Overview of Service Diagnosis

Service diagnosis allows maintenance personnel to create a diagnosis object using command lines. When a user matching attributes of the diagnosis object gets online, the switch automatically creates a diagnosis instance for the user based on the diagnosis object and monitors and exports instance information including status changes and protocol processing during user access.

A diagnosis object is a database of users with some same attributes. For example, all users on an interface can be defined as a diagnosis object. A diagnosis instance is created based on a diagnosis object and maps a user.

A diagnosis object is defined based on the following attributes:

Interface number
VLAN ID
QinQ VLAN
Access mode
User name
IP address
MAC address

Multiple users may get online or offline simultaneously and debugging information about a specified user cannot be displayed. Therefore, it is difficult to locate faults during user access based on debugging information on existing networks. Maintenance personnel need to capture information about services of a specified user.

The service diagnosis function of the switch meets this requirement.

Currently, the device supports diagnosis for Dynamic Host Configuration Protocol (DHCP), Authentication, Authorization and Accounting (AAA), and Network Admission Control (NAC) services. The switch diagnoses and exports complete key information about exchanges between modules during user access. This helps maintenance personnel know about service implementation and locate and rectify service faults based on the information. Table 1 describes key information about exchanges between modules during service diagnosis.

**Table 1** Key information about exchanges between modules during service diagnosis
Service		Key Exchange Information
DHCPv4 or DHCPv6	DHCPv4 client	IP address request, release, lease, and conflict.
	DHCPv4 server or DHCPv6 server	IP address allocation, release, and lease.
	DHCPv4 relay or DHCPv6 relay	IP address request, release, and lease.
	DHCPv4 snooping or DHCPv6 snooping	IP address request, release, lease, and adding or deleting of dynamic DHCP snooping binding entries.
AAA		User access, authentication, authorization, and accounting. NOTE: Service diagnosis supports only common AAA users.
NAC		User access and authentication.