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Midterm Reports of MPTCP-Related Middlebox Behavior. Michio Honda, Keio University Yoshifumi Nishida, Dyyno.Inc / WIDE project Costin Raiciu , UCL Mark Handley, UCL MPTCP WG, Nov.10, 2010 79 th IETF@Beijing. Today’s Data. Now we got data from more than 100 paths from around 20 countries
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Midterm Reports of MPTCP-Related Middlebox Behavior Michio Honda, Keio University Yoshifumi Nishida, Dyyno.Inc / WIDE project CostinRaiciu, UCL Mark Handley, UCL MPTCP WG, Nov.10, 2010 79thIETF@Beijing
Today’s Data • Now we got data from more than 100 paths from around 20 countries • Today we show some of data in 81 paths obtained between 25 September and 22 October, 2010 • 36 (44.4%) home networks (Home-gateway+ISP) • 12 (14.8%) university networks • 11 (13.6%) cellular career (EDGE, 3G) • 11 (13.6%) hotspots (e.g., hotel, public Wifi, hall) • 6 (7.4%) company networks • 4 (4.9%) hosting agents (e.g., Amazon EC2)
Middlebox Behavior MPTCP Should Care • TCP Options • MP_CAPABLE, MP_DATA, MP_ACK, TIMESTAMP • Passed, removed, modified, zeroed (and at outgoing or incoming)? • Retransmission and Gapped Sequence • When MPTCP retransmits the segment on another path, • retransmitting “TCP-level sequence number” might have different payload • Or, original sequence number might be skipped
TCP Options • Port 34343 • 3.7 % (3 out of 81) remove MP_CAP • All of them are cellular networks • The same 3.7 % also remove MP_DATA • Port 80 • 12.3 % (10 out of 81) remove MP_CAP • 4 cellular networks, 3 university networks, 3 hotspots • Include all paths removing MP_CAP at port 34343 • 8.6 % (7 paths) remove MP_DATA • Part of paths removing MP_CAP (3 cellular and 2 university 3 hotspots) • 3.7 % (3 paths) didn’t deliver non-HTTP payload • The other part of paths removing MP_CAP (1 cellular, 1 univ.)
TCP Options (cont.) • Port 443 • 6.2 % (5 out of 81) remove MP_CAP • 3 hotspots and 2 cellular networks • All of these remove MP_CAP at port 80 • The same 6.2 % also remove MP_DATA • Summary • None of paths drops segments including MP_CAP or MP_DATA • 3.7 – 12.3 % of paths (depending on the port number) remove MP_CAP or MP_DATA
Retransmissions with Different Payload • Port 34343 • 1.2 % (1 cellular network out of 81) discarded retransmission of different payload • Ack is advanced, but retransmitted payload has not reached the receiver, because middlebox retransmitted • Port 80 • 7.4 % (6 out of 81) discarded retransmitted segment including different payload, but Ack is advanced • 3 hotspots, 2 cellular networks, and 1 home network • One of them also does the same behavior at port 34343 • 1.2 % (1 out of 81) sent back RST against different payload retransmission • 1 company network
Retransmissions with Different Payload (cont.) • Port 443 • 3.7 % (3 out of 81) discarded the retransmitted, but Ack is advanced • 3 hotspots • Part of paths doing the same behavior at port 80 • Summary • 1.2 – 7.4 % of paths do not deliver retransmitted segment, and the middlebox retransmits instead • 1.2 % sends back RST against retransmission of different payload for port 80
Gapped Sequence Number • Port 34343 • 1.2 % (1 cellular network out of 81) discarded the gapped sequence • 1.2 % (1 cellular network) replied Ack to resend the correct sequence number • Port 80 • 4.9 % (4 out of 81) discarded the gapped sequence • 2 cellular networks, 1 company network and 1 home network • 6.2 % (5 out of 81) replied Ack to resend the correct sequence number • 3 hotspots and 2 cellular networks
Gapped Sequence Number (cont.) • Port 443 • 1.2 % (1 out of 81) discarded the gapped sequence • 1 cellular network that also discards such segment at port 80 • 4.9 % (4 out of 81) replied Ack to resend the correct sequence number • 3 hotspots and 1 cellular networks (part of paths doing the same behavior at port 80) • Summary • 1.2 – 4.9 % of paths discard the gapped sequence • 1.2 – 6.2 % of paths respond to resend the correct sequence
Thank You for Your Contribution • We’re still collecting data, please send us log files from our experimental tool • http://www.ietf.org/mail-archive/web/multipathtcp/current/msg01150.html • If anybody stays in the hotel other than Shangri-la, please run it at your room! • If anybody can connect to Chinese 3G career via iPhone (MyFi) or Android tethering, let us know!