I'm confused as to why I need iBGP in order to maintain traffic outside of my network. Is iBGP able to make changes to my eBGP peering sessions that would be helpful to my cause? Or are you just saying I should be running iBGP internally to make things less messy in general?
It is possible it is going over my head. Would you be able call me and explain? On 11/1/2017 10:09 AM, Faisal Imtiaz wrote: > See answers inline .. > > Faisal Imtiaz > Snappy Internet & Telecom > http://www.snappytelecom.net > > Tel: 305 663 5518 x 232 > > Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net > > ----- Original Message ----- >> From: "Ethan E. Dee" <e...@globalvision.net> >> To: "Faisal Imtiaz" <fai...@snappytelecom.net>, "Mikrotik Users" >> <mikrotik-users@wispa.org> >> Sent: Wednesday, November 1, 2017 9:51:56 AM >> Subject: Re: [Mikrotik Users] BGP Question >> I am only referring to traffic leaving the internet and entering my network. > This is called inbound traffic... yes that is exactly what I was talking > about too. >> I do not want A's traffic to come in thru C unless it is absolutely >> dire. i.e. the BGP session on A quits or the router itself dies. >> > I understand, what you desire to do.. however it may not match up to what > your Upstream Desires.. > (e.g. if you advertise A's prefix as 'normal' and C's prefix as 'backup'... > A's network will see C as local connected and insist on using it over an > external route) > > > >> I have tried setting BGP prepend to 16x on C. > Like I said, that will not work for you... > >> I have used At&t and Charter Communities to announce a different local >> pref (100 on At&t 70 on Charter.) >> > Sort of right track, but you have to evaluate as to how they have their > network configured. > Keep in mind Local Pref is only Local to that ASN.. you have to look at their > network traffic engineering to determine if you are making yourself more > attractive or less attractive ... and use the local pref figures comparative > to their's.... i.e. local pref of 70 does not mean the same thing on all > networks ! (it is a relative parameter) > >> No luck. Looking at the looking glass, Charter is largely the preferred >> path for HE. See attached. > Welcome to solving a 3 dimensional equation... Charter may be Purchasing IP > Transit from HE or peering with HE.... > Which would explain this.. > >> Get a similar answer from Cogent's looking glass. > Not sure if you are reading the 'details' as some of the LG's show.. or just > the 'best path' along with ASN's >> I am using OSPF as my IGP btw. I can route the traffic out the correct >> router just fine. It is the returning traffic I have a problem with. >> > This is not the proper way to do things... > The recommended best practices are :- > > use OSPF for distributing loop back IP's > use iBGP (a requirement) between all the routers (each router needs one > session to each of the others) for re-distributing your BGP routes > > If you want to run your network as three islands, I suppose you could do it > they way you are trying to.. > but you are going to have some interesting issues to deal with (especially if > there is an anomaly on one of the paths, and your asymmetric traffic will > show weird stuff). > >> Do not be afraid to assume I have no idea what I am doing. I have >> followed every rule I can find online so obviously I'm doing something >> wrong. >> >> >> >> On 11/1/2017 9:45 AM, Faisal Imtiaz wrote: >>> I wish there was a simple answer to your question... >>> >>> But... there are some more questions.... >>> >>> With the setup you have described..... >>> Are you running iBGP sessions between all the routers ? >>> if not.. then you are not properly configured. >>> >>> In today's day and age, one needs to do Traffic Engineering to have the >>> type of >>> traffic flow one desires. >>> I wish there was a 'one solution' that fits all situations.. but there >>> isn't >>> one. >>> Each IP Transit provider is doing their own 'style' of Network Traffic >>> Engineering >>> One has to understand that first and then try to compensate for it. >>> One should ask their upstream for a list of their BGP Communities, >>> that gives a >>> good starting point. >>> Using the upstream's Looking glass, if available is also a great >>> tool in >>> verifying the traffic engineering >>> >>> simply passing ASN's does not work (most of the time, but varies with >>> upstream) >>> >>> BGP Traffic engineering is more like steering a Boat Rudder than steering a >>> car... :) >>> >>> If what is listed above makes sense to you, then you have some starting >>> points >>> to read up and understand BGP >>> If the above does not.. then I suggest you get someone to help you with the >>> setup. >>> >>> Regards. >>> >>> Faisal Imtiaz >>> Snappy Internet & Telecom >>> http://www.snappytelecom.net >>> >>> Tel: 305 663 5518 x 232 >>> >>> Help-desk: (305)663-5518 Option 2 or Email: supp...@snappytelecom.net >>> >>> ----- Original Message ----- >>>> From: "Ethan E. Dee via Mikrotik-users" <mikrotik-users@wispa.org> >>>> To: "Mark Grigsby via Mikrotik-users" <mikrotik-users@wispa.org> >>>> Sent: Wednesday, November 1, 2017 9:06:27 AM >>>> Subject: [Mikrotik Users] BGP Question >>>> I am multihomed. I have a router that peers with charter and advertises >>>> a few subnets. (Let's call it C) >>>> >>>> I have a router that peers with AT&T at a tower (lets call it A) >>>> >>>> And a router that peers with Spirit at a tower (lets call it S) >>>> >>>> AT&T seems to have quite a low preference to the world. And I have no >>>> idea what I'm doing. Though I feel like I do. >>>> >>>> Nothing works. >>>> >>>> All three routers are mikrotik. How do I tell the world to forget about >>>> Charters advertisements unless you can no longer see AT&T? >>>> >>>> >>>> >>>> >>>> -- >>>> This message has been scanned by E.F.A. Project and is believed to be >>>> clean. >>>> >>>> >>>> _______________________________________________ >>>> Mikrotik-users mailing list >>>> Mikrotik-users@wispa.org >>>> http://lists.wispa.org/mailman/listinfo/mikrotik-users _______________________________________________ Mikrotik-users mailing list Mikrotik-users@wispa.org http://lists.wispa.org/mailman/listinfo/mikrotik-users
