Hi Vince, ,
I am not quite clear about how OUTSIDE_COVERAGE works, if the database
is in charge of returning a list of alternate database with OUTSIDE_COVERAGE
error, does it means the database has to
maintain some information, such as coverage area, of other databases? And how
it works when databases are managed by different companies?
If a master moves from USA to UK, can the database that the master
originally connected return available database in UK to master?
Another question is, if a Database Listing server is used, what
interface will be deployed between master and Database Listing server, is there
an existing one, or a new one should be devised?
Finally, when HTTP redirect is provided in the protocol, can you
explain it to me when "DbUpdateSpec" be used and when HTTP redirect will be
used, if database wants to provide an alternate datebase?
Thanks!
-Xinpeng
From: Vincent Chen [mailto:[email protected]]
Sent: Wednesday, June 05, 2013 10:21 AM
To: Weixinpeng
Cc: Mark Jones; [email protected]; Peter McCann
Subject: Re: [paws] draft-wei-paws-database-discovery-01
Xinpeng, All,
Thanks for putting this together.
It seems that discovery involves two aspects:
- Deployment of LoST servers, which also impacts discovery of LoST severs
- Protocol (format of messages that is communicated)
The current document is placing deployment out of scope, but does suggest that
preconfiguration is a strategy.
That just leaves the protocol, which, may be characterized as:
1. Device sends request with its location
2. Server responds with a list of (name, uri) pairs
Given that this is relatively simple, should we just build it into PAWS
protocol itself?
For example, the current revision (r05) of the PAWS protocol allows for the
following:
1. Device asks database for available spectrum in a location outside the
coverage area for the Databae
2. The Database returns OUTSIDE_COVERAGE error and MAY include a list of
(name, databaseUri) entries to "recommend" alternate databases
This provides almost the same capability.
Should we just add a ListDatabase to PAWS?
-vince
On Thu, May 23, 2013 at 6:57 PM, Weixinpeng
<[email protected]<mailto:[email protected]>> wrote:
Hi Mark,
Please see comments inline. Thanks!
Best Regards,
Xinpeng.
From: Mark Jones [mailto:[email protected]<mailto:[email protected]>]
Sent: Thursday, May 23, 2013 10:31 PM
To: Weixinpeng; [email protected]<mailto:[email protected]>
Cc: Peter McCann; Zhulei (A)
Subject: RE: [paws] draft-wei-paws-database-discovery-01
Hi Xinpeng,
Thank you for your responses. I have some further comments/questions inline
below (prefixed by mj>).
From: Weixinpeng [mailto:[email protected]]
Sent: May-22-13 11:13 PM
To: Mark Jones; [email protected]<mailto:[email protected]>
Cc: Peter McCann; Zhulei (A)
Subject: RE: [paws] draft-wei-paws-database-discovery-01
Hi Mark,
Thanks for your feedback, and I think there are some issues that I
need to clarify.
we have to be clear that the discovery mechanism is provided as an
optional method that can help master device to find the correct WSDB, which
means the master device can get WSDB by, such as, pre-configuring of WSDB,
provision etc.
mj> Understood.
The dynamic discovery mechanism provides more convenient for master
device to find WSDB, for example, when a new WSDB is setup for providing
service or when some deployed WSDB goes down and never work.
mj> In this regard, DNS resolution would appear to be equally convenient
mechanism to manage WSDB instances being commissioned or decommissioned. I view
LoST as a kind of "location-aware DNS" so I understand its applicability to
discovery of the appropriate WSDB. I still think the draft needs more
information on how the Master device finds its WSDB DS so that implementers
understand if/when this optional discovery method is applicable to their
deployment.
[Wei] Yeah, because we cannot covey location information in DNS query message,
so DNS is inappropriate to find the WSDB. I think I will do more clarification
about how master device finds WSDB DS later.
About the DHCP you mentioned below, technically speaking, there have
been some extension of DHCP for supporting the provision of LoST server, refer
to RFC5223.
mj> I understand that the DHCP option specifying the LoST server would be
provided to the Master device when it initiated its backhaul connection (non-WS
connection) to the internet. Correct?
[Wei] Yeah.
Besides, using DHCP method doesn't means IP network provider must have some
business relationship with WSDB DS provider, if the network provider wants to
provide master device with FQDN of WSDB DS it can use DHCP.
mj> If the backhaul network operator is configuring his DHCP server to send
options to provision the WSDB DS then I assume he has some business interest in
doing so. What am I missing?
[Wei] I think there may be some relationship between network operator and WSDB
DS. But the reason why DHCP is mentioned here is because in the LoST protocol
DHCP is extended to provide LoST server's domain name to the LoST client.
Thanks
Mark
Best Regards,
Xinpeng.
From: Mark Jones [mailto:[email protected]]
Sent: Wednesday, May 22, 2013 11:29 PM
To: Weixinpeng; [email protected]<mailto:[email protected]>
Cc: Peter McCann
Subject: RE: [paws] draft-wei-paws-database-discovery-01
Hi Xinpeng,
In section 3, you state:
The URL or IP address of WSDB DS can be found by any method such as
DNS, DHCP, manually configuring etc, and it is out of scope of this
document.
I'm unclear on how the Master device obtains the URL of a trusted discovery
server unless there is some pre-configuration involved. I understand that DNS
could be used if the Master device is already pre-configured with a
preferred/home TVWS DS URL (or a preferred/home domain that is then resolved
with U-NAPTR) but I don't see how DHCP could be used to bootstrap this
information in the TVWS scenarios. Please could you elaborate.
Thanks
Mark
From: [email protected]<mailto:[email protected]>
[mailto:[email protected]] On Behalf Of Weixinpeng
Sent: May-21-13 9:11 PM
To: [email protected]<mailto:[email protected]>
Cc: Peter McCann
Subject: [paws] draft-wei-paws-database-discovery-01
Hi all,
I have uploaded a new version draft on database discovery. Comments
are welcomed.
http://tools.ietf.org/html/draft-wei-paws-database-discovery-01.
Xinpeng Wei
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-vince
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