SNR S2989G-8TX — настройка и управление протоколами ULDP и LLDP в сетях [81/553]

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S2989G-24TX Operation Manual Chapter 2 Layer 2 services

Configuration

 The hello interval of sending hello messages can be changed (it is10 seconds by

default and ranges from 5 to 100 seconds) so that ULDP can respond faster to

connection errors of links in different network environments. But this interval should

be less than 1/3 of the STP convergence time. If the interval is too long, a STP loop

will be generated before ULDP discovers and shuts down the unidirectional

connection port. If the interval is too short, the network burden on the port will be

increased, which means a reduced bandwidth.

 ULDP does not handle any LACP event. It treats every link of TRUNK group (like Port-

channel, TRUNK ports) as independent, and handles each of them respectively.

 ULDP does not compact with similar protocols of other vendors, which means users

can not use ULDP on one end and use other similar protocols on the other end.

 ULDP function is disabled by default. After globally enabling ULDP function, the

debug switch can be enabled simultaneously to check the debug information. There

are several DEBUG commands provided to print debug information, such as

information of events, state machine, errors and messages. Different types of

message information can also be printed according to different parameters.

 The Recovery timer is disabled by default and will only be enabled when the users

have configured recovery time (30-86400 seconds).

 Reset command and reset mechanism can only reset the ports automatically shut

down by ULDP. The ports shut down manually by users or by other modules won’t be

reset by ULDP.

2.5

LLDP

2.5.1

Introduction to LLDP Function

Link Layer Discovery Protocol (LLDP) is a new protocol defined in 802.1ab. It enables

neighbor devices to send notices of their own state to other devices, and enables all ports

of every device to store information about them. If necessary, the ports can also send

update information to the neighbor devices directly connected to them, and those

neighbor devices will store the information in standard SNMP MIBs. The network

management system can check the layer-two connection state from MIB. LLDP won’t

configure or control network elements or flows, but only report the configuration of layer-

two. Another content of 802.1ab is to utilizing the information provided by LLDP to find

the conflicts in layer-two. IEEE now uses the existing physical topology, interfaces and

Entity MIBs of IETF.