Cell Relay Archive

[Jim Millar <jmillar@dl.com>]

S.Ramkumar wrote:

> Hi,
>
> Can't the encoding of the link info in the ICP cells be simplified
> as follows:
>
> NE Tx - 2 bits (NOT IN GROUP, UNUSABLE, USABLE, ACTIVE)
> NE Rx - 2 bits (NOT IN GROUP, UNUSABLE, USABLE, ACTIVE)
> Defect - 4 bits (could indicate both the receive and transmit defects)
>
> The current link info field has lot of UNUSABLE states reported
> through the ICP cells, viz., UNUSABLE - no reason, UNUSABLE -
> misconnected, UNUSABLE - fault, etc.
>
> Basically, we could just have one UNUSABLE state and report the
> reason through the defect field.  This way, the triggering of the
> state machine becomes straightfoward.
>
> Would appreciate any response on this.  (Chris are you there?)
>
Yes, this is true. You can just use "unusable no reason" for all
unusable conditions for any reason. There is no requirement to break
down the unusable state into subreasons when reporting across the link.
This is optional.

These sub-reasons are left over from previous revisions' state machines
that had actual sub-states that were reached through optional failure
conditions. While the sub-states were ripped out of the state machines
by the final version (since this whole area is optional and not an
interoperability issue), the reporting of the substates across the IMA
link was left in (since this is an interoperability issue).

--Jim Millar