[Sis-csi] 2:30 Eastern it is -- IDEA VxWorks info

Thu Feb 1 16:15:59 EST 2007

What would a frame size of 1024 bits do to the performance.  Is the 
limit bit rate/volume of data unit handling?

At 3:09 PM -0500 2/1/07, Scott, Keith L. wrote:
>Wow, that's great info!
>
>OK, so those machines top out somewhere between 15k and 30k packets
>(VCDU frames)/s and can handle at least 132Mbps through.  To a rough
>order approximation, let's say that any IP QoS (marking, cbq, etc.) we
>might want to do is about as compute-intensive as whatever VCDU
>processing is done.  In any case, that kinkd of uplink rate is waayyyy
>over current envisioned uplink rates, and probably close to the limits
>of the RF system (as I feared it would be).
>
>VxWorks images are determined by the set of features enabled, but I
>suspect that most run around a few tens of Megabytes, so even a 10Mbps
>uplink rate should cover a full (base) software reload in under a
>minute.
>
>Since there's almost surely a trade between speed and
>reliability/correctness, do we foresee any kind of BER requirement we'd
>like to see on these high-rate uplinks?
>
>I think I should work with Greg to see what the next 'ceiling' above
>10Mbps might be in terms of coding / framing.  I suspect that once we
>can do 10Mbps up then (from the baseband processing standpoint, not RF)
>15, 20, or even 40 might not be too hard.
>
>		--keith
>
>-----Original Message-----
>From: Schneider, Larry [mailto:larry.schneider at nasa.gov]
>Sent: Monday, January 29, 2007 6:31 PM
>To: Scott, Keith L.; sis-csi at mailman.ccsds.org
>Subject: RE: [Sis-csi] 2:30 Eastern it is -- IDEA VxWorks info
>
>We know Linux well but are not VxWorks experts. If someone has some
>commands we could run or tests we could perform within reason we'd be
>glad to.
>
>The VxWorks systems we have are TSI FDPs. They are  about 4 years old.
>We think they are ~ 300 MHz. We recall
>discussions about upgrading them to 433 MHz though that never happened.
>
>There are a total of 21 of them located at MSFC (6), JSC (3), WSC (6) ,
>and a couple of support facilities (2). We have four in our lab.
>
>The systems process the ISS Ku-band 150 mb/s downlink as well as the
>S-band downlink.
>
>The systems process 15,000 1100 byte VCDU frames / second in and out.
>We
>demonstrated the systems can not process 30,000 1100 byte VCDU frames /
>second in and out though we didn't try to probe any further.
>
>We also demonstrated that they can't record and distribute 15,000 1100
>byte VCDU frames at the same time.
>
>
>
>
>
>
>
>-----Original Message-----
>From: sis-csi-bounces at mailman.ccsds.org
>[mailto:sis-csi-bounces at mailman.ccsds.org] On Behalf Of Scott, Keith L.
>Sent: Thursday, January 25, 2007 2:42 PM
>To: Scott, Keith L.; sis-csi at mailman.ccsds.org
>Subject: RE: [Sis-csi] 2:30 Eastern it is
>
>People I heard on the call:
>	Keith Scott
>	Howie
>	Keith H.
>	Scott B.
>	Ed Criscuolo
>	Will Ivancic
>	Larry Schneider
>	Ed Greenberg
>
>** Request from the high-rate uplink WG
>
>Current TDRSS uplink rate is 25Mbps (Dave?) There seemeed to be some
>confusion about what the real rate(s) were:
>	S-band is 2-4 mbps
>	Ku ~3Mbps up and down
>
>Scott: to estimate the required uplink data rate, find out the maximum
>rate at which you can forward packets, and use that.  If the first
>spacecraft on orbit has to serve 3 others or 60 others, doesn't matter,
>they get what they get but at least we'll be able to get the data up as
>fast as we can forward it.  For this exercise, assume a dedicated
>processor for packet handling.  Keith H. notes that several years ago
>i386 class machines could saturate a 10Mbps Ethernet, so even rad hard
>things nowadays should be able to do that.
>
>What rates can VxWorks forward at over the past N years?
>VxWorks -- how fast can the network stack forward.
>Scott and/or flight software people at Goddard may have some VxWorks
>machines.
>Larry Schneider has a lot of VxWorks machines to handle the ISS
>high-rate uplink
>	VxWorks expert is off this week but email out questions to
>Larry
>(to give to
>	Alex).
>
>Ed -- driver for uplink may be HD uplink video (~5mbps) Cap everything
>by about 30-50Mbps because we don't think uplink radios can do more.
>
>Will sent email
>"What is 'uplink'?"
>
>
>		--keith
>
>-----Original Message-----
>From: sis-csi-bounces at mailman.ccsds.org
>[mailto:sis-csi-bounces at mailman.ccsds.org] On Behalf Of Scott, Keith L.
>Sent: Thursday, January 25, 2007 12:35 PM
>To: sis-csi at mailman.ccsds.org
>Subject: [Sis-csi] 2:30 Eastern it is
>
>Ok, we're on for 11:30 pacific, 1:30 central, 2:30 eastern on
>Thursdays, starting today.
>
>Phone Number:
>	703 983 6338 (x31550) in Washington
>	781-271-6338 (x16338) in Bedford
>	866-648-7367 (866-MITRE-MP) Toll Free
>
>Meeting ID: 55555
>
>Today's Agenda:
>	Recap from Colorado Springs Meeting
>	Request for requirements info from High-Rate Uplink WG
>	Red Book 1 Items:
>		Collect information and distribute
>			GPM (Jane)
>			CANDOS (Dave/Keith H.)
>			SNIS (Dave)
>			Shuttle&ISS (Larry)
>			Surrey satellite (Loyd/Will)
>		Mash these against requirements
>		From the 'assumptions' slide, list possible solutions
>to each of the requirements
>		Downselect possible solutions
>		Assign people to write text
>		Publish book
>
>		--keith
>
>-----Original Message-----
>From: sis-csi-bounces at mailman.ccsds.org
>[mailto:sis-csi-bounces at mailman.ccsds.org] On Behalf Of Scott, Keith L.
>Sent: Thursday, January 25, 2007 9:34 AM
>To: sis-csi at mailman.ccsds.org
>Cc: Greg.J.Kazz at jpl.nasa.gov
>Subject: [Sis-csi] Telecon scheduling and request for requirements
>
>========== Telecon scheduling
>
>I apologize for this but we're going to need to reschedule our weekly
>telecons, starting with today's.  Hopefully this will be the last time
>we'll have to do this for a while.  I'll start off by proposing one
>hour earlier on Thursdays (11:30 pacific, 1:30 central, 2:30 eastern).
>Please let me know if this works for you and, if not, what would.  If
>we can't come to consensus quickly we'll wave off this week's telecon,
>but please see below on a request for requirements from the High Rate
>Uplink WG in SLS; I'd like to hash this out over email and get them an
>answer by next week.
>
>========== Request for Requirements from High-Rate Uplink WG
>
>Following up from the Colorado Springs meetings, we've received a
>request for requirements from the High Rate Uplink WG (CWE at
>http://public.ccsds.org/sites/cwe/sls-hru/default.aspx?RootFolder=%2fsi
>tes%2fcwe%2fsls%2dhru%2fPublic%2fCharters&View=%7bED7A93D1%2d1BB1%2d403
>3%2d8432%2dD7382F71947D%7d).  In particular they want to know what
>kinds of uplink rates the cislunar architecture would require.  I think
>that our DOWNLINK requirements should at least cover current shuttle
>and station rates of ~150Mbps, but I don't think we require full
>symmetry on the uplink.
>
>The largest driver for the uplink rate might be crew accommodation of
>live HDTV events, which would be on the order of 5-10Mbps, if they were
>actually provided.  If we had that then we should be able to cover most
>or all of the operational uplink traffic in the margin!  :)  Just as
>another point of reference, 150Mbps of TCP downlink would require
>~2Mbps of TCP ACK traffic.  We also need to remember that in a
>networked world such as we've proposed, one uplink may be serving
>several spacecraft.
>
>In any case, we need to provide them with a number that:
>	1) Is large enough to cover our requirements for a reasonable
>amount of time
>	2) Is not so large that they roll on the floor laughing at us
>
>Regardless of the rate requirement, RFC3819 (Advice for Internet
>Subnetwork Designers) and maybe rfcs RFC3155 (End-to-end Performance
>Implications of Links with Errors) and RFC3366 (Advice to link
>designers on link Automatic Repeat reQuest (ARQ)) seem relevant.
>
>		--keith
>
>_______________________________________________
>Sis-CSI mailing list
>Sis-CSI at mailman.ccsds.org
>http://mailman.ccsds.org/cgi-bin/mailman/listinfo/sis-csi
>
>_______________________________________________
>Sis-CSI mailing list
>Sis-CSI at mailman.ccsds.org
>http://mailman.ccsds.org/cgi-bin/mailman/listinfo/sis-csi
>
>_______________________________________________
>Sis-CSI mailing list
>Sis-CSI at mailman.ccsds.org
>http://mailman.ccsds.org/cgi-bin/mailman/listinfo/sis-csi
>
>_______________________________________________
>Sis-CSI mailing list
>Sis-CSI at mailman.ccsds.org
>http://mailman.ccsds.org/cgi-bin/mailman/listinfo/sis-csi