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VoIP: Is the tech ready?

Tags:
Security,
VoIP,
Cisco,
Hacker

Ong Boon Kiat CNETAsia

Published: 26 Nov 2004 09:45 GMT

Toughening the voice pipe
A partial answer to improve the robustness of VoIP-based telephony environments is to strengthen the voice pipe, as AT&T did with its recently-launched VoIP on Enhanced-VPN services, where packetised voice is prioritised through MultiProtocol Label Switching (MPLS) technology, then encapsulated in a virtual private network (VPN) tunnel.

"If you have an MPLS trunk carrying voice between two offices, you basically have a closed network between both offices," said AT&T Asia Pacific's director of planning and engineering John Mulligan.

Or if you are building your own VoIP systems, Cisco's Frendo offered two ways to toughen the pipe. First, enterprises and service providers can encrypt VoIP signalling over a secure tunnel, he said, by using transport layer security (TLS). Secondly, they can then follow this up by encrypting the actual voice traffic, using secure real-time protocol (SRTP). The combination of both measures, he said, will protect IP phone systems against phone-tapping and caller ID-spoofing.

But the larger question of simple reliability remains.

Most VoIP applications will ride on open systems, as opposed to circuit-switched telephony systems which are almost mainframe-like in their closed-ness. To stretch a crude analogy, moving to a VoIP-based telephony system is akin to moving from an IBM RS/6000 to a Windows XP system. It's hard to see how the latter can be as robust as the former.

Actually, as any network administrator know, it is easy to trip up an IP network. Frendo recalled a customer which had been frustrated by a network that was resetting itself every 30 seconds. The problem was eventually traced to a spanning tree-error in its network switch.

"Now this customer was able to live with this problem and initially did not even worry about it because the problem only meant that their employees' Web browsers were taking longer to fetch data. With a voice platform, however, this will become an intolerable quality issue," he said.

In fact, it may take less network quirkiness to render a VoIP platform unsatisfactory. As Mulligan pointed out, all it takes is a slight jitter in a voice conversation to introduce tension, which can eventually lead to a lost business deal. To put his quote in context, however, he said that while expounding the virtues of AT&T's VoIP-EVPN service, but his point about voice being extremely intolerant to network quality inconsistencies is generally valid.

Me? I am going to give vendors the benefit of the doubt -- with a caveat.

Given the excellent quality of the current crop of VoIP products and services, and collective momentum of the platform, which IDC predicted will be worth $15bn in worldwide equipment sales three years from now; I have to believe vendors will be more than capable of solving any quality or security challenges as they roll out new equipment and services.

My caveat is this: I agree with ISS' Graham when he said that VoIP vendors and users alike tend to only react when hackers come knocking. Right now, that has not happened because the technology is still niche. But when hackers and viruses come calling in drones (can someone say Blaster?), I hope VoIP vendors will be ready for it.