HCIP-Datacom H12-821_V1.0 Huawei Study Notes

Comprehensive and Detailed Step-by-Step Explanation:

BGP ConnectRetry Timer:

The ConnectRetry timer is used when establishing a TCP connection between BGP peers.

If the connection is successful, the timer is disabled.

If the connection fails, the timer restarts, and the router attempts to reconnect after the timer expires.

Behavior:

This timer prevents excessive connection attempts and ensures efficient resource utilization.

References:

HCIA-Datacom Study Guide, Chapter: BGP Session Establishment

Huawei BGP Timers and Session Management

High-availability Stateful Backup (HSB) ensures synchronization between active and standby devices. If the HSB channel fails to establish, the following causes are possible:

TCP channel not established: The HSB channel relies on a TCP connection. If the TCP session cannot be established, the backup process cannot start.

Mismatched retransmission settings: If the retransmission count and interval for HSB service packets are inconsistent between the two devices, the synchronization process fails.

Incorrect source and destination configurations: If the source IP address and port number on one device do not match the destination IP address and port number on the other, the channel cannot be established.

Option C is incorrect because the priority of the two ACs affects active/standby roles but does not directly impact HSB channel establishment ​.

The provided BGP error display shows the error timestamp as 12:40:39 on March 22, 2010. The error message confirms a mismatch in the peer AS number, as indicated in the "Incorrect remote AS" error info. This eliminates options related to other causes, and the timestamp in Option A is incorrect ​.

The DHCPNAK message is sent by the DHCP server to the client to indicate that the requested configuration is not valid. Messages like DHCPDiscover, DHCPRequest, and DHCPRelease are initiated by the client in the DHCP process ​.