[c-nsp] UDLD enabling port prematurely?

[Lukas Tribus]

>> Why? If ethernet autonego provides this natively via RFI?
>
> Autoneg is useful when either the TX or the RX fiber is
> interrupted, however, when you have a hardware failure in the
> sfp/linecard/asic etc (which causes an unidirectional link),
> than you need UDLD to intervene.

Just had another hardware defect leading to a unidirectional link,
this time it was a 10G port on a WS-X6708-10G. Links up/up on both
sides but no RX on the 10G port on this linecard.

This time it was a L3 link, but if this would have been STP without
UDLD or loopguard, it would have caused a meltdown.


Looks like this kind of hw-failure is more than a once-in-a-lifetime
occurrence on 6500/7600 chassis/linecards ...


Lukas