SIP Communications For Dummies, Avaya Custom Edition
50
ߜ Deployment and Administrative Costs: Communications
solutions often require on-site technical installation serv-
ices. Additional costs are incurred when local support is
required to fix problems, add capacity, or perform basic
administrative tasks.
ߜ Speed: For many small offices, competitive advantage
is all about speed — time to deployment drives time
to market. In contrast, communications solutions deploy-
ment is a relatively time-consuming event often requiring
detailed planning, staging, and manual administration.
ߜ Business Continuity: Business relies on resilient com-
munications that work. Though available, business
continuity often requires additional upfront capital
costs.
ߜ Risk Aversion: Small businesses are more sensitive to
disruptive events than are larger businesses. For small
businesses, service and responsiveness are critical, and
the consequences for disruptive events are great.
Peer-to-Peer SIP
Communications Overview
In large enterprises, SIP is most often implemented using cen-
tralized services such as proxy servers, presence servers,
gateways, and location servers. But SIP endpoints can also
function without all of these central services in small-office
settings — those environments that can least afford the
investment and maintenance required of these big-company
services.
A new, simpler variant protocol of SIP, called peer-to-peer (P2P)
SIP, promises a solution. P2P SIP collapses some of the more
complex server functions into the phones (or other endpoints)
themselves. P2P SIP relies on the core SIP philosophy that
intelligence in communications solutions should reside in the
endpoint (refer to Part 2 for more about the variety of SIP
endpoints available). Contrast this approach with that of old-
fashioned analog telephones that did little more than amplify
voice signals and rely upon intelligent switches to function.
10_041498 ch06.qxp 3/16/06 5:50 PM Page 50
