packet probing for bandwidth estimation:
packet-pair?
active probing?
meron bang triple probe?
Thursday, July 22, 2010
Wednesday, July 21, 2010
Ikalabingwalo
A reliable byte stream is a common service paradigm in computer networking; it refers to a byte stream in which the bytes which emerge from the communication channel at the recipient are exactly the same, and in the exact same order, as they were when the sender inserted them into the channel.
A reliable stream is not the only reliable service paradigm which computer network communication protocols provide, however; other protocols (e.g. SCTP) provide a reliable message stream, i.e. the data is divided up into distinct units, which are provided to the consumer of the data as discrete objects.
------------
* Larry L. Peterson and Bruce S. Davie, Computer networks: a systems approach, 3rd edition, Morgan Kaufmann Publishers, 1996, Section 6.2.
* Steve Steinke, Network Tutorial, Elsevier, 2000, page 163.
A reliable stream is not the only reliable service paradigm which computer network communication protocols provide, however; other protocols (e.g. SCTP) provide a reliable message stream, i.e. the data is divided up into distinct units, which are provided to the consumer of the data as discrete objects.
------------
* Larry L. Peterson and Bruce S. Davie, Computer networks: a systems approach, 3rd edition, Morgan Kaufmann Publishers, 1996, Section 6.2.
* Steve Steinke, Network Tutorial, Elsevier, 2000, page 163.
Tuesday, July 20, 2010
Ikalabingpito
my proposed research topic:
'Effective Multihoming in Mobile Networks'
-Efficient rules on switching
-Minimize false degradation of congestion window due to fading, blackout, etc.
-Minimize spurious retransmissions and timeouts ?
read 'SCTP Applications' (2003)
this is OK
Multihoming for availability and fail-over
Congestion and switching in multihomed connections is still for further research, specially on mobile networks.
We can extend or combine different congestion control approaches from TCP and use them on multihomed SCTP
As of now, multihoming is used for availability and fail-over, not CMT
Why use multihoming?
Why not mSCTP?
Why not CMT? -> bandwidth aggregation (link aggregation)
Why switch from TCP to SCTP?
What are the advantages of using SCTP on mobile networks?
From RFC4960 (2007)
"The limited scope of TCP socets complicates the task of providing highly-available data transfer capability using multi-homed hosts"
"When an endpoints peer is multihomed, the endpoint will calculate a separate RTO for each different destination transport address of its peer endpoint"
"When its peer is multihomed, an endpoint SHOULD try to retransmit a chunk that timed out (not 3 or 4 dupacks) to an active destination transport that is different to the last destination address to which the DATA chunk was sent"
"When its peer is multihomed, the SCTP endpoint should always try to send the SACK to the same destination address from which the last DATA chunk was received"
"SCTP sender MUST keep a set of these control variables cwnd, ssthresh and partial_bytes_acked for EACH destination address of its peer (when multihomed). Only one rwnd is kept for the whole association (no matter if the peer is multihomed or has a single address)."
PS:
Eto sana ung techniques pag topic is TCP:
X How slow-start ends?
Change error threshold to n (eg. n=3) before going to congestion avoidance stage.
X Decrease of cwnd & sshthresh - di dapat ganun (eg. Reno, SACK). Must use probing to check "blackout", "handover".
X For fading, interference, RTT computations must be done.
X Probes should be greater than 2. (eg. NOT packet-pair algorithm)
'Effective Multihoming in Mobile Networks'
-Efficient rules on switching
-Minimize false degradation of congestion window due to fading, blackout, etc.
-Minimize spurious retransmissions and timeouts ?
read 'SCTP Applications' (2003)
this is OK
Multihoming for availability and fail-over
Congestion and switching in multihomed connections is still for further research, specially on mobile networks.
We can extend or combine different congestion control approaches from TCP and use them on multihomed SCTP
As of now, multihoming is used for availability and fail-over, not CMT
Why use multihoming?
Why not mSCTP?
Why not CMT? -> bandwidth aggregation (link aggregation)
Why switch from TCP to SCTP?
What are the advantages of using SCTP on mobile networks?
From RFC4960 (2007)
"The limited scope of TCP socets complicates the task of providing highly-available data transfer capability using multi-homed hosts"
"When an endpoints peer is multihomed, the endpoint will calculate a separate RTO for each different destination transport address of its peer endpoint"
"When its peer is multihomed, an endpoint SHOULD try to retransmit a chunk that timed out (not 3 or 4 dupacks) to an active destination transport that is different to the last destination address to which the DATA chunk was sent"
"When its peer is multihomed, the SCTP endpoint should always try to send the SACK to the same destination address from which the last DATA chunk was received"
"SCTP sender MUST keep a set of these control variables cwnd, ssthresh and partial_bytes_acked for EACH destination address of its peer (when multihomed). Only one rwnd is kept for the whole association (no matter if the peer is multihomed or has a single address)."
PS:
Eto sana ung techniques pag topic is TCP:
X How slow-start ends?
Change error threshold to n (eg. n=3) before going to congestion avoidance stage.
X Decrease of cwnd & sshthresh - di dapat ganun (eg. Reno, SACK). Must use probing to check "blackout", "handover".
X For fading, interference, RTT computations must be done.
X Probes should be greater than 2. (eg. NOT packet-pair algorithm)
Tuesday, July 13, 2010
Ikalabinganim
read 'Congestion and Flow Control in the Context of the Message-Oriented Protocol SCTP' (2009)
medyo di kelangan pero ok na rin
read 'Performance Improvement of SCTP for Heterogeneous Ubiquitous Environment' (2007)
some good implementation discussions are shown here.
need to find more articles on congestion control on multihomed connections.
medyo di kelangan pero ok na rin
read 'Performance Improvement of SCTP for Heterogeneous Ubiquitous Environment' (2007)
some good implementation discussions are shown here.
need to find more articles on congestion control on multihomed connections.
Friday, July 9, 2010
Ikalabinglima
Read stuff about Reno, New Reno, and SACK
don't need MobileIP. Its used to maintain a permanent ip address on a mobile node moving to another network.
still have a dilemma on thesis topic :(
about use of sctp multihoming:
http://www.ietf.org/mail-archive/web/tsvwg/current/msg05084.html
latest SCTP RFC (2007):
http://tools.ietf.org/html/rfc4960
don't need MobileIP. Its used to maintain a permanent ip address on a mobile node moving to another network.
still have a dilemma on thesis topic :(
about use of sctp multihoming:
http://www.ietf.org/mail-archive/web/tsvwg/current/msg05084.html
latest SCTP RFC (2007):
http://tools.ietf.org/html/rfc4960
Thursday, July 8, 2010
Wednesday, July 7, 2010
Ikalabingtatlo
read 'SCTP Congestion Control: Initial Simulation Studies' (2003)
-describes SCTP congestion control
-differentiates congestion control between SCTP and TCP
read 'SHOP: An Integrated Scheme for SCTP Handover Optimization in Multihomed Environments' (2008)
-An SCTP endpoint maintains one receiver window (rwnd) for the entire association, while other variables, such as congestion window (cwnd), slow-start threshold (ssthresh) and RTT, are kept on a per destination address.
-handover ="a procedure in which an endpoint replaces the primary address with a secondary one, as well as redirects ongoing flows from the original path (towards old primary address) to the new one (towards new primary address)."
read 'SCTP Switchover Performance Issues in WLAN Environments' (2008)
-"Switchover" is the same as "Handover" in the previous paper
a useful wiki page:
http://en.wikipedia.org/wiki/SCTP_packet_structure
(My new thesis topic is something like "Enhancing througput of multihomed SCTP connections on mobile networks")
-describes SCTP congestion control
-differentiates congestion control between SCTP and TCP
read 'SHOP: An Integrated Scheme for SCTP Handover Optimization in Multihomed Environments' (2008)
-An SCTP endpoint maintains one receiver window (rwnd) for the entire association, while other variables, such as congestion window (cwnd), slow-start threshold (ssthresh) and RTT, are kept on a per destination address.
-handover ="a procedure in which an endpoint replaces the primary address with a secondary one, as well as redirects ongoing flows from the original path (towards old primary address) to the new one (towards new primary address)."
read 'SCTP Switchover Performance Issues in WLAN Environments' (2008)
-"Switchover" is the same as "Handover" in the previous paper
a useful wiki page:
http://en.wikipedia.org/wiki/SCTP_packet_structure
(My new thesis topic is something like "Enhancing througput of multihomed SCTP connections on mobile networks")
Monday, July 5, 2010
Ikalabingdalawa
My adviser's advice on SCTP, why SCTP? why Multihoming? check these thesis in library:
Ibabao, Joana EEE
Villacorta, Rachel EEE
Balagtas, Florence CS
Tiglao, Nestor EEE
read 'Experimental studies of SCTP multi-homing' (2001).
-it explains some rules specified in RFC 2960.
-ns2 simulation using 2<->2 IP. single-homed, multihomed, w/ w/o packet losses.
read 'Retransmission policies for multihomed transport protocols' (2006)
-AllRtxAlt and AllRtxSame
"Without a priori knowledge about the available paths, a sender cannot have a static policy that decides where to retransmit lost data and expect to guarantee the best
performance. Through simulation, we have measured and demonstrated the tradeoffs of three policies in non-failure and failure conditions"
Ibabao, Joana EEE
Villacorta, Rachel EEE
Balagtas, Florence CS
Tiglao, Nestor EEE
read 'Experimental studies of SCTP multi-homing' (2001).
-it explains some rules specified in RFC 2960.
-ns2 simulation using 2<->2 IP. single-homed, multihomed, w/ w/o packet losses.
read 'Retransmission policies for multihomed transport protocols' (2006)
-AllRtxAlt and AllRtxSame
"Without a priori knowledge about the available paths, a sender cannot have a static policy that decides where to retransmit lost data and expect to guarantee the best
performance. Through simulation, we have measured and demonstrated the tradeoffs of three policies in non-failure and failure conditions"
Sunday, July 4, 2010
Ikalabingisa
Decided to work on Congestion control of SCTP's multihoming in mobile networks.
On 'Host-to-Host Congestion Control for TCP' (2010), the authors suggested researching on this.
On 'Host-to-Host Congestion Control for TCP' (2010), the authors suggested researching on this.
Friday, July 2, 2010
Ikasampu
Got to present my ideas on panel. Panel suggests:
1. mobile IP or not? -> medyo di ko gets.
2. "Markings" of packets before hand-off/etc. (like ECN?)
3. Cross Layer communications
4. Try "patch" to different TCP standards.
i tried to differentiate my technique to TCP-Probing. Here are my findings. The advantage of my protocol from TCP-Probing is:
1. Simple
2. Better througput (goodput)
3. Sender side modification only.
4. No need to modify TCP header. Don't use other TCP options (eg. Timestamp, SACK)
5. The algorithms can be "patched" to other TCP standards.
ps: Need to change my mindset about "probing". Mine is not really probing. It just sends packets to "check" why packets are lost.
1. mobile IP or not? -> medyo di ko gets.
2. "Markings" of packets before hand-off/etc. (like ECN?)
3. Cross Layer communications
4. Try "patch" to different TCP standards.
i tried to differentiate my technique to TCP-Probing. Here are my findings. The advantage of my protocol from TCP-Probing is:
1. Simple
2. Better througput (goodput)
3. Sender side modification only.
4. No need to modify TCP header. Don't use other TCP options (eg. Timestamp, SACK)
5. The algorithms can be "patched" to other TCP standards.
ps: Need to change my mindset about "probing". Mine is not really probing. It just sends packets to "check" why packets are lost.
Thursday, July 1, 2010
Ikasiyam
On 'Host-to-Host Congestion Control for TCP' (2010)
will read on related topics:
1. packet reordering as congestion control
-eifel*
-Door
-PR
-RR
-TD-FR
2. UCLA research on wireless
-TCP Westwood
-Westwood+
-ABSE
-CRB
-BBE
-BR
will read on related topics:
1. packet reordering as congestion control
-eifel*
-Door
-PR
-RR
-TD-FR
2. UCLA research on wireless
-TCP Westwood
-Westwood+
-ABSE
-CRB
-BBE
-BR
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