Transcript 3GPP PCC in 30 Minutes

SIP/IMS or Skype – who will win it all? (Author: Uri Baniel, May/2010)
0. Yes, indeed. It is two (SIP and IMS) against one (Skype). No fair. But then who said life is fair.
1. LTE is the future. If you agree keep reading. 2. Skype has a dynamic signature (IP, port hopping), which varies many times within the lifetime of a single
second! 3. SIP/IMS has a steady signature – the 5-touple {src IP, src port, dst IP, dst port, Transport protocol} is well defined throughout the entire life of a
SIP/IMS based VoIP call. 4. In order to receive a high QoS (Quality of Service) along the critical path (UE <==> P-GW) …
… a dedicated bearer (pipe) has
to be established between the
UE and the P-GW
(controlled/policed by the
PCRF). 5. This requires an a
priory knowledge of the filters
(5-touple). In addition, at any
moment both the UE and the PGW need to know the filters, in
order to route the traffic along
the correct (dedicated) pipe
(bearer).
6. NAT traversal (SIP/IMS
Achilles tendon) is solved by
deploying an SBC, which has to
be there anyways for security
and admission control.
7. In addition, with IPv6 there
is no NAT traversal issue to
begin with, as all addresses are
public.
8. Ok. You do the math.
LTE (Long Term Evolution) is the name given to the 4th generation of cellular network within 3GPP.
It is essentially a wireless broadband Internet system with voice and other services built on top. It
supports high speed (data rate) traffic. And when we say high we mean it. We are talking about…
Figure: The 4 G cellular network – packet switched domain
PCRF
E-UTRAN (LTE) Radio Access Network
Ctrl
Web Server
Ctrl
Core Network
IP packets
UE
IP packets
eNB
IP packets
S-GW
IP packets
P-GW
Dedicated bearer (pipe)
Ref: 3GPP TS 23.401/23.402
Web Phone
Email Server
Bearer (VoIP/Data) path (MME and HSS are not shown for spacing reasons)
Exit
©2003-2010, SIPKnowledge
May/2010
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