[c-nsp] ISP LAN Design

[Jon Lewis]

On Wed, 25 May 2005, Gert Doering wrote:

> On Wed, May 25, 2005 at 01:06:54PM +0100, Mark Tohill wrote:
> > Everybody claims layer 2 problems are easier to troubleshoot than layer
> > 3 problems.
>
> L2 problems are MUCH harder to troubleshoot than L3 problems.  L3 is either
> "there are all relevant routes" (traceroute will tell you) or "not".
>
> L2 brings you loops, spanning-tree blocks, spanning-tree oscillations,
> unwanted flooding of packets, and lots of other fun.

And with L3, you see the hops, so you know where your packets are going
and and pretty easily see what path they're taking.  With L2, you have
invisible L2 hops and won't realize packets are taking a suboptimal path
unless you look very carefully at ports and their counters.

----------------------------------------------------------------------
 Jon Lewis                   |  I route
 Senior Network Engineer     |  therefore you are
 Atlantic Net                |
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