Zhongxing MingJavier Ubillos

Mingwei Xu

23/4/10 1Tsinghua University

FQDN resolution and IP management is dealt with by the application

All cool stuff have to be implemented by the application.• Mobility• Multi-homing• IPv4/IPv6 agnosticism• NA(P)T traversal• Path diversity exploitation• Etc…

23/4/102

addr = gethostbyname (someString );……connect( …, addr, … );write( … );close( … );connect (…, addr, …);write( … );colse( … );

Tsinghua University

Developers seem to like them… One implementation for every

framework More often than not

• Resolve once• Resue IP• Resue IP• Resue IP• Resue IP• Resue IP

• ……

23/4/103

Tsinghua University

Provide the socket abstraction developers like.

Do allow all the cool functions of surrogate addresses• But don’t introduce new indirections• And be explicit about that it is different

23/4/104

Tsinghua University

23/4/10Tsinghua University5

New API

Not binary compatible

A session layer

Easy transition

Minor changesor none

Compatible

Middle-boxesunaffected

NetworkHost

23/4/10Tsinghua University6

Application

Transport

Network

Outside the host

Name-based sockets

HIP

LISP

SCTP

listen() – Prep for incoming session• Fd = listen(src_name, dst_name, local_port, transport);

open() – Initiate outgoing sesion• Fd = open(src_name, dst_name, remote_port, transport);

accept() – Receive incoming session• (src_name, dst_name, fd) = accept(fd);

read() – Receive data• Data = read(fd);

write() – Send data• Write(fd, data);

close() – Close session• Close(fd);

23/4/107

Tsinghua University

It has been a long struggle to manage mobility in today’s IP networks.

NBS allows mobile device users to move from one network to another while maintaining the connection.

DNS and Shim6 is involved to support mobile NBS• No triangular routing• Fast handover• Good reliability

23/4/108

Tsinghua University

23/4/109

src_name dst_name

src_ip dst_ip

src_name dst_name

hash(src_name) hash(dst_name)

hash(src_name) hash(dst_name)

src_loc dst_loc

NBS

NBS Shim6

Before shim6 state establishment

After shim6 state establishment

Tsinghua University

23/4/1010

Original Shim6 State Machine

Modified Shim6 State Machine

Tsinghua University

23/4/1011

DNS

①

②③

④

⑤DNS

⑥

⑦AR3

AR1

AR2

Mobile Node (A)Name: www.mobile-node.comIP: 166.111.3.4

Mobile Node (A)Name: www.mobile-node.comIP: 202.111.2.3

Correspondent Host (B)Name: www.corres-host.comIP: 59.72.38.236

166.111.1.1 202.111.2.1

59.72.38.1

⑥

Tsinghua University

DNS

①

①

②

②

③

③

③

③

AR4

AR1

AR2

AR3

④

⑤

⑥

④

⑤

A

B23/4/1012

Tsinghua University

23/4/1013

Tsinghua University

23/4/1014

Handover time for different IEEE 802.11b cardsTsinghua University

Throughput graph during movement

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• Bernhard Age et al studies various DNS resolvers aroundthe world and found that there are only less than 1\% of the cases for which DNS resolvers take more that 100ms to answer

• Concurrent move is not very likely to occur

• Thus DNS delay won’t be a problem in practice

Tsinghua University

Propose and implement name-based sockets as a socket-API abstraction so that an application developer may use names instead of IP-addresses.

improve Shim6 and integrate it with name-based sockets to provide mobility functionality.

Evaluate the performance of the proposed mechanism using a real testbed.

23/4/1016

Tsinghua University

Questions?

23/4/1017

Tsinghua University