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The same old networking question is
constantly being addressed as network managers assess the
speed, simplicity and lower cost of Layer 2 switching (bridging)
against the greater network control afforded by routing
technology.
The cost and management burdens of routers
is justified in WANs due to the high recurring costs and
relatively low speeds of these links. Typically general
purpose routers were adopted in the campus, but in recent
years LAN switches have replaced such routers providing
significant price/performance and density advantages.
The networking requirements are constantly changing and this justifies a new
look at an age-old question. Networks have grown-in both size and importance
and responses to familiar problems like broadcast containment, security and
support for complex topologies have changed since routers first appeared.
And of course there's the introduction of LAN technologies, such
as Gigabit Ethernet. Since high-speed technologies like Gigabit Ethernet
put additional pressure on the forwarding requirements of the core
and surrounding devices, we must now ask ourselves if traditional routers
will be able to keep pace.
The performance gap-in both throughput and packet processing-between high-performance
LAN switches and general-purpose routers in the campus enterprise network is
widening fast. Other issues contribute to this mismatch:
- With the rise of corporate intranets,
unpredictable "any-to-any" traffic patterns
are replacing standard "80% local/20% backbone" traffic
planning assumptions.
- Class and quality of service guarantees
are needed to support emerging multimedia services without
affecting response times of existing mission-critical
applications.
- Organizations need to leverage
their existing network infrastructures while simultaneously "future-proofing" new
investments.
This article is excerpted from “Switching
and Routing - And Everything in Between” by 3Com and
the remainder of the article discusses these issues and
suggests solutions in line with 3Com's products.
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