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Re: [802.3_B400G] Proposed Liaison Response



Jeff,

 

I think the point made during the discussion yesterday is that it is not necessary to go into this level of detail in the liaison letter to the OIF. We just need to draw OIF’s attention to the fact that in 802.3dj we have introduced a significant new feature called ILT.

 

Gary

 

From: Jeffery Maki <00000d5963b8071f-dmarc-request@xxxxxxxxxxxxxxxxx>
Sent: Tuesday, May 13, 2025 8:50 PM
To: STDS-802-3-B400G@xxxxxxxxxxxxxxxxx
Subject: Re: [802.3_B400G] Proposed Liaison Response

 

Dear P802.3dj Task Force Members,

 

Please read our own draft. We speak towards whether an optical or electrical interface does or does not support training.

 

178B.5.1 Interface behavior

 

ILT on each interface includes some independent functions on each lane.

 

If training is available on the interface the behavior is as follows:

— Local variables are sent to the peer interface via the training frames. Remote variables are received

from the peer interface.

— When both local_rts and remote_rts are 1, after a specified delay (propagation_timer, see

Figure 178B–8), the device switches to its normal functionality (tx_mode = data, see 178B.14.3.1),

forwarding data between its interfaces in both directions. The condition is shared by all lanes within

an ISL, and therefore the switching of all lanes occurs in a period within the limits of

propagation_timer (see 178B.14.3.3).

— There is no specified timeout when waiting for either rx_ready or remote_rts to change to the value

1.

— While waiting for rx_ready and remote_rts, losing frame lock and not recovering it after a specified

recovery time (recovery_timer, see Figure 178B–8) or losing frame lock a configured number of

times (recovery_event_count, see Figure 178B–8), would cause training to fail and squelch. Training

may be restarted by management after an unspecified time.

— Management may access devices and restart training on a specific ISL if desired.

— The SIGNAL_OK status variable of the interface is OK if local_rts and remote_rts are both 1.

 

If training is not available on an interface (disabled or not defined for the interface type) the behavior is as

follows:

— local_rx_ready is generated on each lane based on internal criteria, similar to the signal indication

logic (SIL) in existing AUI components or PMDs.

— remote_rx_ready is set to 1 (there is no way to get it from the peer interface).

— local_rts is independent of local_rx_ready and is generated only from the variables of the other

interface of the device. It is communicated to the peer interface by squelching (local_rts = 0) or

unsquelching (local_rts = 1) the output.

— remote_rts is set to 1 (there is no way to get it from the peer interface).

— The variables local_tf_lock and remote_tf_lock are undefined and not used.

— The SIGNAL_OK status variable of the interface is OK if local_rts and remote_rts are both 1.

 

Jeffery Maki

Distinguished Engineer II

Juniper Networks

 

Juniper Business Use Only


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