+1 On Jan 24, 2014 12:41 PM, "Owen DeLong" <o...@delong.com> wrote:
> Some networks I have worked with took the average latency of each link and > assigned that (with some constant multiple) as the interface cost. > > Of course this all fails miserably if you are using anything like MPLS > underneath your OSPF. > > Owen > > On Jan 24, 2014, at 12:26 PM, Erik Sundberg <esundb...@nitelusa.com> > wrote: > > > I understand OSPF default calculation for cost doesn't include delay. I > am looking for a formula that I can use to manually set the OSPF costs that > factors in delay. > > > > When using OSPF's default costs, the shortest path is not always the > optimal path. > > > > > > Example > > > > New York to Los Angeles. Assuming all links are the same bandwidth and > have a ospf cost of 1. > > > > Path 1 (75ms) - OSPF Cost 2 - New York > Dallas > Los Angeles > > > > Path 2 (65ms) - OSPF Cost 3 - New York > Chicago > Denver > Los Angeles > > > > If I left the default cost's alone then path 1 would win because it has > a lower ospf cost, however it take traffic 10ms longer to get there. > > > > However I would like traffic to take Path 2 by adjusting the OSPF cost. > > > > > > I am looking for a formula that other people are using .p > > > > Thanks > > > > Erik > > > > > > -----Original Message----- > > From: Randy [mailto:randy_94...@yahoo.com] > > Sent: Thursday, January 23, 2014 9:03 PM > > To: Erik Sundberg; nanog@nanog.org > > Subject: Re: OSPF Costs Formula that include delay. > > > > > > > > ----- Original Message ----- > >> From: Erik Sundberg <esundb...@nitelusa.com> > >> To: "nanog@nanog.org" <nanog@nanog.org> > >> Cc: > >> Sent: Thursday, January 23, 2014 4:47 PM > >> Subject: OSPF Costs Formula that include delay. > >> > >> What is everyone using for an OSPF cost formula that factors in a > >> circuits delay and bandwidth (10M-100G)??? > >> > >> Thanks in advance > > > > > > > > umm..are you sure your question is not about EIGRP? > > OSPF has no concept of interface-delays. > > > > The default reference bandwidth for OSPF is 100M > > > > In your case if you set your reference bandwidth to 100000 your 100G > links would have a link cost of 1, 10G - 10, 1G-100, 100M-1000 and 10M-10000 > > > > A vendor specific list would be a better place to ask. > > > > > > ./Randy > > > > ________________________________ > > > > CONFIDENTIALITY NOTICE: This e-mail transmission, and any documents, > files or previous e-mail messages attached to it may contain confidential > information that is legally privileged. If you are not the intended > recipient, or a person responsible for delivering it to the intended > recipient, you are hereby notified that any disclosure, copying, > distribution or use of any of the information contained in or attached to > this transmission is STRICTLY PROHIBITED. If you have received this > transmission in error please notify the sender immediately by replying to > this e-mail. You must destroy the original transmission and its attachments > without reading or saving in any manner. Thank you. > > >
