[c-nsp] Devil's Advocate - Segment Routing, Why?

[Saku Ytti]

On Thu, 18 Jun 2020 at 22:25, Benny Lyne Amorsen via cisco-nsp
<cisco-nsp at puck.nether.net> wrote:


> > I don't understand the point of SRv6. What equipment can support IPv6
> > routing, but can't support MPLS label switching?

> This probably does not change anything for SRv6, as that too will likely
> be an extra cost license. It makes non-MPLS tunnelling solutions very
> attractive though, since you can get away with a very "cost-effective"
> core and only require smarts in the edge.

This is simply not fundamentally true, it may be true due to market
perversion. But give student homework to design label switching chip
and IPv6 switching chip, and you'll use less silicon for the label
switching chip. And of course you spend less overhead on the tunnel.

We need to decide if we are discussing a specific market situation or
fundamentals. Ideally we'd drive the market to what is fundamentally
most efficient, so that we pay the least amount of the kit that we
use. If we drive SRv6, we drive cost up, if we drive MPLS, we drive
cost down.

Even today in many cases you can take a cheap L2 chip, and make it an
MPLS switch, due to them supporting VLAN swap! Which has no clue of
IPV6 or IPV4.

-- 
  ++ytti