At most networks scale you won't notice the difference, but OSPF will also converge faster then BGP at very large scale. Adding on top the costs of re-using AS's in a eBGP world, verses mutual-RR with iBGP, having a good summarization plan with OSPF is a bit more trivial and retains a overall net smaller configuration on-box even if you are generating it programatically. The concerns about chattiness is also overblown as even Quagga can keep up with massive Leaf/Spine deployments on really small CPU's in a only OSPF world.
I would caution that the auto-discovery can also have a downside as it more readily opens you up to mis-cabling, which can be fairly negative in a Leaf/Spine topology. It's one of the reasons Cumulus came up with PTM so that you can deploy a described version of your topology and have the device alert/react when the actual version is different. Some embodiment of that is useful, but need not be on-box. David > On Jun 25, 2018, at 10:37 AM, Scott Whyte <swh...@gmail.com> wrote: > > In balance then, we have better filtering versus less config, which has > already been noted can (must) be completely automated. Where one's shop is > on the NetDevOps curve probably has a lot of impact on the decision, which is > unfortunate. > > > On 6/25/18 10:29 AM, Thomas Bellman wrote: >> On 2018-06-25 18:22, Scott Whyte wrote: >>> BGP, as you say, provides excellent filtering capabilities. What >>> does OSPF/ISIS bring to the table? >> Automatic discovery of peers, and thus less unique configuration. You >> don't need to configure each peer individually, just the interface. If >> you do unnumbered links, you don't even need to allocate link networks >> for your routing links, giving even less unique configuration. Just >> set interfaces xe-0/0/17.1 family inet unnumbered-address lo0.1 >> set interfaces xe-0/0/17.1 family inet6 >> set protocols ospf area A.B.C.D interface xe-0/0/17.1 interface-type p2p >> set protocols ospf3 area A.B.C.D interface xe-0/0/17.1 interface-type p2p >> and you're done. The nice thing is that the only unique piece of >> configuration is the interface name. >> Doing unnumbered links for BGP seems to at least be more complicated, >> but Cumulus Linux is supposed to have support for it, making it as easy >> to configure as OSPF. >> (https://blog.ipspace.net/2015/02/bgp-configuration-made-simple-with.html; >> I've never used Cumulus, just read about it.) >> /Bellman > _______________________________________________ > juniper-nsp mailing list juniper-nsp@puck.nether.net > https://puck.nether.net/mailman/listinfo/juniper-nsp _______________________________________________ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
