Huawei H12-821_V1.0 Online Access

Comprehensive and Detailed Step-by-Step Explanation:

Route Policy Overview:

A route-policy is a policy-based routing tool that filters and modifies routing information.

It consists of one or more nodes, and each node can specify match conditions and apply actions to routes.

Maximum Number of Nodes:

The maximum number of nodes supported in a route-policy is 1024, allowing flexibility in route filtering and control.

The MED (Multi-Exit Discriminator) is an optional, non-transitive attribute used to influence the exit path. MED is considered after attributes such as Local-Preference, AS-Path, and Origin during route selection. By default, if a MED value is missing, it is treated as 0 unless the bestroute med-none-as-maximum command is configured to treat it as 4294967295 ​.

In IPv6, fragmentation is handled only at the source node. Intermediate routers do not fragment packets. Instead, if a packet is too large for the next link, the router sends back an ICMPv6 Packet Too Big message to the source, which then adjusts its packet size.

This design:

Reduces processing load on intermediate devices.

Supports Path MTU Discovery (PMTUD).

Reference from Huawei HCIP-Datacom-Core Technology Study Guide:

“In IPv6, routers do not perform fragmentation. Only the source device fragments packets if needed, based on ICMPv6 feedback.”

(Chapter: IPv6 Fundamentals – Section: Fragmentation and PMTUD)

RSTP improves convergence by introducing changes to the BPDU handling mechanism and port roles. However, RSTP does not rely on a fixed timeout of four Hello intervals for negotiation failure. Instead, RSTP uses a more dynamic mechanism to detect topology changes. The other options describe valid RSTP improvements ​.