Subject: [Tsvwg] QoS provision in a dynamic line speed

From: "Dor Snapir - Israel" <[email-masked]>
Date: Thu, 28 Sep 2006 10:35:49 +0300

Dear tsvwg members
I would like to ask if there is any work regarding flow-control
mechanism (algorithm) to inform routers and QoS devices about a
dynamically changing line speed, i.e. consider an ingress border router
that is connected to an interface that may change its speed (throughput)
according to environment condition (rain fade in this case), how does
this router can notify the upstream device about the current line speed?

I know that ECN may be used for that but is there a more explicit
protocol for that that can also notify about increased speed and not
only about decrease?

Thanks a lot and best regards  

Dor Snapir
Gilat Satellite Networks Ltd.
Email: [email-masked]

IMPORTANT - This email and any attachments is intended for the above named addressee(s), and may contain information which is confidential or privileged. If you are not the intended recipient, please inform the sender immediately and delete this email: you should not copy or use this e-mail for any purpose nor disclose its contents to any person.

---

From: Xiaoming Fu <[email-masked]>
Date: Thu, 28 Sep 2006 09:49:36 +0200

Hi Dor,

There could be several choices to notify this info, e.g.,
- XCP (http://www.isi.edu/isi-xcp/), in which data packets carry a 
congestion header in which the sender requests a desired throughput, 
while XCP-aware routers make a fair per-flow bandwidth allocation, and 
the sender is eventually notified with the e2e/bottleneck throughput, 
without maintaining any per-flow state in routers. (This can be regarded 
as an extension of ECN)
- path-coupled signaling, like RSVP (http://www.isi.edu/rsvp/) or NSIS 
(http://www.ietf.org/html.charters/nsis-charter.html), in which an 
explicit protocol may be used to dynamically update the resource (e.g., 
bandwidth) reservation along the path in a soft state fashion, providing 
end applications with certain QoS assurance.

Cheers,
Xiaoming

---

From: Erblichs <[email-masked]>
Date: Thu, 28 Sep 2006 08:48:53 -0700

Group,

	Wouldn't it be implicitly stated within the number of inflight
	segments / inflight byte counting & acks for TCP over time?

	However, a  change from one time frame to another 
	could also simply indicate a change in the amount of 
	application data for xfer.

	Mitchell Erblich
	------------------

Subject: 
        [Tsvwg] QoS provision in a dynamic line speed
   Date: 
        Thu, 28 Sep 2006 10:35:49 +0300
   From: 
        "Dor Snapir - Israel" <[email-masked]>
     To: 
        <[email-masked]>

Dear tsvwg members

I would like to ask if there is any work regarding flow-control
mechanism (algorithm) to inform routers and QoS devices about a
dynamically changing line speed, i.e. consider an ingress border router
that is connected to an interface that may change its speed
(throughput) according to environment condition (rain fade in this
case), how does this router can notify the upstream device about the
current line speed?

Dor Snapir

Email: [email-masked]