Page 437 - Handbook of Modern Telecommunications

3-228 CRC Handbook of Modern Telecommunications, Second Edition

IP UDP GTP Payload (IP or PPP)

IP TCP Payload

Identify the GTP session

Identify the GTP’s well known port (3386)

Identify the flow between the SGSN and GGSN

FIGu RE 3.9.1 GPRS Tunneling Protocol example of multi-level IP addressing.

3.9.2.1 New Technologies—IP Services
The worldwide communication infrastructure is moving rapidly to Internet Protocol (IP) as a tech-
nology basis. Traditional fixed and mobile voice services are being replaced with IP-based equivalents
across the board, and newly enabled services are adding to the mix. IPTV adoption is early but growing
fast. Mobile IP has pushed the mobile operators to the forefront in terms of revenue growth, competi-
tion, and focus on customer service quality as a result of inexorable demand for easier nonfixed access
to multimedia content and applications. Greater and greater exploitation of full multimedia by content
providers is enabled via IP transport, and is directly driving substantial growth in total traffic volumes,
stressing capacity.
One of the greatest challenges facing operators who are deploying new, next-generation IP-based
services is the fact that with new service flexibility comes new protocols and delivery chain complexity.
This new technology brings with it an entirely new set of protocols that are used in the middle protocol
layers (Layers 2 through 4) of the delivery network. More concerning than that, there are also a virtually
limitless potential variety of types of layer 7 (application) traffic that will be traversing the infrastruc-
ture. To make matters more interesting, there can be multiple layers of encapsulation and addressing
within IP traffic. For example, see Figure 3.9.1, where IP tunneling is used to transport IP traffic across
the core bearer network of a mobile operator using GPRS Tunneling Protocol (GTP). This same concept
can be applied multiple times, meaning that understanding just what is contained within flows of pack-
ets transiting an IP network can be very difficult without directly and deeply inspecting the live traffic.
Most of the actual service traffic will be predefined and offered as revenue-based services; however,
as soon as IP-based transport is made available, subscribers find ways to transport whatever traffic
they deem desirable. An example of this is Skype—a bulk toll-bypass form of IP Telephony that uses a
variety of adaptive approaches to identify means of establishing and delivering voice calls over public
IP networks.
Multitier service delivery architectures now commonly include off-net content sources. Reliance on
these external providers raises a need for selective direct testing to assure availability and responsive-
ness of noncontrolled elements, especially if they are perceived to be an integral part of the service expe-
rience. Ultimately, measurements and sensory system input must be brought together across multiple
domains in order to provide promised operational value.

3.9.2.2 Merging of Traditional Signaling onto IP Networks
Signaling Transport (SIGTRAN), which enables the transport of traditional public switched telephone
network (PSTN) signaling over IP networks (see Figure 3.9.2), is enjoying a rapid embrace by providers
who need to meet capacity demands and lower operational cost. SIGTRAN standards are defined by
the Internet Engineering Task Force (IETF), and allow providers to operate smoothly in hybrid envi-
ronments, where services may originate from or be terminated within the PSTN, hence requiring both