It will take years to fully assess the impact of the events of Sept. 11,
2001. However, it is already quite clear that as a result of the terrorist
attacks, the security of circuit-switched and packet-based
telecommunications networks has become a vital national concern. Efforts to
ensure the safety and integrity of the telecommunications infrastructure
will lead to greater government involvement, which will escalate the
implementation of existing regulations, drive the creation of new
regulations, lead to greater participation in the development of industry
Enhanced Emergency Services
As rescue workers and families searched for victims of the Sept. 11 attack,
the need to identify a calling partyï¿½s location was demonstrated
dramatically. Basic 911 service provides the ability to deliver the calling
partyï¿½s number to designated public safety answering points (PSAPs).
Enhanced 911 (E911) service actually provides the location of the calling
party. The most stringent requirements specify location accuracy to within
50 meters of the handset.
E911 service will potentially be mandated for emerging packet-based
networks -- VoDSL, VoCable, and VoIP. However, providing location
identification in a packet network creates a challenge. In a VoIP network,
how do providers pinpoint the location of a user on a LAN? In addition, the
new networks must be compatible with legacy 911 tandem switches and with
PSAP equipment. And, the implementation of E911 service will require service
providers to maintain and constantly update location databases in the
Law Enforcement Surveillance
The 1994 Communications Assistance for Law Enforcement Act (CALEA) requires
telecommunications providers to incorporate surveillance technology into
their networks. In the wake of September 11, the government is pushing CALEA
implementation forward, and it appears that packet telephony will not be
exempt. In a Sept. 27th ruling, the FCC denied a request made by the
Cellular Telecommunications and Internet Association (CTIA) for a blanket
extension of the Sept. 30, 2001 deadline for wireline, cellular, and
broadband PCS carriers to implement a packet-mode communications electronic
surveillance capability. The FCC mandated that carriers come into compliance
or seek individual relief by Nov. 19, 2001. All carriers, including packet
telephony carriers, must be fully CALEA compliant by June 30, 2002.
The technical requirements for CALEA implementation are still being
identified within the industry. The FCC is accepting input from industry
associations and operators in the form of ï¿½safe harborï¿½ documents. The
Telecommunication Industry Association (TIA) subcommittee TR45.2 developed
one such safe harbor document, J-STD-025, popularly known as the J-Standard.
A portion of the J-Standard covers packet-mode communication. These
requirements were included in the FCCï¿½s November 19 order.
CableLabs filed a similar safe harbor document covering VoCable, and the
International Softswitch Consortium (ISC) is currently working on a safe
harbor document for the softswitch architecture. These organizations are
actively working with the commission on CALEA issues related to the packet
Protecting The Signaling Network
The security and reliability of the public telecommunication infrastructure
is receiving greater government scrutiny. There is a general perception that
as a result of network convergence, the PSTN is more vulnerable to malicious
attacks. Government reports and statements from high-ranking government
officials reflect these concerns.
Signaling is critical to all network operations. The PSTN signaling
infrastructure is very much a closed network. In todayï¿½s voice network,
signaling is transported on a separate, dedicated resource to ensure the
integrity of call control.
As convergence opens the networks, the security of the signaling messages
may be placed at greater risk. In packet networks, both signaling and data
can be transported on the same network. Unless a higher QoS is guaranteed
for signaling in this shared network, critical services may be severely
impacted during network congestion. The use of invalid signaling messages
can take trunk groups out of service, prevent resources from being released,
direct calls to incorrect destinations, or instruct switches to throttle
calls. Therefore, enhanced mediation and firewall capability will be
required to protect the network.
Prioritizing Service For Critical Communications
Many government organizations have implemented emergency telecommunication
services (ETS) to provide priority communication during crisis situations.
In the past, the agencies relied primarily on private networks for emergency
communication. However, as the reach of these agencies becomes global, they
must rely increasingly on the public telecommunication infrastructure in
emergency situations. This reliance will drive new regulations and
In the United States, the Government Emergency Telecommunication Service
(GETS) delivers ETS. An important and recently introduced capability of GETS
is the high probability of call completion (HPC) feature, which is supported
by major local exchange carriers, AT&T, MCI WorldCom, and Sprint. The
feature marks emergency call signals as a priority and the network provides
preferential treatment without preempting the calls already in progress.
Several national governments have recognized the need for such a priority
service and have implemented emergency communication services in their own
network. International Recommendations E.106, the definition for
International Emergency Preparedness Scheme (IEPS), was established by the
ITU-T standard organization in March 2000 to provide priority services
across national boundaries.
In its June 2001 report, the NSTAC CTF recognized the need for ongoing
standards development efforts to support the national security/emergency
preparedness (NS/EP) priority requirements in converged networks. The
rollout of this service will likely take place in two phases. In the first
phase, IP-based voice calls will support PSTN-like priority access and
transport transfer. The second phase expands the priority processing to
include e-mail, instant messaging, and other multimedia communication.
Efforts are under way in both the ITU-T and Internet Engineering Task Force
(IETF) to expand and include additional provisions for multimedia services
in an IP-based telecommunications network. ITU-T Recommendations F.706 will
provide similar framework for the next generation International Emergency
Multimedia Service (IEMS).
Following the recent attacks, issues concerning the security of the
telecommunications networks have been brought to the forefront. The
telecommunications industry will be challenged to take measures to enhance
personal and national security by ensuring that the future telecommunication
infrastructure is reliable and secure.
Mr. Ravi Ravishankar is director, Advanced Technology Planning,
Tekelec. His focus is on defining signaling solutions and products for the
next-generation packet telephony and 3G wireless networks. Tekelec is a
leading developer of telecommunications signaling infrastructure,
softswitches, testing and diagnostic solutions, and service applications.
Please visit their Web site at www.tekelec.com.
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