Devil's Advocate - Segment Routing, Why?

Mark Tinka mark.tinka at
Thu Jun 18 11:51:23 UTC 2020

On 18/Jun/20 13:23, adamv0025 at wrote:

> You do have the LDP vs SR choice (in v4 anyways) yes there's not a good 1:1 feature parity with v6, but the important point...

But the lack of IPv4/IPv6 parity is a crucial one.

There is only so long we can stretch IPv4, if one can still manage the
tangible and intangible costs of doing so. But that's for another

>  is the current state is not the end state, this is a pretty dynamic industry that I'm sure is converging/evolving towards a v4:v6 parity, however the pace may be, which is understandable considering the scope of ground to be covered.

Which I am fine with  - if you give me a time line to say LDPv6,
SR-OSPFv3 and SR-ISISv6 will be available on X date, I can manage my
operation and expectations accordingly.

But if you say, "No LDPv6, no SR-OSPFv3, no SR-ISISv6... only SRv6",
then that's an entirely different issue.

The good news is there currently is choice on the matter, but upending
hundreds or thousands of boxes to prove that point should really be a
last resort, as there are more pressing things we all have to deal with.

>  Yes you're right in acknowledging that we're not living in a perfect world and that choices are limited, but it's been like that since ever yet we managed to thrive by analysing our options and striving for optimal strategies year by year.  

We can thank NAT44, CIDR, DHCP and PPPoE for that strategy over the
years :-).

IPv6 is the future, and at some point, we'll have to stop hiding from it.


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