Because the CDN delivers to your customers not you. It’s your customers link requirements that are the ones you need to worry about. If you support jumbo frames to all of your customers and their gear also supports jumbo frame then sure go ahead and use jumbo frames otherwise use the lowest common denominator MTU when transmitting. This is less than 1500 on today Internet and encapsulated traffic is reasonable common. embedded CND <--> NAT64 <--> CLAT <--> client 1500 14XX 1500 embedded CDN <--> B4 <— > 6RD <— > client 1500. 14XX 1500 Now you can increase the first 1500 easily. The rest of the path not so easily.
On 19 Jan 2018, at 9:53 am, George Michaelson <ggm@algebras.org> wrote:
if I was an ISP (Im not) and a CDN came and said "we want to be inside you" (ewww) why wouldn't I say "sure: lets jumbo"
not even "asking for a friend" I genuinely don't understand why a CDN who colocates and is not using public exchange, but is inside your transit boundary (which I am told is actually a bit thing now) would not drive to the packet size which works in your switching gear.
I understand that CDN/DC praxis now drives to cheap dumb switches, but even dumb switches like bigger packets dont they? less forwarding decision cost, for more throughput?
On Fri, Jan 19, 2018 at 6:21 AM, Dovid Bender <dovid@telecurve.com> wrote:
Vincent,
Thanks. That URL explained a lot.
On Tue, Jan 9, 2018 at 3:11 AM, Vincent Bernat <bernat@luffy.cx> wrote:
❦ 8 janvier 2018 15:08 -0800, joel jaeggli <joelja@bogus.com> :
N00b here trying to understand why certain CDN's such as Cloudfare have issues where my MTU is low. For instance if I am using pptp and the MTU is at 1300 it wont work. If I increase to 1478 it may or may not work. PMTUD has a lot of trouble working reliability when the destination of the PTB is a stateless load-balancer.
More explanations are available here: https://blog.cloudflare.com/path-mtu-discovery-in-practice/ -- Don't comment bad code - rewrite it. - The Elements of Programming Style (Kernighan & Plauger)
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