SNR S2989G-48TX-DC — layer 2 Services Configuration and Remote Fault Detection Guide [97/553]

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S2989G-24TX Operation Manual Chapter 2 Layer 2 services

Configuration

including Errored symbol period event, Errored frame event, Errored frame period event,

Errored frame seconds event.

Errored symbol period event: The errored symbol number can not be less than the

low threshold. (Symbol: the min data transmission unit of physical medium. It is unique for

coding system, the symbols may be different for different physical mediums, symbol rate

means the changed time of electron status per second. )

Errored frame period event: Specifying N is frame period, the errored frame number

within the period of receiving N frames can not be less than the low threshold. (Errored

frame: Receiving the errored frame detected by CRC.)

Errored frame event: The number of detected error frames over M seconds can not

be less than the low threshold.

Errored frame seconds event: The number of error frame seconds detected over M

seconds can not be less than the low threshold. (Errored frame second: Receiving an

errored frame at least in a second.)

3. Remote Fault Detection

In a network where traffic is interrupted due to device failures or unavailability, the flag

field defined in Ethernet OAMPDUs allows an Ethernet OAM entity to send fault

information to its peer. As Information OAMPDUs are exchanged continuously across

established OAM connections, an Ethernet OAM entity can inform one of its OAM peers of

link faults through Information OAMPDUs. Therefore, the network administrator can keep

track of link status in time through the log information and troubleshoot in time.

There are three kinds of link faults for Information OAMPDU, they are Critical Event,

Dying Gasp and Link Fault, and their definitions are different for each manufacturer, here

the definitions are as below:

Critical Event: EFM OAM function of port is disabled.

Link Fault: The number of unidirectional operation or fault can not be less than the

high threshold in local. Unidirectional Operation means unidirectional link can not work

normally on full-duplex link without autonegotiaction. EFM OAM can detect the fault and

inform the remote OAM peers through sending Information OAMPDU.

Dying Gasp: There is no definition present. Although device does not generate Dying

Gasp OAMPDU, it still receives and processes such OAMPDU sent by its peer.

4. Remote loopback testing

Remote loopback testing is available only after an Ethernet OAM connection is

established. With remote loopback enabled, operating Ethernet OAM entity in active mode

issues remote loopback requests and the peer responds to them. If the peer operates in

loopback mode, it returns all packets except Ethernet OAMPDUs to the senders along the