Hi Acee,
Thank you very much for your valuable comments.
My answers/explanations are inline below.
Best Regards,
Huaimo
-----Original Message-----
From: Acee Lindem (acee) [mailto:a...@cisco.com]
Sent: Friday, February 05, 2016 7:32 PM
To: Acee Lindem (acee); OSPF WG List; draft-ietf-ospf-...@ietf.org
Subject: Re: [OSPF] Working Group Last Call for "OSPF Topology Transparent Zone"
The WG Last Call has ended. I do have a couple minor comments.
1. Section 1 list the advantages for setting up an LSP over a TTZ as
opposed
to an area. The details of this are not described in the document so
this
should either be removed or the document should explicitly state the
details
of LSP setup are out of scope.
[Huaimo]: This will be removed from the document.
2. In section 11.2, I can see some race conditions if different TTZ
status is
configured on different routers in the TTZ during the
migration/rollback
period. This is addressed by saying a warning message will be issued
if
this occurs. How is this detected and will the conflicting operation
be
rejected?
[Huaimo]: We will add some details about the detection and operation.
The conflicting/racing condition/operation can be detected on a router on which
a configuration is issued.
When a configuration for controlling an action for migration/rollback is issued
on a router, the router should check whether the action is in a correct
sequence of actions for migration/rollback through using the information it
has. For migrating a part of an area to a TTZ, the correct sequence of actions
is as follows in general:
1) configure TTZ on every router in the part of the area to be migrated to TTZ;
2) configure on one router in the TTZ to trigger every router in the TTZ to
generate and distribute TTZ information for migration; and
3) configure on one router in the TTZ to trigger every router in the TTZ to
migrate to TTZ.
For rolling back from TTZ, it is similar.
After receiving a configuration on a router to migrate to TTZ, which is for
action 3), the router checks whether action 2) is performed through checking if
it has received/originated a TTZ LSA with T=1. If it has not, it gives a
warning to an operator (generation and distribution of TTZ information for
migration to TTZ are not done yet) and rejects the configuration at this time.
After a router receives a TTZ LSA with M=1 for action 3) from another router,
it checks whether action 2) is performed through checking if it has
received/originated a TTZ LSA with T=1. If it has not, it should give a
warning. The operation for migration will continue.
After receiving a configuration on a router to generate and distribute TTZ
information, which is for action 2), the router checks whether action 1) is
performed through checking if TTZ is configured on it. If it is not, it gives a
warning to an operator (TTZ is not configured on it yet) and rejects the
configuration at this time.
3. I guess one misconfigured router (no TTZ ID configured) will keep
migration
to TTZ from occurring. What happens if a misconfigured router is
introduced
on a broadcast link? Do all routers on the link revert to non-TTZ
operation?
[Huaimo]: You are right. When there is one mis-configured router on a broadcast
link, this link will not be migrated to TTZ. If a mis-configured router is
introduced on a broadcast link, this broadcast link will be revert to non-TTZ
link. In other words, each of the routers on the link reverts the status for
its connection to the link to non-TTZ.
I also have a number of editorial comments but will send those offline.
[Huaimo]: We will address them accordingly.
Thanks,
Acee
On 1/17/16, 3:30 PM, "OSPF on behalf of Acee Lindem (acee)"
<ospf-boun...@ietf.org on behalf of a...@cisco.com> wrote:
>This is the start of the WG last call for the “OSPF Topology Transparent
>Zone” protocol extensions draft. We’ve had a number of discussions on this
>and Huawei has a prototype implementation. The WG last call will end at
>12:00 AM PDT on February 1st, 2016. For your convenience, here is a URL:
>
>https://datatracker.ietf.org/doc/draft-ietf-ospf-ttz/
>
>Thanks,
>Acee and Abhay
>
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>OSPF mailing list
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