Technical Summary
When a link is being prepared to be taken out of service, the traffic
needs to be diverted from both ends of the link. Increasing the
metric to the highest value on one side of the link is not sufficient
to divert the traffic flowing in the other direction.
It is useful for routers in an OSPFv2 or OSPFv3 routing domain to be
able to advertise a link as being in a graceful-shutdown state to
indicate impending maintenance activity on the link. This
information can be used by the network devices to re-route the
traffic effectively.
This document describes the protocol extensions to disseminate
graceful-link-shutdown information in OSPFv2 and OSPFv3.
Working Group Summary
There was considerable discussion on both the use case and whether
we could use signaling amongst the routers on the link. However,
this would not allow a controller to be informed. Additionally,
there was discussion as to whether this could simply inferred from
a high forward metric. After some discussion, it was agreed explicit
signaling was preferred.
Additionally, there was some intertwining of requirements with the
signaling of other OSPF link attributes. Now that these are resolved
we can move forward with this draft.
Document Quality
This document has been a WG document for more a year. There have
been several iterations due to the controversy over area-wide versus
neighbor signaling. Now that we have reached consensus, the document
is fairly stable from a protocol standpoint. There has been some
discussion on the use cases and they have been refined in the current
version.
Personnel
Acee Lindem is the Document Shepherd.
Alia Atlas is the Responsible Area Director.