Vendor support for IS-IS is quite limited - many options for OSPF. On Nov 9, 2016 8:47 PM, "RT Parrish" <[email protected]> wrote:
> I will definitely be looking up the notes from AOL that John referenced. > But working for a vendor and getting insight from multiple ISPs, here are a > few of the things that I hear most frequently: > > 1) Network Topology support - The differences between a single OSPF > backbone area and a contiguous set of Level-2 adjacencies will occasionally > be a deciding factor. > 2) Feature Support on a per vendor basis - Some vendors will roll new > features out in one or the other protocols prior to the other. Segment > Routing and some of its enhancements come to mind as being in ISIS first. > 3) Layer 2 adjacencies - I think someone already mentioned that you form > adjacencies at layer 2 which also means that with a single adj you can > support multiple protocols (v4/v6). OSPF would require two different > instances to support both. Maybe good, maybe not. Depends on your desired > level of isolation between the two. > 4) CPU performance is academic at this point - The SPF calculations in most > networks would require next to no difference between the two protocols even > if running both IPv4 and v6. > > End of the day, use the right tool/vendor/technology for the right job. > > Hope this helps, > RT > > On Wed, Nov 9, 2016 at 12:12 PM, Michael Bullut <[email protected]> wrote: > > > Greetings Team, > > > > ​While I haven't worked with IS-IS before but the only disadvantage I've > > encountered with OSPF is that it is resource intensive on the router it > is > > running on which is why only one instance runs on any PE & P device on an > > ISP network. OSPF is pretty good in handling the core network routing > while > > BGP & EGP handle the last-mile routing between PE & CE devices. BGP & EGP > > can run on top of OSPF. I came across this *article* > > <https://routingfreak.wordpress.com/2011/03/05/why- > > providers-still-prefer-is-is-over-ospf-when-designing- > > large-flat-topologies/> > > when > > scrolling the web a while back and I still want to find out if am the > only > > one who thinks its a matter of choice between the two. Although there > isn't > > distinct 1:1 argument, it's good we discuss it here and figure out why > one > > prefer one over the other *(consider a huge flat network)**.* What say > you > > ladies and gentlemen? > > > > Warm regards, > > > > Michael Bullut. > > > > --- > > > > *Cell:* > > *+254 723 393 114.**Skype Name:* *Michael Bullut.* > > *Twitter:* > > * @Kipsang <http://twitter.com/Kipsang/>* > > *Blog: http://www.kipsang.com/ <http://www.kipsang.com/>* > > *E-mail:* *[email protected] <[email protected]>* > > > > *---* > > >
