On 22/Jul/16 15:42, Chris Kane wrote:
> > My experience has been making a view phone calls and agreeing on 9,000 > is simple enough. I've only experienced one situation for which the > MTU must match and that is on OSPF neighbor relationships, for which > John T. Moy's book (OSPF - Anatomy of an Internet Routing Protocol) > clearly explains why MTU became an issue during development of that > protocol. As more and more of us choose or are forced to support > 'jumbo' frames to accommodate Layer 2 extensions (DCI [Data Center > Interconnects]) I find myself helping my customers work with their > carriers to ensure that jumbo frames are supported. And frequently > remind them to inquire that they be enabled not only on the primary > path/s but any possible back up path as well. I've had customers > experience DCI-related outages because their provider performed > maintenance on the primary path and the re-route was sent across a > path that did not support jumbo frames. DCI links tend to be private in nature, and 100% on-net or off-net with guarantees (NNI). The question here is about the wider Internet. > > As always, YMMV but I personally feel having the discussions and > implementation with your internal network team as well as all of your > providers is time well spent. I don't disagree. The issue comes when other networks beyond your provider, and their providers/peers, whose providers/peers, and their providers/peers, is something you cannot control. This falls into the same category of "Can QoS markings be honored across the Internet" cases. Mark.