During WLAN roaming, the STA sends a Reassociation Request frame to the foreign AP to maintain connectivity. Association frames are used during initial connections, not roaming.
APs with which a STA is associated before and after roaming can work on different channels, as roaming often occurs across channels in environments like multi-SSID or multi-channel setups.Options C and D are false, as they contradict standard WLAN roaming procedures .

Comprehensive and Detailed In-Depth Explanation:
* The Flag field in a routing table entry provides specific information about the route.
* G (Gateway flag): This flag indicates that the next hop is a gateway (another router) rather than a directly connected destination.
* S (Static flag): This flag indicates that the route was manually configured as a static route.
* H (Host flag): This flag means that the destination is a directly connected host, not a network.
* D (Dynamic flag): This flag is used for dynamically learned routes from protocols like OSPF, EIGRP, or BGP.
* Since we are looking for the flag that indicates the next hop is a gateway, the correct answer is G.
# Reference: Huawei HCIA-Datacom Study Guide, Chapter on Routing Table and FIB Entries.

Comprehensive and Detailed in-depth Step-by-Step Explanation:The Network Entity Title (NET) is a unique identifier assigned to an IS-IS router. It is derived from the Network Service Access Point (NSAP) address and consists of the following components:
* Area Address:
* Identifies the area in which the router resides.
* Multiple routers in the same IS-IS area must have the same area address.
* System ID:
* Uniquely identifies the router within the IS-IS area.
* The System ID is typically derived from the router's loopback IP address or another unique value.
* SEL (Selector Field):
* The SEL field is always set to 00 for IS-IS NETs.
The NET is used by IS-IS for route calculation and to identify the router within the IS-IS domain. Therefore, the statement is TRUE.
References:
* Huawei HCIA-Datacom Study Guide, Chapter on "IS-IS Addressing".
* RFC 1195 - Use of OSI IS-IS for Routing in TCP/IP and Dual Environments.

IPv4 supports three main transmission modes:
* Unicast: One-to-one communication.
* Broadcast: One-to-all communication within a network.
* Multicast: One-to-many communication to a group of interested receivers.Anycast is not a native IPv4 mode but is introduced in IPv6 .

The Local-Preference attribute is used within an AS to influence outbound traffic paths. The default value is
100, and it is a well-known discretionary attribute, meaning it is not mandatory and does not travel across AS boundaries .