS label extended community that has the standby bit set to 1. The autodiscovery route is advertised per ESI, and the ESI label is set to 0 when active-standby mode is in operation.

mohdemaOptions: BC
Dec 8, 2022

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.