Transcript Development of IPv6-IPv4 Translation Mechanisms for SIP

Development of IPv6-IPv4
Translation Mechanisms for SIPbased VoIP Applications
Advisor: Dr. Kai-Wei Ke
Speaker: Wei-Ying Huang
Outline
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Introduction
BIA
BIS
SLT
SIPv6 Translator
Implementation
Introduction
 SIP VoIP application is an important
driving force to promote IPv6.
 This paper presents the deployment
of two IPv6-IPv4 translation
mechanisms (i.e., Socket-layer
Translator and SIPv6 Translator) for
SIP VoIP applications.
IPv4/IPv6 Transition Mechanisms
 Dual Stack
 Reduce the cost invested in transition by running
both IPv4/IPv6 protocols on the same machine .
 Tunneling
 Reduce the cost in wiring by re-using current
IPv4 routing infrastructures as a virtual link.
 Translation
 Allow IPv6 realm to access the rich contents
already developed on IPv4 applications
Dual Stack
 Dual stack hosts run
both the IPv4 and the
IPv6 in Network Layer.
Tunneling
Translation
 Translation Mechanism is used when
the IPv4 network connects to IPv6
network
Translation (cont)
 Install between the IPv4 network and
IPv6 network.
 NAT-PT (Network Address Translation
and Protocol Translation)
 ALG (Application-Level-Gateway)
 SIIT (Stateless IP/ICMP Translation)
 Install on host computer
 BIS (Bump-In-the-Stack)
 BIA (Bump-In-the-Application)
BIA (Bump-in-the-API)
 Allows the dual stack hosts to
communicate with other IPv6 hosts
using existing IPv4 applications.
 Provides the translation method
between the IPv4 APIs and IPv6 APIs.
 The goal is simply achieved without
IP header translation.
BIA (cont)
 The BIA technique inserts an API
translator between the socket API
module and the TCP/IP module in the
dual stack hosts.
Components of BIA
Components of BIA (cont)
 Function Mapper
 It translates an IPv4 socket API function
into an IPv6 socket API function.
 Name Resolver
 It returns a proper answer in response to
the IPv4 application's request.
 Address Mapper
 It internally maintains a table of the
pairs of an IPv4 address and an IPv6
address.
Behavior of BIA
 ---> A DNS message for name resolving
created by the applications and the name
resolver in the API translator.
 +++> An IPv4 address request to and
reply from the address mapper for the
name resolver and the function mapper.
 ===> Data flow by socket API functions
created by the applications and the function
mapper in the API translator.
BIS (Bump-in-the-Stack)
 Between a TCP/IPv4 module and
network card driver modules and
translate IPv4 into IPv6 and vice
versa.
Components of BIS
Components of BIS (cont)
 Translator
 It translates IPv4 into IPv6 using the IP
conversion mechanism
 Extension Name Resolver
 This action is the same as Name
Resolver in BIA
 Address mapper
 This action is the same as Address
mapper in BIA
SLT (Socket-layer Translator)
 BIS and BIA can successfully translate NAT
friendly protocols (e.g. HTTP and TELNET)
 Both of them only process the networklayer and transport-layer header
information.
 Some protocols such as FTP and SIP
contain IP address and port information in
the application-layer headers
SLT (cont)
 The SLT translates NAT friendly protocols by
redirecting IPv4 socket functions to IPv6.
 For non-NAT friendly protocols (e.g., FTP
and SIP), we implement Application Layer
Gateways (ALGs) and ALG Manager.
 ALGs and ALG Manager allow the dual-stack
hosts to access IPv6 resources through
IPv4 applications without any modification.
Components of SLT
Components of SLT (cont)
 BIA Component
 Operates the same functions as the BIA
mechanism
 ALG-Manager
 The ALG-Manager forwards the
parameters to SIP-ALG or FTP-ALG by
port number.
Components of SLT (cont)
 FTP-ALG
 Translate both IP/port information in the FTP
messages and the FTP commends.
Components of SLT (cont)
 SIP-ALG
 The SIP-ALG modifies IP address and
port number information in SIP From, To,
Via, Contact header fields and Session
Description Protocol (SDP) c and m fields.
Comparison of Transition Mechanisms
SIPv6 Translator
 Problem :SIP UA cannot directly
communicate with IPv4-based SIP UA.
Components of SIPv6 Translator
 NIC (Network interface controllers)
 One NIC connects to IPv6 networks and
the other connects to IPv4 networks.
 Packet Forwarding Engine
 Intercepts the incoming packets,
forwards to the NAT-PT Component.
 Sends the translated packets to the
destination NICs.
Components of SIPv6 Translator
(cont)
 NAT-PT Component
 Consists of the Stateless IP/ICMP
Translation (SIIT) component and an
IPv6-IPv4 mapping table.
 Performs IPv6-IPv4 translation for IP and
ICMP headers.
 ALG-Manager
 Dispatches the incoming packet to DNSALG and SIP-ALG according to the
transport port number.
(Port 53->DNS, Port 5060->SIP)
Components of SIPv6 Translator
(cont)
 DNS-ALG
 Translates an IPv4 (or IPv6) DNS query
to an IPv6 (or IPv4) DNS query and
instructs the NAT-PT Component to
builds the IPv6-IPv4 mapping.
 SIP-ALG
 Translates the IP/port-related fields in
the SIP and SDP header and instructs
the NAT-PT Component to builds IPv6IPv4 mapping.
SLT Performance
 Measure the NCTU SLT performance
on FTP applications transfer.
 environment
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Server: vsftpd running on Linux Fedora
Client: SmartFTP running on Windows XP
Network Bandwidth: 100Mbps Ethernet
Files size: 10KB to 2GB
Transmission Delay (sec)
Transmission Delay with and
without NCTU SLT
Evaluation of SLT and SIPv6
Translator Deployment
SIP/SDP header fields that are
checked by SIP VoIP devices
Conclusions
 Present two IPv6-IPv4 translation
mechanisms (i.e., SLT and SIPv6 Translator)
and their deployment.
 SLT
 Translate a SIPv4 UA to IPv6 version.
 SIPv6 Translator
 Assist the SIPv6 UA to interwork with all SIPv4
UAs and PSTN gateways on NTP VoIP platform.
 SLT only translate SIPv4 UA to IPv6 version,
but maybe can try to translate SIPv6 UA to
IPv4 version in future work.
Reference
 Whai-En Chen; Wu, Q “Development and Deployment
of IPv6-Based SIP VoIP Networks” IEEE CNF 31-04 Jan.
2005 Page(s):76 - 79 Digital Object Identifier
10.1109/SAINTW.2005.1619982
 Whai-En Chen, Chia-Yung Su and Yi-Bing Lin.“NCTU
SLT: A Socket-layer Translator forIPv6-IPv4
Translation”. Accepted and to appear inIEEE
Communications Letters.
 S. Lee, M-K. Shin, Y-J. Kim, E. Nordmark, A.Durand.
“Dual Stack Hosts Using Bump-in-the-API(BIA)”. IETF
RFC3338. October 2002.
 K. Tsuchiya, H. Higuchi, Y. Atarashi. “Dual Stack Hosts
using the Bump-In-the-Stack Technique (BIS)”. IETF
RFC2767. February 2000.
NAT-PT