Figure 32: Grace Tlv Active Node With Soft Reset - Alcatel-Lucent 7750 Configuration Manual

The difference between the two is subtle but important. When an active node performs this
function it will generate an Informational TLV with the Local TLV following the successful soft
reset. When it receives the Information PDU with the Grace Ack it will send its own Information
PDU with both Local and Remote TLV completed. This will complete the protocol restart. When
a passive node is reset the passive port will wait to receive the 802.3ah OAM protocol before
sending its own Information PDU with both the Local and Remote TLV thus completing the
protocol restart.
The renegotiation process allows the node which experienced the ISSU or soft reset to rebuild the
session without having to restart the session from the discovery phase. This significantly reduces
the impact of the native protocol on data forwarding.
Any situation that could cause the renegotiation to fail will force the protocol to revert to the
discovery phase and fail the graceful restart. During a Major ISSU when the EFM OAM session is
held operational by the Grace function, if the peer MAC address of the session changes, there will
be no log event raised for the MAC address change.
This feature does not support the clearing of an IOM which does not trigger a soft reset. That is a
forceful event that will not trigger this graceful protocol renegotiation.
7750 SR Interface Configuration Guide
Passive
1/1/1
Port State: Down
Port State: Up
Info PDU (Local & Remote TLV)

Figure 32: Grace TLV Active Node with Soft Reset

Discovery: Start
Discovery: Complete
Info PDU
Info PDU
Info PDU (Grace 900s)
Info PDU (Grace ACK)
Info PDU (Grace 900s)
Info PDU (Grace ACK)
Info PDU (Grace 900s)
Info PDU (Grace ACK)
Info PDU (Grace ACK)
Info PDU (Grace ACK)
Info PDU (Local TLV)
Info PDU (Grace ACK)
Info PDU
Interface Configuration
Active
2/2/2
Port State: Down
Port State: Up
Operator Initiates
ISSU / Soft Reset
ISSU / Soft Reset
Commences
ISSU / Soft Reset
Completes
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