Additional Port Roles in MSTP
* Master Port: Indicates the port on the shortest path to the root bridge in a region.
* Regional Edge Port: Identifies a port at the boundary of the MST region.
* Backup and edge ports exist in RSTP and are not newly introduced by MSTP.
HCIP-Datacom-Core Reference
* MSTP port roles are elaborated in the MSTP configuration sections.

30 seconds
Explanation:
By default, a router interface sends PIM (Protocol Independent Multicast) Hello messages every 30 seconds to maintain neighbor relationships. This interval can be adjusted using configuration commands .

Comprehensive and Detailed in-depth Step-by-Step Explanation:
AnArea Border Router (ABR)is an OSPF router that connects multiple areas, including the backbone area (Area 0). It plays a critical role in summarizing and propagating routing information between areas. The types of LSAs that an ABR can generate include:
Network Summary LSA (Type 3):
ABRs generate Type 3 LSAs to summarize and propagate routes from one area into another.
For example, an ABR generates a Type 3 LSA to inform other areas about the networks in the area it is connected to.
ASBR Summary LSA (Type 4):
If an ASBR exists in one of the OSPF areas connected to the ABR, the ABR generates Type 4 LSAs.
These LSAs provide information about how to reach the ASBR.
NSSA LSA (Type 7):
If the ABR is connected to a Not-So-Stubby Area (NSSA), it can generate Type 7 LSAs.
These LSAs are used to describe external routes imported into the NSSA.
AS External LSA (Type 5):
These LSAs are not typically generated by an ABR unless the ABR is also functioning as an ASBR. Type 5 LSAs are used to describe external routes imported into OSPF from other autonomous systems.
Therefore,NSSA LSA (A),Network Summary LSA (C), andASBR Summary LSA (D)are valid answers.AS External LSA (B)would only be correct if the ABR were also functioning as an ASBR, but that is not explicitly stated in the question.
References:
Huawei HCIA-Datacom Study Guide, Chapter on "OSPF LSAs and ABR Functions".
RFC 2328 - OSPF Version 2.

Understanding the Network Setup:
* The OSPF network consists of three areas (Area 1, Area 0, and Area 2).
* The server's subnet 192.168.1.0/24 is directly connected to R1 and imported into OSPF using the command:import-route direct type 1 cost 2 The server's subnet 192.168.1.0/24 is directly connected to R1 and imported into OSPF using the command:import-route direct type 1 cost 2 The server's subnet 192.168.1.0/24 is directly connected to R1 and imported into OSPF using the command:import-route direct type 1 cost 2
* The type 1 specifies the route as an OSPF Type 1 external route, meaning both the external cost and the internal OSPF cost will be included when calculating the total cost.
* The external cost specified for the imported route is 2.
* Cost Calculation to R2:
* The interfaces between the routers are GE interfaces, and the default cost for GE interfaces is 1.
* The path from R2 to the server goes through the following hops:
* R2 # R1: Cost = 1 (intra-area link).
* R1 # Server: External cost = 2 (specified in the import-route command).
* Total cost to R2:Intra-area cost (1) + External cost (2) = 3
Total cost to R2:Intra-area cost (1) + External cost (2) = 3
Total cost to R2:Intra-area cost (1) + External cost (2) = 3
* Verification of Each Option:
* Option A (2): Incorrect. This only accounts for the external cost, ignoring the internal OSPF cost.
* Option B (4): Incorrect. This overestimates the cost by adding an extra hop.
* Option C (3): Correct. The total cost is 3 (1 for the intra-area link + 2 for the external cost).
* Option D (1): Incorrect. This ignores the external cost of the imported route.
References:
* HCIA-Datacom Study Guide, Chapter: OSPF Route Types and Cost Calculation
* Huawei OSPF Cost Configuration Details

Comprehensive and Detailed in-depth Step-by-Step Explanation:BGP (Border Gateway Protocol) uses specific message types to establish and maintain peer relationships between routers. The primary BGP messages involved during the establishment and maintenance of peer relationships are:
* Open (D):
* The Open message is the first message sent after a TCP connection is established between BGP peers.
* It is used to exchange parameters such as the AS number, BGP version, hold time, and BGP identifier.
* Keepalive (A):
* After the Open message exchange, Keepalive messages are sent periodically to maintain the BGP session.
* These messages confirm that the connection is still alive.
* Update (C):
* Update messages are used to exchange routing information after the peer relationship is established.
* They contain information about network prefixes and their associated path attributes.
* Hello (B):
* Hello messages are not used in BGP. They are typically used in protocols like OSPF or IS-IS to establish and maintain neighbor relationships.
Thus, the correct answers are A (Keepalive), C (Update), and D (Open).
References:
* Huawei HCIA-Datacom Study Guide, Chapter on "BGP Message Types".
* RFC 4271 - Border Gateway Protocol 4 (BGP-4).