Moreover, the SIP is associated with MIP to support
terminal mobility, because SIP extends the MIP protocol,
and avoids the failings of MIP. SIP has only been utilized
in real-time communication over User Datagram Protocol
(UDP); therefore, the best solution would be a cooperative
scheme. That is, SIP for real-time services and MIP for
non-real-time services.
B. SIP/MIP Combined for Macro-mobility Management
in EVOLUTE
This section introduces the approach of
macro-mobility management in EVOLUTE [3].
EVOLUTE proposed macro-mobility is based on a
combination of SIP and MIP. Routers in the domain edge
separate traffic from/toward a MH; therefore, SIP
signaling supports Real-time Traffic (RTP over UDP), and
MIP supports non-real-time traffic, as shown in Figure 1
[3].
2
1
3
4
5
4
3
Home
Agent
SIP
Server
Correspondent Host
Gateway
Foreign Agent
Gateway
Foreign Agent
Router/NAT
Router/NAT
Internet
Router
Tunnel
Home Ntework
Mobile
Host
M
o
v
e
Macro-mobility
Hybrid scheme
based on the
synergy of
Mobile IP with
SIP
Micro-mobility
Support fast
handoffs and
paging
data
signaling
1. Local Registration
2. SIP INVITE transaction
3. Real-time data traffic
4. Non-real-time traffic
5. Home Registration
Fig. 1: Combine SIP and MIP for macro-mobility
management in EVOLUTE
The MIP aids non-real-time traffic, which bypasses
Network Address Translation (NAT). Through the MH
home network, this traffic is routed toward the MH using
tunneling. Additionally, IP encapsulation is unimportant
for these non-real-time applications. However, the
real-time traffic of macro-mobility is facilitated by SIP
signaling. The use of NAT for real-time traffic creates the
problem involving the blocking of IP communications
because IP voice and video devices behind the NAT have
private IP addresses that are not routable outside their
local domain or on the public Internet. The issue is
currently under investigation by the IETF working group
Middlebox Communication (Midcom). Simple Traversal
of UDP through NATs protocol (STUN) has been
proposed as a possible solution for the problem faced by
Midcom. Furthermore, integration of SIP user agents with
STUN client functionality will work based on NAT
infrastructure and will allow a wide variety of applications,
such as Voice over IP (VoIP).
Both MIP and SIP can be complementary; however,
they are unsuited to handling micro-mobility. High
mobility within a single domain or Intranet is common;
therefore, the MH must be allowed to move freely among
wireless Access Points (APs) or Base Stations (BSs). The
solution of the move freely can make the movement
without informing the distant HA, redirecting services in
every movement, and offering idle movement to preserve
connections. Multiple standard options will likely be
available in the future. Current research exploring
micro-mobility management protocols, includes
Hierarchical MIP (HMIP), HAWAII, CIP, Cellular IPv6
(CIPv6), and Edge Mobility Architecture (EMA) [7]−[8].
This paper refers a novel architecture M&M that increases
the efficiency of micro-mobility management. The CIP
infrastructural is utilized to assist the M&M mechanism in
providing IP paging, soft handoff, QoS, and context
transfer capabilities. The next section introduces the
M&M.
C. Multicast-based Mobility (M&M)
In future networks, handoff and packet routing
efficiency are vital. By supporting various communicative
applications, and developing new services, extra
consumers will be attracted to join 4G, and the wireless
networks will be popularized. Additionally, a domain with
one micro-mobility management method is no longer able
to meet the various communicative requests [9].
INTERNATIONAL JOURNAL of COMMUNICATIONS
Issue 2, Volume 1, 2007 48