Transcript The Design and Implementation of Mobile Session Controller

The Design and Implementation
of Mobile Session Controller
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Session Controller
Network Mobility
SIP & SIP Mobility
NAT Traversal
Our Enhancement on Session Controller to
Support Mobility
• Future Work
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Session Controller
• Border
• Firewall
• NAT
• http://www.sessioncontrollerforum.org/
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Network Mobility
• http://www.ietf.org/html.charters/nemocharter.html
• Managing the mobility of an entire network
• The mobile network includes one or more mobile
routers (MRs) which connect it to
the global Internet.
– It could be multi-homed.
– None of the nodes behind the MR will be aware of the
network's mobility, thus the network's movement needs
to be completely transparent to the nodes inside the
mobile network.
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Network Mobility (2)
• A basic approach for network mobility support is
for each Mobile Router to have a Home Agent,
and use bidirectional tunneling between the MR
and HA to preserve session continuity while the
MR moves.
• The MR will acquire a Care-of-address from its
attachment point much like
what is done for Mobile Nodes using Mobile IP.
• In this paper, we propose to handle SIP-based
sessions with SIP mobility instead of Mobile IP,
which is a better choice for VoIP, because it
removes the “triangular routing”.
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SIP & SIP Mobility
• Shiang-Ming will provide the viewgraph of
pre-call mobility & mid-call mobility
• However, this seems to be redundant with
the call flows below. Probably we only
need to briefly introduce SIP in this section.
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WiMAX
AP
WiFi
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The MSC Architecture
WGSN Node
SIP-based
Push Center
RAS
iSMS Server
AS
SIP
Redirect
GPRS
Module
GPRS
Network
Network
Controller
OA&M
SNMP
Agent
Billing
Handler
Log
Handler
MIB
External Ethernet Module
Authentication
Center
DHCP Server
Firewall
GMM
Handler
Internal Ethernet Module
External
PDN
Wireless LAN
Gr
Handler
SS7
Module
SS7
Network
HLR
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NAT Traversal on Session
Controller
• Registration
• Call Setup
– Call Origination
– Call Termination
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NAT Traversal for SC
NAT
SIP ALG
mapping table
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Registration
UA
Session Controller
REGISTER
SIP Registrar
Allocate a port for UA
Contact: sip:ua@private_ip:5060
REGISTER
Contact: sip:ua@public_ip:12348
200 OK
200 OK
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Call Origination
• Allocate public ports for UA.
– The design of Mobile Session Controller should
adopt a port-restricted cone NAT.
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Call Origination
UA
Session Controller
UA2
INVITE + SDP1
Reserve two contiguous
ports for a media stream
INVITE + SDP1’
200 OK + SDP2
Add RTP ports to the ACL
200 OK + SDP2
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Call Termination
• Similar. Just draw another figure.
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Enhanced Session Controller to
Support Mobility
• Pre-call Mobility
• Mid-Call Mobility
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Pre-Call Mobility
UA
Session Controller
SIP Registrar
SC detects IP address
change and update the
mapping table
REGISTER
Contact: sip:ua@new_ip:12348
200 OK
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Mid-Call Mobility
UA
Session Controller
UA2
RTP
SC detects IP address
change and update the
mapping table
INVITE (new Contact and
Via) + SDP1” (new c=)
200 OK + SDP2
ACK
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Future Work
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