3
Explanation:
Understanding EVPN (Ethernet VPN) Label Allocation and ARP Handling
# What Happens in This Scenario?1## CE1 (192.168.1.1) sends an ARP request to discover the MAC address of CE2 (192.168.1.2).2## PE1 receives the ARP request and needs to forward it over the EVPN fabric.3## To send the broadcast ARP request across the EVPN network, PE1 forwards the packet to PE4 using BUM (Broadcast, Unknown unicast, and Multicast) forwarding.4## PE4, as the Designated Forwarder (DF), forwards the ARP request to CE2.
Role of Labels in EVPN VXLAN/MPLS Networks
# EVPN uses BGP to distribute MAC/IP reachability information using different route types.
# EVPN Type 2 Route (MAC/IP Advertisement Route):
* Used for MAC-to-IP address mapping announcements.
* Ensures remote VTEPs (PE routers) learn MAC-to-IP bindings dynamically.
# EVPN Type 3 Route (Inclusive Multicast Route):
* Used for BUM traffic (Broadcast, Unknown Unicast, Multicast).
* Assigns a multicast label (e.g., 201) to be used for forwarding broadcast packets like ARP requests.
# In this case:
* The label 201 is used for BUM traffic forwarding.
* BUM traffic is handled using an EVPN Type 3 route.
Why is the Answer 3?
# EVPN Type 3 routes carry labels for BUM traffic, which includes ARP requests.# Label 201 is used for multicast distribution, which is managed by Type 3 routes.
Real-World Application:
* VXLAN Data Centers: Uses EVPN Type 3 routes to control BUM traffic efficiently.
* Campus Networks: Prevents unnecessary flooding of ARP requests across VXLAN domains.
# Reference: Huawei HCIE-Datacom Guide - EVPN BGP Route Types and Multicast Labeling

Network Slicing Using Channelized Sub-Interfaces and FlexE
Bothchannelized sub-interfacesandFlexE (Flexible Ethernet)are used fornetwork slicing, but they have differentapplication scenarios:
#A. Channelized sub-interface is recommended for interfaces with bandwidth < 50 Gbit/s.
Channelized sub-interfacessplit a physical interfaceinto multiple logical sub-interfaces.
Best for lower-bandwidth links (<50 Gbit/s).
#B. FlexE is recommended for 50GE and higher-rate interfaces.
FlexEdivides a high-bandwidth physical link(e.g.,100GE, 400GE) into multiple virtual slices.
Used in high-speed backbone and data center networks.
#C. Only FlexE-based network slicing can be deployed across OTN devices.
FlexE is compatible with Optical Transport Network (OTN)and can be used for long-haul slicing across OTN.
#D. Only channelized sub-interface-based network slicing can be deployed across MSTP devices.
Incorrect!While MSTP supports channelized interfaces,FlexE is not restricted to MSTP deployment.
Reference from Huawei HCIE-Datacom Documentation:
Huawei FlexE Technology Whitepaper - Network Slicing in Transport Networks HCIE-Datacom Training Material - Channelized Sub-Interface and FlexE in Network Slicing