Re: RE: 3750 as edge routing

Routers support multiple interface types, and traditionally that often required
their use at the network edge. Provider links were also much slower than those
within campuses.

Routers were designed to cater for the needs at the edge, switches within the
campus. Routers are more suitable for cases where there are different
interface types required (modular, supporting not only ethernet); speed
mismatches (larger buffers); BGP (more memory can handle more NLRI, more
advanced BGP features e.g. IPv6 address family); and lower port densities.
Router performance was also lower, partly because they were expected to apply
complex security, encapsulation, translation and other advanced features.
 
Switches were largely packet pushers, but have grown layer 3 features to add to
their high port densities. This evolution has required their capabilities to
be more closely aligned to those of routers, but differences still exist in
the same areas. Switches have less memory, cut down feature sets, and support
only ethernet, but this simplicity allows them to push packet faster. Routers
often still cannot achieve line rate (at the lower end of the cost scale at
least).

The traditional drivers apply less and less these days, and hybrid modular
devices are becoming common at the edge,as well as the core of networks. We
(HEAnet) provide 1G or 10G Ethernet links to customers for instance - often the
same as the bandwidth within the customer networks.

Paul.

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Received on Wed Jun 03 2009 - 05:46:21 ART