Hello, On Tue, Oct 16, 2018 at 4:56 PM Sebastian Benoit <benoit-li...@fb12.de> wrote: > > Tommy Nevtelen(to...@nevtelen.com) on 2018.10.16 15:11:51 +0200: > > On Tue, Oct 16, 2018 at 10:21:37AM +0200, Claudio Jeker wrote: > > > On Tue, Oct 16, 2018 at 09:13:20AM +0200, open...@kene.nu wrote: > > > > Hello, > > > > > > > > Only relying on OSPF hellos effectively makes it mimic BGP with its > > > > keepalives. I will ponder the value of transporting the underlay in > > > > OSPF, effectively transporting loopback peering addresses for BGP in > > > > OSPF. I am not sure that it will make my life easier but will consider > > > > it. > > > > > > OSPF is generally faster at converging after reroute and it is possible to > > > set the router-dead-time to minimal which will give you a 1 second > > > timeout. Also the default of 40sec is lower than the 90sec of BGP. > > > Additionally OSPF may give you multipath routes so the failover for BGP > > > may be not noticable. Also GRE has a way to emulate link state but to be > > > honest if I use OSPF on a GRE link I will not turn it on (unless > > > requested). > > > > I guess the brewing BFD support would speed this up for BGP when it arrives > > and make OSPF less useful if speed is the thing that needs to be solved. > > > > Also I've been thinking about the following config in ospfd > > > > rtlabel label external-tag number > > Map route labels to external route tags and vice versa. The > > external route tag is a non-negative 32-bit number > > attached to AS-external OSPF LSAs. > > > > What exactly does this mean? As I understand it is to map rtlabels to LSA > > Type 5 tags. But what do you do with it then? Could this be used for what > > this thread is talking about or is it totally off? > > If you do this on two (or more routers) you distribute the routes and they > end up in the fib with that rtlabel (note the "and vice versa"). > > You can do all the things you can do with route labels, for example use > them in pf filters. > > And yes, you could also use it to redistribute them into bgp (although that > needs to happen on another router i think): > > ospfd ---type5 lsa---> ospfd --> fib with rtlabel --> bgpd ... > hostA hostB hostB hostB > > /Benno
I might be wrong here but in prder to have ospfd generate type 5 LSAs one needs both a BGP speaker that announces the prefix in question into ospf and two different ospf areas in your network? Or can I make ospfd generate type5 LSAs in some other way? I see that rtlabels would do it but that implies I have an already existing route in the fib which preemptively I tag in some way. In my case the routes are generated by interface statements in ospfd.conf (so type1 and 2 LSAs). >
